Air in Fuel Testing

[chuntag95]

Okay, after hearing all of the talk about air, I decided to put on a clear hose before I ever put on the Mega system, just as a sanity check. I put a 1/8" nylon braid reinforced clear hose from the OEM filter to the engine. After running around for a little bit to get the air out, I saw no bubbles, no fog, no nothing. COOL :cool:
I had a brain storm that maybe the filter was letting the air out (okay, it was a weak storm :rolleyes: ) so I put a clear line from the EDU to the OEM filter. Now I have clear lines running into and out of the OEM filter. Again, I made a mess purging and pumping to get the air out, but could not get one HUGE bubble to leave the top part of the hose. I cranked her up and let it pull the bubble into the filter. I started getting pea size bubbles going to the engine. Shut it down and tried to purge out the air. Still did not get 100% out. Went for a ride and ran a few WOT runs. It was to help purge, honest! :D Came back and checked and all of the big bubbles were gone, but I was seeing the occational drifter. It started to rain, so that was it for last night.

Drove in this morning (45 minutes) and checked to see what was going on when I got to work. No bubbles going into the filter, but a steady stream of tiny (head of a pin and smaller) bubbles coming out of the filter. Tried to purge the filter and got nothing but fuel. I put JK's gauge on and am getting around 4" Hg at idle and 4.5" at 1400 rpm. (Slick gauge setup JK.)

Now the question is what's going on? Differences between the no air and air testing. First, only one hose was changed with no air and now both have been change. I double checked to make sure the clamps are tight. The other item is I am at under 3/8 a tank (by the gauge) where I was almost full with no air testing. I think I will go and fill up tonight and see it that makes a difference. It shouldn't since I do not see air going into the filter. The other possibility is the primer pump is leaking a little bit of air. One other item could be the restriction isn't enough pre filter to pull any gas out of solution, but after the filter it is. I really don't think less than 5" Hg should do it, but don't have the pressure vapor curse for #2 laying around. I am perplexed on what to do next since I can't see air coming into the filter. It also doesn't appear to collect air in the filter, just moves on through. If that's the case, then I have a leak in my filter, that wasn't there 4 days ago. I might put some dielectric grease around the ends of the hoses and the pump. :confused:

All ideas and things to check will be noted and reported on if possible.

Chris

[NWDmax]

Nice work Chris!Looks like your covering a lot of ground. :cool:

[Kennedy]

Chris,

Glad you like the gauge. I figured if it were compact it would be easy to carry, and also it would eliminate any variance due to positioning.

If you can get away from the braid in your hose, it will make things easier to see. When idling, pump the primer a few times and watch the line coming from the EDU.

Some fuels may be "gassier" than others. Some push locks may leak more than others, and some not at all.


The OE filter head does not have a "dirty side" bleeder, so all of the area above the suction point is subject to trapping air. I've been threatening to pull my OE filter head off and add a bleeder to it...

[a64pilot]

Chris,
Pure theory here and maybe just B.S.
If the O-ring seal or primer were marginal in their ability to hold a vacuum, then maybe the increased vacuum required to pull the fuel up from a low fuel condition may be just enough for a vacuum leak in either to show up. Remember it is much harder to hold a vacuum than it is to prevent a fuel pressure leak.
Any way it is almost a sure thing that your vacuum leak is in the stock air filter assembly and not downstream from it.

[chuntag95]

JK,
I would like to get away from the braided, but it was the only 1/8" thick I could find. I have some clear 1/16" that is really flimsy. It would be okay for testing with backup hose to install if something went wrong, but not to drive with all week. It pinched off as well due to the curve as the engine warmed up making it softer still. The engine didn't seem to care though. As far as a bleeder, I was trying to come up with something I could put in the line to use as a purge port, at least temp till I stop swaping all of these lines around.

