engine not starting properly and not keepeing revs while idle

[clk1]

Hi,
SInce 4 months I am struggling to come back with my W124 CE300 automat LHD from 1991, to normal working condition. Engine is not starting properly, only if starter turns into higher revs it catch-up. Also when engine is working, it is not keeping revs while on idle, often turns off if I am not keeping throttle slightly pressed. I have already changed 2 workshops who were not able to cope with a problem and now hope to find any suggestion from your side. Here you have a full story:
While towing caravan on the highway, bearing of cooling fan fall into pieces, fan fell of and belt driving all auxiliaries went loose.. no charging.. no cooling.. etc. I was trying to find parking place and I was driving couple of minutes until engine completely stopped by itself - engine was boiling... :-(
Later found that there is no compression in any cylinder.
After couple of weeks in first garage engine been completely overhauled, it was necessary to plane the cylinder head, as I was informed. Al other maintenance was done to make engine runnig but it was observed that motor is not starting properly.. after another couple of weeks they gave up and I placed the car in another "pro" hands. He was trying to solve this problem, found faulty houses for vacuum, replaced, found foulty switch for ABS which also cotrols some current for engine (at least I was told so), replaced, but engine is not starting properly...
When engine is cold it is more difficult to start it, while is warm it is little easier.
It is LPG converted engine and starting on LPG is much easier, but engine revs has to be more than 2500...
Please give me some ideas what could cause such a problem... I dont;want to give up.. me and my wife we like our "merc" and I really do hope to find some help from you guys,
If you need any additional information please ask.
All the best for the rest of the day..
Walter

 

[brandwooddixon]

Sounds as if the head warped - hence skimming procedure - which is what I would expect from what you described.

Check out the compression on the cylinders - this should now be OK, but always worth a look in any case.

The temperature sender is probably damaged and will need replacing. This would be my first port of call. This will be needed for correct fueling at startup.

Thermostat probably also needs replacing, although this wont effect startup.

If there are still problems. Check all of the usual, plugs, leads etc. i.e. sparks and fuelling.

If there are still problems it may be that they have got the timing out when rebuilding the engine. It wouldn't be the first time that I'd see the cam shafts out by 180 degrees.

 

[walter_sopot]

Chris,
Thanks for your reply.
Anyhow i try to translate it for my mechanics. Please clarify for me what does it mean "timing out".
Thanks in advance
Walter

 

[brandwooddixon]

Sorry Walter I missed your reply.
Have you sorted this problem yet?
What I meant was that I have seen engine rebuilds go awry because the cam shafts were fitted 180 degrees out i.e. TDC for exhaust stroke when it should be a compression stroke. This may not be the case, but worth a double check.

In trying to solve the problem, don't use the LPG system, stick with the standard fueling.

Have you changed the temperature sender?

I'm also trying to think of the injection system fitted to your car. I know that in some of the earlier versions theres a wax temperature sensor within the injection system which can fail.

Does the engine turn over well? Are you trying to using another battery or vehicle to help jump start the vehicle?