We have a 95 Z28 that won't start. June of last year the optispark went bad & was replaced. Worked for 6 months and then stopped. Bf is just getting around to working on it. Replaced the opti - nothing. Replaced the computer - nothing.
Has spark, gets fuel but won't start. He is at a complete loss of what it could be. Any help would be much appreciated. TIA

 

What diagnostics did you do that led you to replace the Opti and the PCM?

Have you checked the fuel pressure?

Does the fuel pump restart when the starter is cranking the engine? That is controlled by the PASS-Key II (VATS) system.

Is the “SECURITY” light on?

Is the “SES” light on?

Have you scanned it for codes?

When the key is first turned to “START”, is there any sign, even brief that the cylinders are firing? Does is run for a few seconds, then stall?

 

No codes. No security or see lights

Getting fuel. Does not start at all

TeplwceReplaced the opti because it stalled and wouldn't start just like it did when the first opti failed. Replaced the pin because the old one showed scorched marks

 

It may be “getting fuel”, but is it at the correct pressure? Have you checked?

Additionally, VATS gets involved in the fuel supply. The fuel pump primes for 2-seconds and shuts down. It will not restart until the starter is cranking the engine and the PCM sees the low res pulse from the Opti, and the theft deterrent module (TDM) sends the “fuel enable” signal to the PCM. It is possible for the TDM part that sends the fuel enable signal to fail. That will set DTC 46 in the PCM. With this specific problem, the engine may actually fire and seem to start for a few seconds.

Since you indicate you have spark, the Opti is not the problem. That makes fuel supply suspect. Many of the questions were meant to investigate that possibility. That's why it's important to answer all the questions.

 

Would a fault TDM cause it not to start?

He hasn't been able to check fuel pressure as of yet.

 

To clarify my previous response:

..... may seem to start for a few seconds then stall.

 

It won't start at all though.

 

You need to pull the codes. DTC 46 does not turn on the "SES" light. If it turns out the TDM is not sending the signal, there is an inexpensive bypass module available - not the same as the resistor bypass.

 

Have you resolved it?

 

Have not resolved the issue. He is all but decided to yank the LT1 motor out and replace with a sbc 350

 

I noticed your IP address is from Bharti Airtel Limited from India. Are there many Camaros in India? Do you own one?

ADMINISTRATOR

 

Yes, I am from India. There are Camaros in India but they are rare.

 

Interesting. We've had about 20 accounts opened from India over the past year, most of them embedding advertising links in their posts…. basically spammers. The all seem to have “western” names, and often enter country codes other than IN. Is this a little Camaro admirers club you have?