sailor92a

1990 conv check engine showing and both fans running. Any ideas

Sid.123

C409

..... Sounds like you're ECM is in limp home mode .....

mlm0

I agree. Limp home mode

BlowerWorks

Bad chip (BIN) or not seated MemCal Pack

Cruisinfanatic

Not till you pull codes, LOL

WVZR-1

Ideas ain't going to fix it! Might lighten the wallet but I'd say you either have it checked or learn the "how to"!

How long have you owned the car? Any recent attempts at some repairs or maintenance that you've attempted yourself? If you've recently done anything - go back to what you've done and sort from there.

If you've done nothing -

http://tech.corvettecentral.com/2011...trouble-codes/

With a '90 and if it has C68/ATC you could use the AC Control to maybe check the coolant temp that the ECM sees and use that as maybe a "clue/hint". If no C68 rely on the diagnostics.

I imagine you don't have a FSM (Factory Service Manual) and if the car is a keeper I'd suggest you buy one. Print or "electronic media" are both available - some have and use both, some have preferences, some might have made a different choice after buying one or the other.

I have both but use "digital media" more frequently.

sailor92a

i have a fsm and am looking things up! new to this, how do you pull codes and where do you see them in the car

WVZR-1

That's why I posted the link. That should be self explanatory and answer any questions. Review the content in the link and see if you've still questions. Since you have the FSM you can review the C68 section (if your car has C68) to check for CTS temps that the ECM is seeing.

1C1 section of the FSM

sailor92a

what is a memcal pack? also a bad chip BIN?

aklim

Hook up a scanner so you can see NOT ONLY the codes but ALSO the data stream.