1992 W124 diesel will not stop running off the key

EireJames

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Jeep Grand Cherokee OM642 power
HAd to go home to Cork last night anb back again to Galway unexpectedly, the old lady performed faultlessly over the 240 mile round trip as I have become accustomed to her doing :)

However when I arrived back in Galway she continued to run with the ignition key removed, all gauges etc went to 0 though, rev counter, temp gauge etc, even radio turned off.

Some sort of vacuum hose / pipe somewhere I take it.

Funny thing is there is a chap viewing her this evening :shock:
 

Bolide

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There's a vacuum pipe off somewhere. This is a standard fault - do a search and you'll find lots of info on it

BTW The manual shutoff valve is between two of the inlet manifold pipes and has a red marker

Nick Froome
www.w124.co.uk
 
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EireJames

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Cheers for that, central locking is still working along with everything else. Will have a look after work, hope it's an easy spot and fix, fingers crossed. Would have to happen before someone wants to view it.
 

wireman

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nice 201 2.5D 1993 & very nice 129 SL500 1994
My 124's pneumatic capsule (on top of the injection pump) failed with the same result.
A vacuum is applied to it to stop the engine.

Prior to the capsule's total failiure my engine had developed the habbit of taking its time to stop and juddered sluggishly to a halt.
With its new capsule the hand lever stays down overnight untill the key is turned on.

A 4mm pipe runs from the servo pipe (some where near the front of the engine) to the ignition lock and another runs back from the lock to the capsule.
The vac system is connected together by rubber joints which can split and leak rendering the system a shade iffy.

On my 250D the pipes are brown to the key and brown with a grey stripe to the fuel pump.
If you have a vacuum gauge try lifting the pipe (brown/grey) off the fuel pump and connecting it to your gauge, when you turn off the key it wont stop the engine but the gauge should read at least 20"Hg.

Your central locking does not work of the engines vac system, it has a seperate pump.

The engine vac also drives your headlamp level adjuster, if this works the fault is probably confined to the engne stop system.

If you do change the capsule be sure to fit it correctly, it operates direcly on the fuel pumps control rack and miss fitting it could result in the pumps govenor being disabled and then once started the engine could run away, go over safe speed and self destruction of the engine will result.
 
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EireJames

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Brown tube connection is broken where it taps into the main vacuum line, bad luck really.
 

Alex Crow

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good luck really. easier to fix than changing the vacuum capsule/bowl, they are a pig.
 

television

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good luck really. easier to fix than changing the vacuum capsule/bowl, they are a pig.

On the earlier car you could have a piece of string from the red lever going into the cab,,and just pull the string to stop it :D
 

Alex Crow

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back in the days of trafficators and 2, 4 and 5 star fuel.
 
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