Since i am changing my fan bearing bracket, i checked on my smog pump also, and although it does not screech or grind, there is a slight wobble in the bearing which tells me it is on its way out...

we don't have emission testing in florida so i will be taking it out....

http://www.peachparts.com/shopforum/showthread.php?t=132218&highlight=smog+pump+removal

the thread describes the right belt size for my car which is great, now i am not sure what to do with the plumbing, but if someone explains to me better how the smog pump and valve work, i will have a better understanding of what to remove/ block in the remaining plumbing going into the engine head ...

any feedback?

thanks in advance......

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1993 300E, 2.8 M104 .....

Ok, so now i am completly confused on belt size....

first, allmercedes and Autohous list two belts for my specific engine ...

6PK2415
6PK2475

which one is the stock with the pump? I have read so many posts about shorter belts, yet they seem very inconsistent especially for the 104 engine.....

any ideas?

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1993 300E, 2.8 M104 .....

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1993 300E, 2.8 M104 .....

Correct belt is dependent on engine serial number. Check this link for production breaks

http://catalog.peachparts.com/ShopByVehicle.epc?q=&yearid=1994%40%401994&makeid=63%40%40MERCEDES+BENZ%40%40X&modelid=6391%3ABT%7C5%3AMBC%7C1508%3AED%7C10000022%40%40E320+Sedan&keyword=belt&subcatid=P:242348@@Multi+Rib+Belt&mode=PA

Early production 104.992 had belt tensioner with adjusting barrel, late production 104.992 had different style tensioner. That's the reason for different belt lengths. Autozone and other mcparts outlets have incorrect information on their database.

If your engine calls for the 2415 belt (old style tensioner) a 2375 (Gates 935K6) will work with smog pump removed. I currently am running this belt on my 94 wagon while I wait on smog pump rebuild parts. If anything, this belt is very slightly to loose, if I were at the parts store again, I'd try the next shorter.......

If you have the later style tensioner, I would try a belt that is 0040 or 0045shorter than stock.

Hope this helps.

J. M. van Swaay

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1994 E320 Wagon, 230,000 miles
1995 E320 Sedan, 106,000 miles
1994 E500 Sedan, 79,000 miles

Thanks, that is helpful. yesterday i picked up a 93.0 belt so i think that should be perfect...my engine has the older style tensioner....

do you know what needs to be blocked if i remove the pump completely?

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1993 300E, 2.8 M104 .....

Sorry, link doesn't work. Here are production breaks for 104.992

Notes: 21.36 X 2475
Engine Range: From 12-072237 To 12-102821

Notes: 21.36 X 2445
Engine Range: From 12-102822

Notes: 21.36 X 2415
Engine Range: From 0 To 12-072236


Only thing you need to do is block off the plumbing to the exhaust manifold. There are two valves that are part of the plumbing between the the pump and the manifold. Metal pipe bolts to middle side of block on pass side just below cylinder head. Check valve threads into end of this pipe. Rubber hose connects check valve to pneumatic shutoff valve, another hose connects shutoff valve to back of pump. I just capped the check valve.

J. M. van Swaay

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1994 E320 Wagon, 230,000 miles
1995 E320 Sedan, 106,000 miles
1994 E500 Sedan, 79,000 miles

Sorry, just saw you were working on a 2.8 That is a 104, but I don't think it is a 104.992 Don't know if belt configuration is different from 104.992.

By the way, what ever happened with your timing mark alignment dilemma?


J. M. van Swaay

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1994 E320 Wagon, 230,000 miles
1995 E320 Sedan, 106,000 miles
1994 E500 Sedan, 79,000 miles

what about the switch over valve on the front timing cover? also, are you having codes with this?

much appreciated!

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1993 300E, 2.8 M104 .....

Oh yea, I forgot the switchover valve. I just plugged it with a short piece of hose with a machine screw in the end.

I'm expecting to get a CEL, but I think it takes two or three occurances of the ECU demading pump run without the corresponding response of the O2 sensor. I'm a bit of an electronics hack, I suppose it should be possible to fake the ECU into thinking the pump is running by altering the O2 sensor voltage. I know some of the hotrodders have developed O2 signal generators for just these purposes. The voltage supplied to the magnetic clutch coil when the ECU demands pump on could probably serve as a trigger for the the fake voltage signal........I might try to rig something up.

By the way, my musings here are about how to do this, not whether or not we should.................

J. M. van Swaay

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1994 E320 Wagon, 230,000 miles
1995 E320 Sedan, 106,000 miles
1994 E500 Sedan, 79,000 miles

I never saw this post for some reason,

anyhow, the timing problem remained unsolvable. i just went according to the manual and let it go...to much testing and adjusting for nothing.....i think after i put in the tensioner and all the other accessories it came to be as close as it could be...

you helped me there a lot, and now you helped again.....thanks alot

i might have further questions once i tackle this next week, i will update possibly with pictures !!!!

Regards,

latief

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1993 300E, 2.8 M104 .....