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Ask Chad Farhat Your Own Question
Chad Farhat
Chad Farhat, ASE Certified Technician A6 - Electrical / Electronic systems A7 Heating / Air conditioning systems
Category: Pontiac
Satisfied Customers: 3940
Experience:  Owner at Carolina Auto Service & Sales , 20 years Experience in Foreign & Domestic vehicles
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NO INJECTOR PULSE ,NO SIGNAL TO FUEL PUMP STARTS ON BRAKE

Customer Question

NO INJECTOR PULSE ,NO SIGNAL TO FUEL PUMP STARTS ON BRAKE CLEAN
JA: Will the headlights turn on? Is the battery fully charged?
Customer: YES
JA: What is the model/year of your Pontiac?
Customer: 2001 GRAND PRIX
JA: Are you hoping to fix this yourself? What have you tried so far?
Customer: YES FUEL PUMP WORKS IF I JUMP POWER AT RELAY GETS SPARK SOME ONE CHANGED CRANK SENSIOR ALL FUSES ARE GOOD
JA: Anything else you think the mechanic should know?
Customer: NO
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the Pontiac Mechanic about your situation and then connect you two.
Submitted: 1 year ago.
Category: Pontiac
Customer: replied 1 year ago.
no signal to fuel pump relay for it to activate the fuel pump
Expert:  Chad Farhat replied 1 year ago.

Hi, I' m Chad. Welcome to JustAnswer. I' m reviewing your question now, and I will be post back with your reply ASAP

Expert:  Chad Farhat replied 1 year ago.

On the fuel pump relay on the DRK GRN /WHITE wire coming from PCM with are you getting a 5 volt reference on that relay pin , if you are not the pcm is not commanding the fuel pump on ,lets start here first , now try this with one person on the relay box and one person trying to start it ,at that moment any 5 v reference on that wire ?

I have sent you a diagram to help you identify the powers & grounds expected, look at it carefully it shows you exactly how the circuit for the fuel pump works.

Thank You

Chad Farhat ( aka -Customer)

ASE Certified Tech

Expert:  Chad Farhat replied 1 year ago.

the GRY wire on fuel pump connector is it getting 12 volt while trying to start it ?

if you are getting 12 v check the othe side of the circuit are you getting ground to it ?

Check fuel pump fuse in the under engine fuse box the 15 amp is it good .

that supplies power to one side of the relay ?

please check and let me know

Chad(aka-Jhook1398)

Customer: replied 1 year ago.
no power from pcm also scan tool wont read pcm
Expert:  Chad Farhat replied 1 year ago.

well ,does your scanner powers up when hooked up to obII plug , but no pcm , communication ?

Customer: replied 1 year ago.
yea pin 16 has power to it i think it was pin 34 has ground been a while since i tried to figure out what was wrong
Expert:  Chad Farhat replied 1 year ago.

That is okay

I forget stuff too :)

Expert:  Chad Farhat replied 1 year ago.

If you are not getting 5volts reference from pcm to the relay and you can not communicate with pcm module and fuel pump fuse 15 amp good

Then i say we have a bad pcm ?

Expert:  Chad Farhat replied 1 year ago.

http://www.ebay.com/itm/ENGINE-COMPUTER-PROGRAMMED-PLUG-PLAY-PONTIAC-GRAND-PRIX-1999-2001-09380717-3-8L-/351480396364?hash=item51d5dd3a4c:g:eS4AAOSwd0BVzMva&vxp=mtr

Check out this link , here you can buy and already programed to your car and no dealer needed

It will plug & play

Expert:  Chad Farhat replied 1 year ago.

Hope I was helpful to you , Please let me know if you need anything else on it

A Positive Rating is Much Appreciated

This Post Will Stay Open For You to Come Back and ask me any Follow up Questions you may have on this issue Even after you Rate Me.

Thank You
Chad Farhat ( aka -Customer)
ASE Certified Technician

Customer: replied 1 year ago.
thanks i thought it was that but could be a broken wire
Expert:  Chad Farhat replied 1 year ago.

definitely do a continuity test on all 4 wires coming to that relay before you order pcm

please don't forget to rate me since that is how we get compensated

good luck

Thank You

Chad Farhat ( aka -Customer)

ASE Certified Tech

Customer: replied 1 year ago.
very helpful
Expert:  Chad Farhat replied 1 year ago.

Thats great i m happy u satisfied

If you like to request me in the future for a different problem , just start your new Question with (FOR CHAD FARHAT ONLY ORCustomerONLY)

Chad