w124 estate running oddly....

[gina2201]

Brothers car, w124 220TE Auto estate, had a new engine in Feb this year, recent new plugs and points, but still has running "problem."

Excuse my non-technological post....

Starts first time every time, and runs well generally however;

Often a clunking sound can be heard when changing gear and holds back even with foot down or to the floor and then suddenly will "engage" and you'll fly! Or like the other day, foot down and car just slowed and slowed, almost like it didn't know the accelerator pedal existed (had to pull over, switch off and restart).

It does sometimes run fine, this is usually when you drive it in "E" and accelerate slowly and smoothly. As soon as you use kick down or accelerate faster it runs funny?

Any ideas? Thankyou

 

[bolide]

Most of the 220 problems I've come across have been throttle body-related. But if the car has a MAF then I'd start there. Search this forum for MAF and you'll find lots of info

Nick Froome
www.w124.co.uk

 

[grober]

Lots of possibilities! Might be the MAF as Bolide says. Might be a vacuum/manifold leak---that might affect the kickdown/gearchange------but after you said the engine was replaced it could be the dreaded engine wiring loom degradation problem where the insulation goes brittle and this leads to all manner of weird running symptoms. Did a mercedes dealer or mercedes specialist do the engine swop? Does the engine misfire at all----These engines are known for ignition coil/ ECU output failures

 

[Ian B Walker]

Also check the ATF as too much or too little will affect the gear changes.

 

[andy_k]

Graeme...I didn't think the wiring loom issue applied to the 4 cylinder cars?

I'm with Nick on this one, throttle body and MAF are prime candidates.

Try running it without the MAF (for a short period) and see if it makes any difference

Andy

 

[grober]

Graeme...I didn't think the wiring loom issue applied to the 4 cylinder cars?
Andy

Your right Andy-its not nearly so common as on the 6 cylinder and V8(usa) models due to higher underbonnet/ambient temperatures I guess. I don't think they are totally immune from the fault tho - probably just takes much longer to develop. Problems tend to emerge after the wiring loom has been disturbed---as in an engine rebuild/refit as in this case ------- should be fairly easy to check tho by a quick inspection ----other wise I would go along with you and Nicks's diagnosis as the most probably cause. and Ian's tip to check the ATF is a good one too Engine swops always entail lots of connections to be broken/ remade and levels to be checked and its easy to overlook something.

 

[gina2201]

Bro dsconnected the maf today and the car ran worse than ever! Idle was all over the place and generally made the problem worse.