Ignition problems on 1995 E200 estate petrol

You probably got a W124... I would change the overload protection relay first. I am assuming you just cannot start the car... only cranking works.

Yes, the old shape big estate. The car will start if the accelerator pedal is depressed and you keep the engine revving. i guess the cylinders that work have enough power to turn the crank and the non-firing cylinders like this. Will try what you suggest. Many thanks. Jonathan

I assume that the "very expensive part" is the ECU of the ME-SFI injection system.

Has your mechanic read the diagnostics codes from the ECU (If not, I am not sure, whether he knows what he is doing)?

If yes, what does the information tell?

Of course, if the ECU does not work at all, you cannot read out diagnostics codes, but then you wouldn't mess around with plugs, leads and coils. And if it does not work at all, has the power supply to it been verified then?

Maybe the dealer is expensiver, but he will have the right equipment and qualifications, and that may turn out to be cheaper in the end.

I assume that the "very expensive part" is the ECU of the ME-SFI injection system.

Has your mechanic read the diagnostics codes from the ECU (If not, I am not sure, whether he knows what he is doing)?

If yes, what does the information tell?

Of course, if the ECU does not work at all, you cannot read out diagnostics codes, but then you wouldn't mess around with plugs, leads and coils. And if it does not work at all, has the power supply to it been verified then?

Maybe the dealer is expensiver, but he will have the right equipment and qualifications, and that may turn out to be cheaper in the end.

Sorry for double answer.

And I can see on your crossing answer, that some of the cylinders do work.

Then the ECU must be operating, and then it should be possible to extract the diagnostics codes.

Fully describe the problem. At cold start? At hot start. Anytime?

What exactly happens other than the engine struggling - how long does it struggle and then????

T G Lambach Okay, it started as hunting when idling at lights. Later that day it was actually difficult to keep running - I was afraid to let it idle so kept revs high all the time. On the couple of occasions when I did let her stall she was difficult to start and needed lots of throttle. She lacked power to the extent some of the hills round where I live had to be tackled in 1sr gear or 2nd gear. The garage has now said they are actually struggling to get her going now.

It will struggle for somewhere between 10 seconds and 30 seconds on idle before stalling

She also sounded very clattery when hunting and struggling at low revs. She is not massively high mileage (150k) and has always been serviced regularly

Jonathan

With this description, I suspect your timing chain has slipped and you need to change out the timing chain and reset the timing marks.

Two things come to mind:

Could be a large vacuum leak (from the power brake booster) that's so diluting the air / fuel mixture that the engine is actually starved for fuel (needs about 14.5 (air) to 1 (fuel) to run well). A vacuum leak could raise this to, say, 17:1 - much higher and it would not run at all. This hypothesis is supported by the motor's inability to idle but marginal ability to run at higher rpms - a vacuum leak is constant so its effect is greatest at low rpms vs. high rpm when the absolute air volume entering the motor is higher making the leak's percentage of the total less.

A workshop may not think "vacuum leak" because they're so focused on the motor's components and may roll their eyes at the suggestion. Don't be surprised. Temporarily disconnecting and plugging the vacuum line to the brake booster will easily prove or disprove this suggestion.

Or, as Tiger suggests, discontinuity between the engine's crankshaft and camshaft timing or that the crank position sensor is sending bad data to the computer and the spark timing is very much retarded.