1995 SL500 Cut-Out Problems - AGAIN

[tmwsccsh]

Hi all,

I'm getting fed up with this now and sorry for those who recall my previous posts on the topic.

Every year when the Spring comes I get the same problem - lack of performance once she has warmed up. All is fine when she's cold, as soon as the temperature gauge passes about 70 degrees sluggishness ensues. If I push hard on the accelerator to the "turbo" button under the pedal it will kick in and go but normal acceleration is just slow and really struggles - she even stalled out on me yesterday at a roundabout and almost wouldn't fire up again - embarassing for a few minutes...

Had to left-foot brake home to keep the revs up each time I stopped, and then pulling off was sluggish again. It's as if once she reaches 2,500rpm or so she comes back to life, but getting to that is the hard part.

I have had the distributors changed 3 times now in the last 4 years and this always solves the problem but I can't believe that is the answer - a new set pretty much each year (costly too!). It's not like I don't use her over winter either as I do. Just that the spring brings these problems again. Winter does have similar issues, however they take longer to manifest.

Symptoms are, once at temperature, hunting at idle which starts by just jumping around 100rpm or so, but can be fluctuating by 400rpm by the time it's really got going, hence the cut-out yesterday. Reverse is the same, although in Neutral it is more stable, but still hunts a bit.

So my question is, where else can I be looking at this? I just want to know that she is reliable again - I don't trust her at all at the moment so hesitate using her, however my main car is going for MOT in 4 weeks and I know it's going to be a bad one and may be off the road for a few days - I need the SL running confidently so that I can use it in the Jag's absence.

Any other thoughts greatly appreciated.

And sorry if this sounds like a rant - it's been a bit of a brain dump of frustration.

Thanks in advance.

Regards

TMW

 

[brucemillar]

HI

Wow that is frustrating. Strange that replacing the distributor "fixes" it. This would lead me to thinking that something is breaking your new distributor. Possibly an over-voltage problem?

That would be my favourite to look at first on the basis that when you change the cap it "fixes" it at that point. How long does it stay fixed for? - Is it that it stays fine after a new cap, until you lay it up for the winter? Or does it start to break down without any laying up?

Temperature sensors can also cause havoc if they are reading incorrectly. Check the wiring to the sensors and replace the sensors if in any doubt. They are not normally very expensive items.

Others who know this engine well, will be along. Keep the faith.

 

[Doodle]

Forgive the response with a similar brain dump.

The insulator discs on the distributors (from your previous thread) - are they sloppy or tight around the camshaft end?
When were plugs, leads, coils last checked/changed?
Has the engine harness been replaced yet? Your car of the right age to require it.

It sounds as if new cap/rotor are restoring the system enough to start working, but as they wear it falls down again.

 

[BlackC55]

The caps probabably have moisure in them again...

Did you replace the seal that stops moisure getting in when you replaced the caps?

 

[tmwsccsh]

Hi all,

Sorry for not coming back sooner - been one of those weeks.

Not sure if the seals were replaced as well - will check the invoice from the last time they were changed.

Assuming it is moisture again, is there an easy way to dry it out without having to take everything apart / off? A good run holding a certain amount of revs for a period of time, for example?

Or am I looking at more expense do we feel?

Thanks in advance.

Regards

Tim Watts

 

[Codger49]

Probably not relevant, but in the 1970s I had an Alfa which had vent holes in the distributor cap. Probably fine for Italy, but gave similar issues to yours in Manchester winters. I cured it by placing thin Elastoplast over those vents.

Nowadays, my garage is detached from the house and I run a dehumidifer in it throughout the winter just as a precaution against damp and condensation.

 

[Doodle]

Just pop the caps off and wipe out, should only take 5-10 mins. Don't try and dry them by running it.