2000 grand prix gtp fuel pemp relay/pcm problem PLEASE HELP!!!!!!!

**Albertg9** · 02-16-2012

ok guys i have a 2000 grand prix gtp and it wont start.... ive narrowed down the problem to the fuel pump relay and pcm.. the pcm does not give power to the relay to energize it... ive already checked the ground to the relay and it turned out good... also a wierd thing ive noticed is that if i take the relay out, the pcm will supply power but as soon as i put the relay back in, the pcm no longer gives power to the relay... any ideas? THANKS

**GTPSHAWTY** · 02-16-2012

did you buy a new relay?

**Albertg9** · 02-16-2012

yup... actually i bought two. (one for the fuel pump and another fo the fuel pump

**Albertg9** · 02-16-2012

one for fuel pump and another for fuel pump spd control*

**GTPSHAWTY** · 02-16-2012

when i had this problem my fuel pump completely died on me... thats what it sounds like in this case... i brought relays too but still had my problem.. changed the pump and smooth since....

**Albertg9** · 02-17-2012

yeah that was what i was going to do but i noticed the pump wasnt even getting power at the connector... wierd

**GTPSHAWTY** · 02-17-2012

yea thats true too.. has the pump been replaced at all?

**Albertg9** · 02-17-2012

no... only thing i replaced was the fuel filter

**BillBoost37** · 02-17-2012

Take a look at the diagrams. I am seeing the pcm supplying only ground to control the pump.

**Albertg9** · 02-17-2012

im using a different wiring diagrm than that one

**BillBoost37** · 02-17-2012

Care to post it so we can join you in the info?

**Albertg9** · 02-17-2012

**Albertg9** · 02-17-2012

i dont have power at A5

**BillBoost37** · 02-17-2012

Hmm have you checked all the expected inputs of power to the pcm? I've never found anything clear on the supplies to the PCM as to what they are used for and supply when they come out of the pcm.

**mikedinthecity** · 02-17-2012

does the fuel guage work? my guess would be try chaqnging the pump....also there is some type of resister under the front bumper by the windshield washer bottle...maybe faulty....also id look at ignition... if all these check out change the pcm.... my bet would be the pump tho. we know they are notorious

**BillBoost37** · 02-17-2012

Originally Posted by mikedinthecity

does the fuel guage work? my guess would be try chaqnging the pump....also there is some type of resister under the front bumper by the windshield washer bottle...maybe faulty....also id look at ignition... if all these check out change the pcm.... my bet would be the pump tho. we know they are notorious

He said he's not getting power to the connector going to the pump. Should rule out the pump.
Said he isn't getting power to the relay, which can not relay the higher power to the pump.
Resistor would cause the car to have a litle furl to start and run for a couple seconds then die each time the ignition is cycled from on to start and back off.
Ignition is a possibility if it feeds the power the pcm uses to send to the relay.
Wiring is possible as it might be leaving the pcm and have a short from the pcm to the fuel panel.
PCM is also suspect.

**Albertg9** · 02-17-2012

Yeah the fuel gauge works fine. i dont think its the pump... also a weird think i noticed is that with the relay out, i do have power at A5 but as soon as i put the relay back in, A5 no longer has power