E280 W124 ignition?

[alloam]

Folks,

Wondered what you thought. E280 has started a few days ago hesitating and won't rev beyond ~4,200 rpm. Feels like only 5 cylinders are firing - lumpy vibration at idle.

Ignition fault? Or something more sinister?

Not sure if it is connected, but missus 'fessed up to driving through "the deepest water I've driven through" on her way to work when i later drove the car and realised something was not right!

ADvice appreciated... more as a warning of bill to come!

Peter

 

[Hanzz]

How does it perform when driven? Is there a lack of performance?

I'm not that experienced, but had a E280 which suffered from awful idleing, it would shake and almost stall when idle. The performance difference was extreme. It happened to be the loom that damaged and then the burnt the ECU..

As I said, I'm not experienced, but that's what happened with mine. Water could of got in somewhere

 

[grober]

The direct HT ignition on these cars is better protected from the elements than most being under a plate on top of the cam cover. HOWEVER their close proximity to the engine can precipitate failure due to overheating of the ignition coils or associated wiring. a known fault. Likewise the engine ECU is behind the battery under the scuttle normally safe from water. However there are several sensors which are in more vulnerable positions which may have been affected. First thing to do is thoroughly dry out/inspect ( hair drier ) all the electronics for water ingress. You will have to remove the "cross over" air intake pipe above the engine to remove the access plate to the HT coils and plugs. If everything is dry then you may have the failing coil/wiring problem. The fact the fault occurred after the "flood incident" seems to point towards water in the electronics. Don't let this go on because misfiring HT can eventually knock out the ECU= EXPENSIVE!!

 

[kth286]

alloam

You cannot rev a Merc to red line when it is out of gear. It is a safety thing.

But are you also saying it will not rev beyond 4200 when it is driven ?????

If so it is in limp home mode.

You need the codes reading.

Where you based ???

 

[andy_k]

Folks,

Wondered what you thought. E280 has started a few days ago hesitating and won't rev beyond ~4,200 rpm. Feels like only 5 cylinders are firing - lumpy vibration at idle.

Ignition fault? Or something more sinister?

Not sure if it is connected, but missus 'fessed up to driving through "the deepest water I've driven through" on her way to work when i later drove the car and realised something was not right!

ADvice appreciated... more as a warning of bill to come!

Peter

if it feels like only five cylinders are firing then I'd start by having a look at the plugs and cleaning them

I'd also suspect the MAF

Andy

 

[alloam]

Thanks all for comments. Yes, it is definitely down on power. Still pulls hard enough that you are not at risk in traffic though it does feel like it is about to stall when at standstill in Drive.

kth286: You're quite right! Just took the car for a wee run up the road and it will rev right up though it is hesitant and then surges - still feels like a cylinder is coming in and out of providing power. Never knew (in 7 years of owning it) that it had a safety on revving in Park - you learn something new every day!

It is actually almost dry today, but the last week it has never stopped raining enough that I would want to take hairdryer outside!

Have booked the car into TJ O'Neill's in Glasgow on Friday so will report back what is found.

Hoping it is straightforward, and that it is not ECU or new wiring loom required...

Peter