TDG was correct, the old truck is sucking air through the filter bowl. I have never had this problem but the last filter I put in was Purolator. Anyone have any bad experiences with them? I have changed it yet, but I'm going back to GM filters. Any other suggestions? Also, I can't see a crack anywere in the filter housing and you really have to run it hard to see were the fuel is coming from. Shouldn't the ring around the filter be just hand tight?

Thanks Everyone and especially TDG
Dan

The ring that secures the filter is plastic, so no more than hand tight.

Every filter I've ever seen for one of these, no matter who's name was on the box, was made by Stanadyne and says so right on the filter.

I have found the same thing as Ron, all filters are stanadyne

Dan, I appreciate your commendation, but I'm afraid your diagnosis is impossible. You can't draw air at the filter bowl, its under pressure, it can ONLY leak. The only possiblity to draw air is either from the lift pump, the tank pickup or the lines between them where there is a partial vacuum. So if you've now confirmed your drawing air somewhere, then you need to go further back to fix the problem.

The only way the filter bowl or any place past the lift pump can draw air, is if the lift pump is not functioning or intermittent, creating a partial vacuum in the filter base/lines.

Well back to the drawing board. Thanks TGD. :(

atleast you know what the problem is now :)

If the lift pump isn't working then maybe he is drawing air in at the filter bowl. I'd double check that lift pump myself.

Well I have seen systems draw air under pressure but not in this case. When a fluid under pressure goes thru a restriction similar to a venturi air can enter. I guess a vacuum is created at the restriction. I've seen this phenomenon in clear hoses before at connections. Quite entertaining when you think about it and quite aggravating when you least expect it.

This phonomenon would be pretty much impossible to occur at only ~5psi pressure, and no orfices. But you are right, fluid flowing through an orfice does create a localized vacuum.

I've had my filter bowl fill with air from a loose seal at the "in" fitting(metal line). I've also stalled out after the bowl filled with air from cornering too fast with the needle on the last click on the fuel guage.

Hi bow!

In building race engines we took serious looks at each fitting to reduce any chance of air entering the system. Oil lines where of utmost importance. All the fittings where of generous size and generally cut in a lathe to reduce venturi effect and/ or cavitation in which microscopic bubbles of air could enter the system. Pressure is not what causes it but the differential in pressure through a restriction similar to what happens in a carburetor.

Hi Everyone, I have fixed the leak at the bowl and that was not the cure. I have opened the water bleed tee when running and no stall. I know the LP is running during crank time and at idle. I am searching for a leak from the LP back with no luck so far. I will also put a fuel gague on it a test it on the road.

I sure appreciate the help you have all offered. I damn well wish there was someone up here in Northern Vermont that knows something about 6.5's. I'll report back with what i find.

Thanks Again
Dan

Dmitch, Just A Wild Stab At This. Have You Looked At Your Fuel Cap? Do You Have A Vacume At It? Is It On Tight? I Have Heard Of Various Problems That Are Solved With A Simple Fuel Cap.

I fisxed the leak around the filter bowl and that did not solve the problem. I am looking for a leak from the LP back with no luck yet. I am sure the lift pump is working during cranking and at idle. I can open the water drain and have plenty of fuel. Tommorrow I will put a fuel pressure guage and teszt it on the road.

I really appreciate the help from everyone. sure wish there was a good 6.5 diesel man up here in Northern Vermont. I will report back what I find.

Thanks again everyone,Dan

The fuel cap is vented for both pressure and vacuum - fuel system will vacuum lock if that function is plugged, Inj Pump will run out of fuel.

As bowtie suggests, the cap would be an easy check, and could be part of the problem, if not all.

Wash it clean, then do the ole 'hickey' thing on it -:t - should vent.

Or, an automotive vacuum\pressure tester will work, or a vacuum cleaner (don't let the significant other catch you using the vac, tho! ;) ).

lol, good one GMCTD! :lol:

OR just go buy a new one for bout 5.00 buck or so.

I agree with bow, new ones are cheap and easy to get a hold of.

However, I think what you are going to find is that this is not your problem...I've seen many of these trucks drawing air, and almost every time its coming from the pickup in the tank.

I will replace the cap first thing in the morning. The old girl says no deal on the vac ! :lol:

dmitch, the lifter may run fine at idle, but you may still have a voltage problem or grounding problem at lifter or even at the ops. you may want to check that out also. that is also a cheap fix - free just takes a little time and a multi meter. never know it is worth a shot. also might want to take lift off and inspect it visually. i just replaced my old one and i am glad i did. even though there was nothing wrong with it, it did have a lot of rust on it, especially where i could'nt see against the frame. may have a small problem there. good luck!

Could also be the o-ring at the inlet to the lift pump has deteriorated and your drawing air right there, or from the pump itself, I"ve seen both.

Wells folks this is what I have done. I have checked all I can with the capability I have. New fuel cap, checked for leaks as far back as I can checked LP for o-rings etc. Out of frustration I took it into the local chevrolet dealer yesterday and they say the IP is bad. The good news is that they will replace it under the 11 yr. 120,000 mile extended warranty. I hope this cures it. I will update when I get the truck back.

Thanks to all for the continued support

Dan

Good luck and, GO TEAM WARRANTEE!!!!!

See if you can get TDC offset @ -1.5 to -1.94 for a cold morning -1.94 is, a bit rough for my taste, I settled on -1.85 as a compromise advance timing and a little less racket.



Wells folks this is what I have done. I have checked all I can with the capability I have. New fuel cap, checked for leaks as far back as I can checked LP for o-rings etc. Out of frustration I took it into the local chevrolet dealer yesterday and they say the IP is bad. The good news is that they will replace it under the 11 yr. 120,000 mile extended warranty. I hope this cures it. I will update when I get the truck back.

Thanks to all for the continued support

Dan

I got the truck back today and I guess I had forgotten how good it used to run. I took it for a good highway run and it seems to run better than ever.

Many thanks to all who have helped me through this process. I have learned a great deal and I greatly appreciate your help.

I have owned the truck for a long time and it has never skipped a beat although it only has 65,000 miles. The lessons learned were very valuble.

By the way the local Chevy dealer was great, did the entire job under warranty with a smile.

Again, thanks to all, I have become a big fan of the Diesel Place and the great people who frequent and monitor it.

Best Regards to All,
Dan