HELP! 92 gmc 5.7 has no spark

[454ss]

oil pressure sending unit cuts power to the fuel pump not sure if it disables anything with the ignition?

 

[wcr65d]

I have spark and fuel. Had timing light on it and noticed the timing mark on the damper a couple times and then would not be there when the light fired. Intermitent spark? Firing when it shouldn't?
Still no start. I have not checked the oil sending unit. Will have to wait till next weekend.
Thanks for the responses thus far. If anyone has anymore ideas, I'm listening.

 

[Mik3]

Don't just start replacing parts. Diagnose the problem and correct it. Throwing parts at it is no good. Before replacing spark plugs or wires, verify they need to be replaced. You said you replaced the distributor.. Are you sure you timed it correctly? It will run if within maybe 20 degrees of TDC on either side(BTDC/ATDC). I once got a dodge 318 to fire at -16 BTDC which kinda amazed me lol. Because you said you saw it light up a few times on the damper, the coil is functioning as are the wires. So that leads me to believe it's incorrectly timed.

For the 350, 1 is the first piston in the firing order. Piston one is in the front of the engine, on the drivers side. You have to time it with that piston at TDC, on compression stroke. So pull the plug out and stick ur finger in there, while turning the engine clockwise until your finger gets popped out. You should turn it with a nice big breaker bar because using the starter is kinda hard to get it lined up perfect. Once you are on compression stroke, look at the damper and turn it to like 5-8 degrees after TDC(When the piston is traveling back down, so you're gunna go after the mark for TDC(To the right of it)). Then drop the distributor in with the rotor pointing at Cyl. 1. When you put the cap on, adjust it to point at the closest point on the cap, and that point will now be Cyl 1's plug wire spot. Then just put the other plug wires on the cap going clockwise based on the firing order (1-8-4-3-6-5-7-2). It should fire right up even if it's not timed perfectly, it just has to be close. Once it fires, just use the timing light to get it perfect, and then lock her down.

 

[wcr65d]

Could the ecm cause something like this? Curious

 

[93SierraWT]

Have you checked the ICM? My truck lost spark and I replaced every component until finally replacing the ICM.

 

[chevy_man]

Could the ecm cause something like this? Curious

Yes, I had an alternator fail and take out my ecm. But it also stopped the injectors, not just the spark.

I'd try another ignition control module, if your timing is correct. I've had them DOA on me before. Also check your wiring connections inside the distributor to the module. I had a wire fail and you couldn't see it, but it showed open on a meter. I always carry a spare ecm and icm in the toolbox because of this.

 

[wcr65d]

Got it running today I had not done anything to it for a couple weeks. It ended up being the new distributor. I installed it 180* off. So the only things that were replaced were the distributor assymbly, coil, and spark plugs. Thank you all for your help with this.