'95 C124 - judder (gasping for breath) when put into Drive..?

[charan_singh]

Guys,

The C124 judders when placed into D on a cold start...like its almost about to die, but doesnt.

It also does this in traffic (intermittently) when coming to a complete stop whilst driving....its like its gasping for air and threatening to cut out, but hasnt...yet.

?

 

[kth286]

have you checked the pulsing of the MOT valve on the NS inner wing.

it should pulse at approx 2 beats per second when engine at full temp.

 

[charan_singh]

have you checked the pulsing of the MOT valve on the NS inner wing.

it should pulse at approx 2 beats per second when engine at full temp.

HMMM. i have no idea what a MOT valve is, but the car has just been sprayed and the wings replaced...so maybe someone has fiddled with something they shouldnt have....?

What does this valve do?

Thanks mate - sorry for the fact that I am a mechanical idiot.

 

[kth286]

the valve, vents the fumes from the petrol tank via a charcoal filter (inside wing) into the engine to be burnt off.

BUT it should only be switched on (by the ECU) to pulse and let fumes go to engine after engine has reached operating temp, and even then, only at certain engine conditions/revs etc.

It can get gummed up and will often seize in the permanently open position.

This means the petrol tank fumes will always be sucked into the engine, and the end result is that the engine can stall.

 

[Stratman]

Hmmmm.........

the car has just been sprayed and the wings replaced

via a charcoal filter (inside wing)

Could the two be related?

 

[BlackC55]

You may have a missfire too. Worth checking the coils leads etc.

 

[charan_singh]

All the above items done. And the car has now been serviced, and the MOT valve checked.

Apparently the next item to go through is the throttle body / MAF ?

Any ideas anyone?

Guide prices.....idling problem has got worse...now it does cut out...and stall.

 

[kth286]

Some cars used an air pump for air injection to help with emissions, and some used an EGR system, but I feel that both those systems were discontinued for your model year.

My Aug 1995 coupe does not have either system.

I think at this stage you should find a Merc specialist that can read the stored fault codes from the computer.

Let us know where you based and somebody should be able to recomend a specialist.