View Full Version : Air in fuel filters
I think I'm being saved by the mega filter in more ways than clean fuel.
I am presently troubleshooting air entry problems with my system upstream of the Mega filter. Due to the Mega filter being able to trap air I have noticed that there is air entering the fuel system. About once per tankfull I bleed a significate amount of air out of my Post installed Mega filter. This tells me that prior to the Mega filter installation I was moving small amounts of air through the system without detection. As we all know this is not good for the pump and injectors. By the system running on negative pressure no leaks can be detected the conventional way (Seeing the leak). After further review of the OEM filter and lines leading to the tank I noticed these cheap OEM push together connectors that join the lines together. I can't believe this was used. I guess someone figured no pressure lets use cheap connectors. IMHO there is a potential problem with this. The bad part about it is most owners that use only the OEM would never detect this and it may lead to quicker pump/injector wear. Hopefully there are only a few isolated insidences like myself. Tomorrow I plan on checking the OEM filter O-Ring. I have my fingers crossed on this one. :eek:
If anyone sees air in a post filter that has the ability to trap air you may want to look further.
:D
GM Smitty
03-30-2003, 22:03
As if the "dirty" fuel filtering system on these trucks wasn't enough to worry about.....now we have the dreaded "air in fuel lines" issue...it seems to be one thing after another.
I am by no means any sort of expert nor am I anywhere close to understanding the complexities of this wonderful engine, but good golly, will we ever stop finding faults with it? Can someone explain to me the major problem air in the system? What harm will it cause in the long run? How do we know if it's present? Do I need a special "air trapping" filter now? :rolleyes:
technician
03-31-2003, 05:13
a bear,
I remember in JK's directions and in a few posts here that the Mega-Filter will need to be emptied of air every so often as it accumulates at the top of the filter head.
So I guess that the air you are getting out is "normal" ....so getting out air is a good thing! :D
Hope this helps,
technician,
I spoke with JK about this and we both agree that you should do an initial bleed and then a second bleed later to remove residual air that was trapped in the lines. After that occasional bleeding would be OK. What I'm saying is that I am having to bleed every 350 - 400 miles or my truck will not crank after setting an hour or so. Also I am not blaming the Mega filter because It's not the problem. The Mega filter did however allow me to see that there is a problem that my OEM setup could not detect. I'm not trying to put a panic into anyone here and I'm hoping my case is isolated. Actually I just wanted to put the information out there to see if anyone is experiencing the same problem I am. And if need be we could come up with a solution together as a group. Its hard to find small leaks with a system that runs on negative pressure. I will be checking a few possible leak points today and will let everyone know if I find anything. :confused:
Thanks,
[ 03-31-2003: Message edited by: a bear ]</p>
It's going to take a process of elimination, but my guess is that the OE Racor head is the best starting point. Primer pumps have been notorious for allowing air into the system...
a64pilot
03-31-2003, 10:39
It's starting to look as though the 6.5's lift pump was not such a bad thing after all. A lift pump should eliminate any additional restriction that any aftermarket filter may have, it would make any small leaks easy to find and if you had a momentary switch mounted under the hood bleeding would be as simple as holding a button until clear fuel escapes from the bleeder or if you had water, open the drain and hold button until clear fuel drains from the bottom of the filter.
JK,
I have seen primer pumps that would only leak air on a vacuum and would not leak fuel when pressure was applied. I'm sure that you have too.
a bear,
IMHO those push together connectors are really pretty good. I doubt your air is coming from there. I would replace the stock filter, be sure to lube the O-rings with crisco or cooking oil or another good lube, if that dosen't fix it I believe that JK may be right wit the primer.
BTW you can clean all of the fittings off with alcohol in a spray bottle, blow them dry with shop air and baby powder is a decent liquid leak detector. I know that you are getting air and not leaking fuel, but short of pressurizing the system I don't know what else to tell you
a64pilot' JK
Thanks for the input. As you mentioned I will be going through the process of elimination starting with the OEM filter O-ring seal. I plan on taking this trouble shooting process one step at a time so as to pinpoint the problem for the benefit of others that may run into a similar situation. If I do to much at one time I will be faced with the question of (what worked ?) There will be a short wait between checks to allow time for air to build up or hopefully not build up.
CntrlCalDmax
03-31-2003, 12:49
I also have to bleed the system about every 150 miles. I have been through the mega filter install and do not believe the leak is part of that system. I suspect the oem filter but haven't proven it yet. I am thinking of installing a lift pump and in another thread asked dpearl river how his was working. If anyone else has installed a lift pump I would like to know about it.
