lt1z28camaroguy

I have a 1993 Z28 Camaro, and recently I've been having a lot of issues with my vehicle randomly shutting off. I will be driving down the road, and next thing I know the entire vehicle will shut off. I coast to the side of the road, or an empty nearby parking lot and try to start my vehicle, but it doesn't even turn over. Normally if I wait a good 10 minutes, it will sometimes start, and other times it will start to turn over but not actually start.

In my last experience, I was driving down and I noticed it was about to shut off on me again, so I quickly pushed the clutch in, and shifted to neutral, and the car continued to idle, however it backfired a few times. I then tried to drive home, and a few miles down the road, it shut off on me again.

My mechanic that regularly works on my vehicle thinks that the ECU chip is bad and I have to replace it, but a friend of my thinks it has something to do with the exhaust seeing as it has an exhaust leak (Y Pipe exhaust).

I wanted to get your opinions before I committed to anything. Does anyone have any ideas as to what may be causing this, or what I should try fixing first?

Injuneer

Did you scan it for codes? 93 is so easy to scan there is no reason not to do it.

There are a couple fatal codes that will shut it down (e.g. - DTC 16 for the opti), and do not turn on the SES light.

It seems like I'm seeing a lot of problems with the aging ignition switches as well, on this and other 4th Gen boards. The switches overheat and start to melt the contact area, producing intermittent problems.

shoebox

"Mechanics" apparently like to make money replacing stuff (like computers) that rarely go bad. Ask him just what is pointing him to that conclusion.

97Z28Muscle

Sounds like exactly what my car was doing. It was the VATS, vehicle anti-theft system. Wire in a $35 resistor and you're golden. It takes about 10 minutes to put in and will solve this problem. The part is called a "vats bypass module". Hope this helps.

Injuneer

Couldn't have been too important.... he posted 10 days ago, and never bothered to come back and look for a response.

lt1z28camaroguy

Sorry I didn't respond, I did see your response Injuneer, and thank you for the input.

I'll probably look into that VATS Bypass Module and see if that works, otherwise I will have to scan the codes.

When my mechanic did the scans he said it was one of the chips that was bad, this was almost a year ago however.

lt1z28camaroguy

After looking into this further, we decided to replace the Ignition Module, thinking maybe that would solve it, and it worked great for a few rides, then it shut off randomly. This time we were able to start the car immediately and get it back to the shop, whereas previously I would have to wait for 5-10 minutes to start it.

Our next step is to put a resistor on for the VATS, however the Security light doesn't turn on when the car shuts off.

Does anyone else have any other ideas on what may be causing this? We have not scanned it for codes yet, however we will most likely be doing this early next week. Just want to get some more imput from the experts.

timnfxr

Ignition Module? Are you referring the Ignition Switch (mounted at the base of the steering column), or the Ignition Control Module (ICM) mounted on the coil bracket?
ICM/Coil location

Your symptoms sound like A heat soaked ICM which is common. You can have it tested at many auto parts stores, but it won't be accurate unless it tested many times to heat it.

There's a mod, detailed in the link below, that spaces the ICM from the head, allowing to stay cooler any reduce the drying out of the thermal compound under the ICM.
ICM Cooling Mod

I don't thing the VATS bypass resistors will cure this problem. That mod only eliminates the ignition key pellet value test failure when the ignition is first turned on, preventing it from starting. If it fails it will cause the security light to blink.

tomfric

going through same problem iced down icm car starts right up, driver side front of the head. I am headed to auto parts store to get mine

ZZ

Check the ICM connector while you are at it. Wiggle it with the car running. BTW, I was the person who did before and after temp readings on the ICM spacer mod way back when, and ended up putting it back against the head with thermal joint compound. I'm still using that same original 93 ICM.

lt1z28camaroguy

I was referring to the ICM, sorry bout the confusion. They did try to space the ICM away from the head a bit more, and it seemed to be running fine, but he wanted to test it some more just in case. The resister is only about $30 so I just had him put that on there just in case.

Thank you for that link, it was very informative.

ACE1252

I wonder if the ignition switch is failing(not the cylinder lock). It is located on the lower steering column and might be worth checking out.

I've got problems with my headlamp dimmer switch and it is right there at the ignition switch. I'm going to change both as they are ~19 years old. The steering column needs to be pulled for this and Shoebox has excellent instructions on how to do it.

4th Gen F-body Ignition Switch Replacement

raroz28

out of curiousity, why is the resistor so much more money for the 93?

On my 97 I just wired in a cheap resistor from radio shack that came in a pack for like $3. I just used one that was as close to the key pellet as possible.

Injuneer

Probably for the same reason that people could buy a 50-cent resistor at Radio Shack to eliminate the "skip shift" feature and prevent a code, but fall prey to the ebay sellers who put the resistor in a tiny plastic housing, add a connector and charge $30.

Randy Fulford

where is it located