E36 now running on 5 cylinders

[Palfrem]

Drove home from London this evening - no problems

Out for curry about 2 hours later and it sounds like she's on 5 pots.

Hunting for revs on tickover.

Drives almost OK but no real power and a blown exhaust sort of soundtrack.

Any ideas please?

Many thanks - into my indie first thing in the morning if they have a slot

 

[millo777]

The only time I've had a car lose a cylinder was a down to a dead coil pack, so it might be worth checking the spark plugs and coil packs.

 

[kth286]

the hunting for revs bit is the puzzle.

an under coil extension down to the spark plug can loose contact

I would be plugging a fault code reader into the 16 pin socket and it will tell you which cylinder is the problem.

does your person use a code reader appropriate to this older merc.

He can use the simple flash light codes, and if he cannot decipher, stick them up on here - someone will know.

 

[219]

If it is suspected that one cylinder is not firing , just run the engine for a minute or so before removing the spark plugs - if one was not firing , it will be soaked with petrol .

If a coil pack has failed , you might lose two cylinders .

 

[BlackC55]

Check the wiring loom too. They tend to break up causing missfires.

 

[kth286]

If it is suspected that one cylinder is not firing , just run the engine for a minute or so before removing the spark plugs - if one was not firing , it will be soaked with petrol .

If a coil pack has failed , you might lose two cylinders .

Not with this car, as an electrical misfire will be spotted by the ECU and it will cut the power to the appropriate injector.

 

[hotrodder]

Check the wiring loom too. They tend to break up causing missfires.

Agree the wiring loom is one to check unless it's known to have been replaced but i would have thought the most likely wiring suspect would be a short in the LT side/coil feeds which'd take out two cylinders (and potentially spike the ecu).

A dead coil pack will take out two cylinders as it's a 'wasted spark' set up. If it's only dropped one i would have thought the favorite candidate would be something 'after' the coils... a bad/faulty under coil extension as said or a plug extender, HT lead etc.

the hunting for revs bit is the puzzle.

I would have thought hunting at idle with a misfire would be normal as a result of it trying to maintain it's target idle speed, especially if the misfire is the result of a intermittent/poor spark

 

[horgantrevor]

on my c36 it was coil pack and it was the last cylinder near bulk head

best thing is get a star test done on her

i replaced all spark plugs and leads it made a huge difference to over all performance as they were old try and be care full with the loom as olly has said they do become faulty and the insulation on cables brittle causing short circuits

good luck

i also cleaned the fuel filter at the fuel rail

 

[Palfrem]

Thanks everyone. My C280 went a bit like this and they diagnosed a coil pack.

It's got a insurance type warranty on it, so I have taken in to my local MB.

My indie was reluctant to take a look as he reckoned he couldn't access the codes as he didn't have the right connector.

I'll keep you informed of developments.

 

[GP801]

Be careful. I would not use it other than to take it in. We had similar on our 124 280. Numerous coil packs replaced, Leads etc. Problem always returned, In the end it was a dodgy coil pack that had spiked the ECU and fried it. The part alone was £1400 + VAT! We probably made it worse by using it when it was supposedly cured. Ours would miraculously start running normally for a few weeks so in our ignorance we carried on driving it.

 

[hotrodder]

I can't find the picture/pdf and code list at the moment (google should find several though) but it's simple and cheap to make a blink code reader for these. Would have thought it'd be worth printing them out and waving 'em at your indy for future reference?

 

[Palfrem]

Be careful. I would not use it other than to take it in. We had similar on our 124 280. Numerous coil packs replaced, Leads etc. Problem always returned, In the end it was a dodgy coil pack that had spiked the ECU and fried it. The part alone was £1400 + VAT! We probably made it worse by using it when it was supposedly cured. Ours would miraculously start running normally for a few weeks so in our ignorance we carried on driving it.

The garage is hanging on to it until they have a slot.

Drove about 7 miles in it last night then 2 miles to the MB garage this morning.

I never like driving a car that sounds "not right"

 

[kth286]

thinking about it a bit more the hunting could be a MAF problem, but not the MAF itself as they are very reliable on these cars.

So may be the wiring loom to the MAF as it gets very hot across the back of the bulkhead over the exhaust manifold & downpipe heat.

Has the loom been changed on your car ? If so it will not be that cable.

 

[Palfrem]

Just had a call from MB

They have diagnosed an ignition coil pack and plug leads.

Parts on order and it will be ready tomorrow

Mind you, they had to get some diagnostic tool over from one of their other branches as they had nothing on site to connect it up to.

 

[GP801]

Just had a call from MB

They have diagnosed an ignition coil pack and plug leads.

Parts on order and it will be ready tomorrow

Mind you, they had to get some diagnostic tool over from one of their other branches as they had nothing on site to connect it up to.

That does not sound too bad at all. Much better than the loom or ECU.

 

[Palfrem]

Fingers crossed eh!

It's main dealer, so they should know their stuff....

 

[GP801]

Fingers crossed eh!

It's main dealer, so they should know their stuff....

Yeah thats what I thought but 3 coil packs and a set of HT leads later without a cure we finally ended up with a new ECU. Hope you fare better

 

[Palfrem]

I have the car back now and it's running better than ever.

New ignition coil and two plug leads.

Washed and vac'd as well.

The guys at MB seemed quite impressed with her and hoped I'd be bringing it back when it needs a service!

 

[grober]

There was a thread I posted about repairing the output ignition transistors on these ECU's a while back--- a lot cheaper than a REPLACEMENT ecu!

http://www.mbclub.co.uk/forums/engine/102590-ecu-ignition-output-transistors.html