I really need help with this...my 89 iroc wont start every now and then without a jump. I replaced the alt a few months ago because it wansn't charging...the battery is new. It seems to still be a charging problem but I had the alt and batt tested again and its good. Maybe 1 out of 3 times I shut my car off, it wont start. I turn the key and nothing, no clicking or anything. The lights stay bright as if there is still power, they barely dim when I turn the key. Yet, as soon as i hook up the jumper cables, it starts. (the volt meter shows 10-11v on the batt)

It doesn't matter is its warmed up or not. The voltage acts goofy, it will show a solid 13v and then drop to 9v or 10v for awhile. When I turn on my turn signal, the voltage bounces 1v up and down. I've verified all this with a voltage meter.

 

sounds like the dreaded '89 VATS problem. The next time it refuses to start check and see if the security light stays on for more than a few seconds. If it stays on, the ignition cylinder can't read your key.

 

Thats what I was thinking this morning. Last night when I parked, I shut off the car and tried to start it right away....wouldn't start. This morning it started right up. I was thinking vats or starter problem.

I thought unchecking the VATS constant on the prom chip disabled VATS. Do I need to do anything else? Like the resistor overide thing in the steering column?
Thanks.

 

This just happened again last night and the security light shut off after a few seconds. So I don't think its the VATS. I checked the battery with a volt meter when the car wouldn't start and it showed 12.3v. When I turned the key, the voltage dropped to 11.3v. As soon as I hooked up some jumper cables, the car started.

I'm thinking the starter might be bad? Should I change that next?

 

Try replacing the starter. A remanufactured starter from a big parts store chain doesn't cost more than $40 or so. If it is that cheap, why not try it and eliminate that problem.

 

When VATS detects the wrong resistance the light stays on constantly (ie, poor contact)

When the VATS light doesn't even come on that means that the computer has detected no resistance (ie, bad chip in key, very poor or no contact at all with cylinder)

What I did to temporarily solve the problem was to take some small vise grips and gently squeeze the metal comtacts on each side of the chip on the key so that they would stick out more and make a better connection. Don't squeeze too hard, or you might destroy your key! (they are pretty tough though)

 

The Security light came on for a few secs and shut of like it always does. Thats why I don't think its the VATS.

I'll try the starter next.
Thanks