Leo
I've also found some air accumulating in the KD Megafilter as well. Approx 500 miles since I installed the kit and I have not experienced any starting problems or adverse engine operating events. However, I took fuel samples and had to 'uninstall' the KD fuel line routing to re-establish the OEM fuel line routing to obtain the OEM sample - and then 'reinstall' the KD fuel routing. The system was bled each time and I attributed any air present to the fuel line manipulation.
It's going to be difficult to quantify the amount of air present without knowing the volume displacement of the OEM primer. Since a few of us with the KD Megafilter are seeing air in the filter, I suspect that it is not an installation problem with the Kennedy's kit and more likely originating in the OEM mount/primer. I'll be watching this closely.
a64pilot
03-31-2003, 13:27
Guy's please don't throw any rocks at me please. I am in no way poking holes at anyone or anyones product or products or ideas.
It would be reasonable to assume that by adding any additional filtration, pre or post or completly replacing OEM and decreasing the particulate size by a factor of 5. (From 10 micron to 2 micron) you may increase restriction. On a small number of vehicles that are barely getting by on the stock setup any increase in restriction MAY cause an air leak in the STOCK fuel system.
IF this is the case then CntrlCalDmax's idea of a lift pump would be a very viable one. I stated in my last post some advantages that I think a lift pump would have. One of the challenges is to have the lift pump operating only when the engine is running.(safety reasons) The 6.5 used oil pressure to determine when the lift pump operated I believe.
Getting complicated and expensive looking isn't it.
CntrlCalDmax
03-31-2003, 14:09
a64pilot,
What do you think would be a problem with the lift pump running with the engine static? I would like to have the lift pump pre-pressurize the system before cranking unless there is something I'm missing. To eliminate the air I think the lift pump should run any time the oem pump is rotating. Is there any down side to using a lift pump while the engine is running?
Leo
a64pilot
03-31-2003, 15:21
CntrlCalDmax,
I think that the lift pump SHOULD be running as long as the engine is, but only as long as the engine is. The reason is in the unlikely event of an accident or some other fuel line rupture you are not pouring fuel all over the ground.
It's 1973 and my father has an F250 that we drive to fl. every weekend, can't get fuel every day so has "saddlebag" tanks put on. Being the type he is he dosen't always remember to switch tanks until the engine quits. After replacing two starters I fix the problem by installing a Holley elec. fuel pump that runs whenever the ign. is on.
Fast fwd. a few years, truck is old now and relegated to farm duty only. Poor state or tune and backfires through the carb, no air filter, seems it clogged and caused the truck to run rich so it was removed not replaced. Really wasn't much of a fire until the fuel line burned through. Man that Holley pump had a high flow rate!
I know that we're Diesels and diesel is hard to ignite, but My wife and kids often ride in it and I will never forget having to drag that old Ford away from the house with the tractor before it caught the house on fire.
:eek:
CntrlCalDmax
03-31-2003, 16:10
a64pilot,
I UNDERSTAND!
Now will have to come up with an oil pressure switch in the circuit with an "on" circuit from the glow plugs - or something like that. Any ideas are welcome.
Leo
My take is that this air present in the system, and we are "collecting" it with the filter setup.
While the restriction DOES increase, this increase would ONLY be present before the Mega Filter. The relatively minor increase in restriction should not have any effect on the ingestion of air.
The OE filter seals with a thin oring that seals to what appears to be a non machined nylon surface. This a potential area to look at as well...
Bulldogger
03-31-2003, 18:00
Maybe this is a stupid question,but I'll ask it anyway. With all the talk of air in the system does it necessarily have to be a leak? When I fill up with diesel it foams up quite a bit. I would think driving around with anything less then a full tank and the diesel sloshing around in the tank would cause the fuel to become aerated and this could have something to do with the air entering the system. Dave
Today for a starting point I changed the OEM filter and paid special attention to the sealing surface and cleanliness. For this installation instead of using oil to coat the O-Ring I used a special lube/sealant made by Parker for Vac applications (see below) and tightened the filt. to the max of the filter recommendation. Tight! This stuff really holds the O-Ring in place well.
Tube states as follows:
Parker Super O-Lube <<Silicone based for plastic and rubber / Compatible with all elastomers / Inert to a wide range of chemicals / Non toxic and non irritating under normal conditions / Will not clog micron filters / Usefull from -65 to 400 degrees F. / Moisture resistant.
Super lube is useful as an assembly aid for O-Ring seals. It should always be used sparingly as only a thin film is necessary for best results. Super O-Lube can also improve sealability in vacuum and high pressure systems and makes an excellent thread lubricant.
Bled filters 2X and will monitor for air accumulation. If this doesn't work my next step will be to remove the filter and put about 30-40 PSI on the unit and submerge it in liquid to look for leaks. As I said before one step at a time.
