Yet another Mega Filter question regarding air.

[Chris Todd]

A couple years ago, I watched these threads as guys bantered about the Mega filter by Kennedy diesel and others, like ********. I went with a Mega because I just couldn

[jbplock]

Chris,

I

[OC_DMAX]

For the first 7,000 miles on my truck, when the outside air temp got below about 35 deg F, I would end up with a no-start situation. Since 35 deg F does not happen where I live and only occured ocassionally when I went camping in the CA desert in the winter time, I kind of ignored it.

When I changed the fuel filter for the first time at around 7,000 K miles, it just spun right off, with no effort. It was on very loose. After replacing the filter, I have had no issues with a no-start from the fuel system.

So it is very possible that if your filter set-up worked for the first 30K miles and now it does not that air is somehow seeping in through the gasket surface or elsewhere. Something has changed,,, only the filters and what they mate too have been disturbed.

Maybe try another Mega filter. Kennedy has also mentioned that he has improved upon the original design. Maybe a telephone call to him to see what he can do for you is appropriate.

[Idle_Chatter]

I had three or four start and stall incidents with my Mega when I installed it in Oct 03 at 74,000 miles. I replaced the brass vent valve with a sightglass to extend it up for easier access next to the airbox. The brass vent was reinstalled in the top of the sightglass, but I didn't have any more stalls and drove it without venting or problems. I pulled off the sightglass and replaced it with brass pipe and put a LubeSpecialist vent valve on the pipe just before leaving for Idaho in April. On the run over, I had two start and stalls, one in Iowa and one in Wyoming right after fueling. I just pumped a couple dozen times on the primer in both occasions and fired and went. I figured out later that I had my OEM tank selected in both cases and it was cold out after running for a long stretch at interstate speed. I figure that the warm diesel in the tank cooled while fueling and sucked the fuel line down. I fueled at least twice in the same conditions when the aux tank was selected (it's in the bed and above the filters) with no problems. Now in Idaho at 103,500 miles and have had no stalling or venting issues. I plan to go at least another 10,000 miles before changing out this original Mega cartridge, as it is post-OEM and I change them every 15,000.

[ 06-02-2005, 06:04 PM: Message edited by: Idle_Chatter ]

[Chris Todd]

Thanks.

It is just really strange that I can use the exact same type filters from the exact same box delivered to my door and installed by the exact same people (me and my friend), and the first set is perfect and the 2nd set is an absolute disaster.

The one thing I don't believe, at all, is this outgassing; outgassing should happen regardless of a filter change. This dramatic a change isn't outgassing.

I have had it in 110 degree stop and go traffic all summer long and -20 in MSP for days at a time.

I may just do the lift pump. John says he has one almost ready. I really like dealing with John - he came up with a good solution to a crummy fuel system. The filter is unbelievable and could probably go 45,000 miles.

But the bottom line is this can be fixed without gimmicks; my previous history is proof. If I find it, I'll let you know. In the meantime, any suggestions are greatly appreciated.

[jbplock]

Originally posted by Chris Todd:
... outgassing should happen regardless of a filter change...." The following link contains a good explanation of "outgassing" in a suction side fuel filter..

TSB-94-6R, Suction / Vacuum Side Fuel Filters (http://www.baldwinfilters.com/engineer/pdf/94-6r.pdf)

Here is a snip from the TSB...

"One observation made in the field is the fact that during servicing of a suction-side
fuel filter it is only partially full when removed....

...With the fuel system completely sealed and assumed leak proof, then one may ask,
how is the air generated and where does it come from? The source of air vapor is
the diesel fuel itself. Similar to water, diesel fuel contains a certain amount of
dissolved air, depending upon the fuel temperature, pressure on the fuel, specific
gravity and the amount of aeration to which the fuel has been subjected.
Increasing the fuel temperature or a fuel pressure reduction will release the air. The
amount of air released is dependent upon the degree of the air saturation of the fuel
and the magnitude of temperature increase and pressure reduction."
"

smile.gif

[Kennedy]

I would guess that several factors play here, the largest contributors being media density, and filter mechanical seals. I'm not sure what lies within the crimps on filters, but it is SO hard to keep air out and much easier to keep liquid in.

The bleed orifice while not the best solution does exactly what the OE system does with the air. It lets it pass.

As for filter brands etc. I believe that it is not the mfr, not the sealing of components, but the location of the filter (proximity to engine) and how it plays into drainback issues. I should note that this is not an endorement of the rear located fuel filter concept as I still believe that the OE should be the first filter in the system and changed at or well before the GM 15k recommended service interval.

