89" chevy suburban failed emmision test again!!

failling emmision with high CO (carbon monoxide) levels, first it was HC?s found fouled plug, re[placed all, now the co is to high, it was fine when the hc?s were off. some told me to replace O2 sensor, any one know anything about this? any tricks to try? any help is appreciated, thanks!!! Serve

Reply to
big_swerv
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yeah move to a state without emissions tests, I live in indiana and if we had emissions tests more than half the cars on the road now wouldnt be there, and those arent just older jalapies I think emission tests are stupid ideas anyways, besides, if we had better fuel then that probally would help make things a little better.

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Reply to
Adam Frazier

Hi CO is a "rich" running engine, or a plugged cat. Is this a carburetted engine? The oxygen sensor can be tested with the proper equipment.

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Reply to
Dan Calhoun

Reply to
Black Dog

Reply to
Black Dog

How much did you miss by? I have a 89 burb that has passed every emmision test for last 10 years. What you might try is to check timing and retard it a bit (about 4 degrees) beacause this will increase after burning in exhaust manifols and raise CAT temps and improve the CATs function and also add several cans of alchol to fuel because it adds oxygen to fuel to reduce CO emissions. You need to add about 1 gal per 10 to 15gallons of fuel in the form of Dry Gas or gasoline antifreeze (methol alchol) Do not add isoproply because it is 30 to

40% water as you buy if off the shelve at a Walmart or such. I have gotten a few few problem vehicals through for freinds this way.
Reply to
SnoMan

most of the counties in N C are tough that do the test. i am in wake co. and there pretty tough here, i mean some places will even fail you if you have a lisc. plate bulb out. been there had it happen on a old beater truck i had.

Reply to
Charles H.

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You have the TBI right? The O2 sensor is only part of what the ECM uses to mix the fuel / air. Your MAP sensor might be bad,/or unable to communicate for some reason. Have you ever power washed your engine before?

If the ECM can't tell the vacuum in the intake, it can't know how much fuel to inject. If you have ever blown a head gasket and had antifreeze go out the tail pipe, the O2 sensor could be dead. (as coolant will foul an O2 sensor)

ZZZ

Reply to
zzz

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