1991 MB 300 CE-24 Sportline 5Sp Auto

[rayhennig]

Dear All,

Some comments about the 1991 300CE-24 Sportline 5 speed automatic.

1. Starting needs a few seconds of cranking - I am 80% sure this is a faulty fual accumulator

as it bears all the hallmarks of fuel starvation until the engine fires. Thereafter, it

idles, accelerates and, generally, runs like a dream.

I have a fual accumulator from an earlier 300 TE 4-matic (Bosch 0438170035, as opposed to the

correct 0438170055) and intend to try that. If it makes a favourable difference, I'll get the

correct one.

Does anyone know if they are in any way interchangeable?

2. The suspension. I want and have convinced myself that I need, at least, new dampers. I am

thinking about:

a Bilstein B12 kit
Bilstein B8 dampers _ Eibach/H&R springs
Bilstein B8 dampers + original Mercedes Sportline springs.

Any comments about that would be welcomed. Has anyone had any experience of the Bilstein B12

kit.

Which springs do Bilstein use in these kits?

Interestingly, on our drive this morning, I parked by a step and my wife carefully opened the

door OVER the step to get out. When we got back to the car, she noticed that she was unable

to open the door - the car has sunk in the 20 minutes we were away. I imagine this must be

something to do with the gas in the dampers cooling and compressing.

3. The Auto Gearbox. I was having some fun this morning on the country lanes, driving it like

a manual. For the first 15 KMs, the gearbox behaved strangely:

Imagine travelling at 100 KPH in 5th. Then drag the gearlever to position 3 - this should

bring the box down to 3rd, giving strong engine braking. It didn't.

I then noticed that I wasn't geting any engine braking at all. Whenever I eased off the

accelerator, the revs would drop to 1000 and the car would just coast.

The car would accelerate strongly but, once up to speed, it was as if the gearbox simply "let

go of the engine".

Then, with no warning, when I selected 3rd from 4th, engine braking and normal responses

returned. From that point onward, I was able to use the box like a manual box and have some

fun.

So, something changed, but WHAT?

4. Having got home, with the last 2 KMS being spent in 3rd at around 5000 revs and enjoying

the sound, I left it to idle as I wanted to measure the voltage at the battery. It was idling

smoothly as I got out of the car to open the bonnet and, briefly, the revs rose to, I guess,

about 1200 and then fell away to resume the normal 750 ish RPM. Thereafter, smooth idling.

There are other issues but I've probably lost the audience by this point!

Anyone with similar experiences?

All the very best all all and their MBs.

RayH

 

[television]

I would change the crankshaft sensor for the slow starting.

If the idle starts rising and falling, that will be the OVP relay, its a bad year for your car regarding this component. As you have a meter,pin 30 is the input 12v pins 97 are the outputs,if the 12volts out drop down, then it is dry jointed inside,either solder up or replace.

Re the gearbox, I think you will find that engine braking only takes effect at a certain speed and above that a safety device comes into play to stop the engine from over reving, you can ignore 5th on your car as this was an electric add on

Hope this helps a little. Malcolm

 

[Bolide]

Dear All,

Some comments about the 1991 300CE-24 Sportline 5 speed automatic.

1. Starting needs a few seconds of cranking - I am 80% sure this is a faulty fual accumulator as it bears all the hallmarks of fuel starvation until the engine fires. Thereafter, it idles, accelerates and, generally, runs like a dream.

I have a fual accumulator from an earlier 300 TE 4-matic (Bosch 0438170035, as opposed to the correct 0438170055) and intend to try that. If it makes a favourable difference, I'll get the correct one.

Does anyone know if they are in any way interchangeable?

I'll leave this for someone who knows petrol cars better

2. The suspension. I want and have convinced myself that I need, at least, new dampers. I am thinking about:

a Bilstein B12 kit
Bilstein B8 dampers _ Eibach/H&R springs
Bilstein B8 dampers + original Mercedes Sportline springs.

Any comments about that would be welcomed. Has anyone had any experience of the Bilstein B12 kit.

Which springs do Bilstein use in these kits?