Oh yeah, Lift pumps are almost ready! Control harness is ready in small qtys with more coming soon.


http://www.kennedydiesel.com/categoryresults2.cfm?Category=3&SubCategory=157


http://www.kennedydiesel.com/images/kdliftpump1.gif

[ 05-19-2005, 05:35 AM: Message edited by: kennedy ]

[Kennedy]

I'll also add that we are close to releasing the Super Mega filter kit using full synthetic 1 micron media. No drain, no integral post seal and a bunch more $$$ but the media is a uniform density and may (just may) tend to allow air to pass better. Only time will tell. This element required a major modification to the Mega head as it has no embedded end seal and it will not retrofit to the older units.

[BMDMAX]

That pump looks sweet. Very nice work.

Love the Super Mega too.

[Kennedy]

I spoke with another gentleman today from SC. He had the exact same situation as Chris. 30k trouble free, then filter change and stalls. He will be installing the bypass orifice for now.

When I change my filters I pull the seal out and lube with dielectric grease all around. Dunno if it helps, but...

[Seth McKinney]

Super Mega... CRAP! Looks like I'll have to get that one now ;)

[chrisinkanata]

Can't really add too much, other than after going about the same 30K and changing both filters, I got into the same problem. Start & periodic stall. Took it all apart and noticed one of the clamps on a fuel line installed with the Mega Filter seemed to be stripped. Would only tighten so far and then 'spin'. New clamp, but no change in performance. Still stalling after long crank times. Took it to the dealer after unhooking the filter kit....8 new injectors. Re-installed the Mega and no problem since. Never really did anything else. JK sent me the bypass but I have yet to install it. It just quit stalling. Gone about 10K miles in the last 3 months with no problem. Due to change the OEM filter but I'm kind of scared to. Not really sure what I should do. I'll get around to installing the bypass but if it ain't broke, don't fix it.....to some degree anyway. Too many variables to determine what caused what but time will tell I suppose.

Chris

[Kennedy]

When I installed my lift pumps on my LLY I had the tank out to do the pickup so from the pickup through the quick connect behind the fuel cooler and partially beyond was pure air. I started the truck without priming, bleeding, or energizing the pumps and it ran fine, continuously without any issues. After it ran for a few minutes I started the pumps as they will not prime themselves and rely on fuel dissipate what little heat they generate.

The proximity of the Mega element to the injection pump is a key factor in air related starting issues for sure, yet I certainly would not recommend mounting a filter way back on the frame especially outboard the frame rail.

[RichC]

I am the gentleman from SC that John spoke of. I installed the air bleed, put on a new OEM filter and a new Mega. Truck ran great for 4 days and 300 miles. Stalled three times today. I finally had to stop and bled the Mega. I am like Chris. I do not see why it worked so well for so long and now is a pain in my rear. John, is the lift pump ready to go yet. I can't take mcuh more of this priming!

[Kennedy]

Hopefully mid week I'll have some to ship.

[Chris Todd]

I am on my second Mega element sense the problems started. This one seems to be better, but I do not have enough miles on it to know if that was the problem yet (give me a couple thousand and then I will know).

I changed everyting else, so it had to be something with the Mega element itself (knock on wood)

One thing I didn

[RichC]

After 4 or 5 no start conditions yesterday, I took the truck to the dealer. My mechanic ran a vacuum test on the fuel lines and filters. There were no leaks, vacuum gauge pumps up and holds. It would appear now that my problem may be injectors AGAIN. Only 39000 miles on this set. All 39000 with the mega filter in place. They will run more test tomorrow, but I am not hopeful of the outcome. At least GM extended the warranty to 200,000. I am at 114,000 now. :confused:

[Kennedy]

Rich,

I was kinda looking that way, as the bleed orifice has been 100% successful so far, but was waiting to hear more.

I'd be curious as to how many pumps of the primer it takes to get fuel during a no start.

[Kennedy]

After speaking with Rich, we are also now conducting a test WITHOUT power module installed to see if that could be the cause...

[Chris Todd]

Knock on wood, but it appears the Mega element itself was the cause of the air in my system.

Since I have replaced the Mega element, I have been trouble free for 650 miles. Here is to crossed fingers and hoping for thousands more just like before.

I think the Mega air problems, other than true installation issues, are due to defects in some of the water sediment drains.

Rich, sorry it isn