W126 500 SEC shutting off when putting in D/R gear

[Spurverbreiterung43695]

Hello, I'm not from Germany so im writing in English, I hope you can help me with my problem in my 500SEC that i bought from Germany and shipped it to my town, It has 149,000+ km on it, it was originally bought in Italy, then it was sold to Germany and then i bought it and shipped it to here.

So, today I started the car, started perfectly, idled as it should 750+- 50 rpms, however, as soon i put it in D/R the engine shuts off immediately, I need to mention too that the old plugs were very black looking, like it is running rich on fuel.

similar to this plug on the right: http://www.buckeyetriumphs.org/technical/Carbs/CarbsIII/Plugs1.jpg

And also, a fuel leak has occured since this problem started. it is leaking from the back fuel pump, where the fuel line connects to it, the one that is close to the wheel, i have marked it in the red circle, it is drippig one drop in two seconds, only when the engine is running, i tried to turn ignition on and off a couple of times to let the fuel pump run, it ran but didn't see it leak. However, it will start to leak a couple seconds after i start the engine. Here is a picture: https://lh6.googleusercontent.com/...Hr9nMk6YQhJiLOlThzk=w1920-h950-rw

 

I took a video showing what is exactly happening when I shift to Drive/Reverse: https://www.youtube.com/watch?v=1o59JxQGPLE

Any idea what is wrong ? what should i start checking ? the local mechanic also didn't know what is the problem...

Any help is very appreciated,

Danke

[Spurverbreiterung43695]

Any ideas ?

replaced fuel pump, rotor and distribueter, and the EHA. still has the problem.

[Bamberger_1]

The fuel pump issue and the shut off when shifting gear, are two completely different things. The dripping fuel pump need immediate attention, as this is a serious safety issue. The engine stop when shifting from D to R is a gear box problem. However hard to tell from a distance. It can be many things, from serious to simple, as for example changing the gearbox oil, and cleaning filters. But as I said hard to tell. I guess you need to stop by a MB workshop.

[Trennschleifer134377]

Was this issue visible always present you have the car, or after shipping? Is the problem also visible if you put into 2 or 1 directly? What do you mean about the old plugs were very black... all the plugs were connected at engine compartment? Think it is always an error sources were you have to clean.

[S Klasse Fan]

A possible source could be the distributor, ignition cables and spark plugs. I recently had that issue on my W124. It suffered from a weak idle and the engine stopped when touching the gas.

How does the engine behave after warm up phase is complete? How is the throttle response? What happens if you hit the Gas a little harder in idle? Will the engine rev up or swallow, especially when cold and running rich?

According to your video, it sounds as if the idle is quite weak.

I remember having a dripping fuel line on my 420 SE as well. It was repaired before I bought the car though. No big issue.

I would start out with letting the engine run in idle for 30 Minutes and then try to put in D.

By the way, have you driven the car already?

[Spurverbreiterung43695]

Zitat:

@Bamberger_1 schrieb am 22. Oktober 2016 um 11:16:50 Uhr:

The fuel pump issue and the shut off when shifting gear, are two completely different things. The dripping fuel pump need immediate attention, as this is a serious safety issue. The engine stop when shifting from D to R is a gear box problem. However hard to tell from a distance. It can be many things, from serious to simple, as for example changing the gearbox oil, and cleaning filters. But as I said hard to tell. I guess you need to stop by a MB workshop.

I still believe this problems is related, becuase both occured at the same time, maybe the pump is getting over pressuriesed and then it starts to leak.

gearbox is shifting as it supposed to be, if i give a bit of gas before letting it die, it will drive, and there's no problems while the car is driving.

Zitat:

@mrpw schrieb am 22. Oktober 2016 um 11:27:43 Uhr:

Was this issue visible always present you have the car, or after shipping? Is the problem also visible if you put into 2 or 1 directly? What do you mean about the old plugs were very black... all the plugs were connected at engine compartment? Think it is always an error sources were you have to clean.

after shipping, this problem started a couple of days a go.

Haven't tried putting into 1 and then 2, i will try and report back.

I uploaded a picture, this is photo from the internet, but plugs looked similiar.

yes all the plugs was connected.

[Spurverbreiterung43695]

Zitat:

@S Klasse Fan schrieb am 22. Oktober 2016 um 11:50:27 Uhr:

A possible source could be the distributor, ignition cables and spark plugs. I recently had that issue on my W124. It suffered from a weak idle and the engine stopped when touching the gas.

How does the engine behave after warm up phase is complete? How is the throttle response? What happens if you hit the Gas a little harder in idle? Will the engine rev up or swallow, especially when cold and running rich?

According to your video, it sounds as if the idle is quite weak.

I remember having a dripping fuel line on my 420 SE as well. It was repaired before I bought the car though. No big issue.

I would start out with letting the engine run in idle for 30 Minutes and then try to put in D.

By the way, have you driven the car already?

Looks like the engine is behaving the same when its cold and when its 80+ degrees, throttle responds fast, it will go up in rev, no problems. I will try to give it gas when its cold, and see if it will rev up or swallow.

And then i will try to let the engine rev for 30 minutes and then see how it behaves.

Danke

[Bamberger_1]

..........gearbox is shifting as it supposed to be, if i give a bit of gas before letting it die, it will drive, and there's no problems while the car is driving.

As I understood the motor dies when shifting from D to R in standstill. And this is a gearbox (mechanical control) issue, as per my understanding. Shifting during regular forward driving can easily be ok, as the engine is not in idle, but at higher rpm. Dripping fuel line does not stall the engine, as long your not loosing not more then a few drops. If the fuel pressure was to low, it not even start.

[Reifenfüller5835]

Hi!

I'd say the gas leak is most probably unrelated. Almost every car has those after ~30 years. I guess you only found the leak because you started to look around after the issues.

So the problem became apparent instantly and once the engine is warm it's gone? Correct?

The first guess would be your injection system ("KE Jetronic") running in emergency operation. Can you find the round diagnostic plug "X11" located on your front left wheel house? Can you measure a voltage (even better: duty cycle) between pins 2 and 3 before and after start? If so, what voltages?

yours

ben

[Spurverbreiterung43695]

I am happy to say that the problem has been solved, replaced fuel pump, that didn't fix that the engine shut down. however, adjusting the fuel/air mixture solved te shutting down problem.

Thanks for everyone.

[Spurverbreiterung43695]

Turns out its not just adjusting fuel and air ratio... after a weeks of searching and look up for the bad part.. the mechanic pulled the vacuum lines that is connected to the EZL and blocked the vaccum line. this fixed the problem. and engine doesn't stall... What is the culprit ? is it the EZL ? I know that when EZL die, there will be no spark... Any ideas ?