Hello again,

Thanks for the input from fellow DIY engineers

I decided to do the BG44k treatment as suggested by two of the respondents. See their site…………..
http://www.bgprod.com/

This process is a three part application 1] Inline fuel injection through the gas line, 2] Spray product through the distributor air inlet, and 3] The tank supplement. This process is done via approved garages using special injection process is and is supposed to remove combustion crud, distributor build up and intake crude. This was not cheap, it cost me $250 for the labor and $80 for the stuff. They said Mercedes was more complicated then other auto’s to implement. My initial concern was what would it do to my Kat and o2 sensor. I was assured NO problem!

Anyhow, it’s done and the car runs a lot smoother then before. Lets face it after 200K miles there has to be some gunk in there someplace. This has given me the basis to start again. I adjusted the Lamda settings again for good measure.

However, now it’s intermittent, idling roughly. Not as bad before.
When you come to a stop in drive it will slowly drop RPM until around 500 rpm. Then it will start to what appears to be missing. Give it the gas and the car runs great. Overall performance is excellent.

It almost makes you think the plugs are going. I have new Bosch H9DCO . Anybody think otherwise let me know. These are recommended and listed in the owner’s manual.

I also had another go at my fuel regulator. I actually removed it this time and gave it the air test. I applied air pressure to the pressure side and it held its ground. Nothing coming out of the return line. Incidentally there are two none return valve at the fuel pumps, one for each, which can/could cause issues. I addition to the fuel accumulator at the pumps.

I also had another go at the cold start valve and low and behold the pressure on the input side is not holding. I applied my trusty Mittvac and it wouldn’t hold up. I have decided to order a new one anyway [200k miles?]. This could cause dribbling fuel into the intake manifold if not completely closed, regardless of the computer [CIS] telling it no. It met the electrical specs has previously mentioned.

I also looked at the relationship between the idle stop switch [deceleration stop switch], the throttle position stop and the kick down cable adjustment. Per the specs I readjusted. My wife didn’t tell me that the kick down was not working the way it should have. Now I have a nice gear change if I need it. I was reviewing the way idle is set with this relationship hoping I could get some extra RPM.

I will update you all when I have installed my Cold Start valve.

Anybody have any thoughts on the grounding of the o2 sensor in the exhaust. Did a digital ohm check between the exhaust and the battery ground and I read some 3-4 ohms. The exhaust is the ground for o2 sensor. It seems to me with such small voltages we are dealing with here that a solid ground back to the source would appropriate?
I guess the o2 sensor engineers no what they doing??

Brian
300ce, 240D, 300D Euro and 300SD