www.jec.org.uk

Having ventured out on my fist long distant run since having the coil plugs changed ( see rough running earlier posts), all seem great but eventually the FAIL SAFE engine mode was displayed, intermittently at first, which then led to shutting the power down. The engine malfunction light remained off.

Consequent diagnostics by the AA showed no faults, but further analysis showed that the catalytic converters were hardly working.

A theory here is that during the misfiring/rough running phase had damaged the converters leading to the management systems action in the above. As its an old S type, I guess the onboard computer is quite primitive compared later modes. The engine is running fine!

Having been relayed home, I daren't venture out again and now have the car in my drive with the nearest dealership 35 miles away and a decision on the cars future.

Do you think the theory is correct and would it be an expensive job to put right.

Keith

Keith,

I think you need to get prices for converters, labour and VAT. Then you will be able to make a decision on the future of the car.

It is possible for the cats to close the power train module down. Throttle body failure car also cause intermitant faults as per my articles in the monthly magazine have previously shown.

ECU modules have changed over the years as new models with different features have dictated.

Mike

Thanks Mike,

I am going to re-commission an old Mercedes ( agricultural technology) whilst looking further into the problem.

Keith