shanusanus

Hi all - yet another issue for me.

Cl500 - 56K miles. Recently had a B service with ALL psark plugs replaced and had a small air pump of some sort on the front of the engine (there are 2 on the front - left and right)

BEFORE the service and plugs were changed I had a random shaking at idle. Thought new plugs and the air pump replacement would fix. It didnt.

MB techs have looked at it and said its HT leads and thats not covered by warrenty. My question is - is there not a way of testing each lead and seeing what actual lead is causing the misfire rarher than replacing the whole lot?

Also could there be anything else that may be causing this rather than the HT leads?

As usual - any advice is welcomed.

Thanks

MBtech1

It most likely needs spark plug wires. You just need to check the codes with a scan tool and see what cylinders are misfiring. Then replace both wires on the affect cylinders.

shanusanus

Thanks for the reply - yeah so I guess I need to check those HT leads then. We have a bank holiday here in the UK - 4 days off - so I guess this weekend Ill by in my garage playing

516mbtek

No check eng light? May not be misfiring...may need motor mounts

Highend

run chevron for a about month and check your MAF. also make sure all caps are closed and all wires are dry. sometimes water sneaks in and can cause issues. Just spend about 2 hours poking and adjusting and cleaning, youll be amazed how sometimes its something stupid causing it.

JAYCL600

check your motor mounts

shanusanus

Finally got round to setting up CARSOFT yesterday. Plugged in ODB2 and ran the car - reported misfire on cylinders 2,3 and 7. Great. So made a call to get new leads @ £20 each. Not too bad but then the Tech throws a spanner in the works - he says as the car is dual spark 1 cylinder misfiring wouldnt show up that bad. maybe its the coil packs?!? damn it - coil packs are £120 each - and there are 8 of them! although it may only be 2 max needed - still a damn expensive repair though.

Im taking a look next friday now as im too busy to deal woth it before then.

MBtech1

Not saying it isnt possible but Ive never had one of that style coil packs go bad. However Ive replaced more of those wires than I could begin to imagine. Just buy both spark plug wires for each cylinder thats misfiring and you should be good to go. You will need 6 of them total. They are different lengths so you will need to tell them which cylinders you need.

soundblazers

i had same problem, i changed my egr valve! and problem is history.

shanusanus

OK moved coil packs from the 3 offending cylinders to cylinders I know work - thsi way if the fault moves then its Coil packs the issue, if the fault stays put then its the leads - ha - see my thinking there!!

well did the moves - reset the ME memory in Carsoft and drove 30 miles or so. replugged in carsoft and NO ERRORS WHAT SO EVER. And the shaking is VERY slight now. Im gonna drive 200 or so miles on monday - then plug the carsoft back in again and see if any new errors have appeared.

Could just disturbing and moving coil packs REALLY fix an issue!?!?!

Jud Chapin

Could have had a weak/dirty connection. Hopefully that's the case. Good luck!

shanusanus

OK - I need help here.

I have replaced all Sparks. Then replaced Coil Packs and HT Leads on all cylinders that gave an error. Cleared errors and after 2 days still shaking at idle like a misfire and check engine light on. Checked codes - exactly the same cylinders that I have replaced parts on show misfire again. This cant be right so I'm no guessing its the MAS?

And if it IS the mass air sensor I'm looking at a £250 part and the labour time. I'm guessing I can do this myself BUT my question is - the local MB dealership said that the part needs 'boot strapping' - it needs coding to wrk with my car via Star Diag. Is thsi true?!? I thought I could just replace the part and voila all done. Does it really need coding with Star Diag to get it working in my car?

If anyone has a guide to a DIY job on fitting the MAS on a 2000 Cl500 I would be more than greatful Thanks.

shanusanus

OK so I've found an OEM MAS witprt number the same as mine Bosche 0280217810 MB A1130940048 Brand New £40 inc postage - well happy.

As for the programming I think I know what Merc are on about. My ECU would have adapted to the old MAS - when I install the new one I need to clear ME adaption - I can do this using carsoft so I think I'm good to go. I just really hope this now fixes my rough idle. And it will stop the CEL too hopefully.

Anyone wanna add some encouraging words?!?!

Jay9722

Hey man at least it starts and the paint isnt falling off! See, it could be worse.

shanusanus

I feel for you Jay I really do. So your car still has the starting issue? Is it under warrenty?

shanusanus

This is beginning to be joke. Ok so Ive now changed the coil packs and HT leads on the 4 cylinders that CARSOFT showed errors on. Still shaking. So I replace the MAS today - clear all ME adaption and errors codes. Fingers crossed I start the car - damn it still shaking at idle. What the hell could it be now?

Please - any techies out there wanna give some advice cause thsi is REALLY getting expensive and annoying now

wease206

gas cleaner might help

shanusanus

Already tried that - used REDEX - usd loads

Still no good. Man this is sooooo annoying.

wease206

Bad valve?*
Bad piston?*

shanusanus

Hmm - that sounds very expensive

~CL500~

shanusanus,
This is an odd issue. If I were you, I'd get a diagnosis at a dealership. StarDiag will pick up additional errors that an OBD can't. It'll probably cost you $100, but at least you'll get a solid diagnosis and proceed from there.

You may have 2 separate issues here. The misfires might have been related to the coil packs/maf. The vibration could be a separate issue.

Good luck.

shanusanus

Yes it is a very odd issue.

To recap - car shaked at Idle. Eventually got CEL on. Showed misfire on 4 cylinders. Well I have now replaced ALL spark plugs, and changed coil packs and HT leads on the 4 misfiring cylinders. Cleared all faults - still had shaking at idle 2 days later CEL on again - shows exactly same error with misfiring on same cylinders. So was advised it must be something else causing this - so fitted new MAS. Cleared all faults. Still shaking although yesterday didnt hardly notice any shaking at all - UNTIL I came off the moterway and the car lost power - I'd accelerate but it was real hard for the car and it shaked like mad and CEL light on again. I was 5 mins from Mercedes Brighton so ran into there and they popped STAR on it.

Guess what - exact same cylinders misfiring still. I advised MB what we've done so far - he said I'd have to book it in with my nearest dealer. Mb Tonbridge booked in but cant get me in till 12th may - so for now I have to live with a car thats shaking like mad and constant CEL on.

BUT thsi morning I turn the car on - almost no shaking and no CEL - WHAT THE HELL IS GOING ON?!?!? I guess at some point today it will come on and the shaking will get worse maybe? Ill update here and let you now.

shanusanus

UPDATE:

CEL light on again - now showing mis fire on cylinders 4 and 5. So do I ignor and take it that the errors are wrong - something else is the main cause - or do I spend yet another £300 and replace these coil packs and HT leads?

Well I've decided to go with new coil packs and HT leads on cylinders 4 & 5 - £336 the cost.

Will be fitting later today and we'll see what happens then - fingers crossed - god I hope this solves it - £1250 so far spent on this bloody CEL misfire lark. NOT HAPPY.

nycturbovr6

i am having this same problem on my e500.. just had a service.. no codes

shanusanus

I took the car to my mate who has Sta Diag and the stored error said about it running enleanement above limit at idle. He feels ths my be O2 sensors on teh way out. In fact at high revs with car in Park we get fine running but as soon as the rev drops to 1900 or below it starts shaking and running bad. I guess we are norrowing this down now - and at least O2 sensors are under warrenty thank god.