w124 cutting out under acceleration

[ncundy]

My 320E has a rather disturbing trick of cutting out under full acceleration. It only happens under full (pedal to the metal) acceleration, and always at about 70 mph. Just cuts out. It will start again instantly once I've coasted to a stop, with no seeming ill effects.

Under partial and near full on acceleration it doesn't happen, if I go full acceleration then back off, it doesn't happen. I thought it may be fuel starvation, but I've gone through the fuel system looking for leaks (nothing), it has a new filter, fuel consumption is steady (28mpg on long run).

Any ideas??

Thanks in advance
Neil

 

[kth286]

do you know an indie familiar with that age Merc ?

if so it would be useful to check the diagnostic fault codes, as a first step.

where you located, perhaps someone can recomend one.

 

[BillyW124]

injectors perhaps?

 

[Steven Stoole]

I would look at the fuel pump. When accelerating fast you will require good fuel pressure

 

[grober]

Are you depressing the kickdown switch under the accelerator pedal? Could be a fault /short in its circuitry.

 

[ncundy]

Thanks for the replies;

I'm in Derby, no w124 people around here that I'm aware of?

Yes, I'm using the kickdown - works fine (i.e it always kicksdown, it's only when I keep my foot right to the floor for 2-3 seconds that it cuts out, as described above) .

Fuel pump may be an idea - I had a search through the forum but couldn't find anything similar.

Hmmmm...

 

[grober]

The other thing that happens at full throttle is that the full load throttle switch is activated to enrich the mixture. There can also be a preset engine speed limiting device which suppresses the fuel injection pulses ---don't know if this applies to your car or not. My guess would be a problem with either the electronic throttle --sender or actuator, or with the throttle plate assembly or throttle valve limit switches.