92 Chevrolet Silverado Won't Start

[eagledancer]

I have a 92 chevrolet Silverado that won't start. I started experiencing situations were my truck would not start after sitting for a short period of time. At first, I could crank the engine several times till it started. Then I had to spray starting fluid the other night in the carb to get it started. Got the truck home, shut it off and could not get it started again. Checked and found that I was not getting any spark or fuel. Pulled out the ignition module, took it to auto parts store, had it checked and results were good. Reinstalled ignition module, pulled the coil, took it in, had it checked and results were good. Reinstalled coil, just for grins, cranked the engine and it started. Left the engine running while I put away my tools and it died after about 4 or 5 minutes. Tried spraying fuel in the carb, still wouldn't start. Pulled the distributor, took it apart, replaced the pick-up coil, put the distributor back together, reinstalled it back in the truck. Cranked the engine and it started. Left the engine running while I put away my tools again and it died again after about 4 or 5 minutes. Dropped the fuel tank, pulled the fuel pump, set it up in a bucket of fuel, connected it to the battery and ran it for almost 10 minutes. I am going to put the fuel pump back into the tank. Also I want to note that at one time before this started I went to start the truck, I heard the solenoid engage, then everything went dead. Found the positive cable loose. I wiggled the bolt back & forth a couple of times, then tightened it down. Truck started right up. I have a code scanner, hooked it up when the truck wouldn't start and the only code I'm getting from the ECM is 12, which I am being told is normal. I am also being told that if I'm getting a code that the ECM is working properly. Any suggestions as to what the problem may be?

Thanks!
Don

[Stevetra]

Well, I can throw in 2 cents…but I am not a mechanic, but I did stay at a Holiday Inn Express last night.
Have you replaced the fuel filter located inline below the driver’s door?

See…from what you have said, it could be so many things.
If it only quit after it runs for a few min. then I would say gas starvation.
But you also stated that sometimes it doesn’t even fire up, which sounds more electrical to me.
If it were me I would start at the Fuse box and check for corrosion….just pop the fuses in and out and see how they look.
After you do that I would look around the battery box for wires that are corroded….and could be giving you an intermittent connection.
The next place I would look would be the Hot wire running from the Battery to the starter, sometimes they get up next to the exhaust manifold and ground out …and when that happens nothing works.(and this has actually happened on my 92 C1500)

Hope this helps.

[RatRacer]

Let's call the loose battery cable a fluke and not part of the problem.

Is this the 4.3L engine? If so, there have been very strange problems involved with the two-wire connector that plugs onto the coil. The next time it won't start have someone crank it while you apply pressure in all different directions to the wires going into that connector.

Another problem has surfaced in the inline connector that feeds one of the "black boxes" but I can't recall which one.

[Arrow211]

have you tried the fuel pump relay ?
have you cleaned the fuel pump ground to frame?
have you tested the fuel pressure?
have you thought of a pressure regulator on the tbi (stick to gm regulator) been there done that BIGTIME !

[bowhunter]

This may seem a bit odd....GM used the Oil Pressure Sending unit as a power supply to the fuel pump once the O/P was above 6-10 psi as a back up to the fuel pump relay. If the fuel pump relay is bad you would have an extended crank until the oil pressure came up and supplied voltage to the fuel pump. It is possible that you have both a bad fuel pump relay and a bad oil pressure sending unit.

[GM-TECH]

I am inclined to agree with Bowhunter. If both the fuel and the fire are not occurring at the same time after having been working shortly before, then it would seem that the safety portion of the system is interupting the sequence. Check the pump relay, fuel pump oil pressure switch and especially the wires and connectors. the grey wire coming from the pump goes to both the relay and the switch, so when it is running those two will be hot. check them once it dies. process of elimination, good luck.

Rich