Mercedes 190E cuts out and won't restart

[Digital Driver]

When driving normally the engine can abruptly cut out. The dash warning lights come on. The engine cannot be restarted immediately, but after standing for 10 minutes or so, it will restart and then drives normally. The interval between these incidents may be weeks. Can happen at any roadspeed.

At one such event some simple tests were done. Ignition sparks were ok. Battery was ok. Engine warm. Fuel in the tank. Injectors ok because engine runs normally and smoothly when it does restart. No smell of petrol underbonnet or anywhere after cranking without starting.

My impression is of no fuel reaching injectors, or no activation pulses.

Suspects: Fuel pump, Injector control unit, Loose cable, Ignition switch.

What is going on in the 10 mins when it refuses to start ?

If it stops again, what tests could I do at the side of the road to narrow the problem ?

Mercedes 190E, Year:1990, 2 litre petrol. Automatic.
Please note the car is my friends and not nearby, but I can check things at the weekend.

 

[television]

This has all of the symptoms of the CPS failing, not a very known fault on that engine but it fits the bill perfectly, you can measure it when good at around 1k ohm when good and open circuit when failed

 

[tonychunk]

I dont know if these have a tank strainer like 124's but have a look at that if they do.

 

[Alex Crow]

Might be a dry solder joint in the fuel pump realy, not uncommon on these, and would fit the symptoms.

 

[television]

Might be a dry solder joint in the fuel pump realy, not uncommon on these, and would fit the symptoms.

True I was going to mention that,,easy to test by bridging pins 7 and 8 in the relay socket

 

[star]

early 190e's do not have a CPS, the run of a signal from the distributor. If its equiped with a cat, then it has a CPS. I would hazard a guess at Fuel PR.

 

[WG M-B]

Absolutely go with the guys on fuel pump relay.
Symptoms can also occur when ignition amplifier starts breaking down.

 

[sbryantgb]

Might be a dry solder joint in the fuel pump realy, not uncommon on these, and would fit the symptoms.

I just went through this on my W124. Identical issues to yours. and thats exactly what it turned out to be.

 

[Digital Driver]

Thanks to all for the very helpful replies.

I will check out the fuel pump relay as that is the favourite suspect here.

Incidently, as far as I know, the vehicle doesn't have a catalytic convertor.

Thanks again

 

[jibcl500]

Also check the plug to the fuel distributor, its a 2 pin plug and ive seen the solder joints fail hence no connection and the car can stall and be difficult to restart.

Another as it seems to be heat related could be the ignition control module bolted to the inner wing.

jib

 

[Some guy on the internet]

99% of the time it'll be the FPR.

I'd concentrate on that until you can definitely exclude it as the culprit.