Scoozy009

I've searched here, Facebook, Google, YouTube, and other forums and nothing

I have a 93 ls and when it's warm at idle number 1cylinder quits, every ignition component is new and works

All cylinders spark like they should, has good compression, and fuel to all cylinders, I've grounded out the #1 injector while plugged in and running and the car stumbled I don't know what else could cause this to happen



It couldn't be the ecu by theory because number 1 and 7 are controlled by the same driver in the ecu

deanshark

Might be more ideas but my only thought would be to change the #1 plug wire with a known good old wire to see if it still happens. Might be bad insulation on that wire or it could have been pinched when you put everything back together.

fixmiester

Your approach is solid. Might be a partially clogged #1 injector, but hard to say without visually testing. If you have a scope, you can compare the injector pulse signal with the others, which may reveal an ECU issue, or bad connection. Could also shoot some injector cleaner right into the injector at the fuel rail, and let it work for an hour before starting it up. Good luck.

Scoozy009

I've used an led test light pulse looks (by eye) exactly like 2 & 3 easy injectors to get to flashes just the same as 1 does

Scoozy009

Swapped number 1 & 2 spark plug wire and no change

Pulled the injector and pulse cleaned it with brake cleaner, spray pattern looked great (wide angle, thin and long stream) could it be a battery issue?

PureDrifter

iTrader: (10)

swap the ECU. Have you properly tested your ECU?

If you're 100% confident in ignition and fuel, the ECU isn't a bad place to pay attention to. There's no systemic issue (ie- battery) that would only adversely affect 1 cylinder if the other systems are running properly.

shamanic

Did you ever figure this out? I'm having same problem.

djamps

Check the suspect injector's ohms reading compared to others when it's working vs not working.