86 560SL Idle, missing, acceleration, & loss of power issues

[wws1445]

When I'm sitting at a stop light the car shakes noticeably, and when I go to accelerate from a light, it hesitates and stutters which causes me to back off the pedal... but once moving is fine. To get around the hesitation I have learned to "finesse" the pedal. The second issue has to do with losing speed on the interstate when going uphill. The pedal can be floored but there is no movement of the tach needle and or any increase or maintaining of speed. Again this calls for backing off the accelerator and finessing the pedal. This is not a problem on the level when I need to accelerate.

My mechanic told me when I first got the car that is was missing and he has no idea what the problem is. He suggested an engine rebuild given that the car has 177,000 miles but that's totally not in the budget. I asked him also if it could be a vacuum problem and he said no, the vacuum was fine. The car recently had a tuneup and the problems are still there.

Short of an engine rebuild, the only other options I can think of are 1) take it to the dealer and let their guys do a test drive and go from there and 2) buy a good used engine and swap it out again money that I'm not really willing to spend Can someone please give me some insight into this problem.

Thanks in advance for your replies to this post.

[rocky raccoon]

Similar symptoms on my 560SL turned out to be a problem with the engine temperature sensor that inputs the fuel injection computer (ECU).

These engines have a lot of engine management sensors the failure of which can effect driveability and cause one to think something much more serious is wrong.

[wws1445]

Originally Posted by rocky raccoon

Similar symptoms on my 560SL turned out to be a problem with the engine temperature sensor that inputs the fuel injection computer (ECU).

These engines have a lot of engine management sensors the failure of which can effect driveability and cause one to think something much more serious is wrong.

As far as I know there's no fuel injection on the car, its a carberator, although it does make sense that it could be sensor. This is my first Mercedes so I'm unfamiliar with the German engine management. I don't work on my own vehicles anymore as the complex where I live doesn't allow us to work on our cars. Should I pass this on to my regular mechanic, find another mechanic or bite the bullet with the dealership? I'd very much like to get it fixed right the first time around.

[dugald]

Originally Posted by wws1445

As far as I know there's no fuel injection on the car, its a carberator, .

Unless your engine has been modified, it has fuel injection like all 107SLs.

[rowdie]

I would pack up and move. You can't open the hood to see if it is carburetor or FI?
At least you can read about it.
http://www.startekinfo.com/StarTek/outside/11883/?requestedDocId=11883

MB dealers are not familiar with these cars. Look for an independent shop that is familiar with them. There is a recommended shops area on benzworld dot com and there may be similar on this site.

[rocky raccoon]

Your car IS fuel injected. Remove your air filter housing and you will see the mechanism including the fuel distributor.

IRT mechanics, I believe you need a new, independent Euro/German car specialist. Based on your original posting, your present mechanic does not have a clue about your car. The dealership is dicey since your car is 26 years old and most dealers no longer have mechanics with a lot of experience on old Benz.

Unless you live on the moon, there is an independent shop somewhere in the area that specializes in old Benz. Don't give up on the car. The engines are basically as tough as they come and will go hundreds of thousands of miles without major repair so long as you do basic preventive maintenance.

As you know by now they are rewarding cars to drive. Mine was literally my daily ride to work and to play until my wife totalled it. She was unhurt proving that the body and chassis is equally tough. Replaced it with something even older and tougher, a W123 diesel coupe.

[wws1445]

Can anyone recommend an independent shop/mechanic in Northern VA who specializes in the older Mercedes models, specifically 1971-89 R107s? I've got an 56 560SL. The guy I've been using is Al's Bimmer and MB who was recommended to me, but as stated in an earlier post, he's at a total loss as to what the problem is. Again thanks for your replies in advance.

[kennedy]

I had the same problem and it was the temp sensor, simple fix, bought the replacement part from performance products.

[wws1445]

Thanks again for all your insight, helpful info and links. I finally found someone to work on our 86 560 SL who actually knows what the hell they're doing and he's a keeper as well as reasonably priced. For anyone else in the Metro DC/Northern VA area it's Curry's Auto Service - Arlington.

The culprits ended up being the fuel pump regulator and fuel distributor...ended up costing us $3500.00 but is money well spent. Just got the car back yesterday and PROBLEM SOLVED!!! The performance is back, she runs like a dream and we can't seem to wipe the stupid grin off of our faces every time we step on the gas.

[hobbsdt]

So reposting this from a long long time ago, but my 86' 560SL (White/Blue, 80k miles) is having the same exact issue with stuttering and having a hard time accelerating. Its worse sometimes and better others!

Several people mentioned it being an engine temperature sensor. Researching shows that there might be a couple different sensors that fit that description. Can someone point me to the right part to replace?

Really appreciate it!!

[rmadja]

Hi - I know that this is probably too late but I thought I would reply in case anyone else read the thread. I spent a couple of years and two very expensive shops trying to diagnose mine. They went through everything in both the fuel and electrical system to no avail. In the end, I found a great mechanic and he diagnosed it immediately. The plugs in two cylinders were fouled, and it was a couple of worn valve guides. He replaced those two and bingo, problem fixed. The car only had about 65K miles and has had synthetic oil for the past 12 years.