Kale

My NO was high, and all I've really done to the car that I can think of was replace the maf relays with a no name parts store set. Could they cause my hi N O ?

PeteL

Unlikely.

Post rest of report, HC, CO2, O2 we can try to help.

Kale

15mph

CO2 - 13.8
O2 - 1.5
HC PPM - 11
CO - 0
NO PPM - 1177 FAIL

PeteL

Numbers look very good; just O2 and NOx. Only thing I would try and do is find a buddy with a scanner to check block learn numbers and EGR value. Forgot if you have changed the O2 sensor recently (I would use an AC/Delco or Bosche).

Otherwise retard timing a few degrees and make sure engine temp is as low as possible. NOx is very hard to figure out without the machine.

Low coolant level or bad radiator cap will allow some local boiling in the head with can cause increased NOx emissions. Your O2 levels will reduce NOx reduction in the first stage of the Cat, as it likes to have near 0 O2 to reduce NOx (that's why the AIR tube to the middle of the cat so enough O2 to reduce HC and CO). I'll have to pull some books to figure how you can have 0 CO and 1.5 O2, seems inconsistant, especially with the nice level of CO2 (higher the better) and the reasonable HC.

First impressions are high head temperature or overly advanced timing.

I'll try and find some reasource data.

Pete

Kale

I was low on coolant..
I can't seem to figure out how to read the timing of the car. I had it hooked up like they suggested, but how do I measure it? I found the groove, it's about 3/4" away from the serregated tin "pointer"
Do you think that guarunteed to pass gas additive will help?


[Modified by Smash, 7:30 PM 12/8/2001]

Kale

btw i have replaced the o2, it's BOSCH.
Perhaps if the EGR pipe was leaking?


[Modified by Smash, 3:00 PM 12/9/2001]