Cylinder misfire on M120 engine (SL600)

[PurpleDog]

Cylinder misfire on M120 engine (SL70)

Hi all,

There was some misfiring detected in 2 or 3 of the cylinders in my car.

According to the dealer, it would require about 32 manhours to remove cylinder heads to check (so some £5,000).

Other option is to run some miles on it to see if it clears the cylinders. Downside is that if one of the cylinders blow, it could cause serious damage and potentially require new engine.

Any advice / thoughts appreciated...:

 

[neilrr]

EZL problem?

There are 2 I believe, swap them over & see if the misfire moves to the other bank.

 

[C36fan]

Hi all,

There was some misfiring detected in 2 or 3 of the cylinders in my car.

According to the dealer, it would require about 32 manhours to remove cylinder heads to check (so some £5,000).

Other option is to run some miles on it to see if it clears the cylinders. Downside is that if one of the cylinders blow, it could cause serious damage and potentially require new engine.

Any advice / thoughts appreciated...:

Hi get a compression test done to find out if there is any cylinder low on compression.
That way you know if the engine is sound.

 

[optimusprime]

Plug and coil check .Take it for second opinion .I called out mobile auto diagnostic it cost me £30 ..To find bad leads were the cause of the missing. .

 

[PurpleDog]

Thanks all. Will do further checks.

 

[grober]

depends on what form of ignition your car is running--- it may have 2 EZLs plus distributors or discrete ignition coils - 1 per cylinder later cars had the problematic and expensive ignition cassettes but abit after your time I think. The ignition components on these cars had hard time in a very hot engine compartment so the insulation tends to suffer. This can be the coils themselves, the plug-coil extender or even the low tension wiring from the ECU. The most likely candidate for misfire lies with the HT ignition components rather than any engine head problem.