rmanz28

hello, I just joined...great site!...question:
had to have the Opti replaced after my 95 z28 quit in the street....now it starts on the third try, driving me crazy.....also my low fluid light comes on after a few miles (I plan on replacing since the level is fine)...also, my fan turns on as soon as I try to start the engine.....don't recall it doing that until this summer.....any thoughts would be appreciated!....thanks

Injuneer

Fans are programmed to come on when certain trouble codes are set in the PCM. Is your SES light on? Have you scanned it for codes? There's an Opti code (DTC 16) that does not turn on the SES light. DTC 36 for the Opti high resolution cam position signal does turn on the SES light, and can cause slow starts.

Slow start could be related for example, to a failed coolant temp sensor.

What brand is the Opti?

rmanz28

thanks for replying....
I had the work done at my local garage since I had to have it towed. I use them all the time.....anyway...not sure of brand, but it was about $160 for opti. the SES light comes on after I drive for a while, but never right at start up. I'm going to change the Temp sensor soon.....I don't think he scanned the codes.....what should I do next?.....thanks for your help

Injuneer

A $160 Opti can often be a disaster right out of the box. Only one to use is the AC Delco, and that's $400-450.

Scan it for codes. Doesn't matter when the SES light comes on. Some diagnostics cannot be run until the engine meets certain operating/driving conditions. Your 95 requires an OBD-1 scanner, or a dual capability OBD-1/OBD-2 unit - not an Innova or Equus, because their database for the LT1 is corrupt, and yields a list of false codes.

Your 95 is the only year with an OBD-1 PCM, and a 16-pin OBD-2 style DLC connector. Requires a 12-pin -> 16-pin adapter, or jumper wires:

Courtesy of Shoebox

http://shbox.com/1/xraycable.jpg

Best bet is to download Scan9495 software, and buy a cable. Reads codes in the PCM, SRS, ABS systems. Logs PCM data while the engine is operating.

https://www.camaroz28.com/forums/com...95-lt1-874306/

Strongly recommend diagnosing the problem, rather than just throwing replacement parts at it, and hoping you get lucky.

rmanz28

I appreciate your help, status over weekend: been starting well all weekend "weird"...after a few quick trips no issues, I believe it was up to operating temp. one longer trip low coolant light came on no SES.....I'm confused, but happy...I did go buy a coolant sensor but have yet to install......what's your thought?


thanks again!

rmanz28

ok I'm back.....spring is close here in the northeast.....I tried to star my 95Z28 on a nice day and guess what...no start....here is what I can tell you: fan turns on as soon as I turn the key....it cranks fine, tried to fire once....most of the time nothing but when I let off on the key it rumbles like pre ignition. I replaced the fluid level sensor and that's about it this year......thanks for any help

gaedbo

Your best bet would be to do the things Injuneer suggested for you in his post #4.

Otherwise, just like he said, you will be guessing and throwing money at it !

Injuneer

There is another post updating the problem, which still exists. Actually in two different threads. Not sure why he didn't continue this thread.

https://www.camaroz28.com/forums/lt1...eating-881858/

In any case, I'll close this thread to avoid even more confusion and duplicate efforts.