Car usally cranks right up , leaving work today went to start my car and the check engine light went to flashing on and off rapidly and my car would'nt start , checked under the hood and pulled the fuse to the computer thinking maybe my computer might of had a hic-up , that din't work when I put the fuse back and tried to crank the car same thing happened , I tapped under the dash where the computer is installed an the car cranked , has anyone else had this happen or is the rapid flashing check engine light a warning of a bad or no computer warning . The computer is new , was installed about a month ago .

 

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Pull codes and let us know whats happening.

 

went and checked the codes all I got was code 12 which I know is normal not showing anything else
not tring to be smart but I did search , but did not find anything about a rapid flashing check engine light
I did forget to mention this is an 89 camaro rs with a 2.8 v6 , 78,000 miles 2nd owner , nothing hacked or rigged on the car

 

do you have anti-theft on your car at all, i suppose that could be malfunctioning

 

Normally a flashing light would mean that you could do serious damage to the converter. Why did you replace the computer? Their also is a secruity system in which you need the right chip in the key to start it. I had a problem in which my chip was chipped on the side and would somtimes not start. Their is a pre programed time in which the car will reset itself so you can start it with the right key. Hints anti theft. Correct me if im wrong but if you have the wrong chip in the key i belive the car will still crank however will not start.

 

i thought the flashing check engine light for Cat. damage was only on OBD2 cars

 

checked the key , key seems fine , even when I had the problem that was my first thought and pulled the key out several times,and even tried to wiggle it .
As for why I changed the computer , I could not get the fuel pump relay to work and and had checked everything else out when I had the computer checked it showed that that part of the computer was faulty
The converter ? do you mean the tourke converter ,I know that the computer only controlls lock-up on it but will the computer tell you if it is bad or in danger of damage before the car is even started.

This is the first time it's done this and since this afternoon has'nt done it again ,I have stated the car a few times since I've gotten home and started fine , has me baffled

 

Flashing SES = bad PROM, or some hardware issue that prevents the PROM in the memcal from being read properly. Basically the ECM calculates a checksum of all the info in the PROM, and if it doesnt match whats stored, the computer resets and tries again. Each time it resets, the SES flashes. BTW, when this is happening, the CPU is not operating the engine, or anything else hooked up to it. There is redundant analog hardware in the computer that handles the fuel while the dist. just runs off the base timing.

 

I want to thank you for all your thoughts on the problem but I think I have found it on the site , I did do a search earlier but guess I used the wrong term , but you guys are great for tring to help , I'll leave what I found here and maybe it will help in the future with one of you or someone else .

Originally posted by Trickster
Your flashing ses light when you turn the key on means that pin "B" of the ALDL is grounded somewhere between the ALDL and pin "A9" at the ECM.

 

If its a rapid on/off flashing, then its almost certainly the PROM failing the checksum. Open the cover (secured with two bolts) on the ECMs case and make sure the MEMCAL (blue thing) is seated properly. Might even help to pull it out and check to make sure that water didnt get in and corrode the pins on the main circuit board. Other then that, if it does it repeatedly, either a new memcal or yet another ECM may be needed.