Check Engine Light Question.
 

I pretty much know OBDII processors and information inside and out. But, I have a 91 5.0 (not OBD II:D ) and im not really up to speed on this system. I was driving down the road and my check engine light came on. No big deal, car was still running good. I have my list of codes with me and my jumper wire to check the code. I pull over and turn the car OFF. I turn the key on and begin to check the code and THERE WAS NO CODE. I started the car and the light was OFF. My question is do these computers store the code in memory or do they purge the code as soon as the problem seems ok?? The check engine light hasnt come on sence. Just wondering. :D

Unfortunately as you know OBDII cars have continuous codes...but OBDI does not. OBDI only recognizes on demand codes, you can drive it and be lucky to get a code with the engine still running, once you shut off the key the code goes away. If i were you, i'd wait till it comes on again and try and get the code immediately. Chances are some sensor went out of range for a moment or stuck out of range and it set the code and the computer reset after you turned the key off.

I was under the inpression that the codes went into Continuous Memory and stayed for about 75, or 100, turns of the key, or until you reset the computer. I have a 90 GT and I get KOEO, CM, and KOER codes. The CM are when something isn't right and the computer stores it for the allotted time. Someone feel free to correct me if I'm wrong, but I'm almost positive I'm not.

Caymon

I'm sorry, but that is 100% incorrect.

The continous codes are stored for between 75 and 100 ignition cycles.

Take care,
~Chris

I'm going to agree with prkwud & bigred90gt.......a great resource is Understanding Ford Electronic Engine Control (I hope I got the title right, someone correct me if Im wrong....Im at work and dont have the book on me). The book will go deep as you ever want to go on theory of control, operation stategies, and troubleshooting of all eec components. The book is pretty thick and not a bad price@ 29.95 at your local big book store.

My mistake...i'm full of bs :D
I guess the processor in my car is crap and i'm just used to it. You are right though, i looked it up and i am in fact an idiot ;)
Sorry to blow smoke up your bum.

I have trouble keeping continuous codes in the processor in my car. the check engine light will come on and then maybe a day later when i check for codes none appear, i ASSUMED that your car would be like mine.

Dude, you're not an idiot, you just made an honest mistake. Cut yourself some slack. Hell, if you were an idiot, you wouldn't be here in the first place!

:D

Merry Christmas

Thanks chris, merry christmas to you as well :D
I just feel bad when i give people bad info. on something i could have easily checked, oh well sh/t happens :p

Thank you!

:)