Car stalling

[RichWeath]

Good evening all.

My r129 has recently (3 times) stalled when coming to a roundabout, it's 4 speed auto.

Any ideas? I'm I in trouble?

 

[Ted]

Can’t guarantee it but when this happened to my m112 engine it was the MAF.

 

[RichWeath]

Thanks, will check out

 

[Bobby Dazzler]

Shot in the dark but stalling randomly is sometime a symptom of a faulty crank position sensor (CPS), it happened on my car, albeit a much older M112K petrol V6.

 

[Bellow]

Shot in the dark but stalling randomly is sometime a symptom of a faulty crank position sensor (CPS), it happened on my car, albeit a much older M112K petrol V6.

My initial thought also. No word of it not immediately restarting though.

 

[Smiley]

the distributor cap and rotor arm can be very susceptible to a bit of wear and / or condensation problems as the engine warms up

 

[ray_hennig]

I

Any ideas? I'm I in trouble?

More details on your car would be useful. Model, year, etc.

RayH

 

[WilliamParsons]

Good evening all.

My r129 has recently (3 times) stalled when coming to a roundabout, it's 4 speed auto.

Any ideas? I'm I in trouble?

Experiencing stalling when approaching roundabouts with your 4-speed auto R129 can be concerning. Several factors could contribute to this issue, such as a malfunctioning sensor, fuel delivery problem, or transmission issue. To diagnose and resolve the problem, it's advisable to have a professional mechanic perform a thorough inspection to identify the specific cause and necessary repairs. Addressing it promptly can help prevent further trouble and ensure your vehicle's reliability.

 

[RichWeath]

I


More details on your car would be useful. Model, year, etc.

RayH

93 300-24.
Occasionally(1 in 20 times) when starting it cuts out first time, 2nd go starts immediately.

Have ordered some maf sensor cleaner, will give that a go.
Is going for full service very soon so will ask mechanic about it then too if continues.

 

[ray_hennig]

Have ordered some maf sensor cleaner, will give that a go.

Strange. I think you have a "mechanical" MAF, not one that you would clean, as such.

I have a 1991 300-24 and it has the Bosch KE Jetronic fuel system.

A 1993 car is likely to be the same but could be the later one, in which case it's a 320.

Post a picture of your engine and then we'll all know.

RayH

 

[RichWeath]

Strange. I think you have a "mechanical" MAF, not one that you would clean, as such.

I have a 1991 300-24 and it has the Bosch KE Jetronic fuel system.

A 1993 car is likely to be the same but could be the later one, in which case it's a 320.

Post a picture of your engine and then we'll all know.

RayH

I'll be honest I rrlead the previous post about maf sensor, watched a couple bits on you tube. And ordered the cleaner at midnight on amazon prime, just in case. Can send back if wrong thing.

Will Post pic later. But it's definitely a 300sl-24

 

[ray_hennig]

But it's definitely a 300sl-24

In that case you have the M104.981 (in the SL) engine that looks like this:



Just like mine although mine's an M104.980 in my CE-24. No idea what the difference is.

Underneath the air filter is the "MAF". It's a mechanical plunger that moves downwards as more air is drawn into the engine. This is a mechanical link to the fuel distributor that injects more fuel for more air. In simple terms.

Is your first start failure when the engine is cold? Or hot?

I ask because the handbook advises light pressure on the accelerator if starting hot. I do that and it's always a first start.

So, more info is needed.

Another issue with these cars is the HT system. From coil to plugs, all components must be of the highest quality. I've had mine for 26 years and it's never been better than now. After installation of a complete, genuine MB HT system, from coil to plugs.

And don't forget the EZL - a strange acronym for the ignition controller. Make sure that it has a nice layer of heatsink compound under it. Why? Because that conducts heat away from the module. You do NOT want to blow this up as a new one is 1000€, assuming you can find one. Secondhand, they range from 500 ish to crazy, opportunistic 1600. Madness.

But find a spare if you intend to keep the car.

Tell us more.

RayH

 

[RichWeath]

In that case you have the M104.981 (in the SL) engine that looks like this:

View attachment 146363

Just like mine although mine's an M104.980 in my CE-24. No idea what the difference is.

Underneath the air filter is the "MAF". It's a mechanical plunger that moves downwards as more air is drawn into the engine. This is a mechanical link to the fuel distributor that injects more fuel for more air. In simple terms.

