EGR Help ... High NOX
03-20-2009, 06:30 PM
#16
Registered User
Thread Starter
Join Date: May 2003
Posts: 17
Well, I finally figured it out.
It was the PNP switch circuit A21 on the grey ecm plug.
The wire was grounded so the ecm wasn't showing it was in gear.
The ecm needs to see that circuit open to let the quad driver know
it's in gear while meeting the parameters of the tps, cts, iat and vss to accurately cycle the egr solenoid.
Took it in for the emissions test and it PASSED
Thank to all that offered their advice
It was the PNP switch circuit A21 on the grey ecm plug.
The wire was grounded so the ecm wasn't showing it was in gear.
The ecm needs to see that circuit open to let the quad driver know
it's in gear while meeting the parameters of the tps, cts, iat and vss to accurately cycle the egr solenoid.
Took it in for the emissions test and it PASSED
Thank to all that offered their advice
06-01-2013, 07:36 PM
#17
Registered User
Thread Starter
Join Date: May 2003
Posts: 17
Re: EGR Help ... High NOX
Well, 4 years later, I failed NOX again on the 15 mph test 
The 15 mph maximum limit is only 482 here in CA, and the Jeep was blowing 550.
I re-checked to make sure the EGR system is still functioning from the fiasco I had with it 4 years ago, All was good, and the passages were not clogged.
So here are some things that I did, but not sure which of them made me pass with flying colors.
I replaced the 3,000 mile Bosch platinum + 4 plugs with a set of NGK V-Power TR6/4177 plugs which are a cooler plug.
I added 1.5 gallons of E85 with 5 gallons of premium 91 octane fuel.
I disconnected the egr solenoid hoses and ran direct manifold vacuum to the egr.
Final result was a stunning 171 NOX @ 15 mph
My HC & CO were slightly elevated, but well below max allowable.
All the techs are confused with why I have/had this problem, because everything is functioning and within specs.
Hope this might help someone else out with a similar problem !
The 15 mph maximum limit is only 482 here in CA, and the Jeep was blowing 550.
I re-checked to make sure the EGR system is still functioning from the fiasco I had with it 4 years ago, All was good, and the passages were not clogged.
So here are some things that I did, but not sure which of them made me pass with flying colors.
I replaced the 3,000 mile Bosch platinum + 4 plugs with a set of NGK V-Power TR6/4177 plugs which are a cooler plug.
I added 1.5 gallons of E85 with 5 gallons of premium 91 octane fuel.
I disconnected the egr solenoid hoses and ran direct manifold vacuum to the egr.
Final result was a stunning 171 NOX @ 15 mph
My HC & CO were slightly elevated, but well below max allowable.
All the techs are confused with why I have/had this problem, because everything is functioning and within specs.
Hope this might help someone else out with a similar problem !
07-11-2018, 03:39 PM
#18
Registered User
Join Date: Jul 2018
Posts: 140
Re: EGR Help ... High NOX
Well, 4 years later, I failed NOX again on the 15 mph test
The 15 mph maximum limit is only 482 here in CA, and the Jeep was blowing 550.
I re-checked to make sure the EGR system is still functioning from the fiasco I had with it 4 years ago, All was good, and the passages were not clogged.
So here are some things that I did, but not sure which of them made me pass with flying colors.
I replaced the 3,000 mile Bosch platinum + 4 plugs with a set of NGK V-Power TR6/4177 plugs which are a cooler plug.
I added 1.5 gallons of E85 with 5 gallons of premium 91 octane fuel.
I disconnected the egr solenoid hoses and ran direct manifold vacuum to the egr.
Final result was a stunning 171 NOX @ 15 mph
My HC & CO were slightly elevated, but well below max allowable.
All the techs are confused with why I have/had this problem, because everything is functioning and within specs.
Hope this might help someone else out with a similar problem !
The 15 mph maximum limit is only 482 here in CA, and the Jeep was blowing 550.
I re-checked to make sure the EGR system is still functioning from the fiasco I had with it 4 years ago, All was good, and the passages were not clogged.
So here are some things that I did, but not sure which of them made me pass with flying colors.
I replaced the 3,000 mile Bosch platinum + 4 plugs with a set of NGK V-Power TR6/4177 plugs which are a cooler plug.
I added 1.5 gallons of E85 with 5 gallons of premium 91 octane fuel.
I disconnected the egr solenoid hoses and ran direct manifold vacuum to the egr.
Final result was a stunning 171 NOX @ 15 mph
My HC & CO were slightly elevated, but well below max allowable.
All the techs are confused with why I have/had this problem, because everything is functioning and within specs.
Hope this might help someone else out with a similar problem !
07-11-2018, 06:49 PM
#20
Registered User
Join Date: Jul 2018
Posts: 140
Re: EGR Help ... High NOX
You're correct. I bought the vehicle from the guy and it has been overheating. So I'm hoping that if I address that it will fix itself. But in the off chance that something else is wrong, I'm happy to know you can kind of give it a tune up and pump it with ethanol to try to get it to pass
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