Bulldogger,
Although I thought it was far fetched I did look into what you stated. The last couple fuel stops I made sure to shut off the engine and not let the tank get below 3/4 each time. Saw no difference.
[ 03-31-2003: Message edited by: a bear ]</p>
Tommy,
Thanks for the Super-O Lube recommendation and your efforts in systematically analyzing the air-in the-filter question. The O-Lube sounds like a good thing to have around. I'm going to look for some.
Also regarding air in the filter, when doing my post OEM MegaFilter installation, the first thing I did was crack the bleeder on the OEM filter and it "hissed" (this was before plumbing the Megafilter). I wanted to drain the OEM filter to see if there was any water in it - there wasn't. At the time I wasn't concerned about air in the system, just draining the water. But now looking back it seems that this might indicate (as JK has hinted) that there has always been air in the system. I have not had any problems with loosing prime or hard starting either before or after installing the MegaFilter. But, I have bled some air from (or let some air into?) the mega filter after a few hundred miles of driving. I have a Kent-Moore gauge on the way so I can monitor restriction and do the leak down test. I was also thinking of putting a temporary strip of duct tape around the primer and QD fittings to see if that makes a difference when bleeding. Any thoughts on this?
Bill,
I found that the system stays on vac. for a while after running the engine. If the bleeder is opened right after shut down you may hear air enter the filt. I usually pump the primer some to put a little pos. pressure before bleeding to make sure the air I see was not my doing. IMHO with the low resistance of air flow it would be hard to provide a external seal. For the lines a Liquid seal would probably give a better chance if used while on vac. and sucked into the leak but I'm not sure about that either with a slow leak. I'm hoping to stop the leak before getting that far.
Jim Cobler
04-01-2003, 10:51
Can air really be traped in a fuel filter?
Since I am confused by this issue, I phoned the Baldwin technical people and ask how air could be traped in my filter. Since you are asking specific questions, you must state what filter and mount you are talking about so this only applies to my set up (BF1213 filter & FB1301 base mounted on frame). However, I believe it generally applies to many bases. The Baldwin engineer told me that air in the filter will be passed to the engine since the fuel output is at the top. You would notice starting difficulties and rough idle if you had air. I specially ask if it were possible for a bubble of air to be trapped in the filter and he said no. He further pointed out that any alternation of the base or filter would void any warranties for the filter manufacture.
Could someone tell me how air bubbles can be trapped in a filter?
Thanks,
[ 04-01-2003: Message edited by: Jim Cobler ]</p>
The design of my filter has a suction nipple extending down into the filter nearly 2". The slow flow of fuel through this filter allows any air to accumulate on the "ceiling" of the filter housing. For this reason, I have a bleeder on the "dirty side" as bleeding from the clean side will not be effective at removing any air above the bottom of the suction nipple.
There has been a pretty wide range of air qty. reported by Dmax owners with and w/o my filter setup. This ranges from a slight amount of air in a few hundred miles to an occasional no start after sitting overnight. This no start condition has been experienced by many owners of completely stock trucks, which would lead one to believe that this is an issue with the OE fuel system. By adding my filter, we are also adding an air trap and basically unmasking the problem. We have seen accumulated air cause no starts in as little as 150 miles, and we've seen several hundred miles logged w/o incident. I recently ran nearly 600 miles and did have some air present, but not a ton. My system is clamped securely at all joints, and all significant lengths of OE hose have been replaced with the same Aeroquip hose provided in my kits.
One important thing to remember: If air is being drawn in, so is dirt...
imported_
04-01-2003, 12:29
Does the addition of the Mega filter, or any filter, cause frequent need to bleed air from the fuel system?
Do all Mega filter equipped trucks have no-starts and rough running?
I've got 8,500 stock miles on mine w/o one miss.
Since I've ordered a Mega filter this thread is causing me to ask these questions
HB,
For folks who are installing the Mega filter post OEM the Mega filter is capturing air that is passing through the stock system. (a good thing) I am presently trying to pinpoint the soarce of air pulled into the OEM system and will post what I find. This may take a little time due to waiting to see if any air builds up. Few people that I know of are seeing this problem. Although most probably don't have leaks in the OEM system. My choice is to stop all air Period.... smile.gif
I'm not sure where the air would be getting in. While there is likely air in diesel fuel, I doubt the qty would be as significant as we are seeing.
Now someone correct me if I am wrong, but wouldn't vacuum tend to seperate the air from fuel?
Looking at the factory filter/oring, there is a lot of porosity in the powder paint where the oring seats. It is possible that we could have a minor leak there. I think that this may be like one of those pesky bead leaks...
