W124 220E - Engine Stalls Few Seconds After Startup

[RavzSa]

Hi All,


Get into the car today after not using it for about 2 weeks, the car starts up and then stalls after 10 seconds or so.


I start the car up immediately after it dies and it starts up with a little struggle then idles up and stalls after a few seconds again.


I've had this exact same issue for the last few years but I thought it was resolved after rewiring my ETA just about a year ago.


There is a little bit of a struggle when starting but it starts then idles up and cuts off...


I checked for faults codes and found no errors.


Previously this used to happen at any time, whether the engine is cold or hot.


I took a few videos of what's happening;


Startup after stalling;

https://vimeo.com/476914501


Holding the throttle open;

https://vimeo.com/476915043


Fuel pump buzzing after engine stalls;

https://vimeo.com/476915224


Things that have checked or done;

Replace fuel pressure regulator

Soft disable the alarm and immobiliser

Left the battery disconnected for a few hours


Could it be a faulty fuel pump or fuel relay?


How do I check fuel supply?


Any help will be greatly appreciated

[John Green]

What does "Soft disable the alarm and immobiliser" mean? Remove it completely, it is a liability to the car. I have removed so many alarms over the years which have fixed issues like this.

Also I would presume the engine wiring harness has been replaced?

Checking fuel pressure is best done with a gauge, but there are a few methods that you could use. Very basic is to run it till it stops and then crack a fuel line on the rail, big squirt, I would say it's fine. You could also bridge out the fuel pump relay to remove that from the equation. It is a green relay in behind the battery.

[RavzSa]

What does "Soft disable the alarm and immobiliser" mean? Remove it completely, it is a liability to the car.

I disabled the alarm using the onboard alarm override. I agree that I need to disconnect it altogether to rule this out as the problem.

Also I would presume the engine wiring harness has been replaced?

Yeah, the engine wiring has been replaced.

Checking fuel pressure is best done with a gauge, but there are a few methods that you could use. Very basic is to run it till it stops and then crack a fuel line on the rail, big squirt, I would say it's fine. You could also bridge out the fuel pump relay to remove that from the equation. It is a green relay in behind the battery.

Which pin outs on the relay socket would I need to bridge?

----------------------

So after a week of standing, I reconnect the battery (I always keep the battery disconnected, when not using it on a daily basis), and it cranks up and runs perfectly. Took it for about a 15km drive to do some errands and it ran without issue.

One thing I did notice is that the fuel pump does not seem to be as loud as in the video...

[John Green]

Look for the relay, if the same as the cars we got, it will be green and behind the battery somewhere. It may have a fuse in it. There should be a diagram on the side that will help. With most relays it is a bridge between terminals 30 and 87.

[RavzSa]

Great thank you! will give it a shot