egr and emissions datamaster scan
Thread Starter
Instructor
Joined: Apr 2008
Posts: 153
Likes: 7
From: Painesville Ohio
egr and emissions datamaster scan
I ran a scan with datamaster to pinpoint the cause of a failed emissions test (high Nox). I suspect the egr but need to know what I should look for. The scan shows the egr only opening for a split second and not very often. The first time it opened I had been driving the car about 10 min., then it would open every so often for 1 or 2 records of the scan. Shouldn't the EGR be opening more often or stay open except at idle and WOT?
Thanks in advance for any info.
Thanks in advance for any info.
Racer
Joined: Sep 2004
Posts: 258
Likes: 0
From: Coram NY
I have an 86 that failed emissions for hi nox also. I ran the datamaster scan. I remember the egr opening for a perion of time and closing, sorry but i do not remeber how long it was, but doing a vaccum test (hand held ) the egr would not hold vacuum, so it really wasnt opening and therefore not operating. I replaced the egr and passed emissions.
I do not know what year your car is, but I also had problems with the solenoids in the "air" system, it was constantly pumping air into the exhaust causing the O2 sensor to think there was a lean condition, consequently opening the injectors more, this really had the emissions thru the roof, but the egr valve is a good place to start.
Tom
I do not know what year your car is, but I also had problems with the solenoids in the "air" system, it was constantly pumping air into the exhaust causing the O2 sensor to think there was a lean condition, consequently opening the injectors more, this really had the emissions thru the roof, but the egr valve is a good place to start.
Tom
Thread Starter
Instructor
Joined: Apr 2008
Posts: 153
Likes: 7
From: Painesville Ohio
Thanks Tom, I'm going to get my hands on a vacuum pump this week and test the egr system. I think it may be the solenoid but will probably replace the valve too. 106K miles may be enough on it.
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Joined: Oct 2007
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From: So. Cal.
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Nox?
I thought high NOX readings had to do with high combustion chamber temps?