FirstDiesel
04-01-2003, 15:24
Wow did I have air in the filter tonight!! I installed my Mega filter about 2 weeks ago and have bled it 2 or 3 times since then. My proceddure is to pump up the primer until it's hard and then crack the bleeder on the Mega. Until now it would hiss a little and then out came some diesel. I'd close the bleeder pump it up again and open the bleeder and all that would come out is diesel. Tonight I had to pump and bleed about 4 times before I got diesel. This seems like a ton of air to me! I haven't driven that much in the last 2 weeks. 100 miles max.
My vote for the air leak is the primer pump. This thing has just never felt good to me. I'm wondering how it can be tested.
GM Smitty
04-01-2003, 17:29
Holy Cow! Today, my truck took in SO much air through the fuel system that it FARTED! That's right...I heard it fart...it sounded like a bad night after some refried beans. :D
I feel as though I may have sounded a bit angry in my previous post, but I'm not bitter. I'm just trying to get to the bottom of these problems. From what I'm gathering, it's a bad thing to have air pockets in the fuel. Why? Bad for the pump? Bad for injectors? Bad for my trucks rear end? ;) John said that if air is getting in, then dirt is making it's way in too. I guess this would only be a problem if the leak is after your "last" fuel filter (whether it be OEM or aftermarket). If crud is getting in before a filter, I would think it would be trapped by that filter...in theory of course. If the leak is the primer, where does that air go? Clean side or dirty side of OEM? If OEM is your last filter (like in my setup) then that could be a problem if the air is getting in on the clean side.
Is everyone running the mega filter trapping air? If so, then it seems that there is defintely a problem with our fuel system.
I think I've managed to confuse myself...time for a beer. ;)
Josh
[ 04-01-2003: Message edited by: GM Smitty ]</p>
I assume that our diesel fuel is aerated each time will fill the
tank as well as it sloshing around in the tank. Could it be that
JK's Baldwin filter medium is so good at capturing this suspended
air that would normally pass thru the OEM filter system?
[ 04-07-2003: Message edited by: 56Nomad ]</p>
This discussion reminded me of the following link, which was posted earlier in one of the Fuel Filter threads.
http://www.davcotec.com/pages/seeinganim.html
It shows how fuel flows through a conventional spin-on filter. It seems to imply that it’s “normal” for the filter to contain fuel vapor (?). Is this a hint as to what we are seeing when bleeding our filters?
:confused:
Maverick
04-01-2003, 21:03
It would be nice to know whats going on. Should I cancel my Mega Filter order?
OK guys, Hopefully this is something good. Checked for air after about 120 miles of driving and found zilch. (barely a puff) Wow what a improvment. Maybe this OEM filter gasket is a problem. In my post 3/31/03 7:30 pm. I forgot to mention the paint overspray on the plastic beveled sealing surface. I noticed this on both filters new and old but made sure to clean it off this time. For those that missed that post you can check it to see the lube sealant that was used.
Man I hope I'm not getting any hopes up for nothing but this really looks good and I'm leaving for offshore in the morning for a week and didn't want to leave everyone hanging. Please don't bash me if I come back in a week and find air. :eek: Don't be too rough because I do have a computer offshore. Just thought we could use some positive news. If anyone decides to clean and retighten their filt you may have to go through the fender liner to get that factory recommended 1/2 turn with those coarse threads. It's perty tight at this point. :D :D
Lone Eagle
04-01-2003, 22:46
The primer is the highest point in the system and a logical place to allow air into the system or a place to collect. Anywhere else in the system should leak a little fuel when the truck is shut down. We know the negative pressure bleeds off very fast. If we actually have aeration we should have some eratic running engines. Later! Lone Eagle
This morning I had time...... to take the fender splash
shield off and access both bleeders on my filters.
Well, good news. I and first opened the OEM filter
bleeder and pushed the primer...... only fuel
came out. Then I closed the OEM bleeder and
opened my petcock bleeder on the Racor....only
fuel came out. There is absolutely no evidence
that air has been captured by the filter medium
or has entered my system.
[ 04-02-2003: Message edited by: 56Nomad ]</p>
Maverick
04-02-2003, 12:17
Well this is good news. I wish my Mega would get here!
I'll be doing some checking on mine in the next couple of days. I have a few variables to eliminate. I do not recall having air until just recently when I swapped mounts so I need to check out a few things first.
Just a comment:
Diesel fuel has dissolved air in it. Even though you purge the system, any small restriction in the line (elbows, connectors, etc.), will cause a low pressure zone in the fuel flow, and air (and vapor) will come out of solution and accumulate in high areas. It becomes a problem when trapped air enters the fuel flow in large gulps. Smaller bubbles are not a problem as they return to the tank.
