Car won't start - Posible computer problem
 

I hope someone can help me bring my car back to life (1998 Z28 M6). Several days ago I went to move my car into the driveway to wash it and at first when I turned the key nothing happened. After turning the key several times the car started normally. This was the first time my car had ever done this but since it did start I was not too worried. After washing the car I tried to take it for a spin but the engine would not turn over when I turned the key. I did not think it was the battery since it started fine earlier in the day but was suspicious of the starter solenoid. After inspecting the starter I found it to be fine but discovered that there was no voltage on the small wire connected to the starter when the key was turned to the start position. At this point I took the battery out and had it checked and sure enough it was bad so I bought a new one. Unfortunately this did not solve the problem of the car not starting. At this point I noticed that the security light in the gauge cluster was flashing and the SES light was on when the key was in the run position. I then procedded to connect my Auto-Tap to the data port in order to see why the SES light was on, but Auto-Tap was unable to connect to my car's computer.

At this point I am starting to get frustrated. I know that if the security system is faulty it might not be able to check the resistor in the key and therefore go into theft mode which would dis-able the starter and fuel system. This would seem to be the problem, but I thought that my Auto-Tap would be able to still connect to the computer and read codes. I know that the computer is powering up because of the SES light, but I do not know how to tell if it is fried or not.

I have checked all of the fuses and they all seem fine. I wonder if it is possible that the bad battery could have messed up the computer? If anyone has any ideas I'd love to hear them.

Thanks for your help.
Darren

Re: Car won't start - Posible computer problem
 

I'm not 100% sure on this but it sounds kinda like VATS is screwed up. If you have LS1 Edit you can remove it and I would highly reccommend it.

Re: Car won't start - Posible computer problem
 

I agree good call!!! Those chip things do go out. if you disable it, you can get regular 3 dollar spare keys made for it and not these 50 dolllar replacments. good luck and let us know!!

Re: Car won't start - Posible computer problem
 

Check the starter and IGN relays under the hood. You can test them by switching them out with the fan relays temporarily.

Blake

Re: Car won't start - Posible computer problem
 

I tested the value of the resistor chip in both of my keys and it was 7500 ohms. I then disconnected the two white wires with the orange wrap that comes out from under the steering column and found the resistance across these two wires to also be 7500 ohms when the key was in the ignition. This leads me to believe that thier is nothing wrong with the steering column but their could be a problem with the BCM(i think that is the correct term) located behind the stereo. It is my understanding that this box has to send a 50 to 60 Hz signal to the computer for the car to start. I have not tested the wires coming from this box yet but I will try to sometime today.

I did try and swap the fan relays with the ignition and starter relays but nothing happened. My only concern here is if I put the two relays back in correctly. After I removed the relays I was distacted by my daughter and I am now not 100% sure I put them back the way I took them out. I replaced them such that you can read the word OMRON on top of the relays while leaning over the drivers fender without having to look upside down. Is this correct?

I noticed that if I pull both of the fuses for the computer I still get a blinking security light. I do not know if this means something or not?

One last question. If you turn your ignition key to the run position but do not start the car is it normal for either the SES light to stay on or for the SECURITY light to blink. I cannot remember if either of these lights temporarily come on but turn off when the car is actually started.

Thanks for the help. With Christmas around the corner I have already spent my money on my wife and daughter and therefore if I want to drive the hotrod (as my daughter calls it) I will have to fix it myself with help and ideas I get from everyone here.