w140 s500 issues!

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philg1981

Member
Joined
Feb 21, 2015
Messages
41
Location
Costa del Northern Ireland
Car
w140 s500 - got hydraulics fitted! daily - s210 320 cdi mapped and low(ish)
Hi there, just joined up and straight in to ask for help! I've a 1995 w140 s500 (m119 I think - has distributior caps) that I've owned for 7 years but been off road last 4. I'm recommissioning it at the minute. Full service coolant etc. Problem is that when it gets to about 60 degrees it runs like a bag of nails - missing and off cylinders plus cuts out when stop driving. Cold start is fine so it's a heat issue I'm guessing. Have replaced the temp sensors (both of them) and the fan clutch also. Before it was put off road it got new coils, rotor arms, caps and an expensive air flow meter (genuine!) So altho are 4 years old, have done little milage. Could it be as simple as ht leads?? And would a computer show up any faults as no warning lights on dash.
I'm abit fed up with it but I love it and want it back on the road!
Any help greatly appreciated.
Thanks
 
I'd first get it checked for fault codes otherwise you are working in the dark. Book it into your local Merc specialist, well worth the few bob expenditure. Otherwise you could try a new CPS (crankshaft position sensor), might do the trick.
 
I would go back and check dizzy caps and rotors, this is the usual problem. I suspect you have a condensation issue in there.
 
OK will do. Checked the caps and gave them a clean. Not alot of wear on them. I replaced them with non genuine parts (beru I think) I will find a local specialist indie to check codes as last time I went near the main dealer they didn't have a clue about my car as it's nearly older than mist of the techs that work there!
 
Oh if it is the caps is there any way of getting round the condensation issue like a mod?
 
As above condensation on the caps, arms. Go back and clean/dry them. Also have you replaced the ignition leads? Also what about plugs?
 
Yeah new plugs and cleaned the caps. Seemed to rev out quicker and cleaner when cold but still same warm issue. Haven't done ht leads as yet. Will try a code read and check out that link about moisture.

It.was only ever a weekend car so suppose that doesn't help.
 
Quick update - had a read thru that link that @sl300-24 posted. Very good info. Pulled caps off and I've seen less water in a bath! But now a new problem - the 3 allen head bolts on the rotor are being chewed up cos of the damage done by the damp! SO that's something else in my way now. But fingers crossed I can get them out and replace o rings/seal it up and get back on the road.
 
Another update. After taking an hour and a half to get the rotor arm off, found the dust cover at yhe back of it was fractured and broken. Thought I'd try merc for a new one - £112+vat! He'll no! So got a used one off of evilbay and got it cleaned up. Refitted everything and used some spray for keeping the water away also. It seems alot better and restarts at warm temperatures with no issues. Still a bit lumpy at times on idle but I can live with that. Was only a quick drive but went well so hopefully that's the problem sorted.
Thanks again for the help guys.
 
To help the lumpy idle I would put a new set of spark plugs in it before you try anything else.
 
£112+vat! He'll no!

Gone up quite a bit then ! :eek: Bad enough 4years ago when I paid £75 each.

This is why a lot of owners don't bother with this part and just keep chasing the issue. If you love the car and plan on keeping it, they should be replaced as a one time spend.

Did you check/replaced both of these expensive buggers ? How about plugs are they the correct non resistor type ?
 
I only replaced one as the other one was serviceable. I cleaned out where it sits then put new o rings on. I would have bought new but wanted to see if the fix would solve the problem as didn't want to waste £250. If it holds up I'll replace the pair.
As for plugs, I just got some ngk jobs from eurocarparts. Nothing fancy, at around £2 each, and we're fitted in February there. What plugs fo you run/recommend?
 
MB dealer should be sub £2 a plug.

Part of the reason those insulator plates are so expensive is that they are NLA from Mercedes (or were last time I checked). Still available from Bosch though, I paid ~£100 for a pair a couple of years back.
 
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rorf said:
Cheaper to order the parts from the USA - Pelican Parts or FCP Euro
Not a lot in it once you factor in shipping costs and duty. If you can get away not paying duty, maybe. Often not though .
 
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