However, as the vacuum after the filter rises with a plugging filter, the volume of air in the system is increased due to the lower pressure. Bubbles that can't been seen in a pressure side system may grow and fill the fuel line in a vacuum system. This happens in the DMAX system and I know of no problems associated with it, other than stalling the engine. --- Yet another reason not to let your fuel filter get fully plugged before changing it.
Racor,
You have re-stated one of the reasons why some of
us don't think the pre-OEM 2 micron filter is
the best choice in supplementing our filter
system.
Thank you for your input.
Racor brings up some excellent points.
BUT, keep in mind:
In a situation where we are running our additional filtration as a secondary unit, any increase in vacuum/restriction would be between the pump and the secondary filter unit. The air we are finding has to be coming from a point between the tank and the secondary filter unit.
I also believe that most of our (<1"hg) increased restriction (in the case of an under the air box mounting) is due to the additional "lift" required. The difference from empty to full tank has been 1"hg. based upon my observations.
I've got an experiment going, and being that it is such an "off the wall" theory, would rather not comment, but I have a pretty good idea of what direction to take. Time will tell...
Lone Eagle
04-02-2003, 22:24
Racor, I understand what you are trying to say but you seem to be mixing aeration and cavitation togeather. The filters, elbows, hose fitting and even the hose all add up to the total suction head. You have to remember that the pump only creates a partial vacuum or reduced pressure at the pump inlet to create flow. Atmospheric pressure in the tank pushes fuel into the chamber to fill the void. If it were possible to "pull" a complete vacuum at the pump inlet, there would be approxmately 14.7 psi to push the fuel in. The advailable pressure difference should be much less. The number one reason is liquid vaporizes in a vacuum. This puts gas bubbles in the fuel, oil or what ever you are working with. The bubbles are carried through the pump; collapsing with considerable force when exposed to the load pressure at the outlet, and causing damage that will impair the pump operation and reduce it's life. This is almost a word for word description of cavitation that I took out of my Speery/Vickers hydraulic training manual. Even if the fuel has good vapor pressure, which I doubt it does, too low an inlet line pressure (high vacuum) permits air dissolved in the fuel to be released. This oil mixture also collapses when exposed to load pressure and causes the same cavitational damage. Now for aeration: If the inlet fittings are not tight, air at atmospheric pressure can be forced through to the lower pressure area in the line and can be carried into the pump. This air-oil mixture also causes trouble and noise but it is different from cavitation. When exposed to pressure at the pump outlet, this additional air is compressed forming in effect a cushion, and does not collapse as violently. It is not dissolved in the fuel but passes on into the system as compressible bubbles which cause erratic system operation. Before some of you jump on my back remember the source of this data. This is not theory. It is basic hydraulics. I have more but will save it for another time. I hope this will help. Later! Lone Eagle
;)
george morrison
04-03-2003, 09:01
Back to Vickers 101. Cavitation is indeed textbook but from experience, air entrapment can cause similar high pressure pump failure as when the release occurs there is a mini 'explosion' taking place which can suck the surface from a pump piston, pump wall. I have worked with more than one failed Vickers high pressure pump that was being 'aeriated' by an improperly seated filter, leaking seal on a pump input line, etc. which caused premature failure of the pump. Same for motors. And this is in a 6,000 psi system, much less our 25,000+ psi fuel system. Plus of course the high level of contaminants which came in with the air exacerbate the whole process. The failures of these pumps was almost identical in appearance with the cavatation example.
George
Lone Eagle
04-03-2003, 11:37
Dito George, I didn't mean to understate the damage air could cause. I was trying to give a decent definition of cavitation and aeration and to stress the serious problem some could cause if they get too much restriction. You have to know which you have to repair it. The last thing we want is pump particles in the injectors. Later! Frank Blum ;)
Am I the only one here scratching my head over this topic ?? :confused:
Seems but only 4 or 5 individuals here have ever complained of loss of prime do to air in the system...No one has complained of running issue or stall issue associated with AIR in fuel system.....
So as I'm to believe that my truck is generating air behind my back and I don't know it ??
Really .....
I just changed my OEM filter last week.....Took 5/6 pumps from primer to get fuel at bleeder screw..... I then started truck but one stumble and it purred just beautiful as previous....
On word....
After reading all this gallant info,I proceeded to fill my fuel tank from what was left of swamp water mix with fresh premium, after 300 miles of driving,with new filter....By the way, I got 12 miles to the gallon, very mixed driving, without even trying..Gotta luv it....
When I got home, short trip, I shut my mighty Duramax off opened hood and pumped up my primer till firm....I cracked open the bleeder, all most till it was completely out, all I got was less then a babies snot bubble of air ..... :rolleyes: Then raw fluid....No hiss NAFT but fuel,lots of it thanks to pumping fuel primer.....
