Intermittent stalling M130

[CFF]

Good morning! I have a tough one. I’ve been working on my M130 going through everything and I’ve run into intermittent stalling issues. When the car is fully warmed out and I’m coming to a stop sometimes the motor will run rough and stall. It starts right back up. Sometimes when I shift it into and out of gear it will stall as well. It’s a frustrating problem because it only does it when the engine is hot and it’s not consistent.

I have done a ton of work on this car over the past 6 months:
New fuel tank, lines, electric fuel pump, and filters.
123 ignition, coil, leads and Bosch plugs
Re hosed the entire engine, coolant, fuel, oil power steering etc. all new hoses.
New proper battery cable's
Valve adjustment, linkage tour. Checked the idle, checked the timing.

I’m running out of things to check. I’d appreciate any advice so I can start driving this car! The motor fires right up hot or cold, idles great, has plenty of power.

[Jonny B]

Take a look at the small wires around the coil and distributor to make sure they are fully connected with no bare areas. Also check the wires coming and going to the transistor unit under the battery. Just a touch to ground and the engine can cut out.

[Benz280]

I had a very similar issue, after much research it was the transistor unit ( acted differently when hot ).
Was able to find on OE in box on eBay.   

[alchemist]

Sometimes when the ventouri flap is not well adjusted and if it is slightly open, it dies after running for a while. Also, the air crew need to be adjusted using a vacuum gauge intercepted between the distributer and the venturi. This is to tell you if you have good vacuum at the venturi, if not, then there is a leak somewhere. To adjust with vacuum, turn the air screw clockwise and counterclockwise and set it at the max. vacuum possible. Good luck.

[CFF]

The vacuum leak is an interesting suggestion. My dad has been working on old cars for years just not Mercedes and that’s what he thought it sounded like to him. We actually sprayed some of the joints on the manifold with some starting fluid to see if the motor revved up but it didn’t.

(Yeah I know it’s dangerous, and can start a fire)

We adjusted the throttle plate during the linkage tour and cleaned out the throttle body. How much slop is allowed in these linkages? Mine has a little bit.

[Pawel66]

If you want to check the intake for leaks - the efficient way is to use e-cigarette (any flavour) combined with windshield washer pump, you do not have to invest in smoke machine.

[rosch]

@Pawel66

Could you give us a link or short description how you made you smoke generator ?
Air- or vacuumleaks are a quite common problem so a lowcost  tool would be a big help for a lot of users !
Thanks !

[Pawel66]

It is very simple.
With a piece of windshield washer hose you connect windshield washer pump suction fitting to the mouthpiece of the cigarette. Then connect a hose to the output fitting of the washer pump. This hose you may leave a bit longer so that it is convenient to operate. Hook the pump to 12V power source, lit the cigarette, switch on the pump.

Do not be scared if you see smoke coming out from WRD filter - it is supposed to be like that when engine is cold.

Examination takes maybe 10-15 minutes - and you see leaking places.

There may be voices that a cigarette smoke will leave residues in the inlet piping - IMHO - it probably does but it is negligible. At least I have never encountered nor heard of any issues related to that. 

[rosch]

Very nice and usefull hack  Thanks !
I wouldn't  worry at all about residues left behind. They are totally neglectable compared to all the  polluted "inhaled" ambient  air for combustion over many years of driving.

[ctaylor738]

Do you still have the anti-pollution devices installed? They are supposed to activate the pump solenoid to shut off fuel flow when coasting but un-activate the solenoid as the car comes to a stop.  As they age, these devices sometimes don't work as designed.  Try disconnecting the pump solenoid.

Good luck,

CT

[Cees Klumper]

If your car is an automatic, check whether the Constant Speed Solenoid (CSS) is working properly. If old and tired, it may not have the 'oomph' anymore to add the rpms required at standstill, causing the engine to falter. That's what happeded with mine anyway, I sourced a new one and problem solved.
Alternatively, check your idle mixture with an exhaust analyser, make sure that, when warmed up, the engine is not running too rich or lean. And make sure your linkage brackets are all solidly attached.

[Landon]

HI Benz280
I saw that you wrote that you have problems whit the transistor unit. Could you post a photo of that unit?
Or if you have OE number?
Thanks
/Landon

[Benz280]

Hi Landon,
This is an image, not mine but the same part.
It is located under the battery.