A64,
I agree pressure is much easier than vacuum. Also, with pumping you change back and forth between the two and have vibration trying to open any sealing surfaces. You might be right on the head height difference. I guess we shall see when I fill up. How do you explain this to the stealer. "I want a new filter housing because the pump is leaking air. Wanna see?" I thought I read somewhere that someone took the pump apart. I wonder if the leak can be sealed or worked around.

[ 04-22-2003: Message edited by: chuntag95 (Chris) ]</p>

[a64pilot]

Chris,
I think that is exactly what I would do. I would tell them that I was trying to diagnose a hard start problem and stumbled on the air leak in the fuel filter. A picture is worth a thousand words, right. (assuming the filter head is in fact leaking)
I am beginning to wonder if a good dual filter wouldn't be the way to do it and bypass the stock filter entirely. It would appear that the stock head has a few problems.
IIRC, most if not all of the farm equipment I've had over the years had a mechanical pump that pushed fuel through two filters and from there to the injection pump.
How do the OTR trucks supply fuel to their engine? Do any of them run a vacuum system? I really don't know and am soliciting answers from someone who does.

[chuntag95]

a64,
One thought is can we make a device to trap air and install it just before the engine. It would be post OEM, Mega, Frame mount, etc. Maybe it is clear and has a collapible bladder. It has to be at the highest point and have one valve to isolate it from the system (maybe a check valve) and one to release the air. You don't even need to pump anything then. Just let the air out when you check your oil or whatever. It sounds easy, but I'm thinking it won't be. Actually, except for the being able to see it and being the highest, the Mega covers everything. Maybe you just put it on and use a long screw driver to bleed at fill up.
Chris

[ 04-22-2003: Message edited by: chuntag95 (Chris) ]</p>

[a64pilot]

Chris,
Then you are saying that the total of the air leak does not exceed say a cup every 500 miles or so? I thought it would be much more than this.

[a64pilot]

Chris,
Check this out. Will it do what I think it will? http://www.parker.com/parkersql/default.asp?type=2&id=27

[chuntag95]

a64,
I can't say to be honest. I mean, watching tiny bubbles go by at idle and trying to calculate a volume over a full tank at normal use is a bit tricky. Sure as I say yes or no, I'll be wrong. One thing I did "assume" was that the lower the tank got, the worse it got. Seems like I am not the only one who had no air when the tank was full. I am sure I have air post OEM filter showing up. Where from and why are still unanswered. My thoughts were if I can't fix the leaks, maybe I can put in a countermeasure that makes the leaks a non issue.

[a64pilot]

Chris,
Did you look up that link? It would appear that filter will purge air and apparently warn you if air is present as well as have a built in electric pump for priming.

[Kennedy]

Chris,

I'll snip off a piece and send with that "other" package I am sending. Watch the mail as I used USPS Priority Mail on this one.

[a64pilot]

Chris,
Sorry that link doesn't pin point the page It's the FR filter I believe that claims the following.
"Racor Integrated Systems combine a fuel filter/water separator with solid-state electronic repriming, electronic air purge, and a cleanable pre-filter with a stainless steel element in a compact package.

Some of the models in the series are available with genuine Aquabloc filters in a choice of 2, 10, or 30 micron elements and reusable see-thru or metal bowls. Optional remote water and air purge indicator lights can also be specified."
It's the electronic air purge and air purge indicator lights that caught my eye.

[chuntag95]

a64,
Okay, now that you got a little more specific, I'll check it out. I sent you an email basically saying Huh? An auto air purge would be the way to go if possible. Maybe replace the OEM with this and a 10 micron filter going to the mega as a final. Hmmmm.

