Lack of fuel pressure

[budget_crx]

So my buick started idling real rough (at about 600 rpms with a bad hesitation). then it started dying and wouldn't start up again, fuel pressure was a measly 8psi. What do you think could have caused it, I have a Walbro 340 and an afpr which are both relatively new, (within 2 years) so i hope they haven't gone bad already. could this just be a clogged filter or does anyone have some ideas on what else to check?

 

[1BUICKGN]

I would start with a fuel filter an go from there...

 

[1BUICKGN]

i have had many fuel related issues with my car in the past and it could also be corrosion in the plug to the ecm.
if it was me i would:
#1 check the two connectors for corrosion
#2 change fuel filter
#3 swap fuel regulator with spare stock one
#4 drop tank and invetigate fuel sock & pump

but then again that's just me......

 

[budget_crx]

by connector plugs do you mean the two in the back by the fuel pump? I also forgot to mention that it has a hotwire kit, which was installed at the same time as the pump

 

[1BUICKGN]

i mean the the two wiring harness connectors on the ecm or computer.

 

[Nasty]

I would check this stuff first, its quick and free-plus its the first stuff you should check regardless.

1) Make sure you have gas, don't rely on the gauge. (I am sure you already did this, but I have to list it).

2) Check voltage to fuel pump (connector under rear bumper would do). If you don't have at least 12v, fix it.

After this, you really need to determine if you have restriction in the line. 1st I would start by checking pressure coming out of the tank, it can be done by removing the 3/8 feed line above the axle at the body mount location and tee it into your test gauge. No pressure? Then your pump is shot, or the sock is clogged (rust?). Either way the tank has to come out. If you have pressure here, then you have restriction in the line or filter. Change the filter and hope that was it. It will be the 1st $ out of pocket in your diagnosis and its also the cheapest/easiest part you could hope for.

Good luck

 

[Chuck Leeper]

Add to the list: connector hose between the pump and hanger may be "tango uniform". Either the clamps are loose, or the hose is ruptured.

 

[budget_crx]

ok, when i disconnected the ground from the fuel pump, the engine would usually just crank over and never fire up. Today i diconnected the same ground and the engine would struggle, but after a short time (3 seconds) of cranking it would fire up, with about 6-7psi of fuel pressure, idle real rough then die after running for about 5 seconds. It did this multiple times with the fuel pressure dropping about a psi each time. This just seemed very odd to me, any ideas?

I already made sure it had enough gas in the tank so my next attempt will to check voltage to the pump and then to replace the fuel filter

 

[Chuck Leeper]

???

ok, when i disconnected the ground from the fuel pump, the engine would usually just crank over and never fire up. Today i diconnected the same ground and the engine would struggle, but after a short time (3 seconds) of cranking it would fire up, with about 6-7psi of fuel pressure, idle real rough then die after running for about 5 seconds. It did this multiple times with the fuel pressure dropping about a psi each time. This just seemed very odd to me, any ideas?

I already made sure it had enough gas in the tank so my next attempt will to check voltage to the pump and then to replace the fuel filter

"disconnect the ground"?? How/where did you do this?
Is there a grnd strap from the tank, to the rear frame, near the bumper shock?

Are ALL the grounds on the car clean, and tite??

 

[budget_crx]

1. voltage was good to the pump

2. installed the new fuel filter, the car started up and ran (sounding much better than before) but still wanting to die. it was running at only 5-6psi of pressure. my dad was blipping the throttle keeping it alive while i was checking all of the guages and for leaks, the highest O2 milivolts reading i got the whole time was about 150.

my next check point will be trying the pressure regulator.

 

[budget_crx]

"disconnect the ground"?? How/where did you do this?
Is there a grnd strap from the tank, to the rear frame, near the bumper shock?

Are ALL the grounds on the car clean, and tite??

the black wire coming off one of the connectors on the hotwire kit, i was told by the previous owner that was a ground for the fuel pump, which he then preceeded to tell me would be a good line to put a cut-off switch on. when pulled, the engine will crank over but there will be no fuel pressure