[s-cars] Emissions Test Failure

[Kaklikian, Gary]

Thanks for the reply, Jim. The problem appears to be only a rich idle mixture (not adjustable of course). Other than the off-idle stumble, the car runs great - good power, gas mileage, etc - and no ECU codes are stored. No poor starting or uneven idle problems that are typical of vacuum leaks. I think it's a problem with a sensor somwhere, rather than a larger ignition or fuel problem. The air filter, plugs/boosts, and O2 sensor were all replaced recently.
Gary

-----Original Message-----
From: Jim Bonnet [mailto:jimbo at sysdump.com]
Sent: Monday, May 20, 2002 2:30 PM
To: Kaklikian, Gary
Cc: s-car-list at audifans.com
Subject: Re: [s-cars] Emissions Test Failure


Kaklikian, Gary wrote:
> My '92 S4 failed  the emissions test, in particular the hydrocarbons at idle were very high. All other readings (CO,CO2) were normal at idle and at 2500rpm. The car has had a stumble off idle recently, so I suspect it may be running rich at idle. I checked the throttle switch per the instructions on S. Mockry's site, looked for vacuum leaks, and pulled the ECU codes, all to no avail.
> Anyone encountered a similar problem?
>
> Thanks,
> Gary

- Ignition system malfunction (plugs, wires, coil)
- Incorrect air/fuel mixture
- Vacuum Leaks (hoses EGR, Intake manifold, carburetor)
- Incorrect ignition timing and/or idle speed
- EGR valve partially stuck open
- Faulty fuel injector Operation
- Internal engine problem (burned valves, poor compression)
- Inoperative or missing catalytic converter
- Air injection system failure