JK,
Thanks. I appreciate it. I'll be watching for the post dude.
Chris

[george morrison]

Another point that may be relative is that in nearly every case when a secondary filter has been added, there has been a noticeable increase in perceived performance.. Is this the result of the elimination of entrained air, resulting in a more perfect fuel process?
George

[chuntag95]

The BTUs in air aren't nearly as good as fuel. :D You might have the answer to "why did my mileage increase?" I can say that I have seen fewer bubbles opening a bottle of coke, soda or pop (depending on where you are from tongue.gif ) than I did coming through that clear tube. Not a warm or fuzzy feeling. The only way to get to the bottom of this is keep testing, trying and messing with it until all is right and gas free. No Mexican food I guess. :eek:

[56Nomad]

george morrison wrote:

[chuntag95]

56Nomad,
The other thing I have thought about that might explain it would be atomization efficiency improvement. How much MPG improvement are you seeing?
I still don't have my second filter installed yet, but I am seeing air post OEM filter. I wanted to separate the two issues. I agree that it is either going into the injectors or being returned to the tank. I would like to know if it's coming from the tank though, considering what JK found. Mine "appears" to be leaking in at the OEM filter or coming out of solution there. Air should really be considered a particle or defect in this environment. It can do a lot of damage to the injectors on top of the normal gunk. I know it won't hurt to remove it anyway.

[56Nomad]

Chris,

I'm seeing about a 1.5 mpg increase in
my fuel mileage.

[jbplock]

Once we get the leaks out of our systems what about adding a permanent "Sight Glass”(like those used on low side refrigeration lines). It could go between the tank and the FICM (EDU) or after the OEM filter. Seems like it could allow us to monitor bubbles that indicate a leak has developed. The following are a few examples.

http://www.johnernst.com/flow_indicators_p4.html
http://www.refparts.com/Catalog/Major_Components/filterdryers/filter_dryers.asp

Not sure these are the best choices but it seems something like this might be a good diagnostic tool.

I’m hoping to find my leaks this weekend. I finally located some 7/16 fuel hose for replacing the tank to steel line QD’s.

[ 04-22-2003: Message edited by: jbplock ]</p>

[Modified]

Is there a way to measure fuel rail pressure?
If we have air in the fuel, maybe it's accumulating in the fuel pump, and discharge line to the injectors. Air is compressible, which would reduce fuel rail pressure. If there was no air in the fuel, the pump and lines would be solid fuel, which is non-compressible. Fuel rail pressure now may be dramatically higher, which would atomize fuel spray out of the injector better, and you're back to a better, more efficient burn.

[LanduytG]

Instead of a sight glass you could use a section of Teflon. This is what VW uses on the supply line. You can see whats going on real well.

Greg

[Gbenzx01]

Cat filter still collecting air under airbox?
But oem is too!

Our 1st mistake I thimk was the cat pushlok hoses & we still haven't changed them but did double the clamps.
Have to prime every time & if not engine runs 30 to 60 secs & shuts down,
I do think this is worse air prob than most of you have had & using old pickup simply because we now know this much air is damageing the dmax.
The truck still runs well & pulls good but if I get rite close to the tailpipe at idle I can hear the telltale chee chee chee.
I did the no no of changing the oem filter w/3100 miles on it in the middle of cat filter installation & made it hard to isolate the problem. This is the 4th filter chng for the truck in 25k mi. Now don't have to bleed every time we start truck, just thumb pump it up.
Abt midnite last nite out at the shop decided I would bleed it again after abt 15 mins. Bingo, I had same thing as before. Well I tried I min = same thing & when fuel came clear I just hesitated pumped again & little tiny bubbles appeared again! I then hammered my hand down enough I could touch the bottom of the water sensor & found wetness on my finger. Not much but
wet! Felt around top edges of filter for moisture & none to be had. So today I ordered this little thin piece of trash that looks like unfit for a push lawn mower @ $48.70 & takes 5 days to get one from he said, you guessed it CA!
We've tried to be careful with this little jewel for fear of just what has now happened. Next thing I'll hear is, O my they only 7500 of em & the dealers got all sorry baaaaaaack odor!

Modified the idlewire is doing just fine, thnx

Still looking for pump w/o sprnding 300 biguns f/ the Stanadyne ei, my aux tank $$$!

