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No power to fuel pump relay from PCM? *Update issue resolved*

txslow6

txslow6

New member
Switched to a racetronix pump and the pump isn't priming. The one before had stopped and wasn't priming either.

I have tried with the caspers rewire and the factory wiring and still no luck. The fuel pump fuse is good. What should I check next? :th_scratchhead:

I will be pulling the pump back out to double check connections, but in the meantime any suggestions?
 
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Re: Racetronix pump installed and not priming?

Are you getting power from the harness?

Check with a digital multi meter.
 
Re: Racetronix pump installed and not priming?

No power to the fuel pump fuse. The relay clicks but the fuse has no power. How would one go tracking down the problem for that?

Thanks
 
Re: Racetronix pump installed and not priming?

No power to the fuse or after the fuse?

Technically these are for a Regal, but they are the same for the GP
99FuelPump.gif


99FuelPump2.gif
 
Re: Racetronix pump installed and not priming?

Ok fuse has power I didn't hook the meter up right. Double checked it and it's getting power. No power going out of pin 8 of PCM to fuel pump relay. If I apply power manually the fuel pump turns on. What reasons would keep the PCM from turning on the fuel pump relay. Checked voltage at PCM supply and getting 12 volts.
Tried a 2nd known good PCM and it did the same.
 
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Re: Racetronix pump installed and not priming?

I didn't think the 97 had a security feature on it. Any idea how to test.
 
Re: No power to fuel pump relay from PCM?

Fuel pump relays? If you have someone turn the key to on, do you have power at the fuel pump harness for about 3 seconds? Where is pin 8 of the PCM supposed to go? What was the original condition before you changed the fuel pump (Did the pump go out unexpectedly, were you working on something else when it stopped working, etc.)?
 
Re: No power to fuel pump relay from PCM?

Copy and pasted from another forum:

Vehicle in question is a 97 Pontiac Grand Prix GTP. This issue has me scratching my head.

A little background on the issue:
Before installing the new fuel pump the vehicle would lose power(like fuel was cutting out). All accessories would still be active. I assumed the fuel pump was going bad as one day I tried to start the car and it wouldn't. Fuel pump wouldn't prime so I ordered a new one.

Got it installed and was still seeing the same issue. Took the fuel pump back out and double checked everything. It all checked out and went to try again-Same fuel pump won't prime the system. And I have no fuel pressure.

I began to diag the electrical. First was the fuel pump fuse since it is hot at all times-checks out) Next wents to the fuel pump rewire(bypasses the fuel pump resistor which is a known problem in the GTP's). It's getting the full voltage to and after the fuse all the way back.

Checked the fuel pump relay and replaced it to be on the safe side.

I went ahead and forced the pump on manually by giving it power and it kicked on. Tried to start the car and it didn't(haven't checked the fuel filter but that will be later).

Went back to checking the relay and found that it wasn't getting power at the pins on the fuse panel. No problem let's check the continuetity and power. No power to it at all. Checked for power at the wire off of the PCM and no dice. Went ahead and checked the pin off the PCM and still not getting power. Then checked to see if I'm getting 12 volts at the PCM supply which it is.

I found out the BCM cuts the fuel signal to the PCM if it doesnt registers, and theft deterant relay does as well.

Next step was to look at the BCM(body control module) which sends the signal to the PCM.

No shorts on the pins of BCM. BCM will initialize, but is not sending the 5v pulse for the fuel cutoff. Tried to pcm with same results.

I also pulled every fuse to see if something is blown and all are showing good.

The Drivers Information Center is blinking 0. I also have tried using a 2nd known good PCM and it does the same. I even tried hooking a scanner to the vehicle to pull codes and it won't connect with either PCM. I tried the scanner in a different vehicle and it connceted just fine.
 
Re: No power to fuel pump relay from PCM?

Going to trailer it to a shop for further diagnostics. I'll post what the issue is incase there's someone else out there who runs in to this same problem. I hate it when cars defeat me.

