Does Yours Do This ? (not singing in the rain..)

[angst]

I've changed the distributor cap, rotor arm, leads, plugs and the 260E goes fine until..it hears the weather forecast on the radio for rain.

Soon as mild rain comes it starts stuttering, or not firing on all cylinders unless I rev it. I've sprayed dampstart everywhere. There's no hole in the bonnet!

Surely mercs were meant for English weather too!


Any clues, anyone, would be gratefully received.

 

[Xtractorfan]

Some models were prone to water collecting in the windscreen/wiper channel, and then dripping on to the distributor, check the run offs at each end for leaves and debris and clean out accordingly..

 

[Uncle Benz]

Also examine the ignition coil for any evidence of cracking/tracking near the HT lead tower.

 

[television]

Run the engine when its dark and you will see the fault

 

[angst]

Well thanks everyone, this looks promising.

As it's dark I've just done the dark test. No sparks. Mind you, it didn't want to stutter then.

I'll check the other things in the daytime!

 

[angst]

daytime checks

Well I've cleaned out the bird's nest or whatever in the windscreen channel.

The nearside drain tube at the nearside where the ignition stuff is was blocked. Managed to get water flowing through it although it mysteriously likes to keep the tube looking full of water after draining water down it?!.


Couldn't see any cracks in the coil, but sprayed that with dampstart along with the ignition control unit that I didn't know was there till I looked in the Haynes manual.

 

[angst]

More bits needed?

Well I've discounted any damp problem which I think was there - certainly was in mild flood last month!

Car still can stutter in bright warm weather today and falter at high revs.

Could it be asking for a new coil (it's got 150,000 miles on clock) and do the other things ECU and sensors ever need changing?

 

[Xtractorfan]

is it possible you are getting condensation inside the cap, due to the heat from the engine and the damp conditions.. whip the cap off next time and check inside for condensation

 

[angst]

whip the cap off ..

Clever mercedes benz made that a 20 minute job on the 6 cyclinder with horizontal cap but I'll try that when I get back some time from a stutter ride.

Thing is today it was very warm here and makes me think it's something other than damp. Will try spraying fuel injector cleaner into inlet.

 

[television]

The silicon sprays do help inside the dizzy cap.

Coils when bad they start fine OK and when short circuit the bad short circuit turn will cause the coil to heat up and the voltage output will slowly fall away form any thing from 2-20 mins There are 15000 turns on the secondary and you cant measure this.

Where a condenser is fitted, this acts as a gate to stop the secondary voltage coming out via the open points or photo cell.
The correct value is 2.2mfd 12 coil and 3.3mfd on a 8v coil (ballast)

 

[angst]

The silicon sprays do help inside the dizzy cap.

Coils when bad they start fine OK and when short circuit the bad short circuit turn will cause the coil to heat up and the voltage output will slowly fall away form any thing from 2-20 mins There are 15000 turns on the secondary and you cant measure this.

Where a condenser is fitted, this acts as a gate to stop the secondary voltage coming out via the open points or photo cell.
The correct value is 2.2mfd 12 coil and 3.3mfd on a 8v coil (ballast)

What's silicon spray? The coil bit lost me! Perhaps I could get it checked.
It's an intermittent problem, most on rather than off. When it's off the car runs fine.

Also the Haynes manual mentions possible intermittent fault in ECU and I don't want to spend much more money on the car, it's had enough spent on it, what with exhaust as well. I''m starting to wonder whether old mercs actually last and what with problems I've read with new mercs whether I should stay away from mercs altogether!

 

[television]

What's silicon spray? The coil bit lost me! Perhaps I could get it checked.
It's an intermittent problem, most on rather than off. When it's off the car runs fine.

Also the Haynes manual mentions possible intermittent fault in ECU and I don't want to spend much more money on the car, it's had enough spent on it, what with exhaust as well. I''m starting to wonder whether old mercs actually last and what with problems I've read with new mercs whether I should stay away from mercs altogether!

If it runs OK at times then forget the coil.

You can buy aerosols of Silicon and PTFE these are good insulators to spray inside the dizzy cap,, I will assure you that these old MB's will keep going when the others have stopped

 

[angst]

thanks

If it runs OK at times then forget the coil.

You can buy aerosols of Silicon and PTFE these are good insulators to spray inside the dizzy cap,, I will assure you that these old MB's will keep going when the others have stopped

That's cheered me up!! Does that mean if it runs well at times it's not the ECU unit or the mysterious thing attached to it either?

 

[television]

That's cheered me up!! Does that mean if it runs well at times it's not the ECU unit or the mysterious thing attached to it either?

ECU's for 99% of the time are either good or bad,,there is seldom any middle.

Is the wiring on the engine harness breaking down,,it could pay you to have a diagnosis done at a Bosch service center,½ the MB price,, they made it all in the first place

 

[Blakey]

Hi Angst, You say you have a new distributor cap, - is it a genuine MB part or patent?

When I had a 260E I had exactly the same problems when I replaced the cap with a patent part from Eurocarparts, and it turned out to be the carbon electrode on the cap was substandard. I put the original back in and all was fine.

 

[Aviator]

I had a very similar experiance to Blakey when replacing the distributor cap with a part from eurocarparts on my 190e, within a short period it developed hair line cracks causing missfiring and stalling but unusually only when the car was almost fully warmed up. In critical areas like this you need to use genuine parts.

 

[angst]

Hi Angst, You say you have a new distributor cap, - is it a genuine MB part or patent?

When I had a 260E I had exactly the same problems when I replaced the cap with a patent part from Eurocarparts, and it turned out to be the carbon electrode on the cap was substandard. I put the original back in and all was fine.

That's interesting. All replaced ignition parts are Beru from GSF. I'm told they should be OK.

 

[television]

That's interesting. All replaced ignition parts are Beru from GSF. I'm told they should be OK.

Nothing wrong with Beru

 

[angst]

...it could pay you to have a diagnosis done at a Bosch service center,½ the MB price,,

As a last resort I'll have to - but I always think that one should spend money on a car which is a woman when she's been good :smile:

 

[angst]

@!*%?

Well I got the horizontally mounted dist. cap off despite the bottom bolt placed there by sadists wanting you to take out the radiator first!

There was all this BLUE GOO inside and the centre of the cap inside was burned with the pin missing that goes onto the rotor arm.

The rotor arm had WHITE POWDER and I'm about to use multigrips to get it off as its fixed with those sunken bolts with mini star holes in - none of my collection of star bits seem to fit and the holes seem different sizes anyway.

The cap and rotor arm are new Beru bits this summer!! The rotor arm isn't coming off. It's held in place by three round 'bolts' with 3 different sized round holes now in each and multigrips won't grip on them. Had to clean it on. I've never seen such nonsense in a car.


Can't see how all this happened. The car hasn't been immersed in water.

--
The only silicone spray I saw in halford to insulate was 3 in one professional silicone spray lubricant that's supposed to dry fast and hard, but doesn't dry at all!!