Starting Problems

[Motorvating]

My 2001 CLK 230 recently blew a head gasket, which was repaired along with a head skim.

Since the repair the car has terrible starting problems. When cold the car just turns over without firing, but after numerous attempts it will fire up but misfiring for around a minute, then it runs OK. At the point of firing up, and whilst it is misfiring, if you switch off and back on again it will run OK.
Once you've got the car running it will switch off and on OK as long as the engine is warm/hot, however once the engine is cold I've got the starting issues again.
Error codes are intermittent, but when they did show it was misfire on 1,2 and 3 cylinders.
When the engine does start the radiator fan comes on for about 30 seconds and is very loud, however my mechanic thinks this has nothing to do with the starting issue and is an aircon issue which is now playing up as well.

The car was converted to LPG over a year ago, and has run really well on it. The system is a fully automated Prins system i.e. it automatically starts on petrol and cuts over to LPG when at running temperature. This is still running OK, and when starting the engine from hot it will start on LPG, so really don't think this is the cause, however I have asked the question on an LPG forum.

Today I changed the Fuel Pressure Regulator as the fault had all the symptoms of a faulty pressure regulator, but is hasn't made any difference.

Has anybody got any ideas of what it could be?

 

[Motorvating]

Bump

 

[BlackC55]

Check the fuel pressure and crank signal firstly.

You mechanic should know how to do this.

 

[flango]

Valve seat regression? Wouldn't have expected it this early if the car was only converted just over a year ago. Did they check the seats when you had the head gasket done?

 

[Motorvating]

I've replaved the fuel pressure regulator, so pressure is OK. I'll ask my mechanic about the valves and crank signal today.

The LPG forum had an installer advise me to pull the fuse from the LPG styem and test the car, and if its still doing it then it rules out the LPG system.

One chap on this forum who used to convert Mercedes said I should check the engine coolant sensor because on these cars if that's out it could give me starting problems.