Random fuel shut-off while driving.

95opal · Dec 30, 2021

Jason.Silus said:
Managed to jump start it a few minutes ago, feeling blessed that I don't have to install a new starter.

Unfortunately, the car is dying after revving passed 3,000 rpm, and then it will refuse to start without priming the fuel pump a few times. Is it possible this is just because it's new, or is there a different problem all together?

Another set back, despite the new fuel sending unit having much more consistent resistance readings, the fuel gauge continues to not work. Guess a new gauge cluster will be the next part. Not truly sad about it, as I planned on getting a new one anyways. Might be smart to try taking the cluster out and checking the right prongs for some voltage to make sure it's not a wiring issue.

The biggest hurdle right now is trying to differentiate what is actually a problem. Without the fuel gauge, I can't monitor my gas levels to see if I'm just running really rich and burning through more gas than I realize or if there's still a problem with the pump. However, whenever I prime it, it sounds perfect, whereas before when it would die, there would be a very audible whine coming from the pump.

I would suspect fuel pressure regulator. But without a gauge on it to monitor its just a guess.

Jason.Silus · Dec 30, 2021

As soon as I get the gauge fixed, this will be the plan.

Jason.Silus · Dec 31, 2021

Getting the fuel pressure gauge today. I decided to go ahead and mess around with the regulator and see what happens. I pulled the vacuum line and let it run for a bit, and it died after about 5 minutes of running, per usual. I expected it would run at least a little different, probably richer, but it seems to run normal. I think that would mean it's always running rich, but I'll wait until I get the gauge on it before making any decisions.

Edit: Also wanted to clarify that there were no leaks in the regulator.

lwarrior1016 · Dec 31, 2021

Did you swap the fuel filter when you installed the new pump?

Monday · Jan 4, 2022

That regulator has a little O-ring... did you lose it?

THE FLIGHTLESS KIWI · Jan 5, 2022

Have you checked the emergency(side impact)shut off switch for the fuel pump. If that has a fault, maybe it could be causing all your intermittent problems. This is a resettabe switch and I have heard of owners activating them to prevent vehicle theft

Jason.Silus · Jan 9, 2022

Finally got the fuel pressure gauge in. The first one got lost in shipping so I had to wait for another one to send unfortunately. Wasn't too bad tho, just meant more waiting.

Happy to report, I'm rocking a respectable 2.5psi of fuel pressure, when measuring from the Schrader valve on the stock fuel rail! I'm running on better gas mileage than a prius.

All jokes aside, where do I go from here? At first I thought I just wasn't doing this right, and maybe I'm still not, but I double checked that the maybe 6 inches of hose and adapted in the kit for leaks and found none, so I think it's safe to say this is what I'm getting.

ttocs · Jan 9, 2022

your car would not start with 2.5 psi. Get a pic of what your kit looks like

Jason.Silus · Jan 9, 2022

ttocs said:
your car would not start with 2.5 psi. Get a pic of what your kit looks like

The car did not start funnily enough

Jason.Silus · Jan 10, 2022

So the battery is pretty dead again, so I set it up for a jump, and I got it to fire, but, again, it died within seconds. I'm not sure what's wrong, but the fuel pressure gauge doesn't move. I'm not sure if it just wasn't hooked up right, but I can't test it anymore because the car refuses to turn the crank despite reading at about 12 volts.

ttocs · Jan 10, 2022

try the key on/off/on/off waiting 5 secs after its on for the pump to prime and see if the pressure increases any.

Jason.Silus · Jan 10, 2022

ttocs said:
try the key on/off/on/off waiting 5 secs after its on for the pump to prime and see if the pressure increases any.

Despite the fact the car still hasn't ran, I'm apparently out of gas. Feel like I'm losing my mind because it seems like fuel just evaporates by the gallon every few days. I've not found a single drop of fuel since I had the whole fiasco with the shop not tightening my sending unit, but perhaps a thorough inspection of the fuel lines from back to front is in order.

After depositing another gallon, the fuel pressure climbed about 3psi for every priming of the fuel pump, until I hit 35psi, where it stayed no matter how many more times I turned the key. This seems a little low to me, but not to the point that it wouldn't run; however I still have the battery issue, so the car will not start, and I don't think trying to start a straight-piped V8 at 10pm would be very kind to the neighbors.

This makes me think that the fuel regulator is not the issue, but if anybody has any more insight, it would be appreciated. After this, my next plan is to inspect the lines for the entire run, and make sure I'm not leaking gas anywhere.

Edit: Checked after about 15 minutes, and pressure had dropped less than 5psi.

ttocs · Jan 10, 2022

check the fuel filler neck grommet on the back pass side of the tank, and around the tank in general.

Notthenow · Jan 10, 2022

I believe the Ford spec is 39 psi, so not far off. 15 minutes is a decent time for only losing 5 psi. I think you said the filter is new. That said, pump works, check valve in pump holds, and filter doesn't seem plugged. Especially if now that the line is reprimed you can get 35psi in one or two hits of the pump.

Notthenow · Jan 10, 2022

Yeah, grommet will let slosh out the side. Not sure that much, especially if the tank only has a gallon or two.

Jason.Silus · Jan 10, 2022

Notthenow said:
Yeah, grommet will let slosh out the side. Not sure that much, especially if the tank only has a gallon or two.

Many of the install videos were adamant that I do not tear the grommet. I don't believe I did, but even if I did, as said the car hasn't moved so I'd imagine there isn't much force pushing it out of the grommet hole in the first place. Haven't had any issues with it leaking when it has been filled, so I don't think that would be the cause.

ttocs said:
check the fuel filler neck grommet on the back pass side of the tank, and around the tank in general.

The tank would've been my first guess, especially because it leaked from the sending unit there last time, but no dice. Can't find or even SMELL gasoline anywhere near the car.

Edit: To me and my basic physics brain, it seems that fuel makes it through the main lines just fine, but I'm losing fuel somewhere along the return. If the return line was blocked, would the car be able to run rich, or would it not run at all?

Notthenow · Jan 10, 2022

Not sure on that, but I happen to have both fuels lines off my 98 right now. I was able to blow air through the return line and hear it bubble in the tank.

Notthenow · Jan 10, 2022

I take that back it was the supply line. There is a diaphragm on the return just off the rail. That does not allow low pressure air through.

ttocs · Jan 11, 2022

you cant see if the grommet if torn and they generally do get torn when the tank is dropped and the filler pulled out/in. If you dropped the tank, check for leaks, follow your nose