Hellbent
NAXJA Forum User
- Location
- san diego, california
Sorry if this is a bit long, but I want to include all pertinent info.
For the last month, I've been attempting to get the new-to-me renix to pass smog. as of this afternoon, she's failed three times now.
First test nothing was really done in preparation(cap/rotor/wires/plugs were recently changed before i bought it). all numbers were well under max EXCEPT nox-which was around 1100 at both 15 & 25mph(max is 714/616).
Before the second test, I decarbonized it with the water spray method, changed the oil, and just kind of went over everything. that test failed with almost identical numbers, except the NOx went down to 975 @ 15, and 977 @ 25.
Yesterday I changed the plugs to one heat range colder, and installed a new egr valve as I discovered the transducer diaphragm was totally shot. I also changed the o2 sensor and the coolant temp sensor just because they were clearly old.
Went down again this afternoon, and failed once again. Now nox was back up to around 1074 @ both 15 & 25. the other numbers improved slightly, still around "average".
I'm a bit shocked that going from a nonfunctional egr to a new one(did test it, it is good) did nothing at all to improve the results.
the jeep runs great, has good power, good mpg, doesn't overheat, etc.
I drove around this evening with a vacuum gauge on the dash hooked to the egr line AFTER the transducer to verify it was getting vacuum to the valve when it's supposed to. It does seem to be working properly, as I see anywhere from 10" of vacuum to full engine vacuum at the valve under mild acceleration and slightly loaded cruising depending on throttle position.
I have done the lambda calculations and I'm right at 1.002 @ 15, and exactly 1.0 @ 25. This tells me that the air/fuel control and combustion is perfect.
The smog guy swears it has to be the cat, and it is an aftermarket one that looks to have been replaced a long time ago. Also, he and I agree that it looks kinda small?
I don't want to waste money on cat replacement unless I'm very sure that's the solution.
Also, I'm not sure if this matters, but I am running the high altitude cps. I'm wondering firstly- would a dead/dying cat affect the nox in the range of 900ppm? And secondly, does anyone think the +5-6 deg of advanced base timing would be enough to screw up the nox to this degree?
Thanks for any input...
For the last month, I've been attempting to get the new-to-me renix to pass smog. as of this afternoon, she's failed three times now.
First test nothing was really done in preparation(cap/rotor/wires/plugs were recently changed before i bought it). all numbers were well under max EXCEPT nox-which was around 1100 at both 15 & 25mph(max is 714/616).
Before the second test, I decarbonized it with the water spray method, changed the oil, and just kind of went over everything. that test failed with almost identical numbers, except the NOx went down to 975 @ 15, and 977 @ 25.
Yesterday I changed the plugs to one heat range colder, and installed a new egr valve as I discovered the transducer diaphragm was totally shot. I also changed the o2 sensor and the coolant temp sensor just because they were clearly old.
Went down again this afternoon, and failed once again. Now nox was back up to around 1074 @ both 15 & 25. the other numbers improved slightly, still around "average".
I'm a bit shocked that going from a nonfunctional egr to a new one(did test it, it is good) did nothing at all to improve the results.
the jeep runs great, has good power, good mpg, doesn't overheat, etc.
I drove around this evening with a vacuum gauge on the dash hooked to the egr line AFTER the transducer to verify it was getting vacuum to the valve when it's supposed to. It does seem to be working properly, as I see anywhere from 10" of vacuum to full engine vacuum at the valve under mild acceleration and slightly loaded cruising depending on throttle position.
I have done the lambda calculations and I'm right at 1.002 @ 15, and exactly 1.0 @ 25. This tells me that the air/fuel control and combustion is perfect.
The smog guy swears it has to be the cat, and it is an aftermarket one that looks to have been replaced a long time ago. Also, he and I agree that it looks kinda small?
I don't want to waste money on cat replacement unless I'm very sure that's the solution.
Also, I'm not sure if this matters, but I am running the high altitude cps. I'm wondering firstly- would a dead/dying cat affect the nox in the range of 900ppm? And secondly, does anyone think the +5-6 deg of advanced base timing would be enough to screw up the nox to this degree?
Thanks for any input...