Author Topic: Engine Rough Running - any ideas  (Read 3105 times)

paul_GB

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Engine Rough Running - any ideas
« on: June 05, 2010, 18:13:48 »
Gents - After rebuilding my 230SL engine it actually started first time (after lots of starter cranking and encouraging fuel to the pistons by cracking the injector pipes etc). I was overjoyed until I realised I cant get it to run anything like smoothly. Reckon Ive spent 4 full days chasing this and Ive learnt loads about the car.. ;o) .. but havent sorted the problem yet.

The symptoms :

- White smoke from exhaust on tickover then more on rev increase
- Plugs fowl up quickly with unburnt fuel
- Cant adjust air or fuel controls to compensate for rough idling
- Ignition timing adjustment make no difference

Note,
- CSV not leaking - checked by looking thro the air venturi with fuel being pumped
- WRD seems fine - I used the stethescope approach and the air valve seems to shut down ok

Ive read heaps of excellent threads which have been real useful to get me to where I am now. My suspicion is the camshaft timing.. on investigation it was about 8 deg behind the crank TDC. Ive improved it to around 4 deg after the crank now by using an offest key (and aim to order more offset keys on Monday to get to 0 deg). However, the bad news is its still running like a dog :o(. Is the cam timing that critical - would 4 deg have the effect I am seeing...? Or any other suggestions that I need to check out..?

My other half thinks Ive moving into the garage (not a bad idea cos theres a beer fridge here).

Cheers
Paul
1964 230SL - Dark Blue

paul_GB

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Re: Engine Rough Running - any ideas
« Reply #1 on: June 05, 2010, 19:17:16 »
.. Forgot to add that the compression readings are all low.. 100-110 psi.
Paul
1964 230SL - Dark Blue

ja17

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Re: Engine Rough Running - any ideas
« Reply #2 on: June 06, 2010, 06:44:04 »
Hello,

The cam timing will not normally cause major running problems unless it it a full link (18 degrees) or more off. Make sure the rack in the injection pump is not stuck. Also make sure that the WRD (warm running device) in the injection pump is not stuck also.
Joe Alexander
Blacklick, Ohio
1969 Dark Olive 280SL
2002 ML55 AMG (tow vehicle)
2002 SLK32 AMG (350 hp)
1982 300TD Wagon turbo 4spd.
1963 404 Mercedes Unimog (Swedish Army)
1989 flu419 Mercedes Unimog (US Army)
1998 E430
1974 450SLC Rally
1965 220SE Finback