My '89 300E was running great, all of a sudden it started blowing black smoke, low vacuum and the fuel range dropped in half.

I took it to a mechanic who swore it was ignition related and he replaced all the plugs, wires, and other ignition components. When I got it back, it ran exactly the same. When I returned it, he said it now needed a catalytic converter, Ox sensor, fuel pressure regulator, and fuel distributor. And he wanted about $4,000 to do the work.

I'm not convinced he knows what he is talking about, so I wanted to check here first. Does this sound right?

When I disconnect the wire on the EHA, it runs a lot better, less smoke and better mileage, but there is still some black smoke and I don't get anywhere near the mileage I used to get.

I appreciate any responses.
Phil

 

First let me give you a bit of advice. when you have a problem like you described, your probably better off taking the car to a Mercedes Dealer or a private shop that specializes in Mercedes. It seems this mechanic is working the "old" replace a part and hope it works. Even an 89 has some complicated systems. In the long run you would probably save some money. I don't have a clue what is wrong as I am not familiar with diesels. But for $4K, I would go to a dealer's shop, who knows it might cost you less? These wonderful cars are also wonderfully complicated and not main stream mechanically built. German are tempermental people, I know I'm German, so are their cars.

 

The car is gas not diesel.

I'm a mechanic as a hobby, but I tried taking a shot with an authorized mercedes shop, and I think their diagnosis was bad. I can't believe that four devices all went bad at the same time, considering it was running perfect two weeks ago. I thought I would give this forum a shot and see what experiences other people have had. I will then decide whether to fix it myself or elect to go to another mercedes shop. With some more knowledge under my belt, I can deal with the mechanics better. With no knowledge, they can walk all over me like the first shop did.

Phil

 

need to hook up fuel gauges to see if you got .4 of a bar differnetal pressure...you ABS light is not on right ..?

 

Anything is possible, perhaps not probable, but possible. I'm hobby mechanic myself, but I stopped if I think I am getting in too deep. My wife's previous car was an 94 Audi100S. It gave her excellent service and reliability for almost 11 years. It started having problems, oil spots, rough running, electrical troubles, long story short after 10 plus years and 110K miles, the cost of 5 items which needed repair was cost close to $3K, twice the book value. So she sold it for a Hyundai XG350L and is very happy with her new ride and I am impressed with the quality of the car. Which were considered the Yugo successor 10 years ago. So yes, 4 things could go wrong on an older car.

 

problem lies between EHA and air flow sensor signal.

adjust/calibrate them.

 

Where do I connect the fuel guages?
Where do I make the adjustment?

No ABS light on.

Thanks,
Phil

 

Sleepwalker,
Could you be more specific?
I have the Mercedes bible, so if you wouldn't mind describing in more detail. I would appreciate it.

Thanks,
Phil

 

read here to get all the points