C200 sport misfire after snow today!

[BenzDude]

Hi all,
Took the 1995 C200 sport for a drive round today, steady driving nothing stupendous. Was driving up a hill and suddenly got this misfire which is right through the rev range. Panicked thinking it was a fuel problem and went to pour some in it before it ran out. Nearest petrol station was about 2 miles away. Engine temp was fine but on tickover in gear it was trying to die. Made it to the petrol station, got it home still no different. Pulled the plugs out, all looked fine. Checked the rad cap and found sludge which has always been a problem for this car ever since i owned it, from 69000. It now has 136000 after 4 years.
Only thing I'm suspicious about is I didn't clean the snow from around the vents by the windcsreen can't see any damp by the ecu but is there something further down electrical that may be breaking down because of the ammount of water?
I'm thinking it more than likely is the head gasket, but the symptoms are minimal, no water in oil either.
I replaced the cat out of old age few months back and thats about it. Just all seems to sound like fuel starvation or similair, but it starts 1st turn of the key.
Any help would be appreciated.. Cheers

 

[television]

Hello benz dude, and welcome, take a look at the fuse box with 2 lids to see if any moisture is in the box

 

[roofless]

also have a look at the coil packs. ht leads & wiring to the coils pull the leads from the coils check for condition then if still no good try under the washer bottle you will find the control unit with two large plugs + vac pipe then isolate the battery & pull out the plugs in the c-unit & look for any sign of damp or rust on the pins

 

[BenzDude]

Hi there thanks for the quick reply, checked the 1 that is furthest away (closest to front of car) but other has screws in it, will take a look at that in the a.m. Started it an hour ago to see if it did it cold or if the fault cleared and it was just lumpy as you like from stone cold, but will def look into that tomorrow. Cheers.

 

[BenzDude]

I checked the electrics today, Inbetween the hail stones and sleet. All seem pretty dry and corosion free. Didn't get to check the C-unit or coil packs, due to the weather.
However I am slightly concerned now about the head gasket more than anything. Opened up the rad cap today to see a real dark brown sludge, had to put my finger through it to see the water and there is lots of it. Tried to start the car just for a giggle and it didnt want to fire. When it was trying to fire it sounded like the wrong cylinder firing to start.
Well I had to hold my foot flat on the floor to get it to start, then it was running like a 2 stroke, so i'm taking a random guess that the gasket could have gone between the oil and water ways and between 2 cylinders. Honestly you would think it was a 125 motor cycle. The engine has done 136000 miles now and never been touched, it's had a hard life but mainly motorway work. Now I have no work it's doing the round town stuff and I dont think it likes it! It has always had a small weep of oil round the corner of the head by the timing case which has never been an issue, but it is making me wonder. Anyhoo, thanks again for the advice and if anyone has any input I'd appreciate it, but I am feeling the worst.
Cheers,
BenzDude

 

[roofless]

sorry to hear that but you best get it tested first just to confirm it first

 

[television]

Bezdude this could just be a coil pack gone down, and any leak may not be part of this fault, is there a spark on the missing cylinders

 

[BenzDude]

Battling against the weather here i'm afraid fellas, but I will look into it further tomorrow, weather permitting. Would like to think it was a simple electrical fault but the sludge in the water disturbs me a bit as I had a Renault 5 gt turbo once that cracked the head in 3 places and caused the same colour sludge. Different type of engine I know and very fragile. I will check for spark though as you good guys say and hope for the best. Fingers crossed! http://www.facebook.com/photo.php?pid=1742371&l=77198&id=602501782

 

[Cosworth]

Hi mate, sorry to hear about your problem, you have a c200 1995, very common problem you have there. I would bet that 9 of 10 you have a ECU failure.

The ECU is located under the white windscreen washer bottle.

You need to check weather you are getting spark in all four cylinders.

One way to check is to get a spark tester which fits in between the plug lead and plug.

Coil packs do go faulty but not that often.

 

[BenzDude]

Hi Cosworth and all. Ok been a while on this car now and yes I hate to say it, Cosworth 10 out of 10 you got it. Coil pack has failed and taken out the ECU, trouble is every ECU repairer in Poole, including the Bosch people turn round, shake thier heads and sayy ooh no mate won't touch that it's too old. So basically I am faced with a dilema, either I try find £400 for a second hand one and hope that isn't faulty (huge risk) or still struggle onward and try find someone willing to repair it as I'm not prepared to pay the £1300 Mercedes want for a new one. I'm also told though that the ECU is coded for each car??
I am also considering breaking the car now which will (scuze the pun) break my heart as it's so clean for the year and been reliable as you like until this year. Watch this space though if I do break it, many new parts on it now and all sorts of goodies.
Thanks for all your help with this problem and I hope it will help others with similair problems, cheers peeps.

 

[television]

There was some one posting recently say that they fixed these things, was it the power steering guy

 

[BenzDude]

If there was someone who could repair them it would save me a load of grief as I still have no one willing to take them on. I'm almost thinking there is some nuclear plant inside the ECU! All I seem to get is the same response which I find disturbing, oh no it's too old. It is the early PMS ECU which I'm thinking should have been named the PMT ECU now. If anyone can the part number is as follows: 0185451132.
Thanks again all.
Ian

 

[power-steering]

Hi Ian,

We can certainly repair these units. It's a growing common fault and the coil packs do blow the ecu's out, you may change the coil pack and find it makes no difference (the new coil pack will be damaged if you replaced it with the faulty ecu connected).

Once we've repaired the ecu and sent it back to you, you will need to change the coil packs again otherwise it will simply blow the ecu out again.. nightmare I know.

I've sent you a pm with a price for repairs, it will come with 12 months warranty for piece of mind

You can call us on 0208 853 3343.

Cheers,
Jay

 

[ventech]

ECU Repair

Had the same problem. I looked at several ECU repairers, many had bad reveiews in the forums & wanted £300-£400 to repair the Bosch PSM type. I also first replaced the coils, since a faulty coil can damage the ECU.

I found a repairer in Plymouth who charged £180 including return transport.
http://www.automatec.yows.co.uk/
After refitting, car started straight away, but now I still have a misfiring when cold, but normal after engine warmed up. Still investigating the problem. I will look up the suppliers name later & post them, but the coils were only £12 each,

 

[BenzDude]

Cheers Ventech. I found here the coil packs are a little dearer though from Euro parts, can get a pair of Bosch ones for £80 or 2 other makes for a mere £40, not sure if it is worth the extra £40?!! Did you get any guarantee with that ECU repair? I'm just wondering if this is why most don't repair them because they are a nightmare to repair all the faults. I have found one site for instance that claims it's only a case of repairing the transistor which in my eyes doesn't warrant more than £50. However talking to my dad who is an electronics engineer and not too keen on taking it to bits without a diagram says it may have taken out more components.
I am though looking to repair it now as I need the transport and for the money, I couldn't get a replacement car that was any good.
Thanks again for all your helps peoples..

 

[television]

ECUs are not bad to repair, the hardest thing it finding out what some of the semiconductors are, EZL units are near impossible.

I sit there just doing the normal base to emitter and collector test, if one transistor is short circuit then un soldering 2 of the legs to enable one to go on testing in the normal way.
The last one that I had in was just one power transistor and nothing else, they speak for them selves, 4 cylinder then 4 transistors, 6 cylinder and 6 output transistors