when key to on, fuel pump keeps running
#1
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Thread Starter
when key to on, fuel pump keeps running
When I turn the key to the on position the fuel pump will run. Its supposed to shut off in two seconds but doesn't, keeps running. The motor will start but I have to go straight to start. If I let it prime I believe its saturating the system putting me into a flood. The ecm is supposed to shut it down if it doesnt' recieve a referance signal from the distributor. I'm clueless as to whats going on. I've looked over my shop manual but don't see anything. I need help.
btw injectors have 16k on them and the pump is a new walbro unit. fpr is a stock.
btw injectors have 16k on them and the pump is a new walbro unit. fpr is a stock.
#2
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First of all, you pump could run all day, and it should never "flood" your car. If it does, than you have a bad injector or regulator allowing fuel to dump into the intake.
Second, either the ECM is bad, or the fuel pump is incorrectly wired. The two things that turn the pump on (relay and oil pressure switch) recieve constant power, not switched ignition, so if one of those got stuck, it would stay on regardless of key position. The ECM is the only thing that will turn on the pump when the key is turned on. Either the driver in the ECM could be shorted, or its somehow recieveing an RPM signal w/ the engine not running. Either that, or somebody "rigged" your wiring, giving the pump constant 12V w/ the key on.
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Second, either the ECM is bad, or the fuel pump is incorrectly wired. The two things that turn the pump on (relay and oil pressure switch) recieve constant power, not switched ignition, so if one of those got stuck, it would stay on regardless of key position. The ECM is the only thing that will turn on the pump when the key is turned on. Either the driver in the ECM could be shorted, or its somehow recieveing an RPM signal w/ the engine not running. Either that, or somebody "rigged" your wiring, giving the pump constant 12V w/ the key on.
------------------
If you live in Southeastern US, check us out!
South East Thirdgen
GM Master Tech
ASE Master Tech + L1
Savannah, GA
'87 Trans Am
S/D TPI retrofit including functional PassKey,
22# injectors,
Whatever chip I feel like burning,
JET AFPR, Ported Plenum,
TB Coolant Bypass, Custom Cold Air,
SSM SFC, KYB Shocks, Boxed LCAs, Wonder Bar,
8mm Accel wires,
Flowmaster Exhaust,
16" GTA rims,
Corvette Servo,
3.73 Posi
4wheel Disc Brakes
Summit 1-5/8" headers, 2.5" Dynomax catback.
Best 1/8: 9.519@72.74
'97 Bonneville SSE
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TWON_3rdGEN (03-19-2020)
#3
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Either the driver in the ECM could be shorted, or its somehow recieveing an RPM signal w/ the engine not running. Either that, or somebody "rigged" your wiring, giving the pump constant 12V w/ the key on.
I'm sure I have it wired right. The pump will even run a few seconds after the key is off which makes me think the computer is fine as well. I'm looking thorough my manual, I'm going to do some tests on the distributor, hopefully I can find something.
#4
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<font face="Verdana, Arial" size="2">Originally posted by nitroscj:
I'm sure I have it wired right.
</font>
I'm sure I have it wired right.
</font>
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If you live in Southeastern US, check us out!
South East Thirdgen
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Savannah, GA
'87 Trans Am
S/D TPI retrofit including functional PassKey,
22# injectors,
Whatever chip I feel like burning,
JET AFPR, Ported Plenum,
TB Coolant Bypass, Custom Cold Air,
SSM SFC, KYB Shocks, Boxed LCAs, Wonder Bar,
8mm Accel wires,
Flowmaster Exhaust,
16" GTA rims,
Corvette Servo,
3.73 Posi
4wheel Disc Brakes
Summit 1-5/8" headers, 2.5" Dynomax catback.
Best 1/8: 9.519@72.74
'97 Bonneville SSE
#5
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Thread Starter
I spliced a 12 fused wire into the tan/white off the fuel relay. I did a lot of researching into the wiring of it and wanted to make sure it was right.
I got out the ole helms today and started with the "turns over won't start". I have a question on testing the injectors. When they say blink do they mean on..off...on....off sort of thing when your cranking it or do they mean on...off...on and then stays on with a steady light while cranking.
When I start testing the light is on, goes off comes back on and stays on.
Also while testing i disconnected the four pin connector from the distributor, I checked my fuel pump while doing this. Still continues to run. With no referance signal it should shut the pump off.
I also applied 12 volt to the referance wire while watching my testing light connected to a injector harness. It would go dim but not completely off.
btw I went to autozone and picked up a regulator and a relay. I also checked my plugs....dry with the exception of number 4 and that was a little wet. I can get it to start for about a second then dies. And this is intermittent, sometimes I can crank the crap out of it and won't fire.
I got out the ole helms today and started with the "turns over won't start". I have a question on testing the injectors. When they say blink do they mean on..off...on....off sort of thing when your cranking it or do they mean on...off...on and then stays on with a steady light while cranking.
When I start testing the light is on, goes off comes back on and stays on.
Also while testing i disconnected the four pin connector from the distributor, I checked my fuel pump while doing this. Still continues to run. With no referance signal it should shut the pump off.
I also applied 12 volt to the referance wire while watching my testing light connected to a injector harness. It would go dim but not completely off.
btw I went to autozone and picked up a regulator and a relay. I also checked my plugs....dry with the exception of number 4 and that was a little wet. I can get it to start for about a second then dies. And this is intermittent, sometimes I can crank the crap out of it and won't fire.
