Benz_300ce

Ok i got a 1991 Benz 300CE and i am having some problems...First here is the thing: WHenever i am on park and i rev the engine and the engine sounds really really solid and good, but whenever i am driving the car it has this slowdown at the start and it really takes few seconds to pick up speed and the power isnt there when going from 20mph up to like 40-50mph...Any suggestion guys because i have changed some stuff such as the Rotor and the Cap and some minor stuff but still same, any help would help thanx alot













These are some pics of that small thing that connects to the engine but its broken and its out and it doesnt go back in anymore, i was just wondering what does that do, and whats it for? Do you guys think that could be the problem?

Saijin_Naib

I had similar issues, replaced my MAS unit.

Benz_300ce

I also looked everywhere online for that part but i wasnt able to find it. ANd can you help me try to find it and if you could please tell me what the MAS Unit is for and what does it do? This would be alot of help because for months i couldnt solve this problem and plus the mechanics i sent it too werent sure what was wrong with it,

thanx alot

Saijin_Naib

http://search.ebay.com/search/search...MAS&category0=

Here is a quick Ebay listing of w124 MAS units. I got a used one from a seller in Germany. So far, so good. The MAS unit contains our fuel pump relay, MAS, and other related electronics. I am not saying that this is definately what is wrong with your car, but it is possible your MAS unit has gone bad.

Benz_300ce

Thanks alot man, i will try to get one and replace that, and i am really positive that it might be that, but if not, than oh well i will have to look for a new solution, but thanx again.

Saijin_Naib

Have you changed the ignition wires as well as cleaned all the electric connections? My father did all that in conjunction with the new Cap/rotor/MAS and as of right now, I am all fixed up

Benz_300ce

I actually have changed the Cap and Rotor and cleaned the wires as well but it doesnt seem to be helping much, but i believe that my last stand is the MAS UNIT, and i would think that will fix the problem. What do you think of some sort of vacumm problem? Do you think that would have to do with it?

thanx

Bigpete123

I would definitely explore other potential (read: cheaper) causes before throwing this part at it. As you can see here, this part is very expensive:

http://catalog.worldpac.com/mercedes...S+Control+Unit

I got a rebuilt one from a place called pelican parts. It solved a cold start problem for me, but did not help with a hesitation issue I have (that sounds pretty similar to yours, but occurs betwee 1,000 and 2,500 RPM).

DEFINITELY have the car carefully inspected for vacuum leaks. I still think a vacuum leak might be my problem even though I've had 2 mechanics look for one using smoke machines. I suspect that it's somewhere difficult to find.

My next suspect is my catalytic converter since my car was running super rich for a while when my fuel distributor was bad.

Good luck, don't throw parts at it. Check every single cheap thing first before doing anything expensive.

Saijin_Naib

True, but for the 76$ US I paid for my used MAS, I'd say it was worth throwing the cash at the car. I mean, If I can pay for it :P its not too expensive. But you are right, he should have another mechanic give it a going-over to be sure of what he will need.

Benz_300ce

You guys are right, and i appriciate the help. Like you guys are saying i dont iether want to just throw money into it and not have the problem fixed, however, if i would fix the problem than it would be fine with me. Can you guys tell me if this is the right part for the MAS UNIT, this is the website and i was looking to buy this.

http://cgi.ebay.com/ebaymotors/merce...spagenameZWDVW

vili1982

Do you warm up the car before you drive it?

I had same problems, in the winter time, when the engine is cold, almost looks like the transmission wont kick in,, but I sprayed mafs with some carb cleaner and let the car warm up a little bit, then it seemd to be ok... For how long who knows..

Benz_300ce

Yea i warm up the car everytime about 2-3 minutes, but it seems be like that when its cold where it seems the tranny wont pick up but once warmed up, than it looks good. BUt the power from about 2000rpm is really limited and it seems like electricity isnt going through or some vacuum leak. The people above suggested that the MAS UNIT could be at fault and may as well be, but i will have to check, and see whats going on, because i really dont wanna get rid of this car, i love it and i want to keep it.

Saijin_Naib

Benz, that appears to be the right part, but not of the latest part# series.

Here is the seller I used: http://www.amg340te.de/
It took a while to get to me, but I DID order it right before christmas, and chose the cheapest/slowest shipping, but, the seller was very pleasant and gave me a good feeling to do business with.

These I believe are the MAS part# from every series that work for our 300ce 24v cars
0115458332 , 0115458232 , 0085458432 , 008545 8532 . 0125454832

I got a 0125454832 from AMGte

shdoug

That thing you're holding in the pic looks a lot like the remains of a Hot Film mass air flow sensor to me. If it is, it won't run worth a crap like that.