I have an all stock 88' iroc 305 TPI. My car has problems starting so it takes more then one crank to turn it over.....I hear the fuel pump run and shut off try to start it and it wont start...then I can hear the fuel pump turn back on again and it keeps running for about 5 seconds and it wont start then I go to start it again and if it doesnt start again ill hear it keep running again....I dont know why the fuel pump keeps running like that, I hope it doesn't flood the engine too much :? any ideas???? Oh yeah sometimes when I shut the car off after a short run like moving it in the driveway I hear the fuel pump after I shut it off??? I hope I won't have to replace it soon.

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1988 Camaro Iroc-z
305 ci Tuned Port 700R4
3" Exhaust/Flowmaster 80 series muffler/Dynomax high flo cat
hypertech chip/k&n filters
Cut out MAF screens
TPIS Airfoil
"Camaros RULE!!"
"Theres no replacement for displacement"
SAVE THE F-BODY!!!!

 

The only way you can flood the engine without it running is if you've got a leaking injector. Otherwise, the excess fuel is returned to the tank via the fuel pressure regulator return line.

Sounds like you've got something messed up in one of the circuits that run the fuel pump. You've got a timed circuit that powers the pump when you first turn on the key until it "times out" - 5 seconds sounds a little short; another for the starting circuit; and a running circuit that has the oil pressure switch in series.

If it continues to run after the key is turned off, you've got power running to the right place at the wrong time. Beyond that, I can't help you.

Don't suppose you put a stereo amp or alarm in when this started happening...

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82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R4, 2300 stall TC. Ported World 305 heads, Crane PowerMax 2050 cam. ZZ3/4 intake, oil pump, pan & baffle. Accel HEI SuperCoil & module. Hooker 2055 headers, 3" Catco cat & 3" catback w/dual-opposite Flowmaster 80. 2.93 limited slip. Spohn SFCs waiting to be installed. AMSOIL syn lubes bumper-to-bumper. Daily year-round driver. Best ET, speed TBD...
57 Bel Air, my 1st car. '66 396, 9.7:1 forged TRWs, Weiand Action+, Holley 750VS w/4150 conversion, GK 270 cam, Magnum rockers, Jacobs Omnipack, 1-3/4" Hedders & 3" Warlocks, TH400 w/TCI Sat Night Special conv & Trans-Scat shift kit, MegaShifter, 3.08 8.2" 10-bolt w/Powertrax, AMSOIL syn lubes bumper-to-bumper. Idles smooth @ 700 RPM in D. Best 15.02/95.06 @ 5800' Bandimere (corrected 13.93/102.4 @ sea level).

 

no, it's working correctly. the fuel pump is energized anytime the oil pressure is above a certain value (can't remember the exact value, thinking somewhere around 8psi) so anytime you crank the car and achieve this pressure, it runs the pump and doesn't stop till the pressure drops. Same when you shut the car off, it depends on how long the engine takes to lose pressure. My 383 has a tight oiling system and takes several seconds to bleed down so the pump runs. As stated, the fuel is just returned to the tank via the return line.

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Kyle Osterholt
Okarche, Oklahoma
ASE Master Certified
86 T/A 383 TPI
89 TTA #1002 T-top/Leather
89 TTA #1358 Hardtop/Leather
80 T/A Pace Car
73 Opel GT
73 bronco
2000 Ducati 996 Monoposto
83 MSE #52

 

snakeskinner is right - the fuel pump will run when there is oil pressure.

FYI -
My fuel pump was acting strange last year. Nothing that prevented the car being driveable, just "not right". Then, I walked out to my IROC in the morning to go to work and the fuel pump was running. I guess it ran all night. As it turned out, the fuel pump relay went bad. I took a couple of dollars and five minutes and that was the end of my strange fuel pump behavior...