Thanx to all for the endless efforts,

Gben

[chuntag95]

Well I tried to put the clear hose back on but couldn't convence myself the thin stuff was okay. I see part of the problem with EDU. It's the high point in the system. I could not pressurize, pull, pump enough to get the bubbles out. It needs a bleeder valve up there or something on the other side to catch the air. I did several WOT runs to push most of the air out. I am back to the occational tiny bubble. I cannot purge it well enough to be convenced that I have a leak or that I could tell one way or the other. :mad: I did go and fill up, but when I checked the flow before shutting down to fuel, I saw no real difference between then and when I checked after getting back from fueling. Just a few lazy bubbles going in and coming out. I was considering finding a fitting to make a drain hose at the pressure port on the rail. Some way to be down stream of everything and push fuel through. JK, can you tell me where you got that fitting? I was tempted to take apart the gauge but resisted. I will just watch it morning and night before I shut down for the rest of the week. Sat the Mega goes in and I can start bleeding it. Saturday can't get here soon enough for me. :(

[chuntag95]

Has anyone found clear 7/16" or regular black for that matter online anywhere? Having a hard time finding it local. What happened to the days when an auto parts store had parts and not just stickers and neon? :rolleyes:

[jbplock]

Chris,

I had a hard time finding the 7/16 hose too. The Weatherhead part number is H05707 where H057 is fuel hose, 07 is the size. (05=5/16, 06=3/8, 08=1/2). Napa stores in my area carry Weatherhead but none of them had the 7/16 size. I ended up finding some 7/16 Gates hose at a local auto parts store. I'll post the Gates part number later when I get home (I couldn't find fuel hose on the Gates website).

Greg,

The section of Teflon you described on the VW sounds interesting. Is it a section of thin wall Teflon tube? Is it clear or translucent? How is it connected?

smile.gif

[ 04-23-2003: Message edited by: jbplock ]</p>

[chuntag95]

I checked this morning and still have a few pea size bubbles in the top of the EDU that will not leave, pass through, escape, whatever. :mad: I didn't see much on the line to the engine from the OEM filter, but did see a few tiny bubbles drifting lazily along. I like the sight glass idea, but instead of putting it in line, put it in a tee sticking straight up. On the other end, put a valve and use it to trap air and purge it. The only issue is you would have that weight supported by hose. Might need to support it in some other way. You could get a long piece of 1/8" pipe and put it into the bleeder hole on the mega head piece. Put a sight glass on top of the pipe and cap with a bleeder valve. Don't know if that is even possible, but ..... Hmmm.

[SPICER]

I have the MEGA filter and I have gas. I have not installed clear tubing, but I do have a OE filter problem. My OE is the original on the truck(6000 miles). I noticed that I have a perpetually wet drain nipple on the bottom of my filter. I have only drained it twice looking for water(never found any), and the drain is closed tightly.

I am totally unimpressed with the OE filter assembly. There are so many seams and whimpy O-rings and drains and crappy molded plastic that I would not be surprised if air found its way in through this thing. I purchased a new drain/WIF sensor assembly and will put it on a new OE filter and install it today. I am sure that if the drain nipple is perpetually wet with diesel that air could find its way in here.

I was going to use synthetic grease to seal the O-rings for a more possitive air/fuel seal. Any thoughts or suggestions on this? Also, does anybody else have perpetually wet nipples? ;) SPICER

[jbplock]

Spicer,

You could also use some Parker Super-O lube for the O-rings.

This is what Tommy (a bear) used on his O-rings and he's also solved his air problem. I picked up a tube at a local Parker distributor and it looks similar to dielectric grease but more "sticky". I plan to use it on all my hose connections and O-rings this weekend. I will also check my OEM drain to see if it's leaking. The last time I checked it was wet but I assumed it was fuel that drained down the side when bleeding the OEM filter after my MegaFilter install

[SPICER]

jbplock,

I don't know where I could get this parker O-lube in my area. Do you know what is special about it, and is there any reason synthetic grease wouldn't work? The mechanic said vaseline works too.

