Another 1991 Fails CA emissions... Help!

[RKC]

I have a 1990 that gave me fits getting pass smog. Here are my results from my first failure.

15 mph / 2294 rpm
CO2: 14.7 (no limit)
O2: 0.2 (no limit)
HC: 51 (limit 110)
CO: 0.01 (limit 0.71)
NO: 868 (limit 772) ***

25 mph / 2450 rpm
CO2: 14.7 (no limit)
O2: 0.2 (no limit)
HC: 41 (limit 85)
CO: 0.01 (limit 0.59)
NO: 987 (limit 711)

After I passed:


15 mph / 2190 rpm
CO2: 14.7 (no limit)
O2: 0.2 (no limit)
HC: 109 (limit 110)
CO: 0.10 (limit 0.71)
NO: 611 (limit 772) ***

25 mph / 2440 rpm
CO2: 14.7 (no limit)
O2: 0.2 (no limit)
HC: 52 (limit 85)
CO: 0.01 (limit 0.59)
NO: 667 (limit 711)

I passed the test after using fuel injector cleaner, changed the oil, replaced the spark plugs, and cleaned the air filter. I used Chevron gas. My engine has 45,000 miles and blows a little oil on startup.

I did have new bullet cats on SW headers. The cats may have helped ,but they didn't help it pass the first time. I also have 4.10 gears in rear.

One major difference I noticed is the RPM's at 15 mph. In your test, you're barely off idle at that low RPM. Nearly 900 fewer than mine. About 350 RPM's less at 25 MPH.

Also, I'm not sure of the reasons, but in passing the NO portion of the test, I very nearly failed the HC portion. I tested on a summer day. The technician had the car running for nearly 20 minutes before and during the test. With the aftermarket radiator it ran very hot at idle. I subsequently swapped it for a stock radiator and dramatically improved the idle temperature. My point being, the engine coolant temperature had to be extremely high during the test.

Also on the first test failure, they failed me on my gas cap. I replaced it with a new one. Don't know if that would cause any actual exhaust emissions change, but on a newer OBD II vehicle of mine it set an error code that I couldn't solve until I finally replaced the gas cap. It immediately cleared the problem and never reset.

[Z51JEFF]

Not to hijack your thread here but you have a law maker,Dave Jones that represents Sac THAT NEEDS TO GO.This moron has proposed a bill several times making smog tests annual.Id vote the guy out of office but Im in the Bay Area.

[Dynomite]

Originally Posted by Z51JEFF

Not to hijack your thread here but you have a law maker,Dave Jones that represents Sac THAT NEEDS TO GO.This moron has proposed a bill several times making smog tests annual.Id vote the guy out of office but Im in the Bay Area.

If you are in Bay area......work on getting Nancy Pelosi out of office

[Z51JEFF]

Originally Posted by Dynomite

If you are in Bay area......work on getting Nancy Pelosi out of office

Come November 2010 Ill do my best to get them ALL out.

[Shinto]

Originally Posted by Z51JEFF

Not to hijack your thread here but you have a law maker,Dave Jones that represents Sac THAT NEEDS TO GO.This moron has proposed a bill several times making smog tests annual.Id vote the guy out of office but Im in the Bay Area.

What a @#$&. Unfortunately, I live outside his district so I can't do much to oust him. To me, public enemy no. 1, Sally Leiber from Mountainview has already been term limited out of office. She's the one to thank for rolling exemptions going away.

I don't think Pelosi is going anywhere. Her district (SF) is extrememly liberal and she now has real power (much like her cohort Diane Feinstein).

-----------------

I have half a mind to run a tankfull of injector cleaner, run it hard to really blow out the carbon, and smog it with the engine cold at a different shop instead of using my free retest. (Another $50 down the rathole.) HC and CO should go up, but I've got lots of room to play with there. Colder operating temperatures should get rid of the pinging and lower the NOx. Aside from a partial injector clog or failure, I don't know why it would be running lean. Bad MAF or O2 sensor? I'd imagine that would trigger a SEL code... (which is now an instant fail if you have any codes in memory or the light on.)

I don't think the power key was turned on, as I shut the car down when I got there and they restarted it to pull it into the bay, but I'll pull it out to be sure next time. I may also look into the iridium plugs. Definitely Chevron gas. Any other suggestions?

[tccrab]

Take it to Folsom Smog on the corner of Blue Ravine and Prairie City Road.
Ask for Bob Nailor.
Tell him I sent you.
Bob used to have a '91 ZR1 and I believe he still may have an extra PROM or two for you to try out.

I PM'd Benny C over at the CF, he used to own a smog shop over off of Arden in Sac. He has a '94 ZR1, haven't heard from him yet, tho.

Tom

[zrmynatt]

Have your A/C turned on when they test that will turn the cooling on and cool the engine down, that or move to Texas

[SillyB]

Originally Posted by -=Jeff=-

if you need OEM Manifolds an cats assuming you determine yours are bad I have mine off my 90 I would sell cheap

How cheap is cheap? I have a failing cat on the driver's side in my 1990. I'm ok for now, but I'll be back at the smog Nazi's inspection soon enough and will be needing them.

[-=Jeff=-]

Originally Posted by SillyB

How cheap is cheap? I have a failing cat on the driver's side in my 1990. I'm ok for now, but I'll be back at the smog Nazi's inspection soon enough and will be needing them.

Sold them.. sorry

[cuisinartvette]

Always have the power key off when smogging out here.
On the nox dont know what the problem is there.