I keep failing smog test due to CO at 7.78 and limit is 0.71.

After first fail (which also was written up for too much smoke) I R&R'd the cylinder head that needed to be done due to excessive oil consumption (one quart of oil to Vegas and one quart back).

It was a four day job--rebuilt head, new timing chain, new plastic chain runners, new oil chain runner, water pump, idlers and other parts that were worn. It was a grueling four days that kicked my butt (much thanks to this forum and Dave Barnhart's website-- http://davebarnhart.com/mb300e/Default.htm -- for helping me through).

The engine fired right up and runs great! No more smoke--BUT Extremely high CO?

What should I do now?

That's very high - did you knock off a vacuum line, or not reconnect part of EGR by accident?

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15 VW Passat TDI
00 E420
98 E300 DT
97 E420 Donor Car - NEED PARTS? PM ME!
97 S500
97 E300D
86 Holden Jackaroo Turbo D
86 300SDL
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All vacuum lines are connected (I triple checked all lines) I don't know about the EGR? Didn't see anything that looked like EGR to me.

Maybe a vacuum hose is connected wrong? I can't find a diagram at the library or online. Can someone provide me with a vacuum system diagram.

With readings that high, looks like your Lambda control is not working at all. Check the oxygen sensor voltage to see if it is putting out the proper signal.

Can you walk me through it? What range should the voltage be?

I would have your o2 sensor and EGR valve checked for operation...

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Current cars:
2000 ML55 AMG, 174k miles
2003 C240 T-Modell, 202k miles
1995 S320, 207k Miles

Where is the EGR on this car?

The 89 M103 didn't have EGR.

The guys at the smog place suggested that maybe I needed to adjust the fuel mixture which is through the top of the air cleaner.

I noticed that the little tower at the top of what I think is the meter-control unit has been shaved? I do see an allen screw in there and it takes a #3 mm allen--but it doesn't seem to make any difference when I turn it--not sure if it is working? Maybe not holding adjustment?

History of this fuel injection system: About a year-and-a-half ago I had a fuel leak at at one of the fuel systems electronic pieces (which one I don't remember). I purchased a used fuel system complete from an auto salvage yard in Huntington Beach--and now I find out that they sold me one with a shaved meter-control unit that I believe will not adjust.

I called to complain but the auto salvage yard said not warranty after 30-days and will sell me another for a $100 this time-- which is a $50 discount.

Could this be my problem? Or am I going to waste a $100.?