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Nando559
04-15-2011, 01:37 PM
I got a 1990 thunderbird sc..the radiator fan does not turn off at all..had to disconnect the battery. Any1 know whats wrong?? Also smog test failed on the NO(ppm) test..what should I check on my car??

90coug
04-15-2011, 02:33 PM
I got a 1990 thunderbird sc..the radiator fan does not turn off at all..had to disconnect the battery. Any1 know whats wrong?? Also smog test failed on the NO(ppm) test..what should I check on my car??


I don't know about the smog test but if the fan stays on all the time I would check your coolant level.

92bird
04-15-2011, 03:33 PM
nox is the hardest emissions specification to pass, and makes owning a modified car here in colorado a living hell..

If CO and HC are passing, its most likely a bad catalytic converter, or non-functioning EGR (if your car has EGR).

If it just barely failed nox, you could try a few gallons of E-85 ethanol (mixed in with your premium gas). That will help.

I've found that high nox emissions are not neccessarily related to a rich a/f mixture. Unless your HC and CO emissions are also failing.

If you car has ever blown headgaskets in the past, it likely damaged the catalytic converters to the point where they do not function as well as they should.

David Neibert
04-15-2011, 04:52 PM
I got a 1990 thunderbird sc..the radiator fan does not turn off at all..had to disconnect the battery. Any1 know whats wrong?? Also smog test failed on the NO(ppm) test..what should I check on my car??

Assuming you mean the fan stays on, even with the ignition turned off...it's most likely a bad IRCM (integrated relay control module). It's a black box located between the passenger side headlight and the air filter box.

Nando559
04-15-2011, 08:34 PM
I don't know about the smog test but if the fan stays on all the time I would check your coolant level.

coolant level is perfect. Thankz for the tip!:cool:

Nando559
04-15-2011, 08:37 PM
nox is the hardest emissions specification to pass, and makes owning a modified car here in colorado a living hell..

If CO and HC are passing, its most likely a bad catalytic converter, or non-functioning EGR (if your car has EGR).

If it just barely failed nox, you could try a few gallons of E-85 ethanol (mixed in with your premium gas). That will help.

I've found that high nox emissions are not neccessarily related to a rich a/f mixture. Unless your HC and CO emissions are also failing.

If you car has ever blown headgaskets in the past, it likely damaged the catalytic converters to the point where they do not function as well as they should.
Do you know of a way to check if its my catalytic converters?? I think it may be that which caused the car to not pass because the test was over 1000 and normal is 540!

Nando559
04-15-2011, 08:38 PM
Assuming you mean the fan stays on, even with the ignition turned off...it's most likely a bad IRCM (integrated relay control module). It's a black box located between the passenger side headlight and the air filter box.
TTHANKz! I took that part out and hit it thre times and the problem is fixd!!

ironworker
04-15-2011, 09:37 PM
if u lived in LA i have a guy

David Neibert
04-16-2011, 08:48 AM
TTHANKz! I took that part out and hit it thre times and the problem is fixd!!

You can pick up a replacement pretty cheap in the classified section.

David

Nando559
04-17-2011, 01:16 AM
You can pick up a replacement pretty cheap in the classified section.

David

Really? Thankz! Ill see if i can spot one!:cool: