Joys of Fuel Delivery

As my FB friends know I was left stranded in the road yesterday afternoon with a no fuel condition. Got a tow home and jumped into a different car to make Easter dinner.

I come home from work tonight, and it starts right away. Not the fuel pump issue I'm used to as they usually just up and quit. I ran over to Flash Gumby's house and took the FP gauge off his Jag's LT1 and came home to test. I screwed it on and turned the key. I went to 40. I started it up and it settled in at idle around 36. I put it in gear and out, forward and reverse. I stayed steady except once the it dropped to about 30 for a half second then came back up.

I hooked up Data master and am getting an EGR fault, as well as the two O2 sensors in a lean condition (not enough fuel?) Running the engine up and looking at the fuel matrix almost all of the hits were in Cell 16 which is labeled 'special'. I did get his of 17 and 18 when I ran up the rpm as expected but even though I KNOW I went over 3K the cell 19 (over 2K rpm) never hit either.
Only other cell with hits was 0 and that's probably when it stalled out.

Yes it died once while idling and I think (not sure) it was when it switched to closed loop. It did start right back up though.

Ran out of daylight so no dropping a full tank. In fact I'll have to drop 2 as the wrecked car has 1.5K miles on a new fuel pump and sending unit, so I'll just swap them...

The fact the pump is running, means I can pump out the tank before dropping it which is good. The caveat is I"m gone all next weekend so I really need to get it going in the 2 available evenings I have this week.

I do have 2 brand new TBI fuel pumps which doesn't help me one bit!

Wondering if it might be the FPR....since the pump seems to prime to 40 and usually they just pfft go...

The regulator is a lot easier to access.

FWIW, when I bought mine it would occasionally start hard. Fuel pressure would bleed to 0 in a few seconds with key off. In troubleshooting, I ended up plugging the return line at the regulator. By accident I sent the pressure up near 60 or 70 psi, and then suddenly the problem fixed itself. Must have been a sticky check valve from sitting. The car did always run fine once started though.

Well I troubleshoot it this eve again after reading up on everything. Pretty sure the FPR is good as it passes the test of pulling the vacuum line off and it going up 5ish PSI. Tops out at 43 (FSM says 42-47) and drops to around 37 when idling with the vacuum reconnected to FPR.

Taped the gauge to the windshield and drove around the neighborhood. Couldn't get high speed going as I didn't want to get too far from home and get stuck. Put it in 1st gear and rode the brakes to load the motor down in the mid 20s. Pressure stayed constant the whole time.

My path of least resistance is to swap the tank with the wrecked wagon. That one has 1K on a new FP and sending unit. Also the new wagon the fuel gauge doesn't work so I need to go into the tank anyway. I hooked up the fuel gauge on the wrecked DGGM and it behaved the same, but was 1.5 psi higher across the board. Will swap over the fuel filter too as that was also just replaced on the wreck.

It did stall on me twice tonight but started right back up, which it would not do on Sunday....WEIRD.

Rev Bob

Seems like you beat down the mechanical part of the fuel delivery system with the pressure gage.

If the EGR valve is jammed open, it makes a rough/unstable idle.

Geez, I'm a slacker. FINALLY, got the swap done. Between weather (rain), house guests, and other ****, I got the old tank dropped and the one from the wreck in yesterday afternoon (15 min hard stop for lightning and downpour). Pulled the wrecked tank 10 days ago. Anyway, Flash Gumby was my extra set of hands (he may of sold his wagon, but he ain't gettin out that easy, lol) and we got the old tank out and the new one in in under 3 hours. That included draining a full tank and the rain.

So I drove him home (15 miles RT) and it stalled once on the way to his place. Started right back up (after the momentary OH ****). Collected my child from his swimming pool and headed home. No issue. Today drove it 5 miles to our studio and it died on the way over. Idled rough all of a sudden and stalled at a light. CE light came on. Started back up and No problem. Left there 2 hrs later and went to my Mom's . Only stalled once, but stuttered a few times and I would immediately kill the AC and shift to neutral... Always at a light when stopped.

It's pouring rain out right with lightning so now taking Datamaster and the PC out to the car.


So..... post up what you think, Brand new FP and sending unit, 70K car that sat alot.

Coil. Coil wire. ICM.

Rev Bob wrote:

Rev Bob

Seems like you beat down the mechanical part of the fuel delivery system with the pressure gage.

If the EGR valve is jammed open, it makes a rough/unstable idle.

This may be it. It was throwing an EGR code, so I unplugged the electrical connector to it. Ran fine, didn't stall for 10 minutes. plugged it in and the car immediately stalled. Cleared the codes and fire back up with the EGR plugged in. Would idle ok and stumble every couple minutes, throwing a lean O2 code. Will test the voltage at the plug and if good, pull the one off the wreck and swap them to eliminate that as an issue.

I really just wanna drive my car....would have started tonight, but rain again....summer in FL