Nasty94Z28

I failed the emission test to I live in Stafford,Va. I have a 94Z28.

15MPH
-------
HCppm-Limit-96 Reading-263- failed
CO%-Limit-0.53 Reading-0.81-failed
NOppm-Limit-733Reading-1898-failed
------------------------------------
25MPH
------
HCppm-Limit-93 Reading-268-failed
CO%-Limit-0.52 Reading-0.80-failed
NOppm-Limit-664 Reading-1381- failed

Overall Test Results Failed.
The person at the test shop said he could tell by the test that the Cat was Gutted out.

Robs97Z28

Well, was it gutted out? hum

black95z0122

i checked my fuel pressure again the right way with the vacume line off and it was really high so i turned it down. I also noticed that some gass came out of the vacume line. i dissconnected it from the end that is attached to the intake and after adjusting there was a little pool on top of my intake. Also i got my car scanned and there were no codes and i was getting good signals from the O2s.(or atleast i think it was jumping around from 50 or so to 900)this was at idle by the way.

So its prolly the cat. I'm gonna get some slp headers y pipe and a carsound cat.i'll post if i pass after

thanks alot guys

Robs97Z28

if you are getting fuel out of the fpr vac line. You need to replace it, ASP. you are putting unmetered fuel in the manifold. it is throughing very thing off.

94Sleeper

You should never have any fuel coming out of your adjustable fuel pressure regulator. If you do there is a hole in the diaphragm inside the regulator. This would cause your fuel pressure to be unregulated and you would get raw fuel dumped into your intake via the vacuum line. This would cause you to run rich for sure. If this has been going on long enough it may have taken out your cat.

Sounds to me like at a minimum you need a new regulator.

black95z0122

wow mabye i won't have to spend money on a new cat and headers. Can anyone reccondmend a reliable afpr? should i just replace w/ a stock one?

Thanks again

Robs97Z28

just go with a stock one. there isn't any advantage with going with an adjustable one.

black95z0122

changed out old fuel pressure regulator and replaced with stock one. I passed! thanks guys

Z06Z28

congrats..that it was a simple fix.

Robs97Z28

Great News!

I just took the CA smog test this week. What a PITA!!! I had them do a pretest and I'm glad I did because I failed. I forgot about the block off plate being wide open. So, the egr wasn't woeking, do to the lack of back pressure. When I put the fully close plate it passed. It taek them a couple of tries, though.