QuestionQUESTION: I have a 1997 chevy tahoe, when I turn my key on to start it, it takes the fuel pump around 5 seconds to come on to be able to start the vehicle. I replaced the fuel pump relay switch but it made it worse, took around 20 - 25 seconds to make fuel pump come on. What could be the problem? Thank you
ANSWER: HI TED,THE NEWS IS NOT GOOD.IF YOU REPLACED THE FUEL PUMP RELAY AND PROBLEM IS THE SAME OR IN YOUR CASE WORSE. THIS SOUNDS LIKE A FUEL PUMP PROBLEM.. [IN THE TANK.] WE HAVE REPLACED MANY OF THESE CHEVY FUEL PUMPS. WORD OF ADVISE,ONLY INSTALL A GM FUEL PUMP CALLED [MODULE]HOWEVER TO BE 100% SURE THAT IT IS THE PUMP..YOU WILL NEED 2 PEOPLE 1 PERSON TO CRANK THE ENGINE OVER AND 1 PERSON UNDER TRUCK WITH A TEST LIGHT TO CK FOR POWER ON THE FUEL PUMP CIRCUIT.YOU WILL FIND A LEAD WIRE HARNESS GOING INTO THE TOP PART OF THE TANK,THERE WILL BE A DISCONNECT PLUG TO REMOVE ALONG THE FRAME RAIL, FIND THE POWER WIRE FOR THE PUMP I BELIEVE IT TO BE A GREY [WIRE]..HAVE THE PERSON CRANK THE ENGINE AND YOU SHOULD HAVE 12 VOLTS ON THIS WIRE INSTANTLY,IF SO,WIRING TO THIS POINT IS GOOD..POWER WILL STAY HOT FOR 3 SECONDS EVEN AFTER TURNING THE KEY OFF AS WELL,TO PRIME THE FUEL RAIL FOR THE NEXT TIME IT STARTS..LETS SAY THERE IS POWER AT THIS HARNESS,THE PROBLEM IS EITHER IN THE FUEL PUMP ITSELF OR THERE HAVE BEEN MANY PROBLEMS ON THE CONNECTION ON THE TOP OF THE FUEL PUMP ITSELF.THE WIRE CONNECTIONS BURN OR GET CORRODED. MAYBE HOT LEAD OR GROUND, EITHER WAY THE TANK WILL NEED TO COME DOWN...HOPE THIS HELPS, TOM.
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QUESTION: I replaced the fuel pump (with a GM one) about 3 years ago and when it does come on, it sounds strong. But I noticed when I turn the key on and it doesn't come on right away, neither do my dash lights (battery, engine, brake etc), but as soon as the pump comes on after a delay so does the lights, do you think it could be in the ignition switch? I was told it might be the ECM but we tried a different one and it did the same thing. It is so errotic. Thank you.
ANSWER: HI TED.THIS DOES SOUND LIKE A BAD IGNITION SWITCH. REMOVE THE SWITCH FROM LOWER DASH AND JUMP THE HARNESS AFTER UNPLUGGING FROM THE SWITCH..IT IS POSSIBLE THAT A BCM [BODY CONTROL MODULE] COULD CAUSE THIS, BUT TO ME THIS SOUNDS LIKE A SWITCH..
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QUESTION: Thanks for this info, do you know what wire to test to see if it is the switch? and where is the BCM at and how do you test that? Thanks again.
AnswerHI AGAIN TED,I WAS JUST GOING TO REVISE MY LAST ANSWER. I FORGOT TO TELL YOU THAT A USED BCM WILL NOT WORK WITH YOUR CAR UNTILL YOU HAVE IT FLASHED [RELEARN] GM DEALER OR SOMEBODY IN YOUR AREA THAT HAS A GM SCAN TOOL CAPABLE OF REFLASH...THE FACT THAT THE CAR ACTS THE SAME WAY WITH THE USED BCM SEEMS LIKE NOT A BCM PROBLEM.
THE WIRE YOU ARE LOOKING FOR IS A BIG 10 GAUGE RED OR PURPLE WIRE..JUMP RED BATTERY POWER TO PURPLE STARTER SOLENOID..THIS SHOULD WAKE UP THE SYSTEM TO CRANK AND FIRE UP THE FUEL PUMP RELAY.LET ME KNOW....
