Help!..........Failed Emissions
Before I go crazy with trying to diagnose the problem, I'm hoping someone out there may have had a similar experience and lead me in the right direction:
The car: 1991 with Dali chip, Comptech exhaust and headers. 93K miles
The problem: "Massachusetts" (tough emissions standards including a dyno run under load) Of course trucks and buses are exempt from emissions testing, but don't get me going on that one......
The results:
HC 2.21 (limit 1.20 gpm) FAIL
CO 6.40 (limit 20.0 gpm) PASS
NOx 0.29 (limit 2.50 gpm) PASS
CO2 240.57
By looking at the HC graph, it appears the highest HC reading occurs early (just off idle?). And, it appears the car has a slight skip and rough idle (I had attributed this to the chip, but I've never driven a stock NSX) -- so much so that the steering wheel and rear spoiler shake intermittently at idle.
The car had been sufficiently warmed up, including a high-rpm highway run, sniffer was put into the right-hand tailpipe (does one exhaust outlet run "hotter" than the other?).
Options:
new plugs? (which ones?) -- (no I haven't yet checked to see if they're gummed up) Should I be running special plugs with the Dali chip? Is the Dali chip known for richening the mixture too much?
If the chip is the culprit, would someone have a stock chip in Mass. that I can "borrow" for the test? (I'm assuming the ECU can be swapped easily, yes?)
Any help would be appreciated. Please don't PM-me, as I havent' figured out how to use it, but to save bandwidth, feel free to email me direct at [email protected]
Thanks in advance. --Scott
Before I go crazy with trying to diagnose the problem, I'm hoping someone out there may have had a similar experience and lead me in the right direction:
The car: 1991 with Dali chip, Comptech exhaust and headers. 93K miles
The problem: "Massachusetts" (tough emissions standards including a dyno run under load) Of course trucks and buses are exempt from emissions testing, but don't get me going on that one......
The results:
HC 2.21 (limit 1.20 gpm) FAIL
CO 6.40 (limit 20.0 gpm) PASS
NOx 0.29 (limit 2.50 gpm) PASS
CO2 240.57
By looking at the HC graph, it appears the highest HC reading occurs early (just off idle?). And, it appears the car has a slight skip and rough idle (I had attributed this to the chip, but I've never driven a stock NSX) -- so much so that the steering wheel and rear spoiler shake intermittently at idle.
The car had been sufficiently warmed up, including a high-rpm highway run, sniffer was put into the right-hand tailpipe (does one exhaust outlet run "hotter" than the other?).
Options:
new plugs? (which ones?) -- (no I haven't yet checked to see if they're gummed up) Should I be running special plugs with the Dali chip? Is the Dali chip known for richening the mixture too much?
If the chip is the culprit, would someone have a stock chip in Mass. that I can "borrow" for the test? (I'm assuming the ECU can be swapped easily, yes?)
Any help would be appreciated. Please don't PM-me, as I havent' figured out how to use it, but to save bandwidth, feel free to email me direct at [email protected]
Thanks in advance. --Scott