I'd suggest you tackle any existing problems before changing the suspension setup. You'll more than likely need new front ball joints, new front springs and new front anti-roll bar bushes, and maybe a new steering idler. At the rear check the bushes & track control arms. At the very least, replace the front anti-roll bar bushes before changing anything else

Personally, if the dampers need changing, I'd use Mercedes Sportline shocks as the Sportline setup is an excellent compromise

Interestingly, on our drive this morning, I parked by a step and my wife carefully opened the door OVER the step to get out. When we got back to the car, she noticed that she was unable to open the door - the car has sunk in the 20 minutes we were away. I imagine this must be something to do with the gas in the dampers cooling and compressing.

Dampers don't work like this. If the car is sinking when turned off then it probably has self-levelling suspension and the problem lies there

3. The Auto Gearbox. I was having some fun this morning on the country lanes, driving it like a manual. For the first 15 KMs, the gearbox behaved strangely:

Imagine travelling at 100 KPH in 5th. Then drag the gearlever to position 3 - this should bring the box down to 3rd, giving strong engine braking. It didn't.

I then noticed that I wasn't geting any engine braking at all. Whenever I eased off the accelerator, the revs would drop to 1000 and the car would just coast.

The car would accelerate strongly but, once up to speed, it was as if the gearbox simply "let go of the engine".

Then, with no warning, when I selected 3rd from 4th, engine braking and normal responses returned. From that point onward, I was able to use the box like a manual box and have some fun. So, something changed, but WHAT?

Have you checked the fluid level? When were the fluid & filter last changed? Was the correct fluid used?

It sounds like the torque convertor wasn't locking up after you shifted from 5th to 3rd but I don't know which gears it locks up in and at what speeds

Having got home, with the last 2 KMS being spent in 3rd at around 5000 revs and enjoying the sound, I left it to idle as I wanted to measure the voltage at the battery. It was idling smoothly as I got out of the car to open the bonnet and, briefly, the revs rose to, I guess, about 1200 and then fell away to resume the normal 750 ish RPM. Thereafter, smooth idling.

I think is related to (1) and your fuel pressure / idle stabilisation problem


Nick Froome
www.w124.co.uk

 

[rayhennig]

300CE-24 My Thanks

Thanks all for your comments and advice.

I've been messing about with this issue for some time - back in September it was a real pig and there was fuel leak. Delved in and found weeping EHA on fuel distributor. Swapped out the grommets - still weeping.

Installed EHA from donor 300TE 4-Matic (same part number) and this is the position:

1. Started perfectly with new EHA - no leak. Didn't go for a drive so car remained cold. Half an hour later, started perfectly - engine still cold.

2. Left car for a week - started perfectly. Went for a drive, car hot.

3. Half hour later, it fired immediately then died. Cranked and it started, goes fine.

4. Parked car with hot engine and left it. Cold engine, fired immediately and then died. Cranking gets it started, thereafter goes fine.

That's the picture today. If the car is started and left with a cold engine, it starts later or the day after like a new car.

If the car is left with a hot engine, it fires immediately then dies - needs cranking to start.

My theory:

The problem arises after the HOT engine is switched off.

At that point, residual heat expands the fuel out of the system past the faulty fuel accumulator. The cold engine fires immediately due to the cold-start device supplying the fuel. Then it runs out of fuel after that initial squirt and needs cranking.

Next step is to try the accumulator from the donor car and re-evaluate the situation.

Will advise as and when I've got something to report.

Finally, does this theory sound reasonable or am I talking bo**ocks?

All the very best for the festivities.

RayH

 

[angus falconer]

As Malcolm suggested hot starting problems can be down to a crank sensor - happened to both of mine.

 

[bigasotonuk]

Starting problem sounds more like a faulty fuel pressure regulater

 

[Bolide]

Faults that are really tricky to diagnose are often caused by two (or more) simultaneous problems. So you may have a faulty OVP relay, and a bad crank sensor, and a bad fuel pressure regulator, and a bad accumulator - or a combination of some of these

That reminds why I like diesels...

Nick Froome
www.w124.co.uk