Is your first start failure when the engine is cold? Or hot?

I ask because the handbook advises light pressure on the accelerator if starting hot. I do that and it's always a first start.

So, more info is needed.

Another issue with these cars is the HT system. From coil to plugs, all components must be of the highest quality. I've had mine for 26 years and it's never been better than now. After installation of a complete, genuine MB HT system, from coil to plugs.

And don't forget the EZL - a strange acronym for the ignition controller. Make sure that it has a nice layer of heatsink compound under it. Why? Because that conducts heat away from the module. You do NOT want to blow this up as a new one is 1000€, assuming you can find one. Secondhand, they range from 500 ish to crazy, opportunistic 1600. Madness.

But find a spare if you intend to keep the car.

Tell us more.

RayH

I would say 1st start issue is generally when car is warm. I'll give the throttle a little push when I'm starting hot again.
MAF sounds like a mechanic problem to me, I'll save that for him

Forgive my ignorance, but what is HT system?

Would it be fair to say that mechanically our cars are identical under the bonnet then?

Thanks for your time and responses

 

[RichWeath]

It won't let me upload pic of the engine bay as says file is too large.
But yours looks the same under the hood as mine

 

[ray_hennig]

Would it be fair to say that mechanically our cars are identical under the bonnet then?

Pretty much identical. There is some fifference between the .980 and .981 engines but it is pretty minor.

Do choose your mechanic carefully. You need an MB specialist who has knowledge of cars that are 30+ years old. These people are increasingly rare and most unlikely to be "just round the corner".

Where are you? Someone may be able to direct you to a suitable specialist in your area. With your sort of car, it may be worth travelling for the right person. My nearest specialist is 70 Km away.

HT is High Tension. Basically, the coil, distributor cap, rotor, shield, the plag cables and the plugs. These are all triggered by the EZL that's on the left side inner wing and looks like this:



Good hunting.

RayH

 

[ray_hennig]

Is your first start failure when the engine is cold? Or hot?

I ask because the handbook advises light pressure on the accelerator if starting hot. I do that and it's always a first start.

Well, can I find the reference to this light pressure on the accelerator? No. I have a handbook for the 300E and it says almost the opposite.

Where did I see this?

Was I talking bollocks? No. I read this somewhere and ever since then (2 years?), with my brand new ignition and fuel systems, starting has been perfect under this regime.

Anyone else care to comment on this?

And, in the words of several people who've driven it, "it drives like a new car".

So, I hope I'm not misleading anyone.

To the OP, try what I've said and let us know.

Maybe the owner's manual refers to a K-Jetronic, not the KE. Possible?

Baffled.

RayH

 

[WilliamParsons]

Well, can I find the reference to this light pressure on the accelerator? No. I have a handbook for the 300E and it says almost the opposite.

Where did I see this?

Was I talking bollocks? No. I read this somewhere and ever since then (2 years?), with my brand new ignition and fuel systems, starting has been perfect under this regime.

Anyone else care to comment on this?

And, in the words of several people who've driven it, "it drives like a new car".

So, I hope I'm not misleading anyone.

To the OP, try what I've said and let us know.

Maybe the owner's manual refers to a K-Jetronic, not the KE. Possible?

Baffled.

RayH

It's possible that you read or heard about the recommendation to lightly press the accelerator when starting a vehicle, and it may indeed work for your specific car or setup. However, it's important to note that starting procedures can vary depending on the make and model of the vehicle, as well as the type of fuel injection system it uses.

Your experience with your particular car may be unique, and what works for one vehicle may not apply universally. Vehicle manuals often provide general starting instructions that should work for most drivers and cars, but there can be exceptions or variations.

It's great that your car starts well and performs as if it's new using your method. However, it's essential to consider the manufacturer's recommendations as a starting point, and if you find alternative methods that work better for your specific vehicle, that's perfectly fine. It's always helpful for car owners to share their experiences, but it's important to remember that what works for one car may not work for all cars.

 

[WilliamParsons]

Checking for leaks in the coolant system after a water pump replacement is essential. Inspect the coolant filler bottle, associated pipework, and the water pump itself. Ensure the water pump is a genuine part. If you suspect a leak, address it promptly. Your specialist should have checked for leaks after fitting the pump.

Good evening all.

My r129 has recently (3 times) stalled when coming to a roundabout, it's 4 speed auto.

Any ideas? I'm I in trouble?