W124 e220 coupe - Loss of power

[shanksy]

Hi all,
I've got a few issues creeping up on me now with the coupe........
It passed the MOT as usual first time, however, there is a slight leak in the back of the exhaust.
There is also a missing throttle return spring, which resulted in a hairy moment in the office car park last week.

These issues are easily enough sorted, but I also have a quite significant loss of power and what seems to be an intermittent misfiring engine.

On normal drive now, I can pull away fine, but lose power once I hit around 3000 revs. Flooring it, the engine really struggles and just buzzes loudly through the blowing exhaust. Its at the point where I am struggling to get up some steep hills, having to lose enough speed to drop down to 1st of 2nd gear.

The intermittent misfire (assumed) can occur where the engine starts trying to shake itself out of its mountings. As soon as I kill the engine, wait couple of seconds and turn over, its fine.

My question to those more knowledgeable than I am, is whether these are all likely to be the same issue or whether its time to finally think about finding another car that will give me the same joy of ownership as she has for the last 8 years.

I didn't have any engine issues prior to about 3 months ago, when I had to race home to a heavily pregnant girlfriend who thought she was going into labour. Thats the only time i've ragged and redlined the engine and its been trouble pretty much since then.

Any advice greatly appreciated

 

[shanksy]

Just forgot to add that I also have a leaky / weepy diff. Haven't worked out which yet...

 

[CreosoteChris]

Hi Shanksy

I'm not a big expert, but I had to comment when I saw your avatar. I don't have a great deal of expertise diagnosing problems with old cars, but I do have day-to-day experience of driving a '93 CE220 for the last 2.5+ years / 26,000 miles

And it's sometimes a manic depressive business: On a bad day, it seems like "this is a decaying pile of junk, why I am doing it?" And a good day, it's "this is totally fantastic, far better than a brand new Merc coupe, - super-stylish, super cool, totally fantastic.". And that assessment can invert really quickly, it's dependent on your mood, how long it is since you gave the vehicle a good clean, etc.

So first of all go to the car wash, give it a good going-over, and remember what a classically stylish and elegant car you have there.

Then get the exhaust fixed (possibly read this story here first) http://www.mbclub.co.uk/forums/engine/203230-c124-cat-failure-%A3768.html

Then assess the situation and and if necessary take the car to the local cheapo mechanic. My neighborhood mechanic loves me and charges me little, because he likes working on my car, and I pay cash on the nail. My service and MOT, a few days ago, was £151.74.

And hang on to your 220 CE....
1. There are few left, and they are increasing in value pretty fast
2. Even better then that, you have a car that sets you apart from the crowd. It's a lovely classic vehicle, from the beloved era of Mercedes top-quality products, and shows what great taste you have.

Cheers, Chris

1993 220CE, auto, red / black leather, 124k, Manchester

 

[syncropaddy]

Check your fuel supply, pump, relay etc and then have a look at your wiring harness, it may be giving up

 

[grober]

Sounds a bit like an intermittent ignition problem. Could be one of the coils feeding the 4 plugs- its a lost spark system 2 plugs fire at one time. Could be an HT problem- or a low tension problem linked to the wiring harness problem syncropaddy mentioned. Worst case scenario- one of the two ignition switching transistors in the engine ECU is pegging out! If you are any good with a soldering iron/electronics its a tricky DIY. I posted a how too on here a while back.

http://www.mbclub.co.uk/forums/electronics/144774-how-repair-your-ecu-ignition-part-1-a.html
http://www.mbclub.co.uk/forums/electronics/144776-how-repair-your-ecu-ignition-part-2-a.html

 

[shanksy]

Thanks guys, tinker time is in short supply with a newborn so it couldn't have started playing up at a worse time. I'll try and have a look at these tomorrow.

The misfiring happened again today, and while still shaking the engine it doesn't seem quite so severe as before. Tick over hovers at cutting out point around 400 revs though.

Thanks for the perspective Chris, I know in my ideal case I keep the car as i'll never find another like it what with all the hours i've put in over the years.
Fingers crossed she can be saved............

Any there any MB specialists around here (Andover), or would PCS be the closest ? I might have to let someone else diagnose this one.

 

[Victor1]

Had similar prob with my e220.Would momentarily cut out under full throttle, best answer on forum was not to use full throttle ! First look at condition of engine wiring harness,pullback outer covering near injectors and check condition of wire insulator. If cracked or flaking off that's probably the problem. Check at other points to see if same. If you need a harness don't go to dealers I sent mine to Si-Leck and they rebuilt it, made a good job and cost approx. £400.00.

 

[carat 3.6]

As Victor has said in the last post, check your wiring loom first. The faults you describe sound like a degraded loom to me.

 

[shanksy]

Just a thought, a fair few weeks ago I had a loose connection with the earth cable on my amplifier in the boot.
My subwoofer kept cutting out and I found that where i'd earthed it, the bolt had come loose and the wire was sparking where it was a poor connection.

I've since rewired to correct, but if my issues are wiring loom related, is there any chance this could have caused the issue ?

I had a very brief look at the loom today and couldn't see any major signs of degradation, it was chucking it down though so didn't get round to checking anything properly.

 

[carat 3.6]

Just a thought, a fair few weeks ago I had a loose connection with the earth cable on my amplifier in the boot.
My subwoofer kept cutting out and I found that where i'd earthed it, the bolt had come loose and the wire was sparking where it was a poor connection.

I've since rewired to correct, but if my issues are wiring loom related, is there any chance this could have caused the issue ?

