W124 260E Engine Problem HELP!

[dc2100k]

Hi All,

My beloved 260E died last night and I'm trying to get the the bottom of what's wrong before I get my garage to pull the head. The car is a 1990 model with the M103 12V engine, 64000 miles only and all original. Car was running very nicely until last night, we just did 1000 mile round trip to London with no mishaps. Oil pressure at 2 (idle), 3 (under load). No bad noises, lots of power and very smooth. Would sit at 85 all day no problem. Recent timing cover gasket (to solve minor oil leak) and water pump (£££).

Symptoms: car started and drove 1 mile. Turned off and 1 hour later it would not start. Turns freely but will not fire at all. Fuel is getting to the cylinders. The garage have pulled the plugs and there is a spark (slightly weak). The spark at the distributor is stronger but cap and ignition leads are all original so probably could do with being replaced. The garage suggested this as a remedy until they did a compression test and the readings are 150-50-70-120-90-120 (ie. way too low and wildly differing) so they say no point until the compression issue is sorted. He also expressed surprise that it doesn't even attempt to start when they spray fuel in the intake.

I have asked them to do a leak down test and remove the rocker cover for a visual inspection as that may give a better idea.

My thoughts are:

1. Bad valve or valves
2. Bad head gasket (although no water in oil or oil in water, also unlikely to just stop without any symptoms)
3. Bad timing chain/camshafts.

Does anyone have any ideas or experiences with a problem like this? Garage estimates £1500+ to pull the head, fix any problems, do the stem seals, new head gasket, new distributor cap and leads. Clearly I want to eliminate any other things before I do a top end rebuild, and at this sort of money I'd be thinking about selling the car as a non-runner.

Hopefully someone can help?
James.

[Frank Reiner]

Originally Posted by dc2100k

Symptoms: car started and drove 1 mile. Turned off and 1 hour later it would not start.
Turns freely but will not fire at all.
Fuel is getting to the cylinders.
He also expressed surprise that it doesn't even attempt to start when they spray fuel in the intake.

I have asked them to do a leak down test and remove the rocker cover for a visual inspection as that may give a better idea.

1) If there were a gross mechanical failure in the cam drive, the engine would not, a] turn freely, or b] yield the compression pressures that are quoted.
2) Look to the ignition system for the cause of not starting/running. If the distributor cap is not obviously damaged (it may be quite dirty/oily inside), examine the rotor for cracks, and for the condition of the resistor that is encapsulated in the rotor (~1K ohms). If nothing obvious there, check coil for resistances on both primary and secondary windings, particularly looking for an open circuit, or very high resistance. If all those seem right, try to find an ignition controller (EZL) to borrow for a test.

[dc2100k]

Thanks again. I am going to ask them to do the leak down test and inspect the timing first - as long as it does not indicate a defective head I will get them to renew the ignition components (plugs NGK BP6EF, ignition leads, distributor cap, rotor arm & possibly coil). If this does not fix it then I will get them to take the head off for more scrutiny.

What is the best way to clear the flooded engine if that is the problem giving the low compression readings? Pull the fuel relay and crank with a little oil in each cylinder?

[dc2100k]

Thanks for the great advice Frank. The garage replaced all the ignition components and she's alive and kicking again. Took her out for 100 miles on the road to give here a blast and she's back to her best!

[tinypanzer]

Originally Posted by dc2100k

Thanks for the great advice Frank. The garage replaced all the ignition components and she's alive and kicking again. Took her out for 100 miles on the road to give here a blast and she's back to her best!

M103 is a very revvy engine and wears out the cap and rotor fairly quickly compared to a lot of cars. Glad you got it sorted. Just be aware that this is a high wear item on this car. Plan on replacing the cap/rotor every few years, depending on milage. My 300SE really ate through caps and rotors fast and things would go from just fine to barely running almost overnight when they finally wore out.