High BLMs but high HC ... failed emissions

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Jun 2, 2015 | 06:23 PM

EvelBist

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From: Tijeras, NM

Car: 89 Black GTA

Engine: 'close to' stock 5.7 but trending>>

Transmission: 700

Axle/Gears: 3.27

High BLMs but high HC ... failed emissions

at 2500, my HC is 111. Max on the test is 200.

But at idle which is 750, the HC is 1300! Max is 200.

My BLM at idle is 131, at 2500 its 134.

How could this be?

Could the cat be bad? Could there be an oil leak somewhere - though I dont know if that would affect idle HC since the O2 sensor would pick it up and show it.

Huh??

Jun 3, 2015 | 07:38 AM

ULTM8Z

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Re: High BLMs but high HC ... failed emissions

Quote:

Originally Posted by EvelBist

though I dont know if that would affect idle HC since the O2 sensor would pick it up and show it.

Huh??

Not necessarily... Keep in mind the ECM only monitors the side of the engine with the O2 sensor. You could have a malfunction on the other side and the ECM will think everything is dandy.

I think the O2 is on the driver side on thirdgens? In which case, I'd check the ignition components on the passenger side.