My leaking OE drain is constant. It doesn't seem to drip, and the filter is not wet anywhere, so I am pretty sure it is the drain valve itself. It comes as a drain/WIF sensor assembly and cost $35. I have just noticed that after driving for a while there is always a drip of DF hanging there. It is not wet after sitting overnight(probably evaporated).

Anyway, How tight should the repalcement be? I've heard I need to make it "as tight as I can get it". That scares me. I strip everything! SPICER

[jbplock]

Spicer,

I haven't had my OEM filter off yet (6.8kmi so far) so I'm not an expert, but from what I have read, using some grease helps keep the O-ring in place.
Regarding the Parker Super O-lube it's designed specifically for pressure/vacuum sealing O-rings and seems like pretty neat stuff, but grease should work too. I did a search on the parker website and there is a full line distributor in Madison WI (Ritter Engineering, 3948 Comercial Ave, Madison WI 608-249-9548). Is that far from you?

Chris,

The Gates P/N for 7/16 rubber fuel line is 4219G (SAE30R7).
smile.gif

[ 04-23-2003: Message edited by: jbplock ]</p>

[Lone Eagle]

Look for vacuum grease. Dow-Corning for one. We used it on our industrial systems. I am sure there are a lot other brands advailble. Then again diesel fuel works fine in most cases. Later! Lone Eagle ;)

[Jelisfc]

chuntag95, if the EDU is the high spot and that is preventing air from being purged why not get a piece of flat stock and move the OEM filter up higher than the EDU? There should be enough room to do this.

Has anyone investigated the cost of a new OEM filter head? I don't think we can be sure if any air is being trapped until a second bleeder is installed in one. Maybe a better test is an off truck test of the stock filter setup. Use a fuel pump to draw fuel just like our pump. Plumb the lines with a gauge(s) and a control valve inline to vary the vacuum.

[Kennedy]

The air will draw out of the EDU with several pumps of the primer. Problem is, it just keeps coming. I've been preoccupied with a couple of other projects lately, but plan to go back after this soon.

[chuntag95]

John,
Sounds like you have a leak in the EDU. I pump like CRAZY and can't get the bubble to move into the filter. I have tried both running and not. There is one just before the engine as well. I was trying to think how to rig my camcorder up to video the lines and drive around. It's too big and if I break it, the wife will kill me.

I found a place last night that sells yellow vinyl fuel hose online. They also had some vacuum hose that looked pretty tough. 5/16" wall for the 7/16" ID. No typo. :eek: They have about every type of tubing you can think off.

I have not found a good way to make an air trap and bleeding system. I would like it hard plumbed, but all of the suff is hoses pre and post filter. I need a tube Tee with a NPT going out the side or have it as an elbow going in all 3 directions. I'm sure I could come up with a bracket to hold everything in place, if I can get it plumbed and working.

[chuntag95]

I found an oil sight glass with vent in the Grainger catalog. They didn't have any in stock. That with 2 1/2"hose barb x 1/2" NPT connectors and you have an air trap you can see when you need to bleed.

[jbplock]

Chris,

That sight glass sounds neat! :D

Is the one you are refering to made by Lube Devices?

www.grainger.com PDF Catalog Page 1622
www.lubedevices.com/

[ 04-26-2003: Message edited by: jbplock ]</p>

[chuntag95]

I actually found 3 different ones. 2 required less adaptation. I know the one you are refering to is one of them, but not which one. My local store didn't have any of them. I think part number 1U596 or 5HD44 were the top choices. The 1U892 needed to be capped with a drain cock or bleeder screw and have tees, nipples and adapters.

