Air conditioning problems and possible optispark issues

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Feb 21, 2012 | 11:48 PM

t316rudy

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Air conditioning problems and possible optispark issues

In the past three days my 93 vette started alternating from cold air to hot air and back. The cold air lasts for about a minute and then switches to hot air for about 20 seconds. I had the refrigerant checked and the levels are fine.

I'm not sure if both issues are related, today it just died on me after driving for 5 minutes. After about 30 minutes it started back up and I was able to move the vehicle. After about 10 minutes the same problem happened. We discovered that there was no spark. I had the vehicle towed and I have been able to start it while it is cool, but it will turn off after about 30 minutes.

I was told it was most likely the optispark by my friend that is a mechanic over the phone, but I wanted to get some ideas before I jump in and replace the part.

Feb 22, 2012 | 09:33 AM

jaa1992

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From: Life is just one big track event. Everything before and after is prep and warm-up and cool-down laps

Cruise-In III Veteran

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St. Jude Donor '12

A - do a search here for LT1 issues
B - FOLLOW THE TROUBLESHOOTING STEPS IN THE FSM

You will find and fix your issue for a lot less $$$$$

I've had the same experience and nothing really fixed it until I fixed the harness from the opti to the ECM connector on the passenger intake. Now my initial no start problem was fixed with a new ICM and coil, then the opti died from several coolant baths. Then the shutdown with heat problem started cropping up. The first fix was a shot in the dark based on a buddies fix to his 92. The opti was throwing opti codes when it went. When it started doing the crap when hot it was time to break out the FSM.

Feb 25, 2012 | 02:47 PM

t316rudy

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Ok, I found that the optispark was cracked and that the water pump had been leaking onto it. I changed the wires, plugs, optispark, and water pump. The car turned on for 5 minutes and died again.

Feb 26, 2012 | 08:19 PM

t316rudy

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This afternoon I tried to crank up the car and everything is up and running. I still have the problem with the A/C, but at least the car is moving. Any ideas what can be up with the air conditioning.

Feb 26, 2012 | 08:30 PM

csthews

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From: College Station Tx

Did you make sure the compressor clutch was engaging when you checked the freon levels?

Feb 29, 2012 | 10:26 PM

t316rudy

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The compressor clutch is engaging and everything under the hood seems fine. I had a co-worker look at it and he believes it may be the blend door. He says I will probably have to remove the dash to find out. Any tips regarding this? I'm pretty lost when it comes to this issue. I will remove the dash easily, but I probably won't know what to do at that point.

Mar 2, 2012 | 01:26 PM

t316rudy

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I read on a different forum to pull the fuses related to the air conditioning for 5 minutes and then replace them to see if the blend door will reset. I did this and now I get cool air for about 60 seconds and then no air for 20 seconds and then back to cool. I guess this is better than the scorching heat for 20 seconds. Any suggestions on what I should do?