4.3 Starts but stalls

I seem to have a problem that is driving me bonkers, I will soon be aquiring a 90 s-10 with a 4.3, however i need to get this truck running first. Apperently it ran before i looked at the truck but now that i've been trying to get this truck running all i can make it do is start then stall. I've read the computer data and determined the computer was either wrong/ NFG, I've replaced the computer and it still stalls, if ayone has had this problem and can enlighten me. any help will be greatly appreciated.

Does it stall if you keep your foot on te gas.
Is it losing spark or fuel pressure?
Does the computer data show rpm and injector pulse?
What engine code?
Has it got fuel in the tank?
MT-2500

Welcome to Auto Forums TD.

I see that your a fellow Canadian.

My guess would be the fuel system, but without more data it isn't an educated guess.

The fuel pumps on S-10's burn out easily unless you change the fuel filter on time.

ok, ecm data shows rpm and injector pulse. I haven't played with it much lately. And no it would not stay running if you kept your foot on the gas, i tried that trick, it just dies again. I'm able to get my hands on a running astro van and rebuilt motor for $300 canadian, i'm wondering if i should just go ahead with the engine swap and use parts off the running astro.

Look at the post from fatdaddy62. I have a 1991 S-10 and had similar strange problems. This sounds as if it could be IDLE air Control sensor and or the throttle position sensor. I would not swap engines. You really need to determine if you have fuel or fire. If it runss a few seconds then shuts down I would say that you likely have fire but no fuel. Next would be change the FF easy and cheap. I can pour gas in mine right now and it will run until that is consumed and the spin when I try to restart. There is an oil pressure switch that disables the fuel pump when reading is bad. That is where I am and because I have gauges The OPS is so long I cannot find a socket that will fit it. Anyway test a few more things and tell me the fire and fuel symptoms. I pad $100 for some service manuals and I may be able to help you diagnose your trouble faster than I did. I spent a great deal of time and money before I bought them and still am not on the road thanks to stupid GM designers.

Fatdaddy62
The oil pressure swith doe not disable the fuel pump.
It is only used as a safety switch to keep the fuel pump running if the fuel pump relay fails.
MT

MT your right. I traced the fuel pump not pumping I thought to the relay. I replaced the relay and still it will not pump. I then followed the service manual diagnosis and it appears to be the oil Pressure switch. Unfortunately I did not have the socket to do the job and had to order it. I expect it will be hear this week sometime. None of the local or national chains carried the part. Etools had one. Iexpect this to fix it. I measured and saw the power coming from the computer at the FP relay. This has been a challenging truck. I have a new cat and exhaust system already as well. Thanks for the post I'll let you know if it works.

I think you are barking up the wrong tree. The coon is up the other tree.
A oil pressure switch will not keep the fuel pump from running.
It is only a safey switch to keep the fuel pump running if the fuel pump relay fails.
If you want more info on it post back.
MT

I thought if the oil Pressure did not trigger the the switch to send the signal to the fuel pump relay it would disable the fuel pump. I had already damaged the part trying to get it out without the socket so I have to replace it now. If you think this is not it then what could it be. I have strong spark but no fuel delivery. I do not hear the fuel pump turn on when the ignition switch is turned. I have verified the temp voltage at the fuel pump relay 12 volts for about three seconds or so. I just replaced the fuel pump very recently. That should be ok. The computer I replaced already because I had no spark and and was challenged trying to get it running. Then it ran for about a week and then quit in the middle of highway driving. No fuel delivery. It will run if I pour fuel down the TBI until it burns all that up then it quits again. I assumed the computer is shutting down the fuel pump due to the feedback from the oil pressure switch. I would be happy if you could steer me to the correct culpret because this has been so difficult and a long road with all the money I have spent and still don't have the truck running.

The oil pressure switch is just along for the ride.
It does not shut off fuel pump.
Find the prime test plug singel wire and put 12 volts wirth a fuses jumper on it. That should put 12 volts to fuel pump and make it run.
If not check for 12 volts at fuel pump connection with jumper still hooked up. Also make sure the pump is getting good grouynd there.
If it is getting 12 volts and ground the fuel pump should run.
If so check the ful pressure out put.
If not you need to check fuel pump.
Post back results.
MT

I haven't had time to do this yet but I hope to this weekend. I'll post back.

You are right MT-2500, after I finally got the new oil Pressure it did not fix it. I bought fuses and will test the pump next as you indicated. I volunteer coach three youth basketball teams so I never seem to get time to test these things. I loked at the ground connetion to the frame that day and it appeared solidly connected and no sign of damaged wire. I have to work outside as well here in NC and we have had tons of rain lately. Please continue to check bak as I may need more advise. Happy holidays...Fatdaddy

Fatdaddy
Post back year engine and model with engineand eng code the 8 no in vin.
And we will try to post you the test for fuel pump and fuel pressure.
MT