Help! Replaced Alternator - Now won't start - 1995 Corvette

[SatansVette]

Greetings all. I was hoping to gain some insight into my no start problem that has me stumped. It was running perfect, except for a little noise from the alternator so..., I purchased a new one and installed it in and ever since, it just will not start. Cranking it over and over, it eventually sounds like it wants to start when you let off the key but after a few weak fires, it just dies.

Sounded like weak spark so I replaced the Optispark distributor.... no luck, same result. So, I thought it's got to be a bad ICM so I replaced it, along with a new coil. After all that I am right back where I started, cranks and cranks with a weak firing at the end of a lot of cranking then dies.

So I'm wondering, could an incorrect Alternator, actually cause the computer to prevent firing?

 

[ecss]

Greetings all. I was hoping to gain some insight into my no start problem that has me stumped. It was running perfect, except for a little noise from the alternator so..., I purchased a new one and installed it in and ever since, it just will not start. Cranking it over and over, it eventually sounds like it wants to start when you let off the key but after a few weak fires, it just dies.

Sounded like weak spark so I replaced the Optispark distributor.... no luck, same result. So, I thought it's got to be a bad ICM so I replaced it, along with a new coil. After all that I am right back where I started, cranks and cranks with a weak firing at the end of a lot of cranking then dies.

So I'm wondering, could an incorrect Alternator, actually cause the computer to prevent firing?

Have you checked fuel pressure?

Manually open the throttle body blade and spray some start fluid into the throttle body. See if the engine fires.

I doubt the alternator is causing your problem. Did you disconnect the battery cable when you replaced the alternator?

When you turn the ignition On does the battery symbol light up on the Driver Information Center?

On the back of the Alternator you should measure 12 volts on the large red wire at all times.
On the four pin plug plugged into the alternator there are 3 wires.
On the small red one you should measure 12 volts at all times.
With the ignition On you should measure 12 volts on one of the Brown wires.

The engine doesn't need the alternator to start.