I removed the engine and discovered the male-to-male adapter, connecting the egr valve to the pipe that goes to the intake manifold is solid. The adapter is manufactured that way. Why? Is this a mistake, a mechanics fix to cover another mechanical problem or a Europe/America issue. I also discovered the air pump was unplugged, which I think, is a mehanics fix for another problem. I bought this 2 yrs ago, drove a couple of months and parked in garage since. It drove very well and had no indication that something was seriously wrong. I am now returning it to service, and want to correct everything. The diphram in the egr valve appears to be no good. Why replace it if the adapter prevents egr? What is happening with the computer with a blocked egr tube and a disconnected airpump?

I have discovered that I have a 104.981, which, best I can determine, is from a 300SL. Unknown year, but possibly an early model. Clearly a 300CE body and non-original engine. What is the difference between a 104.980 and a 104.981? And, why a solid egr tube?

Sounds like someone has been messing with it. Run your VIN here - http://old.mbclub.ru/mb/vin/?lng=eng - to find out what you're supposed to have. Yes, a 104.981 would be a 90 to 93 300SL. The full engine number would tell you the approximate year but they were all pretty much the same, and very similar to the 104.980.

Thanks, deanyel. I was told by seller, 2nd owners, they thought engine was changed. I ran my VIN at the link you provided. It definitely is not original engine. I also have the engine out and the block stamping in clear view. The full engine number is 104 981 12 001 061. Four digits follow, the first, is an upside down, backwards "3"(yes, i am sober, standing straight up), followed by 10.0,[(3)10.0]. I would like to find out exactly what this engine is, and also, this clarifies some part identification questions I have encountered. I am also back to my original questions as to what steps should I take to correct everything.

Not sure about the suffix to the engine number but you have the 1061st 104.981 - very likely a 1990 300SL. You can check original parts setup for that engine on the EPC or the Russian parts diagrams - http://www.detali.ru/cat/oem_mb0.asp?TP=1 Does the car have an enabled check engine light?

deanyel, I have never had any lights appear or I would have dealt with it. I do not leave things go. But, this is Florida, it is very common practice for mechanics to disable lights to hide problem indicators. I will make sure all indicator lights works. I have never had any performance problems to indicate a problem. I have only had an occasional rough idle, that I assumed was an injector/injectors issue from infrequent use. I had planned on either cleaning or replacing the injectors. Also, I do not think the engine suffix will hamper my efforts to properly obtain parts, which has been one of my concerns. Before removing the engine, I was assuming a 104.980. Thanks.

I guess there's a more basic question - whether you still have the diagnostic system on the 16 pin connector. Those two cars - 124.051 and 129.061 - have basically the same diagnostic system so with any luck yours is still working. If you haven't already you should build the code reader and learn how to read the fault codes. There should be a fault code on the code list for both EGR and air injection system.

Thanks. Makes sense. I have seen reference to the code reader, but have not made one. I found the thread for building it, so will try that and see what happens.

But, blocking the EGR should not hurt driveability at all, and could actually improve it at idle. It's only an issue if you move to a state with smog testing.

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Prost!

Hirnbeiss, should I then save me some money, remove the egr valve and tube, make a block off plate for the manifold,plug the intake port and plug the vacuum line to the controller?