Mechanics

CHEVY WILL NOT START

1999 Chevrolet S-10

Electrical problem
1999 Chevy S-10 4 cyl Two Wheel Drive Manual 150000 miles

This truck has started sometimes and not started sometimes over the last couple weeks. Now it is not starting at all. I have narrowed it down to the fuel pump is not kicking on. I checked the relay and it is good and have voltage passing through it. 12 volts. But when I check voltage of gray wire at pump I only have 5 volts. I also cleaned ground with no help. My question is 5 volts the correct voltage. If not what else does it pass trhough after relay. If it is correct then do you recommend pulling pump.
Avatar
Letsdrag
May 30, 2010.



It goes through the oil presure switch as well. You probably have a bad pump if you can't hear it at initial fire up. Have someone turn on the key and open the gas cap to see if you can hear it when first starting. If you can then change your fuel filter.

Hmac300
Jun 1, 2010.
Already changed the filter. No pump doesnt come on for the five seconds and doesnt come on when cranking. But I checked voltage there and there is no voltage on gray wire either.

Tiny
Letsdrag
Jun 1, 2010.
Youi'l have to get a schematic and trace it back to see where the power isn't going through. If it goes through the relay then it's someplace between there and the pump. Does it still have no power when the connection is disconnected? You may have to have a small pin to get in to it. If you get power with it disconnected, then probably your fuel pump is shot. Or the tiny wires going to it inside the tank.

Hmac300
Jun 2, 2010.
There is no power with it pluged in or not. I have looked at schmatic in chiltons. The only thing it really shows is a oil pressure cut off sensor, but no one seems to know where that is.

Tiny
Letsdrag
Jun 2, 2010.
It's your oii pressure switch. It should have a 3 way wire going to it. Your switch may be bad then if it's not sending the power out.

Hmac300
Jun 2, 2010.
That is one of the issues I thought it might be, problem is while chiltons and haynes says it has one. Dealership and o'rileys says it dont and dosnt show it on their schmatics.

Tiny
Letsdrag
Jun 2, 2010.
If you have a an idiot light or guage that reads pressure you have one. It might be in a place that's hard to get to. I" ll find out for sure and then let you know where the damn ting is.

Hmac300
Jun 3, 2010.
For some reason I thought that this was/is a colorado lol. Anyhow the oil sender should be around the oil filter it won't be hard to find. Also the relay for teh fuel pump on an s-10 is behind the glove box I thought, unless they have moved it so you may have checked the wrong relay as well.

Hmac300
Jun 3, 2010.
I have the same problem with the same year S-10.4.3 Auto. I am currenty trying to figure it out. It is a intermitten problem over last 5 months.I changed fuses around in the under hood relay box.
1. How do I access relay and what terminals do I next test.
2. Where is the hot wire connection my Chilton book refers to under the hood that you can run a jumper to the battery to fire the pump?

Tiny
Pat bizich
Oct 13, 2012.