I scored a 220 Hydrocarbon while the limit is 57... My C02 was .06.. with a limit of .04. So, after hearing my buddy at the GM Dealership tell me it was $85 an hour to diagnose, and I had to spent $450 for an automatic pass.. I told him I'd think about it.. I called my cousin on my way home, and he plugged in his computer to find out what it was doing... The EGR was working, it kept pulsing back to the laptop... Now the O2 sensor is a different story... We were getting readings of -950 back into the blue of 250... Then to -750... back to 250.. And the car was really running lean... Now, I've changed EVERYTHING I could think of that would cause it to fail an emissions test... Everything except for the wires on the ignition end, Fuel Filter, Oil, PCV, vacuum lines, catalytic convertor, air filters.. blah blah blah... I also put in some Sunoco 93 Octane fuel, and drove the car for half an hour at 100 km/h to have the cat really hot... Still.. Failed... Please help meeee!!! I will be posting the results of plugging in the laptop later on, my cousin hadn't emailed me yet when I had got home... We've got 20,000 + Data logs, so it should be interesting..

Have you checked out the coil?

Just changed it last week with an OEM Replacement.. $75..

Changed O2 sensor, cleaned our airbox, and tried again... Ran worse than before... Next thing is plug wires.


EDIT : Took it for a drive, seemed to actually be smoother than before... It's got a much better feel at WOT, like.. Smoother than before. We'll try the plug wires and see what happens, I also need to replace the trans mount, good thing I have a spare

Changed the plug wires (Man am I cut up), adjusted the TPS to .54 volts DC, cleaned out the port for the IAC, and tested again... Wow... It purrs like a kitten.

Two things:

*Don't run higher octane for an emissions test. Run the lowest octane you can get.

*Not all new O2 sensors are good. Many people have installed brand new O2's and ran worse than before. Some types are better than others.

It was an NKK O2 sensor, and guess what... It failed again... Any ideas?

Guessing doesn't do a lot of good. You need info from datalogging.

Here they are... Notice the oxygen sensor.... What about my MAF?

And the other half.. Almost forgot.

Block learns at 145 - 150 is not good. They should be close if not 128.

The O2 reading determines the BLM's, so a bad O2 sensor could cause the problem.

The O2 sensor could be reading fine and the readings could be the result of several mechanical problems.

There are many possible causes, but I'll give you a brief list of stuff to check for.

*Vacuum leak between MAF and manifold base.
*misfires caused by ignition malfunction - check plugs
*faulty fuel injector or injectors - clogged or failing
*exhaust leak upstream of the O2 sensor
*ECM calibration is not a good match for engine combination
*faulty fuel pump or fuel pressure regulator

*Vacuum leak between MAF and manifold base. - We went around with a can of quickstart and it didn't change idle
*misfires caused by ignition malfunction - check plugs - Brand new AC Delco
*faulty fuel injector or injectors - clogged or failing - Tested at 16 ohms for all of them
*exhaust leak upstream of the O2 sensor - Most likely the problem, you can hear a major leak toward the front.
*ECM calibration is not a good match for engine combination - What do you mean hear?
*faulty fuel pump or fuel pressure regulator - Changed in 2005 by a previous owner

My money would be on the O2 reading a false lean condition given the leak you mentioned. If your O2 is bad (or is getting extra O2 in the exhaust stream from a leak...) and is therefore indicating a lean condition when it's not actually lean, and the car is adding fuel to compensate (i.e. high BLM's), then that could cause a rich scenario which would result in increased HC's...

Forcing open loop *might* help (by taking the false reading O2 out of the picture and running uncompensated default fuel amounts, defaults might be a little rich though I can't remember)... But, it would only be a temporary hack kind of fix, if it even works...

stupd question but... you got your air injection pump on that car?

Yeah, we've got good airflow. How do I force it into open loop? We've only got 3 days left before it's off the road... We're only allowed 2 10 day permits now...

You can force open loop by simply leaving the O2 sensor disconnected. But... Fixing the exhaust leak might be the better idea (for a long term fix, and because I'm not 100% sure that open loop will get you a pass)... On the other hand, if your retests are free and your testing station is close, then I say go for it.

The exhaust leak will be fixed... It needs a new exhaust anyway, as for right now I'm in a crunch to get it to pass. If open loop will be better than what I have now, it'll be a good weekend.

Well, I did some reading on open loop fueling and it appears that it does run rich, and possibly significantly so. With that said, open loop may be less likely to fix your HC issue than I originally thought. However, I have no way of knowing how much your false reading O2 may be enriching the mixture and how that would compare to how much richer open loop runs. So, there is still a chance it may help.

I just keep pushing the leak fix as a better idea because I'd feel bad about wasting your time and possibly money (for gas and a retest) on a suggestion I don't have full confidence in. Hence all the disclaimers. Good luck though man, let us know how it goes...

one thing I used on my cadillac that actually DID work, (it has a MPFI 300 v8 in it, basically an aluminum 305 with floating cylinders) was i went to the GM dealer and bought a bottle of GM top engine cleaner (the liquid, not the spray) and ran it through a restricted vacuum line and cleaned the living piss outta it. car idles much smooother. oh but do check one thing, pull the vacuum line off of the fuel pressure regulator and check for raw fuel (sometimes you gotta sniff at it) if your FPR has ruptured, it will feed fuel into the vacuum system and will get burned off in your cylinders which can and will caue a rich condition.

my bird kept failing to,then 1 of my buddies that does etest's told me to set my timing at 0, and havent failed since,not sure why but worked for my car

It passed!!!
We scored a 48 with a limit of 57.. I nearly cried...

A sparkplug wire had come off, the rear one of the driver side (What a PITA to get to..) We put a gallon of methyl alcohol to 4 or 5 gallons of gas, I retarted the timing to 4* BTDC, and crossed my fingers... Worked out good! Thanks guys!

cool,

1/5...nice mix


Good Stuff....I was thinking it was the Cat. myself but Ive been down this road before and wouldnt dare speculate. Either you put it on the machine, pay up or keep throwing parts at it. Whats the cutoff year for no testing?

'87... If I buy another car... It's gonna be 87 and earlier..... This etesting is bull... Such a big money grab.. I wish we could go in and do inspections on peoples houses every 2 years for their electrical, we'd be loaded..


I was at Costco the other day and saw your car, lookin good!

man cutoff down here is 95. I dont envy you guys

Hey, glad to hear it worked out for you. Our cutoff is 25 years... I guess I can't complain too much,though, cause all we have is the sniffer, no inspection. And, our HC limit is like 150... It's too bad though, my car sounded awesome with no catalytic... And, my wallet was awesomer before the $200 went for the cat...

Yeah thanks man...she'll get there. Its either I got more money than time or the other way around so eventually the two will coincide and shell be a little prettier. Then Ill bring it over so you can do the plugs and wires for me

That is such a huge selling point on the older cars...no etest required.

Alright, sounds good.. I'm getting practiced up on the plugs/wires now, so it's not too bad... The TPI cars are worse...

Yes....yes they are. 9-bolt axle bearings aren't much of a picnic either.

Glad to hear you finally passed. In 2014 my 89 will be test exempt, but I keep hearing rumors Ohio (the last 7 counties in Ohio out of 88 total) are expected to get rid of the tests altogether in 2010, so we will see. Ohio numbers are pretty high as well, my brother almost passed without a tune up on his carb and with blown valve seals.