So if you ask me if your accumulating air, your either sucking air post OEM or truly not getting a good bleed with the new secondary filter.... I would put my money on not getting a proper bleed....Whole lot of line and filter to clear...May take a few cracks of the bleeder to eliminate....What is all the hoopla about ?? I don't get it,scratch,scratch .....
MAC :rolleyes:
One other thing ..... If the primer was leaking air in ,wouldn't these same individuals have issue with getting a primed filter?? I would think the plunger would leak both ways if someone were to think this is a source of air inlet,in a closed system....
[ 04-03-2003: Message edited by: mackin ]</p>
Mack,
There are really a couple of different possibilities:
1) There is air passing through the system continually, and the increased "residence time" of the fuel in my filter is allowing this air to separate and rise to the top.
2) There is a leak between the OE unit and my filter.
Now I'm still investigating things, but the word that describes what I believe MAY be going on is "permeation" of the hose assy. Sounds kinda far fetched, but I have spoken with a guy who used Aeroquip hose to plumb a boat, and after sitting overnight, the hydrocarbon alarm would go off! In the end he went to good old Gates (which is what I first used) fuel hose and the problem was gone.
There will be several "replumbs" going on this weekend. If there is still air infiltration, then there is a leak elsewhere...
Mack,
Due to the design of the OEM head it does not allow air to accumulate in quantity after the initial bleed. IMHO if there was a small leak it could just go through the system without symptoms.
abear What I'm saying is that I am having to bleed every 350 - 400 miles or my truck will not crank after setting an hour or so. Also I am not blaming the Mega filter because It's not the problem. The Mega filter did however allow me to see that there is a problem that
Hmmmmmm did you have problems with your truck not starting before you added the Mega Filter?? Hmmm
Brucec,
Answer to question. NO
Did I get a no start if the Mega was not bled after about 350-400 mi ? YES
Is the Mega to blame? Not directly
Did the Mega unmask a prior undectable problem I was having upstream of it by traping air in volume ? Yes
Did my truck ever stall ? NO
Do I have faith in the OEM system ? At this point not much.
My best guess is that the air that would normally pass through the system in very small quantities and undetected accumulates in the Mega over time. In my case 350-400 mi. Then after setting a while the truck is started, runs for about 10 secs. Then Gulp
Bottom line is if it accumulates in the Mega. Its coming from upstream.
:D
FirstDiesel
04-03-2003, 20:39
abear
Where did you get the sealer your trying on the oring?? I couldn't find it here locally.
So after the truck sits you get a no start...
Do you think that it is more a drain back or an accumulation of air??
I can't see the fuel filters accumulating air assuming the are full while running...Unless the post filter is putting a greater need of vacuum then what is available...Therefore always an open void, or air bubble...We'll that explains the improved fuel economy,starvation,if so...
Is everyone with post filter addition seeing a no start?? Or addition air in the system ??
Before I cut splice or plum I want to make sure I'm not creating a problem...
MAC
Mack,
You're sleeping in class again!
1) Any additional restriction/pressure drop will be between the additional filter and the injection pump.
2) If air is getting into a secondary system, it is coming from between the tank and the secondary unit.
3) If air is getting in, the secondary filter is not CAUSING the problem, it is FINDING the problem. This, of course, is ASSUMING that the plumbing does not allow air in.
mackin wrote:
<Is everyone with post filter addition seeing a no start?? Or addition air in the system ??
Before I cut splice or plum I want to make sure I'm not creating a problem...>
mackin,
As I explained in this or the other string, I've had no air coming into my secondary
Racor unit. I opened the bleeders on both the OEM and the Racor after about
500 miles after installation...... not a trace of air, only fuel came out.
I am curious if any of the other folks who have experimented with post OEM
fuel filters are reporting any air. I think the CAT assembly had an air bleed
on it.
[ 04-03-2003: Message edited by: 56Nomad ]</p>
Larry,
Recently got it from a fellow mechanic friend of mine with Waukesha. Its what there company recommends for overhauls. Tried a Parker Super O-Lube search and found a few dealers. Copy and paste this sight.
http://www.bvmjets.com/Accessories/superlube.htm
[ 04-03-2003: Message edited by: a bear ]
[ 04-03-2003: Message edited by: a bear ]</p>
JK,
I had asked the question before.... could it
possibly be that the mega filter medium is
so efficient that it does stop ALL dissolved air
where the other brand filter mediums are not
working as well to capture air?
Also, the application for the Baldwin mega filter,
says that it is for "mining applications in cold weather"
Could that specific application have less potential
to deliver air in the fuel than what's happening in
our trucks?