#6
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Thread Starter
[QUOTE]Originally posted by GMTech:
Second, either the ECM is bad, or the fuel pump is incorrectly wired.
I think you hit the nail on the head about the ecm. ken
Second, either the ECM is bad, or the fuel pump is incorrectly wired.
I think you hit the nail on the head about the ecm. ken
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TWON_3rdGEN (03-19-2020)
#7
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<font face="Verdana, Arial" size="2">Originally posted by nitroscj:
I spliced a 12 fused wire into the tan/white off the fuel relay. </font>
I spliced a 12 fused wire into the tan/white off the fuel relay. </font>
I think you answered your own question. The Tan/White wire is the feed to the fuel pump. Putting 12V to this will bypass the relay and oil pressure switch and cause it to run as long as there in power on your "new" wire.
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'87 Trans Am
S/D TPI retrofit including functional PassKey,
22# injectors,
Whatever chip I feel like burning,
JET AFPR, Ported Plenum,
TB Coolant Bypass, Custom Cold Air,
SSM SFC, KYB Shocks, Boxed LCAs, Wonder Bar,
8mm Accel wires,
Flowmaster Exhaust,
16" GTA rims,
Corvette Servo,
3.73 Posi
4wheel Disc Brakes
Summit 1-5/8" headers, 2.5" Dynomax catback.
Best 1/8: 9.519@72.74
'97 Bonneville SSE
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#8
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[QUOTE]Originally posted by GMTech:
[B]
I think you answered your own question. The Tan/White wire is the feed to the fuel pump. Putting 12V to this will bypass the relay and oil pressure switch and cause it to run as long as there in power on your "new" wire.
The relay and oil pressure switch work fine. I disconnect the relay no pump. Try startining and as soon as it build oil pressure the pump starts. Turn the key off and the pump runs for a few seconds and shuts off. It is wired exactly as it shows in the wiring schematic that came with my helms manual.
[B]
I think you answered your own question. The Tan/White wire is the feed to the fuel pump. Putting 12V to this will bypass the relay and oil pressure switch and cause it to run as long as there in power on your "new" wire.
The relay and oil pressure switch work fine. I disconnect the relay no pump. Try startining and as soon as it build oil pressure the pump starts. Turn the key off and the pump runs for a few seconds and shuts off. It is wired exactly as it shows in the wiring schematic that came with my helms manual.
#9
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What I meant by the wiring was that I used 12ga wire with a fuse in it running from the pump to the tan and white wire. haha I guess the heat is getting too me and this damn jeep with tpi too!
#10
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OK, try this:
Unplug the fuel pump relay, and hook the NEG lead of your multimeter (or the end of your test light) to the battery negative post. Put the POS lead of the multimeter (or the probe of the test light) to the DkGRN/Wht wire of the relay connector. Now turn the key on. Does the meter read 12V (or does light come on) for 2 sec then go out, does it stay on, or does it not come on at all?
If it comes on and stays on, unplug the puter and do it again. If it still comes on and stays on, something isn't wired right. If it went out, I would be trying a different puter.
------------------
If you live in Southeastern US, check us out!
South East Thirdgen
GM Master Tech
ASE Master Tech + L1
Savannah, GA
'87 Trans Am
S/D TPI retrofit including functional PassKey,
22# injectors,
Whatever chip I feel like burning,
JET AFPR, Ported Plenum,
TB Coolant Bypass, Custom Cold Air,
SSM SFC, KYB Shocks, Boxed LCAs, Wonder Bar,
8mm Accel wires,
Flowmaster Exhaust,
16" GTA rims,
Corvette Servo,
3.73 Posi
4wheel Disc Brakes
Summit 1-5/8" headers, 2.5" Dynomax catback.
Best 1/8: 9.519@72.74
'97 Bonneville SSE
Unplug the fuel pump relay, and hook the NEG lead of your multimeter (or the end of your test light) to the battery negative post. Put the POS lead of the multimeter (or the probe of the test light) to the DkGRN/Wht wire of the relay connector. Now turn the key on. Does the meter read 12V (or does light come on) for 2 sec then go out, does it stay on, or does it not come on at all?
If it comes on and stays on, unplug the puter and do it again. If it still comes on and stays on, something isn't wired right. If it went out, I would be trying a different puter.
------------------
If you live in Southeastern US, check us out!
South East Thirdgen
GM Master Tech
ASE Master Tech + L1
Savannah, GA
'87 Trans Am
S/D TPI retrofit including functional PassKey,
22# injectors,
Whatever chip I feel like burning,
JET AFPR, Ported Plenum,
TB Coolant Bypass, Custom Cold Air,
SSM SFC, KYB Shocks, Boxed LCAs, Wonder Bar,
8mm Accel wires,
Flowmaster Exhaust,
16" GTA rims,
Corvette Servo,
3.73 Posi
4wheel Disc Brakes
Summit 1-5/8" headers, 2.5" Dynomax catback.
Best 1/8: 9.519@72.74
'97 Bonneville SSE
#12
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Thread Starter
Yep had the wiring all messed up. Had the orange from the fuel pump (the one used for diagonistic testing) plugged into 12 volt. Fixed that. Had the injector wires, the ones that go to power hooked up to accesory power, so everytime i tried starting thing they wouldn't get any juice. Found a hot that stayed even during startup and wallla!!! it runs whooooohoooooooo
thanks a bunch gmtech....your the man. later ken
www.geocities.com/nitroscj
thanks a bunch gmtech....your the man. later ken
www.geocities.com/nitroscj
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TWON_3rdGEN (03-19-2020)
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