PDX-Boy[hermit mode]

First off, thanx to <i>Audiboy</i> for turning me onto the tuning forum, I completely forgot about it.

Okay, anyways the thing my car is doing is not passing Oregon <b>DEQ</b>. Kinda pissing me off too since my local tuner shop is telling me their sniffer is taking below what is acceptable for me to pass.

My latest scores are as follows:

<b>THC</b>
Passing: 1.20
My Level: <b>4.71</b>

<b>N0x</b>
Passing: 3.00
My Level: <b>0.17</b>

<b>CO</b>
Passing: 30.0
My Level: <b>255.6</b>

Those are the ones that I am most concerned about.

As I was telling Audiboy, I took it in after the first time it went through and got the FMS (Fuel Managment System) tweaked, and then re-tested it. Still <b>WAY</b> too high for passing levels. So I took it <b>BACK</b> to the shop and had them look at it again. They got all the same readings that they did before.

So today I took it back in and tested it. Making sure to drive it for 10-15 miles doing from 30 mph - 100 mph to make sure it was warmed up.

Still failed and now I just got back from the shop telling me: <b>My best bet is that the computer is messing up the readings under fuel load because everything under 2500 RPM is fine on our machine...</b>

So, with that said, I had a guy from the boards offer me this ECU:
<img src="http://pictureposter.audiworld.com/37430/cis_iii0001.jpg">

I wanted to run past anyone who has a Audi 100 or even just knowledge of ECU's if this one will work fine with my car.

My Car Specs:
Audi 1991 100 FWD 2.3 L Automatic 5 Cylinder

Anyways, thanks to anyone in advance who gives me some advice on this.

If I can't get this worked out, I'm just gonna register the car in Lincoln City by the Coast so I don't have to run the car through DEQ. :-)

cuatrokoop

The PN for your ECU (which is KE-Jetronic) is:
443 906 264F and is located in the passenger side footwell if I am not mistaken.

How old are your:
Plugs (Bosch W7DTC)
Plug wires (only gives individual #'s)
Cap (Audi 034 905 207B)
Rotor (Audi 052 905 225C)
O2 (Audi 034 906 265F)

Check them before replacement, obviously. Also, the NF/NG motors generate fault codes, so you may check that. Try looking at 20v.org or sjmautotechnik.com for info on how to dump them.

PDX-Boy[hermit mode]

Will do, we'll see what they say.

ModifiedA4

did you check spark plugs and o2 sensors? how do you know if your cat isnt busted?

PDX-Boy[hermit mode]

I came to that conclusion this afternoon. Since the fuel just passes through, there's no time for it to convert anything.

They don't think it's the O2 sensors because they checked out fine when they looked at them and tested them.

Baffling to say the least.

However, I don't think the CAT would cause the levels of the THC and the CO to be at those high of levels.

cuatrokoop

You only have ONE O2 sensor. If its like the '86 5ktq, its mounted before the catalytic converter (I think in the case of the NF engine it is mounted RIGHT before or right at the inlet?).

If the shop checked "them" I suggest finding a shop that knows the I5 engine better, because there is no "them"...

PDX-Boy[hermit mode]

Yes, "it" not "them".

I actually watched them test the car this afternoon in the shop.

Audiboy

lowered. CO is a direct result of air / fuel mixture. HC is raw gas (unburned) and generally goes up when there is too much fuel to burn. Usually high HC is due to misfire when all things are set accordingly because during a misfire, raw fuel gets dumped into the pipes - although a misfire will cause the numbers to peak out - in your case maybe around 10

Did they check your 02 to see if it isn't broken? The O2 cannot tell the ECU to back out anymore fuel if the CIS is out of whack, hence it will eventually break. Also when running rich, the cat will work overtime to try to catalize it, and it will glow red hot. Those are signs that the mixture setup is real rich - or the duty cycle solenoid controlling internal fuel pressure is not behaving properly.


check out my quick rendition of CIS
<img src="http://pictureposter.audiworld.com/9/cis.jpg">

As you can see, the air flap drives an arm that pushes a plunger in the fuel distributor, exposing the fuel ports to more fuel when the plunger is pushed in. The balance between the two is a mixture screw. If this is off, at idle it may show slightly rich, but at full throttle, it may even be more rich because of how the lever moves. At idle, the O2 sensor may be able to tell the ECU to back down on the fuel pressure duty cycle solenoid and modulate the fuel goin in, but at high rpm, it may not have enough bandwidth to control it.

So, first, check to make sure that the ECU is responding to the O2 and controlling the CIS. This can be done by the shop by disconnecting the O2 sensor while idling and crusing, and checking to see if the tailpipe levels stayed the same or changed - most likely in your case, go even higher. If they changed, then the mechanical side is out of whack and needs adjustment or replacement. If there is no change, then check O2, solenoids, then maybe the ECU

cuatrokoop

Thats a pretty good rendition...And good tips for some rudimentary diagnosing.

VAG-COM with the 200 (I knew I should have gotten a 200 for a donor car!):
http://www.sjmautotechnik.com/VAGCOM2x2.htm

Code pulling on the NF:
http://www.sjmautotechnik.com/100ecuf.html

PDX-Boy[hermit mode]

and show it to them tomorrow and see what they think.

I think testing the O2 sensor to see what the rest of the car does is a very wise idea since I'm having a hard time believing it's the ECU causing all the problems.

I JUST WANT TO PASS DEQ!!! :-)