Hopefully it will be repaired and I can get back to enjoying the turbo setup.
 


Re: No power to fuel pump relay from PCM?

if you dont have anything coming from the pin on the PCM.. you are in rough shape...

If you do, just bypass whatever other crap is going on and run it direct to the relay... I do it like that in my fiero and it works fine.
 
Re: No power to fuel pump relay from PCM?

RegalGS98s said:
Found this searching Google for DIC blinking 0 : http://www.grandprixforums.net/d-i-c-flashing-issue-28706.html I thought it sounded like a wiring issue. They're saying check your grounds. Here's another from google: 99 GTP DIC flashing 0's - Car Forums and Automotive Chat
Click to expand...

darkhorizon said:
if you dont have anything coming from the pin on the PCM.. you are in rough shape...

If you do, just bypass whatever other crap is going on and run it direct to the relay... I do it like that in my fiero and it works fine.
Click to expand...

I think it's multiple issues. I'm thinking it's a ground, security, and PCM problem. I'm still leaning more towards ignition/theft/BCM though.

If it is a ground I'm anxious to know which one. In fact that would be awesome if it's a ground=cheaper fix.

Not going to the track LOL
e7739a61.jpg


c4bbdf18.jpg
 
Re: No power to fuel pump relay from PCM?

Problem is solved. 1 is my stupidity by bending the wrong tab during diagnosis. I bent tab 36 instead of tab 85.:th_lipssealed1: *FLAME SUIT ON*:D

Next is my awesome PCM that came with the ct turbo kit I purchased from Kuntzie. In laymans terms it's junk and is what's causing the spariodic cutout issue. They're 99.9% sure it's an internal issue. Thanks buddy. ;)

So to remedy the situation I will be purchasing a tuned PCM from ZZP.
 
Re: No power to fuel pump relay from PCM?

txslow6 said:
Problem is solved. 1 is my stupidity by bending the wrong tab during diagnosis. I bent tab 36 instead of tab 85.:th_lipssealed1: *FLAME SUIT ON*:D

Next is my awesome PCM that came with the ct turbo kit I purchased from Kuntzie. In laymans terms it's junk and is what's causing the spariodic cutout issue. They're 99.9% sure it's an internal issue. Thanks buddy. ;)

So to remedy the situation I will be purchasing a tuned PCM from ZZP.
Click to expand...

might not want to get a zzp tune... ask bluegtp91, read his thread, ask members.. you will see.

perhaps 3800 performance or contact Will at Overkill for a more custome tune.
 


Re: No power to fuel pump relay from PCM?

txslow6 said:
Problem is solved. 1 is my stupidity by bending the wrong tab during diagnosis. I bent tab 36 instead of tab 85.:th_lipssealed1: *FLAME SUIT ON*:D

Next is my awesome PCM that came with the ct turbo kit I purchased from Kuntzie. In laymans terms it's junk and is what's causing the spariodic cutout issue. They're 99.9% sure it's an internal issue. Thanks buddy. ;)

So to remedy the situation I will be purchasing a tuned PCM from ZZP.
Click to expand...

97 pcms are a mega*****... I daily drive a 97, and occasionally after I tune it, tons of weird codes come up, and the car runs like a bastard.

I always have to clear the codes and power cycle a few times for it to run right again sometimes.
 
Re: No power to fuel pump relay from PCM?

brandonl2000 said:
might not want to get a zzp tune... ask bluegtp91, read his thread, ask members.. you will see.

perhaps 3800 performance or contact Will at Overkill for a more custome tune.
Click to expand...

I'll pass on asking members. I have NEVER had an issue with ZZP or their PCM's. Infact my last GTP put down 271hp/325tq with a 3" dp, 3.4 pulley, plog, 1.9 rockers, SSIC, ZZP 1.0 PCM. ;)

You guys crack me up. Its like one or 2 members have an issue then all of the sudden. Don't buy from such and such company cause they are terrible.
 
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