What is really strange is that it appears that
only some of your filter assemblies are experiencing
this problem. Are the folks in cold weather areas having
more problems than those who installed them warmer
areas of the country (or vice versa)?
[ 04-07-2003: Message edited by: 56Nomad ]</p>
pinehill
04-04-2003, 02:24
Nomad,
Air (nitrogen/oxygen/CO2) in true solution (not bubbles) exists at the molecular level. A molecule of any of these gases is MANY times smaller than a micron, and should easily pass through any secondary filter we might use. Small bubbles are a different matter, and might well be trapped by the filter.
But note that all of these gases are less soluble in warm fuel than cold. So, with cold or cool fuel in the tank, the heat of the engine compartment could cause them to come out of solution, and since the fuel resides in the large Baldwin filter for quite a while, it has all that time to warm and discharge dissolved gases. This MAY be a reason we are seeing the air in the filter, with temperatures still cool in many parts of the country.
Your Stanadyne filter, being smaller, with lower fuel residence time, may be less susceptible to fuel outgassing. If this is truely a cause of the problem, we may see less of this problem as things warm up this summer.
Of course, it's still a good thing to eliminate any air leaks in the system.
[ 04-04-2003: Message edited by: pinehill ]</p>
John
Have I been sleeping in class ??
Yup ....... ;) Kinda just been lurking on the subject from the beginning....No way in He!! am I reading all these posts.....More info then I'll ever need.....
Hoping all gets ironed out so someday I may have super clean fuel, just not aerated....
"56"
That is encouraging you have a no air setup, I'll stay "awake" for your continued observations.....
MAC smile.gif
FirstDiesel
04-04-2003, 05:25
Thanks Tommy
I did a search and went strat to their website. They list the product and offer to let you buy it online and then tells you it's not there!! :rolleyes:
Larry,
I found some Super O-Lube at a local Parker Full-Line distributor. The Parker.com site has a "Distributor Locator" that lists one in Charleston, SC. Maybe they have some (?)
Allen & Webb, 2800 Azalea Dr., Charleston, SC 843-747-7321
Bulldogger
04-04-2003, 07:27
Nomad your not getting air in your system and Kennedy mega system is. Maybe the problem lies in that the mega system has a 2" lower nipple inside the filter allowing for the trapping of air. The system your using may be more of a OEM style head and filter where the air more easily pass through with less surface area to collect the air.Dave :confused:
Pinehill,
Interesting point on "outgassing" as a possible contributor. There IS a trend of inconsistency here that could be somehow related to assembly, or inconsistencies in the hose.
Bulldogger,
I think you got it with the deep nipple theory.
56Nomad,
I doubt that there is a tremendous difference in "air stripping" capabilities of the various filter medias, but I'll look into this. I believe that most filters will tend to remove most any air that is of sizeable qty as in if you can see the bubble...
[ 04-04-2003: Message edited by: kennedy ]</p>
mackin, I'm with you mine is stock never touched anything and never had any problems. Seems to me everyone that has been having problems are the ones changing things.
I think for now I will just let mine alone it runs good so why mess with a good think.
chuntag95
04-04-2003, 09:50
John,
Let me see if I understand this. You are investigating the potential of air moving "through" (permeating) the hose. Second, due to the lower nipple in the filter, the air doesn't get pushed through the filter head to the rest of the system as it arrives, but collects in the top of the filter. Third, there might be some gasses coming out of solution due to sitting in the filter and it cooling down or being cold. The gas volume is different depending on temperature, fuel source, etc. My gut says something other than installation error is occuring as there are too many people with air showing up.
If I inderstand correctly, then 1st is change the hose type. 2nd would require reducing the nipple depth or some sort of automatic air release bleeder or regular bleeding. 3rd would be solved by 2 as well. The problem with an "auto" bleeder is that the system is under vacuum and not pressure. You put in a small pump that runs only when you want to purge that has a check valve to keep out air/dirt. This is getting complicated to keep from having a bunch of manual intervention. I hope it turns out to just be the hose.
Chris,
That's it pretty much in a nutshell.
Hard to say if it is getting the air from the OE lines/filter head, or where, but it seems to be doing a good job of trapping whatever air is present.
Manually bleeding is not really a difficult operation, and just requires a screwdriver.
There have been SPOTTY occurrences of no start/loss of prime with unaltered fuel systems also...
chuntag95
04-04-2003, 11:00
John,
I agree manual bleeding is no big deal. It is my nature to "improve" (or at least try) a design until it requires as little out of me as possible. (You should see all of the work I have done to my pool to keep from cleaning it. :rolleyes: ) That being said, I don't want to neglect any item that will cause me grief in the future. I have extra filters, screwdrivers and other tools in the truck at all times. I can even use my Swiss Army knife to open the bleeder screw if it came down to it. ;) I enjoy messing with stuff and improving/creating solutions. I just haven't been about to figure out how to make a living at it with my hobbies yet. :D
Chris
pinehill,
I did not use a Stanadyne filter, I used the Racor assembly. I don't recall
that anyone has used a Stanadyne as a post OEM filter.