I had a very brief look at the loom today and couldn't see any major signs of degradation, it was chucking it down though so didn't get round to checking anything properly.

Unclip and remove the plastic cover at the front of the engine, the coolant temp sensors are located there. If you see cracking of the wire insulation the loom needs a rebuild.

See this thread: https://www.mbclub.co.uk/forums/engine/67830-w124-engine-bay-wiring-looms.html

 

[shanksy]

Nothing untoward under the plastic cover that I can make out, see pic 1 attached. There is what appears to be a surplus connector that comes off one of the cables though, guess that must be normal?......
I've attached a few more pics showing various parts of the harness. Again, most looks ok, except there are a few bundles of wires that have the outer ribbed casing cracked and split. Wiring within looks ok for what is visible at least, and I cant imagine there are many of these that don't crack............

 

[shanksy]

Pt2...

 

[carat 3.6]

The spare plug on the loom is normal, there are different combinations of temp sensors used depending on the spec of the car.

Slide the outer sheathing back so you can see the wires inside, the fuel injector plugs are another spot that is easy to check.

 

[Victor1]

In pic 2 the wire in the plug under the vacuum pipe, I think its for the coils ?,looks to be degraded. Have a look at it.

 

[shanksy]

Went in to the local garage today for some proper diagnosis, will hopefully get some response tomorrow............

 

[shanksy]

Things have been a tad hectic last couple of weeks but i've been meaning to give an update on the diagnosis from the garage.

Turns out loom and plugs etc are all ok and it is just the timing chain which is loose and hitting the underside of the rocker cover. Guy said he couldn't believe it
hadn't snapped and car was still running.
Cost to diagnose was £70 and quote to fix is £700 which is split as about £250 for timing chain kit and £450 for 6 hours labour.

I've debated internally whether its worth repairing and keeping or whether to cut my losses and sell as spares/repair, still changing my mind daily! I drove the 2 mins back from the garage and decided I missed driving it so much i'd keep it.

My Dad has kindly offered to do the work for me so it only costs me the parts. I had been looking at cheap E39 5 series as a runaround in the meantime but as nice as they are they don't give me the same feeling on the road as the 124.

Has anyone else replaced the timing chain on a M111 engine and has any tips to offer or potential pitfalls to avoid when attempting ?

 

[grober]

Body condition is paramount with these cars if its sound structurally- [they all have a degree of cosmetic rust except pristine/restored examples]- and the trim,seats windows etc are in reasonable nick- keep it- they are holding their value now- and good ones fetch good money. Barring the complete failure of major mechanical components- mechanical work should not be the reason to get rid. You won't buy sheer road presence like it for the money.
Rebuilding the timing gear of the M 111 can be tricky for the inexperienced- lots of video stuff out there-particularly on the 230 compressor versions of the engine to give you an idea.
In terms of changing the chain you probably need to change the tensioners/guides at the same time and have a look at the crankshaft sprocket This is not a job I would venture, for the uninitiated. Entrust the work to a specialist who has done this work before on this specific engine!
[YOUTUBE HD]rsiqXjtRvk8[/YOUTUBE HD]

 

[horatio]

I agree - if it's solid (check the rear subframe mounts), I would fix it up. Those coupes are lovely cars.

Plus in general it's better the devil you know. I just replaced the head gasket on our W202 for that reason. Totally uneconomical to spend £500 on an R-reg car but then you can easily spend ten times that on a used car and it will turn out to be a troublesome pile of junk. Been there, done that!

 

[shanksy]

Well, after my Dad kindly took a look in preparation for the Timing Chain, it was discovered that there was no issue with the Timing Chain after all !
Diagnosis comments from my Dad ............
"Remove Cam cover to investigate timing chain reported as loose and worn. Timing chain found to be taught and intact, valve timing checked and correct, chain guides all intact, no evidence of any fault with chain or camshaft adjuster.

Investigate rattle from front of engine. Removed fan belt and found noise caused by fan belt tensioner bearing badly worn.

Remove spark plugs to hand crank engine, when checking valve timing. Plugs all appeared to have been firing ok but electrode gaps excessive. Reset to 0.8mm.

Inspect engine bay wiring loom to check for cause of misfire and found insulation completely disintegrated on wiring from MAF sensor to ECU. Wiring at injector connectors also shows insulation disintegrating. Other areas will need further checking."

Disappointed that the garage I have trusted with both mine and the missus cars for the last 10 years could at best, make a lazy assumed diagnosis, or at worst completely fabricate one for financial gain. What he planned to say when £700 didn't resolve the issue I can only guess.

I don't know if naming places to avoid is considered good or bad practice on here so i'll refrain for the time being, just incredibly disappointed when something like this happens.

The only plus to come out of this is that I bought a W208 CLK430 Coupe as a run-around in the meantime and although it doesn't have the road presence of the W124, I have finally got the pleasure of owning a V8

 

[shanksy]

So a quick update to his thread........

After splicing in a manually built part loom to the MAF Sensor and Fuel Injectors from ECU, I have no more misfiring. I still, however, have the loss of power issue whereby up to 3000 revs is slow progress, and from then it won't go any higher.

The more throttle you give it, the more it pulls back. I've used manual gear selection today to try this, however, in normal auto the gear shifts are also very clunky.

I have removed the MAF sensor and given the plate a good clean but to no avail.

I'm a bit stuck on where to look next, anyone with ideas ?

Thanks as always
Lee