rick89formula

I just failed my emiisions test. NOX was higher than it should be. Pass is 3.00 and I ran a 3.62. Converters are 1 1/2 years old. I was told that EGR passages could be plugged and will cause higher NOX. Anyone had this issue and if so, how did you overcome this?

onfire

rick,

check to make sure your vacuum lines aren't clogged to the egr. Trace the line the comes from the evap canister to the throttle body then back towards both the egr and your solenoid. Maybe a line is disconnected or broken. How old is the egr its self? Do you get 32 trouble code?

Rabi C.

rick89formula

The EGR is original and I throw no codes. I flashed the computer to make sure. I did find a disconnected line at the egr solenoid in which I repaired. I tested the egr and it opens and closes ok without sticking and it does hold vacuum. I re-set timing to 6* and fixed the line and made sure the egr ports weren't clogged (they aren't). I just re-tested it and still failed but actually a little worse. I am stumped.

rick89formula

Is there a egr solenoid or vacuum switch on this? I think the egr is fine but no vacuum is getting to it at upper rpms.

onfire

rick,

Yes there should be an egr solenoid right by the coil on the passenger side. Make sure the vacuum lines are connected to this. The lower line comes from the vacuum port under the throttle body which has a T that also routes vacuum to the vapor canister. The upper line goes to the egr valve. I dont think your egr has a temp sensor that screws into it. I believe the '88 style egrs have this temp sensor.

Hows your O2 sensor? Have you checked to make sure your AIR pump is functioning correctly? Your car also has to be nice and warm so your system can enter into closed loop mode.

Do post what happened.

Rabi C.

rick89formula

thanks for the info rabi c. I do have a temp. sensor at the egr. I don't think that I am getting vacuum from the solenoid to the egr. The o2 is newer and all lines seem to be fine. Also, the egr holds vacuum and opens and closes fine. I will maybe have to look into the solenoid next.

onfire

Rick,

when you look at the solenoid there are two fittings one looks like a shinny aluminum fitting---> goes to the throttle body/ T fitting and the other fitting is black and this goes to the egr.

Hope this helps... I know the sniffer test can be frustrating at times but don't worry there has to be a solution.

Do post any updates.


Rabi C.

rick89formula

could using an agressive chip alter emissions? PCM for less told me that I should not have to remove the chip. I wonder if this could add to this.

onfire

Rick,

That could be the culprit just depends on how they tuned your fuel enrichment tables etc. Its hard to tell but yes a proper tune will get you passed the sniffer. Don't really how hard they pushed the tables so its tough to make a diagnosis in that sense but yes it could be it.

Rabi C.

rick89formula

Well it seems that I might have fixed the problem. Before I was getting no vacuum to the egr valve when needed. I came home after work tonight and went to work right away determined to try and repair this or at least find the problem. I pulled the solenoid out of the car and discovered that the solenoid was not sealed where there is a very small o-ring to connect two vacuum pieces. I repaired this and re-routed some hoses and put it back together. I let the car warm up to operating temp. and pulled the line to the egr valve. I put my tongue to the tip of the line and reved the engine and I actually have vacuum now. I hope this helps with my NOX problem now. I will keep you guys posted. Thanks Rabi C.

onfire

Right on glad you where able to find the issue.




Do keep us updated with what happens with the smog test.

Rabi C.