Check engine lite on/no codes
 

Hello again guys,
My check engine lite is on all the time now. (1991 L98) I turn the key on with engine off, and lite comes on steady, (normal) I start it up lite stays off for about 5-10 seconds then blinks for a fraction of a second then on steady. I short out the ALDL pins A and B and nothing, steady lite no code 12. The last time I had a check engine lite it gave me a 12 and another code for the EGR, so I know it did work at one time. Other than following the procedure in the FSM is this a common problem? Car seems to run fine. Also have a SIR light every now and then, anything common with that light? Thanks, Kim

I am not aware of any common problems that would cause the ECM to fail to flash codes, your best bet there is to follow the procedure in the FSM for that condition, it will walk you through the steps needed to determine the cause.
The SIR system is known to have corrosion problems with the impact sensors, see this link for some tips on repairing that issue.

http://www.zr1netregistry.com/Old_Proj/old_proj7.htm