Michael Johnson

I have this odd starting problem that became a different problem. 😂 so I have a 91 camaro rs 305 tbi. It was having this problem where after driving it for a while letting it warm up I would **** it off and it wouldn’t start until I let it cool all the way down to a cold start. It was also running very rich. But I can go to WOT and it will sweep all the way through the rpms and it ran great but with a slight surge at idle. I noticed when it wasn’t starting no fuel was coming out of the injectors. That when I took my fuel pump back out and got it replaced. Luckily it was under warranty. Didn’t do it for a few days and then started again doing it again. I made sure the fuel pump was kicking on and it was. Then it just wouldn’t start at all. Has been sitting for about a week now. I undid the fuel line on the back of the TB to see if it was getting fuel and it was. Which leads me to believe it’s not getting injector pulse. I know from reading that so many things can cause injectors not to fire. I’ve replace a lot on this motor. Spent too much on this 305 than I wanted to. Lol.
heres a list of brand new parts I’ve put in it

new distributor with new icm. Cap and rotor.
new starter
new aic
rebuilt TB with a new fuel regulator
new fuel pump
new fuel filter
new fuel sending unit
new alternator
new battery
new neutral safety switch
new spark plugs and wires
new map sensor

Now a list of semi new parts. Only a year old
tps
oil sending unit
knock sensor
secondary ignition module

now any input or info that could help would be appreciated. Now today I got my multimeter out and check a bunch of stuff but I don’t know what else to check and how to do some of it. I checked the positive leads on the injectors and they’re both getting 12 volts. I check the continuity on all the fuses including the crank fuse. Could anyone tell me which wires on the icm tell the ecm to fire the injectors and also how I could check the ecm with a multimeter?

Schurkey

If this were in my driveway, I'd put the voltmeter back in the toolbox.

Connect a scan tool, look for codes, but more importantly, look at the data stream.

Verify that you have spark when cranking. Verify fuel pressure during priming, during cranking, and while the engine is running.

The ECM provides the ground for the injectors, so it's not unusual that they'd have voltage on both terminals. It's not the power that's switched on and off, it's the ground. That wire harness is typically tested with a 'noid light.

Michael Johnson

It was my ecm. And it’s obd 1 so it’s not very easy to come across a scanner for it. But it’s was all fixed just by swapping ecms out