Brucec wrote:
"everyone that has been having problems"
To date, I haven't had any problems. No air in my system.
As far as restrictions, when you install a post OEM filter, you have to
remove the 11" factory hose from the factory filter to the pump suction port.
The plastic tie the factory used was clearly crimping this fuel line and
it would seem to have been a restriction which we're all trying to eliminate.
With the installation of my secondary filter, I used the 250 PSI blue Parker
hose which is pretty stiff and makes real nice sweeps.
Even if you don't plan on installing a secondary filter, it might be prudent to take a look
at the factory plastic tie and make sure it is not crimping your fuel line.
The only difficult part when I checked my bleeders was trying to find
one of the black plastic pins holding the fender splash sheild that one
of my garage gnomes has stolen. He also steals small tools of mine.
I gave up trying to find it, so I broke down and the dealer has em for
less than a dollar. I've never, ever bought anything from my dealer for
less than a dollar before...............
[ 04-04-2003: Message edited by: 56Nomad ]
--------------------
2002 Chevy 3500HD, ExtCab Duramax/Allison 4x4, White/Graphite, Lucerix Mirrors
Fumoto valve, Amsoil air filter, Kaydenco mudflaps, 22' Weekend Warrior
Secondary Racor (2 micron) fuel filter installed after factory Racor filter, picts at:
http://community.webshots.com/album/66562661oghYok
[ 04-07-2003: Message edited by: 56Nomad ]</p>
pinehill
04-04-2003, 15:34
Nomad,
My point was that any other smaller filter mounted in the engine compartment might not experience this outgassing to the same extent as the very large Baldwin. I understand that *both* the Stanadyne and non-OEM Racor are considerably smaller.
Chris,
The outgassing would occur when warming cool fuel, not the converse.
With all that said, it may turn out that outgassing does not contribute significantly to the problem, since I have no idea how much air might be dissolved in our fuel. I'm looking forward to the results of JK's experiments with the fuel lines.
chuntag95
04-04-2003, 15:47
Pinehill,
Thanks for the correction w/o flames. Add energy (heat up) to outgas. You would think a guy who deals with high vacuum would get that right the first time. redface.gif
TGIF :D
FirstDiesel
04-04-2003, 19:33
Bill
Thanks for the info. I'll try finding that place next week.
Installed the Mega Filter 2 weeks ago and didn't do another air bleed till today.Hit the primer a few times and cracked the bleeder.No air at all only fuel.I did use the clamps that JK provided and have the black Aeroquip hose. smile.gif
Still have that sneaky suspicion about that OEM filter O-RING. Come on Wednesday! :D :D
NWDmax, Awesome
Just wondering, did you use thread sealant on the threads between the filter head and nipple.
HMMM, Scratch! Scratch! :D
[ 04-05-2003: Message edited by: a bear ]</p>
Abear: I did use a pipe thread sealant in the nipple to head location per JK's advice. He said it was to keep the nipple from backing out with the filter when changing.
Curious to see what Wednesday brings.
NWDmax,
Anxious to see if I got the leak stopped. Will return from offshore Wednesday. :D
My feelings, at this point, are leaning towards "natural occurrence" as the air in the fuel is seperating and rising to the top. The design of my system will allow pressurization of the filter housing, and the dirty side bleeder will allow evacuation of most any air that is free. From this point, one must figure out WHERE this air is coming from. It could be from a vacuum leak, OR just from air suspended in the fuel releasing.
An automatic air bleed is only practical in a pressurized system.
So I guess the next step is to install a clear hose setup and see if there is any visible air coming from the OE unit during engine operation, AND when pumping the primer.
From there, I guess it will take an A/C vacuum pump, a refirgerant sniffer on the exhaust, and wafting a bit of a detectable gas at the seams/joints on the OE filter unit. This, of course, is best done as an off the truck operation. One could further check the system with the same procedure by plugging the pick up tube in the tank. Not sure WHEN I will get time to do this...
Truth of the matter is, I'm not too concerned, as regardless of WHERE the air is coming from, catching it is a GOOD thing. I have run 600 miles since bleeding mine, and have had no trouble. I even ran it down to the low fuel light. All it takes is a simple purging to remove any accumulated air.
One thing that DOES seem consistent in all of this, is that after installation, whether a placebo affect, or not, it is most always reported that the truck runs smoother. FWIW, at least one reporting party has an MD in his title...
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