CAN'T PASS CALIF. SMOG, IDEAS/HELP!!!!

[tpr60]

90 zr 63000 miles, changed plugs, wires, one coil, changed 6 injectors[rest ohm OK], fixed vacuum leaks, updated GM prom. Has high hydrocarbons at idle, over 300[needs to be under100] 2500rpm reads 120HC, o2 at tailpipe is 5[should be zero]. My understanding is the car is running lean. Any ideas, comments, or do I need to register it out of state[Calif].

[Kevin]

1: call mark haibeck
2: search for another members thread here and contact him....i think the title is "failed cali smog' or something like that
3: move out of that nazi hell hole

[tpr60]

Thanks for all the links, some I had seen before, took a couple hours to read and refresh my memory. I will run my Snap on scanner and check the o2 sensors and try wrapping the cats. Have a pair of used manifolds/cats coming from Pete in ILL. I am in a rural test zone so my test is a static one at idle and 2500rpm. Thank goodness my smog tech is a car guy that I used to deliver parts to, my pre-tests have been free, he is interested to see what it will take to get the Z to pass. He never seen a ZR before smog testing my two cars. Hope I don't have to do the NLA part routine with the referee.

[Bill]

The referee thing is not all that bad. I was able to handle the whole transaction on the phone, except for the actual emission test. I am now able to run headers and high flow cats with the blessing of the smog Nazis. Good luck and keep us posted

[zr1don]

You should be able to pass the idle and 2500 rpm tests. If your HC,s are high that is an indication of a rich mixture or bad cats. If the cats are bad, both HC and NOX will be high. Post up all your test results for idle and 2500 rpm. I'm sure someone here can help w/the diagnosis.

[rhipsher]

Texas is real bad to. Mine runs real clean. These are the results of mine every year.
http://i301.photobucket.com/albums/nn63/keeno1970/emmisionstest2.jpg
But mine might not pass California either I don't know what the max limits are out there.

[tpr60]

Thanks for the interest guys.

Last pre-test readings, at idle

HC............ppm 387,,,,,,,,Limit 120 HC reading at 2500rpm 110 limit 140

CO.............%0.49,,,,,,,,,,Limit 1.00

CO2...........%10.8,,,,,,,,,,Limit ? [15.2 will pass]

O2.............% 5.4,,,,,,,,,,,Limit ? [1.6 will pass]

P.E.F...........0.496,,,,,,,,,,,Zero Required {I do not know what this is?]
Will try and change both o2 sensors this week, and wrap the converters.
Check for any new vacuum leaks with a propane torch.

[mike100]

less than 11% on the C02 is WAAAY too low. when the cats light off and have a decent fuel mixture, you will have 14.5-15% depending on Catalyst health and fuel mixture accuracy. There isn't a limit on C02, it is just easy to measure and used for diagnostic reasons to see if the catalyst is 'running'.

CO is too high..I only had .35% with a big vac leak that wouldn't idle below 1300 rpm. .10% when I fixed it.

That cat did not light-off. It could be bad if you ran with bad injectors for a long time.

[tpr60]

Thanks Mike, when I got the car in Jan. it had a dead coil 1&6, vacuum leaks[mice] 5 low oms pri injectors and one dead sec. injector, dead plug wire. So the cats were trying to clean up a rich engine. All have been fixed or replaced. Left cat is in the cool side on a thermal temp scan. I have a set of 1990 manifolds/cats coming from Pete in Ill. Thanks for you thoughts.

[mike100]

Here's a really good reference for emissions reading analysis:http://www.ratwell.com/mirror/interro/techgas.html

[tpr60]

Thanks Mike for the reference, that is the type of information that will be real helpful, now and later.

[Coupe89]

Do you have the stock prom in the car?
But your numbers looks lower then mine....

[tpr60]

Stock GM updated driveability prom used on the second pre test, stock prom used on the first test.

[Z51JEFF]

This is the fourth ZR-1 here in Ca that has failed that I know of.My 91 has 18,000 miles on the clock and it failed twice before I took it to a referee and it passed.Witrh tg first 2 smogs car had a Haibeck chip,open filter lid witsh a KnN filter.The last smog was bone stock new 02 sensors,its the Nox levels that are causing the problems.I suggest you join THE SEMA ACTION NETWORK.Ive got a number to call and ask if anything is being done to help owners that cant pass.In 4-2011 the state lowered the max limits in an effort to get older cars off the road.How would I find out what the smog levels were when the car was new?After I failed twice I dug out some of my past smog paperwork and my car with 6000 miles tested at over 500 PPM at the Nox levels.

[tpr60]

Update, my buddy and I did a leak down test on the Z today to rule any possible internal engine problems. Passed with all cylinders showing 3 to 7% leakage. Waiting for some thermal wrap to show up and I will wrap the cats to keep the heat in for my next smog pre test. Keep your fingers crossed!!!

[tpr60]

=D>SHE PASSED the smog test today!!!! After thermal wrapping the cats, new o2 sensors, propane testing for intake leaks we pre tested the Z, would pass the 2500rpm test but failed the idle test for HC ppm. Sh---t!!!. That was last Thursday. Put the car on my lift and removed the manifold/cat assembly, guess what I found??? Someone gutted the cats, no honeycomb at all. 12 hours later both used cats I got from Pete in Ill. were installed. Official smog test showed only 3ppm at both idle and 2500rpm, and 0 CO's, so clean you could breath the exhaust. WAH HOOOO!!

[mike100]

with 11% CO2, I knew you had a bad cat, but it seems these cars really do like a fresh O2 sensor(s). Mine will pass current testing thresholds, but I bet I could get a 10 percent improvement with a new pair of sensors.

Where did you get yours from?

[tpr60]

Mike, I get my ACD parts from my local parts house that I used when I was a GM parts manger, so there is a good working relationship. Took the # off the old Bosch O2 sensor and matched it with the same # on the new sensor. The parts catalog shows only one use but we know there is one on each cat.

[bdw18_123]

...Put the car on my lift and removed the manifold/cat assembly, guess what I found??? Someone gutted the cats, no honeycomb at all. ...

One of my cats was the same way, nothing in there at all. The other side was still intact, so I think in my case the catalyst on one side just got worn out and then probably broke up and got blown out of the exhaust at some point.

[Z51JEFF]

with 11% CO2, I knew you had a bad cat, but it seems these cars really do like a fresh O2 sensor(s). Mine will pass current testing thresholds, but I bet I could get a 10 percent improvement with a new pair of sensors.

Where did you get yours from?

The sensor on the right side is a nightmare to plug in,be prepared to breakout the -special tools- for this one.In my case it was a stiff wire and some sticky dumb-dumb,also known as seam sealer stuck on the end of the stiff wire to help get the 02 plug started.

[tpr60]

YOU GOT THAT RIGHT!!! A real bitch. Found it easier to remove the engine mount nut and remove the mount angle frame brace to give better access. Why couldn't they have extended the harness a couple of inches to make it easy like the left side??? Maybe I should start making a harness extension for the net members???

[zr1don]

Two options for overcoming the problem with plugging in the O2 sensor on the right side:

1. Make or buy an extension, pull the existing sensor wire out at the rt front side of engine, plug the extension in and thread it down the way it came out. You should fasten the excess wire you now have near the O2 sensor.

2. You can remove the O2 wires from the wire loom up to the rear of the engine (the loom runs under the plenum) and reroute the wires down the rt rear of the engine.