B5.5 died while driving like out of fuel but has a half tank.

So to start at the beginning, a couple of days ago, my serpentine belt shredded going down the highway and I kept on driving for 45 minutes to an hour. I got that situation straightened out and everything was good. I drove it less than 10 minutes down the road and it sputtered and died like out of fuel. It definitely has plenty. My lift pump is supplying 10 to 15 psi. As a diagnostic procedure, i hit it with ether and it did hit. Where should I go next? There are no cel's

The lift pump should only be at around 6-8 psi.

how much volume is the lift pump supplying - how did you check it for pressure?

I have not checked the volume, but it seems to be flowing decent into a cup. I installed a pressure gauge on the supply hose at the fuel filter.

What is it about an old lift pump and the half tank issue? Does the pump have to exert more because the "siphoning" action effort increases the lower the fuel level?

Having an extended crank issue last year when my lift pump relay died, mine would only cause a slight issue wen the tank was below 1/4 tank.

Many of these cars show little to no symptoms when the lift pump is non-functional. My suspicion is that a dead lift pump, in conjunction with a worn tandem pump will cause greater symptoms, so for me, it's a combination of the two - if you have a dead lift pump, and a borderline tandem pump, you will have worse issues than if your tandem pump is in good shape.

I was just thinking, I know that my check valve /tee fitting on top of the fuel filter was in question about a year ago. Do you think that it would cause these symptoms? What should I do to check it?

Also, what can I do to test the tandem pump?

I replaced the tee fitting and that made no difference. Any suggestions? Thanks

If you are sure that the lift pump is working by the fuel flow, have you primed it (cycled the key) a few times and then tried to start?

Typically the tandem (fuel) pump doesn't just die, and same thing with the injectors.

Off chance that you may have blown a fuse?

Does the ECU scan OK, and you have a check engine light when the key is turned to on?

It set a cel because I have the intake tube off to get to the fuel filter easier so i assume that it is working properly?

I just retested the fuel flow, this time at the tandem pump inlet. It is definitely good there. I'm not sure where to go next.

I just experienced something for the first time. I swapped engines in my car with a used one of unknown history. It ran great for the first couple of days. I was heading home and getting on it pretty good when it sounded and felt like I blew a turbo hose off.

I pulled over and checked everything including the turbo and all seemed OK.

I drove it gingerly for a few days but it would randomly misfire and also just shut off completely but only when idling. The weird thing is, it would fire back up as if nothing was wrong.

Went through a multitude of checks. I even swapped out the complete wiring harness as well as the CPS.

Finally swapped out the TP with the used one from the old engine and it cured my problem. I need to disassemble the suspect TP to see what is going on.

I just measured my voltage at my injector wiring harness. I'm getting 2.44 volts at pin 7. Should this not be 12v?

I am also getting 0.54 volts at each of the other 4 pins. Pin 2,3,5,6. Any help would be greatly appreciated. Thanks

I had very similar problem. Mine would die randomly without warning, only at idle, putting in the clutch to glide and decide, or while going down hills and not touching the go pedal for a significant amount of time...

New/known good used tandem pump fixed the problem.

Frans has a bunch of good used tandem pumps for not too much money. Worth getting one, just to eliminate it as a possibility. And from your symptoms it sounds like a good probability that the TP is the issue.

Andrew

Do you know if my voltage is correct then at the wiring harness? Thanks

KnoxWilson said:

Do you know if my voltage is correct then at the wiring harness? Thanks

Click to expand...

If you're asking me, I have no idea. But I do know that testing pins for voltage is a surefire way to go coo-coo-cocopuffs-crazy, unless you have a really (exceptionally) strong handle/knowledge of the WHOLE system. Low/off voltage usually means a bad ground or battery. A bad ground might cause your car's symptoms... but probably not.

I'd check, clean, replace the tandem pump (and I'd check the grounds) way before I'd ohm out the pins on the ecu.

Andrew

I was able to test my tandem pump last night and it checked out good. It hit 100psi at 1 point while cranking. I'm now suspecting an injector shorted out as my number 1 injector was ohming weird. I will try to start it this afternoon with it unplugged from the rest. If i do find it to be the problem, is it an acceptable practice to just replace the one bad one with a new one? Thanks

Have you checked your fuel filter??? I did not see this mentioned, but it should be changed if it is nearing the change interval.

I have. I took the three supply line off the tandem pump and I had sufficient flow and pressure.