Emmisions Diagnostic Help????

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Jun 28, 2002 | 04:23 PM

Stngray

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From: Goodyear AZ

Emmisions Diagnostic Help????

I went through emissions three times up in Oregon. The first time it failed on Nox, which I know was the EGR. The second and third times it failed on HC's. I just put a brand new carsound cat in it. Does the EGR affect hydrocarbons? I also have a pretty large exhaust leak on one of the exhaust manifolds, would this affect anything. Any help from you guys would be very much appreciated. Here is a link to the emissions readouts.
http://home.earthlink.net/~stngray78/emissions.pdf
Thanks again
Doug

[Modified by Stngray, 12:31 PM 6/28/2002]

Jun 28, 2002 | 04:33 PM

PeteL

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From: And on the fifth day, subpoenas were served to Obama senior staff

Re: Emmisions Diagnostic Help???? (Stngray)

Manifold leak, if on the side with the O2 sensor, or if you have 2 O2 sensors (did not catch the year), will introduce air into the system which will cause the O2 sensor to think you are lean and therefore add fuel - making you rich and causing excess HC.

Link does not work? Can you post the numbers (all numbers if you have them).

Pete

Jun 28, 2002 | 04:35 PM

Stngray

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From: Goodyear AZ

Re: Emmisions Diagnostic Help???? (PeteL)

Fixed the link. The exhaust leak is on the passenger side the flange at the bottom of the exhaust manifold is doing its best to fall off. It is a pretty big leak. It is an 86.
Thanks

[Modified by Stngray, 12:37 PM 6/28/2002]

Jun 28, 2002 | 05:07 PM

Greenvette

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Re: Emmisions Diagnostic Help???? (Stngray)

If the exhaust leak is near the 02 sensor, that is probably your reason for double the HC count permitted. I would definetly fix the exhaust leak. If you have access to a scanner, that would help. I bet some of your spark plugs are sooty black. you might want to remove a few from each side and see if they are black and sooty. Sounds like you have a VERY rich condition.If the EGR is on all the time(stuck, carbon buildup) you can also get a rich condition.

Jun 28, 2002 | 05:45 PM

Stngray

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From: Goodyear AZ

Re: Emmisions Diagnostic Help???? (Greenvette)

Thanks guys.

Jun 28, 2002 | 06:10 PM

PeteL

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From: And on the fifth day, subpoenas were served to Obama senior staff

Re: Emmisions Diagnostic Help???? (Stngray)

I guess it could be that leak, but it's on the wrong side. O2 sensor is on the drivers side.

Still, it's running rich so O2 sensor should be serviced as a guess if you don't have a scanner. I'd weld up the flange and replace the O2 sensor.

You need a buddy with a scanner! Could be so many things: O2 sensor, CTS, dirty air filter, just may need a tune up.

Pete

Jun 28, 2002 | 07:25 PM

65Z01

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From: SE NY

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Re: Emmisions Diagnostic Help???? (PeteL)

Insert a paper clip into the ALDL pins A&B and start the engine to put the ECM into diagnostic mode.

After a few minutes the SES will begin to flash more slowly, about 1Hz. The on/off periods indicate rich/lean conditon. The flashes should be of equal duration.

If OK at idle, raise the engine speed to about 2,000rpm and see if the flashes are still of equal duration. If so the O2 sensor is OK.

If high HC I would bet on a bad O2 sensor.