Headgasket done now new problem

[derekpayne]

I have completed a headgasket replacement job on my C180 (W203), and it starts and runs, but, I have little control over the throttle, feels like a "flat spot" sometimes when I try and rev it up, it starts "hunting" sometimes and I have no control of throttle at all when that happens, if I stop the engine and restart it, it starts to run fine and then starts after a few moments to run erratic again, and it is ticking over too high at around 1200 rpm when its not "hunting".

I have checked all electrical connections and they appear to be OK, all vacuum pipes also appear to be OK, is it something that needs to be reset, there is probably a simple solution to this one but I don't know it yet.

Cheers

 

[Dieselman]

Sounds like an air leak, knackered MAF or loose valve guides.

 

[derekpayne]

Fault codes

Right had another look this morning in the light of day, started it up and ran fine, no misfires or hesitancy, let it warm up and gave it a run drove sweet.

Connected laptop to OBD socket to see what was going on and here are the fault codes, which I have since cleared and no more codes have appeared since:

P0304 Misfire on 4
P0502 Misfire on 2
P0638 Fault definition not available or manufacturer specific
P0410 Secondary air injection system malfunction
P0010 A camshaft position actuator circuit (bank 1)

I could have introduced some of these faults when I was disconnecting things to narrow the problem down as none of them have reapeared.

Can anyone define what these codes mean?

Cheers

 

[grober]

May simply have been damp that accumulated on the HT components while the car was sitting around. This has now " burnt off" with the engine warming up. The cam actuator may just have needed filling with oil. I would monitor things for a while to see if they settle down.