w140-more problems

sully

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1995 w140 s500. will start fine when cold and drives ok. but when you turn it off by the key and go to restart it it wont go. it will turn over and will start backfiring but wont start up. then when it cools down it will start up fine. what temp sensors in the engine could cause this? went to dealers and they were no help at all coz they wounldnt be fixin it.
help!
 

television

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Backfiring indicates electrics does the car have a dizzy cap or is the ignition electronic,95 was a change of year
 
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sully

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it has dizzy caps on both banks. ive replaced plugs, dizzy caps, roror arms and both coils. was thinking king leads but have to but a complete set at £150 or mayb ignition control module if i could find it! but the fact it wont go when warm makes me think a sensor is playing up and mayb cutting the spark?
 

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temp sensors wont really be connected to the ignition circuit as its got dizzy caps, rather than using a flywheel sensor. i need to think about this, and work it out, if i can. fuel vapuorisation springs to mind. does it wet the plugs when it refuses to start? i think it should if its fuelling ok
 

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When it will not start,,take a look inside one of the dizzy caps and rotor and see if they have any condensation on them
 
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sully

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done some lookin about on the interweb there and it seems that on the american forums similar problems have been put down to melted wiring looms due to the failed heat insulation around them. has anyone encountered this and am scared to ask the cost of a replacement!
 

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I would have though that 1995 was a bit late for this fault,,but you could take a look at the main engine harness to see if the insulation is crumbling away
 

turbopete

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this may sound a strange question, but has the engine had a compression test?
 

jibcl500

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done some lookin about on the interweb there and it seems that on the american forums similar problems have been put down to melted wiring looms due to the failed heat insulation around them. has anyone encountered this and am scared to ask the cost of a replacement!

if the W140 has distributors then its likely to suffer at some time with a failed loom, seen it too many times, £500 roughly for the new loom.

jib
 
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sully

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rite thats a fair list of stuff to check. its at my dads garage so will get 2 it 2moro tho compression test will hav to wait till monday. hope it passes!
£500 for a new loom. f*ck that! but if it solves it i will happily pay it. payed near £500 sheets for an air flow meter last year for it.
thanks again lads

ps are the looms hard to replace - dosent look 2 handy!
 

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Is this the S500 , V8 ? The V12 as in the S600 had twin distributors as it was basically two six cylinder engines joined together , and not noted for reliability , but the V8 models , of which the 500 is one , normally had an 8 cylinder distributor .
 
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sully

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rite udate. the fuelling is fine. there is no damp in the caps. plugs look ok. the loom seems ok but i only checked 2 obivous places coz didnt want to cut into it too much. no obivous air leaks but loads of pipes so hopefully didnt miss anything.
on start up when cold its bit rough but then clears. if you drive smoothly it seems fine. if u give it a boot and use the kickdown, it seems to be rough ie off cyclinders then clears and takes off. then gets hot (about 90-100 degrees) and goes all wrong and at tickover will just die. try and restart and it wont and will back fire thru the exhaust. the cat isnt an issue cos its been de-cated. mayb lamda probe?????
its now cooling off in my dads garage. dont kno what to do. would just giv it into a specalist but not sure i could pay the bill at the end!
 
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sully

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cheers mate. will give that a go and check the egr.
it just seems like a never ending story! but i love the car!
 

television

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cheers mate. will give that a go and check the egr.
it just seems like a never ending story! but i love the car!

They are wonderful cars,, is your engine the 117 rather than the 119
 

jibcl500

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Loom 100%, look at the plug for the injectors and see if the insulation is cracked you need to check as much of the loom as you can without cutting into anything but until your 100% sure the loom is good theres no point going any further.

jib
 

Alex Crow

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w140 will be the 119 malcolm.
 
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sully

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rite loom looks dirty but intact at all joints. maf ok also.
my dad was speakin 2 a different dealer and got speakin to an old hand in the workshop. he reckons from past experiance that its the crank shaft sensor @ £121 that plays up when its hot. any thoughts on this?
 


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