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fuel pump not getting juice


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mkinsey7
User

Aug 31, 2011, 3:21 PM

Post #1 of 8 (1635 views)
fuel pump not getting juice Sign In

I have a 2000 Camaro Z28 5.7 160K. Engine quit, we thought it was fuel pump being that there was no pressure on the fuel rail. We pulled the fuel pump, hooked it up hot and it ran. There is no power at the hook up at pump. Fuse is ok, Relay is new. if we pull relay, put a jump wire in place of relay we get power to rear at fuel pump. We have tried 3 relays. Just stumping any ideas??


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Aug 31, 2011, 3:55 PM

Post #2 of 8 (1621 views)
Re: fuel pump not getting juice Sign In

You should be using a fuel pressure gauge to get a more accurate picture of just when the pump triggers if at all. You need to find out if it's triggering for 2 seconds when the key is first turned on and then look to see if it starts again when cranking. You may also want to check for spark.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



mkinsey7
User

Aug 31, 2011, 5:10 PM

Post #3 of 8 (1608 views)
Re: fuel pump not getting juice Sign In

Thx for helping, we did use a fuel pressure gauge. The first time we let it sit for an hour and it started and had 60 psi fuel. but the next time it had no pressure and would not start, we have spark and still no fuel pressure so we pulled pump. Is there a sensor on the injectors somewhere that regulates fuel pressure?


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Aug 31, 2011, 5:15 PM

Post #4 of 8 (1602 views)
Re: fuel pump not getting juice Sign In

That's just a bypass valve. You need to get the pump running. Find out where it's losing it's power in the circuit.






~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



mkinsey7
User

Sep 1, 2011, 7:09 PM

Post #5 of 8 (1573 views)
Re: fuel pump not getting juice Sign In

been a workin on this. we put it all back together with a jump wire in place of the fuel pump relay and car started. but , we hooked up the scanner to check for codes. when we unplugged scanner car quit. so we took jumper wire away and put back the relay, now all is back to original. we left scanner plugged in, try car and it started, unplug scanner and car quits, did this several times and the same results each time. What in the world is wrong with this thing? we can't drive down the road with scanner always hooked up {:>)


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Sep 1, 2011, 7:13 PM

Post #6 of 8 (1570 views)
Re: fuel pump not getting juice Sign In

Never heard that one before. Does it matter what mode the scanner is in at the time?
Is this a real professional scanner or a generic code reader?



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



mkinsey7
User

Sep 2, 2011, 6:05 AM

Post #7 of 8 (1559 views)
Re: fuel pump not getting juice Sign In

it doesn't matter what mode scanner is in. Scanner is bought at Advance Auto for $250. I guess we will attach scanner and take car to a professional with all the bells and whistles. I appreciate the help that you have been. thx


Discretesignals
Ultimate Carjunky / Moderator
Discretesignals profile image

Sep 2, 2011, 8:55 AM

Post #8 of 8 (1549 views)
Re: fuel pump not getting juice Sign In

I've actually seen this happen. The PCM is using the scan tool or code reader as a ground. You need to voltage drop the PCM ground circuits to the negative post on the battery. If you have an excessive voltage drop you have high resistance in the PCM's ground circuit. The PCM's ground point is located on the back of the left hand cylinder head. Also make sure that your engine ground is good.





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