We put the Mega system on today. I moved the holes back and mounted it as far back as I could. If I drill and tap the head, I could get it farther back, but I forgot my tap set when I went to Silver Bullet's place. The only "trouble was running the hose under the EDU. I ran them backwards in order. The other way would have been easier, but all worked out in the end. Also, one of the guys found a clamp rubbing through my AC line. It appears the stealer put it on wrong when they worked on my injectors. He saved me a HUGE headache. It was a lot of fun working through the install with 4 cheifs helping out. :cool: Only the indian (me) lost any blood, so it was a good battle and we definitly won the war. The fact you can bleed by pulling out the headlight is great. I bleed when I got home (air) and got about 4-5 pumps. I went running around and got 2 later. Between the difficulty getting the hoses to seat fully and the clamps on top of that, no leaks have been found. I just have to decide when to take off my last piece of clear tubing. :confused: For the intial prime, we ended up pressurizing the tank. I lost count on pumps way before I moved to the compressor for help.

Once it was time for the liner to go back in, it took longer to start all the bolts than tighten them. It took 1:12 (minutes:seconds) start to finish to pull the liner. DeWalt is my hero. I did break by socket adapter trying to see if it had enough torque to break the lugs loose. :D

Fun was had by all. SB cooked some elk burgers that were outstanding. Rides and a little hot rodding was done.

Chris

[Raptorrider2001]

chuntag95 (Chris)- Right, lots of fun! Thanks for letting me run the "Hot Juice" JK sent along with the Mega filter. What a blast. It really wakes up a sleeping giant. For anyone that has not tried one out, do it as soon as you can. You will not believe the difference it makes. Gotta have one. smile.gif Thanks JK for loaning us everything. You are first class. :D :D

[LanduytG]

Bill
The Teflon tubing is translucent and thin wall. I got it from McMaster Carr. VW uses the very same stuff on the late model TDI's.

With the OEM in the VW you see a lot of air but with the Cat I am selling you see little to no air bubbles. Not sure way and I have been working on it for awhile.

Greg

[jbplock]

Greg,

Thanks for the info on the Teflon tubing. Sounds interesting. I'll have to check into it further.

Over the weekend I replaced the OEM flex line from the tank sender to the steel line behind the cooler with Gates 7/16 rubber hose and clamps. Still have gas

[a bear]

Bill,
At one point I considered that also. The only difference is that I was going to use a 5 lb. pressure cracking check valve in place of the solenoid valve and also tube to the return line.
Although I have stopped the majority of my air, time showed that I still have a small but manageable amt. Also during testing when I suspected the EDU I considered running my fuel from the tank straight to the OEM filter and using the return flow to cool the EDU. In a week or so I may trouble shoot post EDU to the Mega. Just curious to see if I can stop that last little bit. In terms of measurment I would say that 80-90% has been stopped. Also the no starts have stopped. :D :D

[jbplock]

Tommy,

Glad to hear your no-starts have stopped! :D

Also, the 5 lb. pressure cracking check valve sounds very interesting. Is it a relief valve that opens at a calibrated pressure? That would be much better than wiring up a solenoid valve. Who makes them?
smile.gif

[Idle_Chatter]

a bear, I wouldn't recommend reversing the cooling flow through the EDU. The fuel coming from the tank is going to be a lot cooler than return flow that has picked up heat being compressed in the pump, cooling the injectors and solenoids and in the fuel rails. This is one engineering item that it seems they got right! ;)

[a bear]

Bill,
Thats it. They are preset by spring compression to open at a desired pressure and give a good seal against a soft seat when closed. Instrumentation companies like Parker,etc. handle them.

Idle_Chatter,
Thanks for bringing my poor explanation to my attention. Didn't want to lead anyone wrong. I was planning to do this for a short air test only after realizing the returns was still pretty cool.

[chuntag95]

jbplock,
You got the right part and I just ordered it and all of the stuff to put it in. I hope. :rolleyes: Caught the creeping crude from my 2 year old, so I'm not thinking at 100%. Hopefully, anything I missed can be procured at the local home improvement center. :D This will give me something to do while I'm at the wife's family reunion next Saturday. I'm sure my father in law will help since he has a DMAX too and it's his wife's family. ;) The lenghts a fella has to go to so he doesn't have to talk to relatives. tongue.gif I'll take pictures and all that kind of stuff and see if Silver Bullet will put them on his sight.
Go to go, nap time.

[NWDmax]

OK