Ed Hughes

Peace brothers & sisters. Take a deep breath, hold your thumbs and index fingers together and say Ahmmmmmmmm. I'm going to try a natural method that doesn't require any large outlay of cash to fix my problem, so please wish me luck.

I failed on Friday. Everything was well within spec, except "high speed" (25mph) NOX. Max allowed is 760-something, and I was 1124ppm. So, I went out and got a can of CRC MAF Sensor cleaner, and cleaned my MAF unit today. I also put a fresh bottle of Techron in with a tankful of 93 octane, and I'm going to put my foot thru the floorboard tomorrow on a 75 mile roundtrip to an F1 watching party.

Then, I'm going back in for the retest next week and convince them to test in 2nd gear. Wish me luck.

BTW, as a contingency, I drove over to my local www.928srus.com store and picked up a new MAF as a contingency in case this doesn't work. My O2 sensor is 3 months old.

Mike Frye

Ed,

I'm sitting in the lotus position, at one with the universe and chanting to the god of BWAAA for your car to pass.

In case that doesn't work, could you by any chance have a vac leak? I think my NOx went down when all I did was go around and make sure all the intake rubber was seated, including the MAF.

Link to my emissions saga (5 months of issues with my '85)

Ed Hughes

Thanks Mike. I did give it all the once over today when I pulled my MAF to clean. I'll go thru it again tomorrow.

Bill Ball

I pulled up an image of the Andrew's 928 shrine and said a few Ahmen Ferdies for you. Weird for a 91 to do this - didn't it pass when you bought it? Yeah, it probably needs more exercise.

justin

Ed, make sure the car is good and hot when you get there.

docmirror

With your O2 sensor so new, it gave me an idea. The O2 sensor(all sensors) have a characterization period as the sensor gets coated with products of cumbustion. this may set the calibration of the LH module off juuuuuuust slightly enough to fall out of optimum range.

Potential fix: Remove the ground strap from the battery, wait 5 minutes, then reattach. The LH and EZK will re-calibrate after about 125 miles. Drive the car long distances after reconnection so that it warms up fully, and is calibrated fully warm. During this period, you will notice that your fuel economy is decidedly poorer than normal. It will slowly work it's way back to normal.

Good luck.

largecar379

too bad yours isn't 'older', my '80 Euro just gets a (safety) inspection sticker because it's over 25 years young......

yeah, I knew you didn't want to hear that from a fellow Texan....

regards-----

Ed Hughes

It did pass last year with no issue. It didn't cross my mind that it wouldn't this year. The only change since? X-pipes/cats.

I drove the 4 miles to the inspector with one stop at Starbuck's. It did idle for a bit, and seemed to be up close to temp at least. I truly assumed there would be no issue and didn't give it a thought.
One thing is, this has probably been the slowest point of time in its life with me. I've been driving like a normal person for the last week or so.....So, I'm back to punching it for no reason while smiling, and will exercise her well before she goes back in.

Doc, thanks for the tip, I'll try that before my drive today.

fabric

Ed- I second Justin. Make sure you've gotten it good and warmed up - it's mainly the cats. I'd think new fangled cats would warm up quick, but 4 miles and a bit of idling may still not cut it. In Illinois, the recommend 15 minutes of driving, I usually go more.

Ed Hughes

I've read a lot of the posts on this situation, and it would seem that many feel these cars should pass with no cats on...my 911 with a chip actually did before I put headers on it. I had a cat bypass that the average mechanice would think was a cat, so the visual was OK. Now, forget about it...

But, I agree that the operating temp may not have been optimal for all systems to be at optimal operating temp, so I'm going to make sure it is at full operating temp, however. I'm going to hope that it was a dirty MAF or just needed a good "blowing out". The second gear thing seems to help too.

Mrmerlin

75 miles is not a long enough drive... try going 200 after the battery disconnect, without stopping, stay away from Starbucks it will only make you have to make a pit stop sooner

SeanR

Ed,

There is an inspection place just to the east of you that was recommended to me. I forget the guys name but if you ask him to "take your time" and tell him 5th gear sent you, he will be very gentle.

Mrmerlin

It might be a good idea to install you new MAF before taking off, as it has to be part of the reclibration on the puter and check the air cleaner , you do have a clean factory air cleaner installed dont you???

Ed Hughes

I'm good on the air cleaner. I don't want to take a NEW MAF and turn it into an OLD MAF. Roger is a nice guy, but I only got the MAF in hand if I need to go that route.

Bill Ball

I'm seeing more early failure problems (1 year or so) with aftermarket cats. Two cases locally in the last month. Only solution - new cats. I hope that's not the problem. They had more than high NOx, so probably not.