North American Turbocoupe Organization



Intermittent Fuel Pump Power
vegas_ss Offline
Senior Member
#1
Intermittent problem... started a few days ago. Car would not start, noticed no priming on the fuel pump when key turned to run position... no fuel pressure. Next day started fine when the weather was warmer. Later that night, no FP prime or fuel pressure. Next day when warmer it was fine.

What I've done so far...

When I changed the negative battery cable to an NOS Lincoln cable I had when I first got the car, the fuel pump wouldn't run when the key was turned to run and the car wouldn't start. Changed back to the old cable and car ran fine for months. Finally tested the new battery cable, couldn't find any problems, and swapped it out a month or two ago (old cable was very corroded). Car ran fine until recently.

The ignition switch was replaced within 6 months and seems to be working fine. When the key is put in the run position, the abs pump motor runs and the autoride relays/switches all seem to be working normally as well as the dash lites (check engine etc...) just no fuel pump prime.

I was pretty sure the problem was in the connector running off the negative battery cable from the experience I had when I swapped cables before. I could unplug it and plug it back in and sometimes replicate the problem of the pump not running the prime cycle when the key is placed to run. Figured I would just bypass the connection and wire the two grounds up directly.

Well... fuel pump will not run now. I need to trace this a little further down the circuit but I am not sure where to look...

I did wiggle check the IRCM connections... I'm sure it's a bad/marginal ground somewhere... but where is the question!
1987 TC, 5sp, Boport Stage 3 Head/2.1 Cam
1996 Impala SS
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Pete D Offline
Administrator
#2
Have you looked at Jeffs article on Fuel pump diagnosis?
http://www.turbotbird.com/techinfo/Fuel_...ostics.htm
Pete Dunham


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vegas_ss Offline
Senior Member
#3
Yes I looked through that... I'm sort of at a loss due to the intermittent nature of things.

Well it was intermittent... now it's definitely not operational. I'll dig in further tomorrow... maybe related to the alternator meltdown I had a few months back. It seems that temps had a definite influence on this... cold no go, warm was fine.
1987 TC, 5sp, Boport Stage 3 Head/2.1 Cam
1996 Impala SS
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Ryan H Offline
Posting Freak
#4
Have you checked the inertia switch?
'88 TC Smile Walbro 255HP, Stinger FMIC, PIT BOV, Pro 5.0, Kirban, RR cam, FRPP strut tower brace, T3
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vegas_ss Offline
Senior Member
#5
I'll be attempting to check out all the wiring tomorrow. I guess my main concern is that the problem is intermittent... seems to be related to temperature. That is why I'm thinking the problem is a ground somewhere.
1987 TC, 5sp, Boport Stage 3 Head/2.1 Cam
1996 Impala SS
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vegas_ss Offline
Senior Member
#6
Well it was the inertia switch! Once jumpered the FP ran fine. Couldn't get the swutch to reset, took it off and smacked it, then it reset. I should probably look into replacing it. Are these available anywhere? I found this part number 4W7Z-9341-AA, but can't locate one.
1987 TC, 5sp, Boport Stage 3 Head/2.1 Cam
1996 Impala SS
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