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Pete
Pete, Auto Service Technician
Category: Chevy
Satisfied Customers: 24659
Experience:  14 years GM dealer Technician.
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09/1996 CHEVY S10 4.3 X MODEL ENGINE AUTO, FUEL PUMP TURNS

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09/1996 CHEVY S10 4.3 X MODEL ENGINE AUTO, FUEL PUMP TURNS ON WHEN IT WANTS TOO. INSTALLED NEW FUEL PUMP, FUEL FILTER, DISTRIBUTOR,FULL TUNE UP KIT, COIL, FUEL RELAYS, FUSES, 153,000 MILES WHEN IT DOES RUN VERY NICE RUNNING TRUCK.

Hi my name is ***** ***** I will be happy to assist with this today.In some cases I may need more info to assist better.I apologize for any delay.

Have you tested for power and ground at the fuel pump when it will not turn on?

Let me know so we can continue,thanks Pete

Customer: replied 1 month ago.
1ST PIN HAS GROUND, AND NO POWER TO ANY OTHER PINS, CLEANED GROUND TO FRAME ALSO
Customer: replied 1 month ago.
WE JUST INSTALL NEW FUEL PUMP BECAUSE OF THIS ISSUE AND GAUGE DIDNT WORK.

Did you test for power at the pump on the gray wire with the key on the first 2 seconds the key is on and when cranking the engine?

Customer: replied 1 month ago.
HAS POWER FOR 2 SECONDS AND DURING CRANKING, ALSO PURPLE WIRE IS A GROUND TOO WHEN KEY IS OFF

Is there a second black wire in this connector and if so does it have ground as well?

Customer: replied 1 month ago.
THERE IS A BLACK WIRE ALSO THE FOURTH PIN AND HAS POWER 2 SECONDS AND CRANKING
Customer: replied 1 month ago.
PIN 1 IS BLACK IS GROUND
PIN 2 IS GRAY HOT WHEN CRANKING
PIN 3 IS PURPLE
PIN 4 IS BLACK HOT WHEN CRANKING

I show this for info on this pump connector.

You should have both black wires as grounds.One is a ground feed for the fuel level sensor and one is a pump ground.The gray is the pump power feed and the purple is the feed to the instrument cluster/gauge assembly.

Is there any way you can take a picture of this and upload it here so I can see the connector?

Customer: replied 1 month ago.
THERE IS TWO CONNECTORS 2ND CONNECTOR
PIN 1 IS GRAY
PIN 2 GREEN
PIN 3 BROWN
AND TRYING TO UPLOAD PICS

Do you know if this is a late model year 1996 or 1997 model year,according to the registration?

Customer: replied 1 month ago.
09/1996 ON VIN TAG

O.k.,I would assume 1997 this late in 1996.Is there any way you can upload the pics on this?

Customer: replied 1 month ago.
HOW DO YOU UPLOAD PICS

There should be a paper clip icon that you can see to upload pics.Let me know if you see it.

Thanks Pete

Customer: replied 1 month ago.
NO PAPERCLIP I CAN SEE,,,, JUST +ADD FILES

O.k.,on my end there is a paper clip yours may be the + add files link.Have you tried it to see if you can upload them there at all?

Customer: replied 1 month ago.
I TRIED IT LET ME KNOW IF YOU GET IT

Yep,got it

Did you install this connector new into the harness?

Customer: replied 1 month ago.
NO IT WAS THERE ALREADY WHEN I BOUGHT THIS TRUCK USED

O.k.,someone has wired it in.This is the new style connector you see with the 4 wires in it black,black,grey and purple.The purple is the gauge signal for fuel level,one black is ground for the pump,one black is ground for the gauge and the gray is power.Follow this short new harness on the connector to the main harness and remove the tape and see how well the connections were spliced in when this connector was installed.The new connector you have came with a short harness that is wired into your factory harness.If they crimped the connections poorly or messed up and shorted wires together this issue occurs.This is where I would start.Usually its about 4 to 6 inches away from the connector in the harness that they install this.Let me know if you find any issues.

If more help is needed, use the reply tab to continue our conversation. If no further assistance is needed, kindly rate my service,your 5 star rating is appreciated.You can rate at any time and we can continue to work on your question as this will not close out your question.Keep in mind in some cases it can be difficult to fully diagnose or help repair your vehicle without seeing it and I work on delivering the best possible answer from what I see to work with.

Thanks Pete

Customer: replied 1 month ago.
They look ok and not shorted together, but there is a small black and a bigger black could the have crossed them

This is very possible as one is sensor ground and one is gauge ground.What color wires do these connect to in the harness?

Customer: replied 1 month ago.
Purple to purple
Gray to gray
Big black to big black
Small black to small black
But i 12 volts on big black for 2 seconds and when crancking

That isnt right.You should have voltage on the gray wire for 2 seconds and when cranking.One black should be a ground for sure and is the pump ground.Then the gray wire is the power feed for 2 seconds and when cranking.Somewhere along the wiring harness the wires are shorted or cut into and spliced together incorrectly.

Here is how it is suppose to be wired and what each signal should be.

https://www.dropbox.com/s/2kmte79xfjn2rha/conn-10-18.jpg?dl=0

Customer: replied 1 month ago.
OK I WILL GET BACK TO YOU SHORTLY

Let me know what you come up with here.

Thanks Pete

Customer: replied 1 month ago.
OK FOUND GROUND FOR PUMP SHORTED TO HOT WIRE, REPAIRED AND WORKD NOW, SENDER STILL NOT WORKING, GAUGE IS MAXED OUT. PURPLE WIRE HAS GROUND ON IT. PULLED OUT COMPLETE WIRING HARNESS FROM UNDER TRUCK TRACED EVERY WIRE REPAIRED A FEW THAT DIDNT LOOK GREAT. COULD IT BE THE CLUSTER IS BAD?

I suspect what has occurred here most likely is that the short may have caused damage to the instrument cluster itself.I dont suspect the sender unit as this is a resistance sender and a short shouldnt have damaged it.It sounds like either the short damaged the cluster or the cluster has failed on its own.

Thanks Pete

Customer: replied 1 month ago.
Ok i will change cluster tomorrow and let you know what happens

One other possibility is the PCM has become damaged.Let me know if the cluster corrects this here.

Thanks Pete

Pete and 5 other Chevy Specialists are ready to help you
Customer: replied 1 month ago.
I INSTALLED USED CLUSTER ON THAT 1997 CHEVY S10 FUEL GAUGE STILL DIDNT WORK, BUT I GAVE TRUCK BACK, AND RAN GREAT FOR 2 DAYS, AND THEN DIED ON HIM LASTNIGHT, AND WON'T START. CRANKS BUT NO START, I HAVE TO GET IT TOWED BACK TO MY SHOP.????

I apologize for the delay as I was out of town

It is very possible the PCM was damaged due to the shorted wiring causing the issue with the gauge and stall out here now.