1990 Cadillac Deville wont pass smog. HELP!

JOSEPH RUIZ

MEMBER
1990 CADILLAC DEVILLE
V8
FWD
AUTOMATIC
156,000 MILES

My 1990 cadi sedan deville wont pass smog! Its running 1 & 1/2 times richer than the max allowed. Ive replaced the cad converter & all sensors that can possibly make it run too rich. The diognostic test shows everything is fine, "but" the smog test has it running way too rich! It allows for a max at 100 but its testing at 245 ! Ever heard of this? Please help.

7 Replies

RASMATAZ

MECHANIC
75,992 POSTS

P0172/0175 Rich codes-

Possible causes include a bad O2 sensor, excessive fuel pressure (bad fuel pressure regulator or plugged return line), leaky fuel injectors, dirty air filter or restricted air inlet, or a defective coolant sensor that prevents the engine management system from going into closed loop mode.

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Monday, March 31st, 2008 AT 2:45 PM

JOSEPH RUIZ

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All you suggested has been checked, any further ideas would greatly be appriciated. Thank you very much!

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Monday, March 31st, 2008 AT 8:04 PM

RASMATAZ

MECHANIC
75,992 POSTS

The only thing we got left is the computer

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Tuesday, April 1st, 2008 AT 6:23 AM

BUZZSAW

MECHANIC
1,198 POSTS

Does it run rough or is it idleing fast?

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Friday, April 4th, 2008 AT 2:20 AM

JOSEPH RUIZ

MEMBER
9 POSTS

It doesent run rouph at all it runs really great "but" it does idle a tiny bit, and I do mean a tiny bit rouph when I pull to a stop. Ive had a new computer put in & its still running way too rich!Have you heard of any recalls for this model?Does the computer need to be reset in any way?Help, its eating up lots of cash. Any new ideas would be greatly appriciated. Thank you !