93 Ei fails E-TEST

[i<3bonbons]

Hi, I'm posting mainly to ask a question about my EGR, it's a digital, and I am trying to test it, I've checked the ohms following directions I found online, and according to the article, I'm out of specs. Would that cause me to fail my etest? HC's and Idle test come out great, it's failing on high NO x ppm at 45 km/h test. failed twice, so if it fails again, I'm back paying full price to re test. any help/ suggestions?

[1fatcat]

You got any more info? Is there any codes set, what kind of gas mileage are you getting, does the engine run smooth or rough, do you have full engine power, when was the last tune-up and what was replaced?

[i<3bonbons]

No codes! As far as tune up goes, I only bought the car last fall, so the previous owner had tuned it up, he said recently, plug wires look newer, as do the plugs. Car runs good, it has loads of power, the gas sat in it over winter, so I let it go to 1/4 tank, then i put 25$ worth of 91 octane premium and 1/4 litre of methyl hydrate. the hotter the car gets, the higher the nox count is. Gas mileage is pretty poor, and the car has started to idle a bit rough now that the gas is nearing empty. My first E test I did nothing to the car, but took it in anyway. The second etest(retest) I cleaned the MAF, put in a new air filter, cleaned the egr, and the nox came out higher while all the other tests came out lower. Like I said, I checked the EGR with an ohmeter, and it's out of spec, should I replace it?

[1fatcat]

First I would check for vacuum leaks and leaky fuel pressure regulator, then replace egr valve, then replace the O2 sensors?

[i<3bonbons]

I've checked the car for vacuum leaks, couldn't find any. I'm going to go check the FPR as soon as I wake up a bit, then it's off to the junkyard for an EGR valve. Everything I've heard says O2 sensor would throw HC readings higher, but if all else fails, I will try it. Thanks for the info.

[alec_b]

Lean condition would throw your NOx higher, because of higher exhaust temps. If the O2 was bad and leaning it out, it could be the cause. EGR can cause a lean condition also, but I'd think it would be more evident at idle than at speed.

[i<3bonbons]

I cleaned up the iac today, it was very carboned up. I checked the FPR, and it looks newish, with no evidence of leakage. Rechecked all vacuum hoses, and never found a single leak. checked the tps, and it was good, smooth ohm sweep. the 02 sensor wire was up against a spark plug wire, so I moved it and re routed the plug wire. then I went for a long drive (200 kilometers) Car worked great all the way, but exhaust is still a bit stinky. the 02 sensor looks very new, clean and shiny. I really want to throw an EGR valve on it, just to satisfy my curiousity. I can have one from the jy for around 25-30$ so i think I'll do that tomorrow. If that doesnt help, then I will replace the O2, as well as the fuel filter.

[Whitecrystal1]

I had a problem getting the Park Avenue '93 ultra to pass emissions do to NOx level being to high once when I owned it. Not knowing what was the cause I replaced the plugs, wires, air filter, fuel filter, pcv valve, egr valve and the catalytic converter... the car still failed. I took it to a friend at the dealer and he de-carbon the engine and it passed w/no problems (Something I learned about high NOx level can also means higher than normal engine temperatures) something you might want to try before you have it tested again and or before throwing parts at it as I did with mine. Good Luck

[tripscarcare95]

Change the o2 sensor and pcv valve, what limits were high on the etest?

[i<3bonbons]

pcv is good. O2 sensor should throw HC up high, not N0x, if I understand correctly. I swapped the EGR out with one from the Junkyard, then I decided to pull vacuum lines. found a few with small cracks/ blisters, so I redid all the lines I could find. The car seems to have more power, and it shifts better. There can't be any carbon in this engine, I've been blowing that out with my right foot since we got the temp. sticker last week. Thanks for the advice, but I have done alot of reading and it seems that High N0x comes from the EGR or the Cat. EGR has been replacced, so if it fails, then a new cat will be my only other option.