The dreaded E320 misfire

[benj]

Hi Guys

I have my car with me in Denmark and for a couple of months in very cold weather it has been great. No running problems at all.

I parked up last night and as usual everything was ok.

This morning it started first time as usual, but on pulling away something was not quite right.

On the short trip to work I realised it was a misfire.

Is this the loom degrading, or could there be some other things to check first?

How ofter does this sort of misfire turn out to be the loom?

Im guessing it must be because it was so sudden and is not clearing up at all

Thanks for reading

Benj

 

[MD5]

Benj, I'm no mechanic, and it could be a host of things such as leads or ignition coils, but a careful visual check of the loom at the connector ends may reveal the breaking up of the wire covering, which would be indicative of degradtion of the loom.

 

[benj]

Thanks Mike, I will have a look during my lunch break, im kind of hoping it is, although it is expensive, its easy to fix! I dont want to be chasing the misfire all around the engine bay...

 

[EDZ649]

Well if it is the loom these might be of interest to you...

http://www.mbclub.co.uk/forums/spot...s-w124-engine-repair-loom-300e-320e-m104.html

 

[benj]

im watching them!

is it only that part of the loom that degrade?

cheers

 

[MD5]

Druk, a poster here, has carried out post mortems on a few looms to find they degrade right the way through. My ex main agent indie argues that the MB repair kits should do the job, as they are the only sections subject to movement and the most heat, therefore agitating the cracked loom. You pays yer penny etc. and I hope yours is nothing too serious!

 

[benj]

well, have taken the cover off, its already had a loom repair jobbie!!! (not a full loom, just the wires to the coils..I have checked each ht lead / coil they are all sparking!!!

still a misfire tho and wont rev past 4k.


what else could it be!? any ideas greatfuly recieved!

 

[grober]

Take out the spark plugs and have a look at them. DIFFERENCES in their appearance may help to pinpoint which cylinder/s are misfiring.

 

[benj]

thanks grober

im at a loss of what to do now. I just went to the local danish motorfactors and they have no spark plugs for my car!

my only option for parts its to get them from the uk and fly them back in hold luggage. so i dont have the benifit of finding the problems by swapping out parts bit by bit as i only get home every fortnight.........if i dont get it right first time its going to be a long wait for the second lot.

i need to use the car everyday to get to work!

so to eliminate this problem really i need a job lot of

ht leads @ £55
coils packs @ £45 x 3
spark plugs @ £2 x 6
and new engine loom @ £600

and even after all that it may be my ecu thats wrong, or a number of other things. and i understand I cant just swap the ecu with a 2nd hand one as its coded for my car.

to be honest I think il just park it up and send the v5 as it being scrapped. i would be better off spending 800 quid on a mondeo.

anyone want an e320 coupe that runs on 4 cylinders can pick it up in Grenaa, Denmark.

 

[grober]

Try another motor factors ?? these plugs are not rare and several manufacturers make suitable ones Bosch or NGK or Beru OR use any mail order online site I'm sure there are lots e.g. Spark plugs UK - Champion, Denso, NGK spark plugs and Magnecor leads list NGK's BCP6E at £1-82 each plus vat plus carriage.

Don't go throwing money at the car yet-try tracking down exactly where the problem lies first. Just have a look at the existing plugs- if there are differences post acouple of pics or describe what you find.

 

[RBYCC]

Hi Guys

I have my car with me in Denmark and for a couple of months in very cold weather it has been great. No running problems at all.

I parked up last night and as usual everything was ok.

This morning it started first time as usual, but on pulling away something was not quite right.

On the short trip to work I realised it was a misfire.

Is this the loom degrading, or could there be some other things to check first?

How ofter does this sort of misfire turn out to be the loom?

Im guessing it must be because it was so sudden and is not clearing up at all

Thanks for reading

Benj

Benj

Start with basics...Air, Fuel, Spark.

You've proven spark at the coil so as Grober states look at the plugs.

Next easiest is Air...check filter and intake tubing to see if any restriction.
Clean the MAF .

If okay go to Fuel...
Try a full tank of the highest octane petrol you can get..not because of the octane rating, but more the detergent additives.
Add a can of fuel injector cleaner.
Drive it and get some miles on the tankful..a bit of an "Italian Tuneup".
Also look at the fuel filter.

Usually when something happens as in your case it typically is minor...

 

[benj]

you are right, i do need to be calm and sensible.

its the only motorfactors around here for miles, I will go again with the man. numbers.

I just dont get how it has shown no sign of poor running at all till this morning.

in my experience, plugs, ht leads and coils dont have an on off switch like that. they will degrade or show intermitant faults.

I did try each cylinder in turn and there was a spark to the head of each ht lead / coil lead

Another thing is it ran the same no matter which lead I pulled out, i know this cant be right, but it was..

 

[MD5]

I did try each cylinder in turn and there was a spark to the head of each ht lead / coil lead

Another thing is it ran the same no matter which lead I pulled out, i know this cant be right, but it was..

I wish I was a mechanic, because I feel that has to be a clue in itself, even if it rules out what it isn't?

 

[fisheggs]

Sounds like fuel to me. Probably a clogged filter restricting flow. Get a fuel pressure test done or just change the fuel filter first and see if theres a difference.

 

[benj]

guys, thanks so much for the tips, and keeping me calm!!!

1 full tank of 98 ron
1 can of injector cleaner
6 new plugs

equals one sweet engine!!!!!!

it was spark plug 6 that was knackered and not carrying the spark, it was black and oil while the others were a nice dry brown

way hey!!!!!!!!!!!!!!!!!!!!

 

[benj]

I wish I was a mechanic, because I feel that has to be a clue in itself, even if it rules out what it isn't?

my second statment was bullsh!t !! I must have thought there was no difference, but in fact there must have been!

 

[kwakdonut]

Fantastic - we are all very pleased for you! The forum succeeds again :bannana::bannana::bannana:

 

[RBYCC]

guys, thanks so much for the tips, and keeping me calm!!!

1 full tank of 98 ron
1 can of injector cleaner
6 new plugs

equals one sweet engine!!!!!!

it was spark plug 6 that was knackered and not carrying the spark, it was black and oil while the others were a nice dry brown

way hey!!!!!!!!!!!!!!!!!!!!

Benj

Keep an eye on spark plug 6....something causing it to be wet.
Logically spark plug lead or perhaps a weak coil.

Run it until it acts up again, and at least you know where to start !

Congrats on the easy fix !

Ed A.

 

[grober]

Good advice from RBYCC.

 

[benj]

RBYCC, thanks for the advice. I will order new coils and leads, they look still to be original at the moment.

on a negative side, with the bonnet open i noticed the rust from the nearside wing has spread to the inner wing, so that will need looking at and i have also noticed a large but shallow dent in my nearside door, looks like some scrote has kicked it!!