Hi,

I bought an 87 wagon with 230K on it. It passed safety, but failed emissions. Hence the post. My post is long. I have tried to anticipate your questions.

Based off of posts here, I think I know part of the problem.

On the passenger side of the engine (the engine is marked B230F), there is a shield on what I think is the exhaust manifold. This shield of metal mounts on the piece of metal that has four pipes that mount right beneath the spark plugs. The shield of metal has a crack on the seam that at the widest point (about 1 inch) is wide enough to insert the tip of several playing cards. Further, there is a hose that mounts to this shield and the hose is ripped around at least half of the circumference of the hose (where it mounts onto the shield).

Based off of posts here and my research elsewhere, I have learned the following:
The oxygen sensor analyzes the exhaust and sends adjustments to the engine. If the cracks permit ordinary air to enter the exhaust system (by sucking it in), then the oxygen sensor will send a false signal to the engine and this may cause an emissions failure.

Note that prior to the test that I ran the car for 45 minutes in highway and suburban driving. It sat for about 15 minutes at idle before the test. I have a 93 240 sedan and that temperature gauge is right at 9:00 o’clock within 10 minutes of ANY driving. In the 87 (the one that failed), the temperature gauge is at 7:30 most of the time and occasionally at 8:30 (these results were based off of several trips around town for 45 minutes or more with the temperatures at 50 to 60 degrees. I was driving in stop & go and at highway speeds).

Here are my test results. I live in Arlington, VA which is in the Washington DC metropolitan area; the standards are probably fairly stringent.

15 MPH:

HC ppm: limit=120; reading=135; result=fail
CO%: limit=.48; reading=.51; result=fail
NO ppm: limit=1565; reading=3093; result=fail
RPM=1725; result=valid (I do not know what this means)
Dilution =14.3; result=valid (I do not know what this means)

25 MPH:

HC ppm: limit=217; reading=158; result=pass
CO%: limit=.70; reading=.61; result=pass
NO ppm: limit=1522; reading=3101; result=fail
RPM=1744; result=valid (I do not know what this means)
Dilution =14.3; result=valid (I do not know what this means)

What now? Fix the cracks by replacing the parts and retest? What test or tests is/are effected by the cracks? Can I add any additives to the fuel to improve my odds?

Kreg