W124 300ce-24 Stalling - Solved

rayhennig

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I hope this may help someone.

This is NOT related to a hot engine idle fluctuation that does still cause a stall from time to time, and did today during my test. More on this elsewhere - I suspect weak idle mixture.

This relates to a recent stalling-when-hot problem. Engine would misfire after, say, 15 minutes of warming up and then would die if revs fell, say, at a junction. It would then need around an hour to restart and then needed to be kept 'on the boil' to avoid stalling during rapid return home!

0. Car has 350 K Kms and 2 years ago had new distributor cap and rotor arm. I was in UK at the time, near Ashford, Kent where I bought low-cost Bremi parts from a discount motor store.
All was fine until recently (April 2009) when car died on me after not having been used for a few weeks.

1. I dismantled and cleaned the distributor cap and surroundings.

2. Re-assembled, tested and things seemed OK. Test only lasted an hour or so but involved heating things up and then stopping for 10 minutes before resuming. A week later, the same problem returned.

3. Ordered distributor internal shield and O-ring from Mercedes. Installed and it started immediately but after 10 minutes idling it started misfiring and then died.

4. Disconnected battery for 30 minutes (?) and re-tried – the same, it died again.

5. Replaced 'newish' Bremi rotor arm (easiest course) with cleaned up, ancient (original) Bosch part – this one had Mercedes star on it so may have been original 1991 part. Engine started immediately and settled into steady idle. Left it idling for 30 mins, never missed a beat.

6. Tested for nearly 2 hours including 30 minute stop and a few 5 minute stops. Restarting was better than ever and idling good. Low down torque also seems better.

All seems well now and confidence has returned.

I was tempted to strip out Bremi cap and replace with old Bosch original but ex-Army motor maintenance officer friend said, “Try it for a while.” I will try this but I'm tempted to go back to Bosch original that I've now cleaned up. It is ancient but it looks good after clean up although internal contacts are eroded.

When my economy improves I will almost certainly bight the bullet and get cap and rotor from Mercedes.

My friend did note that the old internal shield appeared to have been varnished and showed me how this stuff easily scraped off the surface. He said this was an army technique that he's used on distributor caps when no replacement part is available. Apparently it's good for quite a while but not a permanent fix. He aslo said he noticed evidence of 'tracking' on the shield and thought my new purchase was probably worthwhile.

This is not a dig at Bremi parts but I would like to hear of any other experiences with these after-market bits. Any comments?

As always, the best to all.

RayH
 

joe1972

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Hi Ray.
I've had a similar experience when I replace the drivebelt on my E300 diesel. It's got a MB labelled belt on now, but the original purchase was a 'much' cheaper one from the local motor factors. delco brand I think. Despite it being listing as the correct one and having the correct number of ribs it was a mm or so narrower than the worn out MB one on there (and the new MB one thats gone on). It seemed weird, particularly as I was more worried about the length of the belt, not the width!....

anyways, for peace of mind a MB was fitted.


I've had similar with ignition parts for old FIATs.......but the distributer caps and rotors from the local motor factors were actually better than the original FIAT/ Marelli parts! lol
 
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rayhennig

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Another bulletin ...

My rotor arm problem was, to me at least, incomprehensible. Why should it fail when hot?

I've learnt that the rotor arm has a series resistor with a cold value of 1K ohm. Doubtless, this resistor is failing or the value is rising more than it should when hot.

The ancient, MB original is still working fine.

I've ordered an MB original from Euromerc and await delivery. For reasons of economy, I'll keep the Bremi cap in there but I think a genuine replacement will follow one day.

I hope this is of use to someone with heat related stalling problems.

RayH
 

television

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Thanks Ray, and nice to know and this info can be passed on
 
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rayhennig

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1991 300CE-24 Sportline
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Rotor Arm replaced

Just to update this ...

Stalling problem traced to failed Bremi rotor arm less than 2 years old - 15 year-old MB original still works.

Euromerc Nick delivered my shining new MB-boxed rotor arm and we have high hopes for that. I looks better finished than the old (new?) Bremi cap so that will have to go soon in favour of a gen. MB dist cap.

My thanks to Nick for timely delivery.

Test today went without missing a beat but the proof will be in a return to the UK or some hot weather stuff in the months to come.

One moral of this story is that it's best not to think the worst when you have a miserable problem. Think of the simple solutions before assuming you're in for a €1500 caning!

ATB

RayH
 

turbopete

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I've had similar with ignition parts for old FIATs.......but the distributer caps and rotors from the local motor factors were actually better than the original FIAT/ Marelli parts! lol

to be honest, knowing what fiats and alfas etc from the 80's were like when i started in the trade in the early 90's, that wouldnt have been too difficult!
 


ACMS Mercedes Ltd is an independent Mercedes-Benz service specialist based in Walsall. The company provides high levels of customer service and quality workmanship, at competitive prices. Call Mark on 01922 634666 or 07530 456000
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