Hi guys, I recently bought a 1993 300E 2.8 US Spec w124. It has 48k miles on it and its in overall great condition. On my short trips with it I noticed that my car is not so perfect as I though. Let me explain to you. In a normal drive, when I get to a uphill section and I press the gas a little bit more, the hole car shakes and doesn't like it. Also, in any gear if I put my foot to the floor ocurrs a quite loud bang in the engine compartment, only after that it downshifts. This loud bang also occurs even if I press the gas more that usual (without the need of downshifting).

Recently, when I am stopped in Drive, my car does a very little and short shake, almost if it doesnt like to idle..

I also own a '90 w124 200D with 1.4 milion km's on it, so I know a thing or to about this cars, but petrol engines are very rare in my country (Portugal).

Any advice could be helpfull

maybe its tuned to run on u.s fuel?
There is an adjuster in the centre of the air filter,the small hole in the centre.

i just realised your car car probably has the m104 engine and will not have the adjustment through the centre of the air filter

sorry,hopefully some one else can help..

Do you have a ezl switch so you can run on premium fuel

No switch what so ever. I increasly think it's a gearbox problem..

The car is imported from US in 1997, so it's not a gas/petrol problem. The most annoying is when i push it a little but more, the loud noise from the engine bay, it seems to be from the transmission tunel area, but not sure

have you checked engine mounts,gearbox mount and condition of propshaft joints?

lts hard to say without hearing the noise...

It might be that! I did not drive it again, so I need to have a good drive in it!

Sounds like the bang you hear, is a back fire ,not enough fuel in there . Check the fuel pressure .

Unfortunally I think it's a gearbox failure. When i lock it in "2" or "3" it doesnt pull as nicely as in Drive. Another thing, if I dont start it for ate least 1 day, when i shift it into drive, i hear some knock from the rear diff.. it's really weird stuff, even more from a 49k miles car with full service history in Mercedes-Benz

One of the many good things about Portugal is that Mercedes dealerships are only 40 euros
an hour.
I have used them there before to diagnose problems and it can save you money in the end.

Still say your engine is running on three cylinders instead of four .It wont pull so good like this .You wont get up to speed for the transmission to change .The engine will shake because its out of balance .Even engine is smooth to tick over..

I think you did not understand it, its a M104 engine 6 cilinder.. And I am sure it's not a engine problem, it drives very well in power only in low revs (1000-1500 rpm) it has some issues.

It will get chcked in a mechanic soon, maybe a gearbox mout or something got loose

just as information only I know you have 6 pot but only running on 5 of them the 6 is backfire.That gives you the bang .

Thanks by the answer. Just one thing then, when I start the car, and I put it in Drive, the car shakes more like in the rear/diff to the gearbox. Its like the car doesnt like to move between 1-5mph until 1st gear is totally syncronized..

Let me explain in a better way: car parked, turn it on first thing in the morning. Put it in drive and let off the brake. Do not accelerate. In the period between I let off the brake until it gets to speed, the car shakes like I doesnt like that velocity, in the 1-5mph range..

Hope I was clear I'm typing on cellphone..

Any question please make it, I can even upload a vídeo of it if it helps

Here is a small vídeo. In 10 second mark in put it in Drive, it starts to make weird noises, 20 second mark back in Neutral

http://youtu.be/ypelMfMc3ic

Thanks

optimusprime one question, qhere is the EZL switch? Just did a complete service of the gearbox, it is alot smoother and drives almost perfect. And after testing with a mechanic, the car is indeed backfiring. Its a US spec car running 95-98 octane fuel..

Can you go to GOOGLE SEARCH in the search box pop this in Mercedes Benz Model- 124 Maintenance Manuals . do put in the - by Model - 124 . You should find lots to keep you happy .Just serch through it all there. Let me know please if it is any help to you.

I think it will need changing to premium 95 ron your set to super at 95 + Some you can change others its wired and sealed so you are not able to change it over .If thats like yours go and fill it up with a cheap fuel 95 ron no higher .If your in a country with no so many gas stations i think its 95 only all over. Try this fill up first with 95 ron , and dont move anything under the hood just now. See if you have an improvment. Please let us know.

Really aprecciate that help. In Portugal we only have 95 and 98 octane gas. Right now I only fuel it up with 95, so I am 95% sure the tank only has 95 in it. Still backfires like hell. On regular driving has no problem What so ever. But every time I push it a little bit more it backfires alot, like 10 times in a row every second while on power.. I am even scared of driving it just waiting for something to blow up :/
I am going to buy a Ebay code reader to check Out if the car got Any error in it. you think could be something like a maf sensor or an engine harness? I'm completly lost on this one, and just found out there is only 10 280E's sold in Portugal, so I am completly alone in here..

Thanks

how old is the fuel in the car? Does it need draining,new filter?

.My first job would be to clean all the fuses .Remove all earth leeds from all locations that you can see ,grease them up.then refit them .L .Look at all the small plastic pipes ,look at all the rubber connections on the end of them for cracking...Then have the fuel pressure checked .

This is the other things to check out .

But you don't have KE injection , sounds like you have a miss fire or bad air mass meter to me

Just looking, and this is the one i was going off is a 1990 300e same injection type.

The fuel age is not a problem, I drive it almost every day in the past month. The last owner drove it 2 times every month if so, because it was impossible to park where she lived, she couldn't use the car.

But back to the fuel age, its basically new, 1 week max before refueling..