Mechanics

WON'T START

Chevrolet S-10

Hello all. First post so here goes. I have a 92 S-10 2wd with the 2.8 V6 and the 220TBI. Truck has 195,000 on her and has one of the best trucks I owned. Runs like a new one up until Monday. Stopped and put in $20 worth of gas Monday morning on the way to work. I have been buying gas at the same store for years (BP). After driving up for about 15 miles I stopped to pick up some material for work and the truck would not start. It turned over just fine and had spark but no fuel.

Had it towed home and did some checking. Fuel pump relay seems fine, power to the pump. I replaced the filter and while having it off I turned the switch to the on position and had a good flow of gas coming out the line from the tank. Put on the new filter and it cranked right up.

Drove just fine for two days and used up most of the gas I had put in, now has 1/4 tank left, and after stopping by another store it would not start again. Same problems. Had it towed home again and after work I tried to start it and it fired up. It did seem a little slugest at idle though.

Seems to me it could only be a few things to check out. Fuel pump, relays and FPR. If a pump is going out is this common? Working and not working? Any good way to check out the relays? The relay for the pump sits right beside a matching relay (oil presser relay?) Is this connected in and could this be the problem?
FPR, how to check this part out?

Many thanks for any and all replies on this.

Randy
Avatar
Rpbbills
September 29, 2007.



You need to check the actual fuel pressure with a gauge-if it drops quickly it has a leakdown problem

To check the FPR it has to be done with the gauge with vacuum and w/o it. When vacuum hose is disconnected @ the FPR the pressure should increase, when connected it goes back to normal range.

Also do this when it starts-remove the fuel pump relay if it stalls inspect and test the oil pressure sending unit thats the one that powers the pump when it starts up before you replace it.

Rasmataz
Sep 29, 2007.
Thanks for the reply. I would guess the Oil Presser relay is the one to the left of the fuel pump relay?

Tiny
Rpbbills
Sep 30, 2007.
Where is the oil presser sending unit located? Also what is the relay to the left of the fuel pump relay? I have a wiring diagram but none of the wires match up for this relay (2 solid green wires, 2 green w/ white stripe and a pink with a black line. I did some more checking today and on the fuel pump relay should I have power on the green w/ white stripe with the switch in the on position?
Gray wire feeds the pump and no power with the switch on. Many thanks.

Tiny
Rpbbills
Sep 30, 2007.
The oil pressure switch is on #8 see below


http://www.2carpros.com/forum/automotive_pictures/12900_1992_Chey_S10_Oil_pressure_switch_1.jpg



Fuel pump relay at #3


http://www.2carpros.com/forum/automotive_pictures/12900_1992_Chevy_S10_Fuel_pump_relay_1.jpg


Rasmataz
Sep 30, 2007.
Heres a photo of the relay in question. The one on the right is for the fuel pump but what does the one on the left controll?

Thanks


http://www.2carpros.com/forum/automotive_pictures/103149_Relays_2.jpg


Tiny
Rpbbills
Oct 1, 2007.
The one beside the FP Relay is the AC relay.


http://www.2carpros.com/forum/automotive_pictures/12900_S10_Ac_Relay_1.jpg


Rasmataz
Oct 1, 2007.
Thanks, on my computer it's very hard to read the diagrames. Found the oil sending unit. Thinking about changing it and the fuel pump relay to see what happonds.

Tiny
Rpbbills
Oct 1, 2007.
Keep me posted

Rasmataz
Oct 1, 2007.
Put on a new oil sending unit and fuel pump relay but still no luck. No gas at all. I unplugged the fuel pump relay and jumped the orange wire and the gray to the pump and pump didn't run. Any way going in the shop in the morning and will let you know what it turns out to be.

Thanks

Tiny
Rpbbills
Oct 3, 2007.
The computer energizes the fuel pump relay.

Do this connect a jumper wire from battery postive terminal straight to the gray wire terminal socket at the relay this will transfer power to the pump-do this before the shop-

Also at dark green and white wire at the relay socket when you turn key to On position it should have power.-If not its coming from the computer

Good Luck

Rasmataz
Oct 3, 2007.
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