stalls hot

[howards@howard]

1994 6.5l 3500 auto 150k random hot stalls, fires dies, let cool over night runs fine for first hour. this week, new lift pump + lines, Wired LP independent w/ relay on key, new FSD and tested suction line for obstructions, new FF.
Fuel pressure at the Tee is 4psi at idle, I would think it would be a little higher. The truck idles high and racey like it's timing is advanced. I have been doing this a log time and it sounds like it's starving for fuel.
The only thing I have left small that I can think of is the fuel shut off solenoid.

Any other recommendations????

 

[itsacrazyasian]

where did you get your FSD and where is it mounted? I had a bad flightsystems pmd right out of the box. I ended up with a grey stanadyne! plus two known good spares in the truck.

 

[itsacrazyasian]

where did you get your FSD and where is it mounted? I had a bad flightsystems pmd right out of the box. I ended up with a grey stanadyne! plus two known good spares in the truck.

btw did you get any codes out of it?

 

[howards@howard]

Well we are on week two. I put a permanent fuel gage on it. this is helping with diagnosis. I put the delco EP-158 10psi lift pump on this helped and dropped the tank and cleaned it. it ran great for a week perfect 8-10 psi I thought we were done. It died yesterday no fuel pressure at the drain valve. plenty of pressure and volume at the lift pump. I am starting to think of some type of obstruction between the lift pump and the top of the motor.

With the motor shut off 10 psi motor running zero psi. NO air bubbles.

get this I thought of the relief valve may be stuck open, so I crimped the return line and the truck dies????? I am going to check to see if the lines are crossed. thanks for your input but it's obviously a fuel issue.

 

[itsacrazyasian]

definatly a fuel issue . With all the problems i;ve had with teh PMD its the first thing i run to. Where is your fuel pressure gauge tapped into? The drain of the filter manager? I put my fuel pressure gauge behind the filter manager and on the line directly to the IP. I found out that once i started running bio the fuel lines were coming apart inside and i had a little piece flake off and block the line acting like a check valve.

 

[howards@howard]

supply problem

Yes my gauge is tapped off the drain. If the gauge is reading zero then I guess it's doing its job for now. So I should disconnect the LP and blow back the line from the filter housing??

Have you ever had relief valve problems and how is that to service?? were is it?? Thanks

 

[Goofyexponent]

My buddy went thought this recently.....the tow bills were getting costly.

It would run fine, then stall out completely. Throw NO codes, and the mechanics couldn't find ANYTHING wrong with it because it would have cooled off by the time it got to the shop. They would simply walk outside, startit up, bring it into the shop and look at it. Then they would call Joey and tell him there is nothing wrong, come get it.

I told him to change out the PMD and relocate it to the inner fender. No problems since he did this. I suggest you get at least a second hand working PMD and try it.

If that solves it, relocate it from it/s mounting plate on the pump to the inner fender. The heat and vibrations will KILL these little buggers.

 

[itsacrazyasian]

Goofy, its not pmd related. The PMD has nothing to do with the lift pump running. On his 94 its dependent on his oil pressure sensor to run.

So when she quits and you loosen the hard line after the pump you get plenty of fuel pumping out? Not just residual from the filter manager gravity draining its way back down to the pump? How old are the rubber lines up to the filter manager and to the IP?

No i havent had issues with the relief valve but i've only owned one of these trucks. It was the truck in my sig and i chased my tail with so many issues with it.

 

[howards@howard]

supply problem

There is plenty of fuel at the lift pump shooting out. Pump is running fine. with a gauge on the drain 0psi with truck running and 10 PSI with the truck shut off.

So A all the fuel is getting sent back to the tank VIA the return

OR B there is a restriction in the supply line between the LP and the IP

 

[itsacrazyasian]

Did you check the lift pump with the motor running? It'll prime the system with the glow plugs, then after the engine runs the OPS takes over.

Also take a pair of needle nose and crimp off the return while its running, see if the fuel pressure incraeses.

 

[howards@howard]

supply problem

Yes the LP runs off a switch on the dash installed by me. thanks

If you crip the return line the truck stalls. do you think someone hooked up the two lines backwards

 

[itsacrazyasian]

Maybe someone mixed the lines up at the filter manager???? Put a pressure gauge at the filter manager. The lines are easy to change if they are questionable.