Burnt Out Ignition Coils

Shannon

New Member
Joined
Jul 29, 2009
Messages
4
Reaction score
0
I have a 2000 CLK 320 which was rear ended and though still drivable, was parked until the garage could subsequently collect it.

When they arrived the battery was flat as a result of the boot light being on for a few days a consequence of the impact damage. The AA partrolman arrived and I had been informed by the insurers not to force open the boot as the claim had not been settled. Therefore the patrolman said he would jump start it from the engine block, he tried using the battery pack they carry, then brought his vehicle over and connected the leads to his additional power source in his vehicle.

He did not connect the lead to the correct points in the engine ( I found this out later through research on this site). After his revving the engine we got my car to start, but the engine spluttered for a long time .

Six weeks later I got my car repaired, but the delivery driver told me the engine sounded awful, plus the check engine light was on all the time.

I took it to my local merc garage who told me that two of the ignition coils were burnt out and the spark plugs were scorched. When I asked it this could be the result of jump starting from the engine block they said yes.

I wrote with a claim to AA, copying in the driver receipt where it stated 'started from engine'.

Then AA three weeks later replied saying there procedures could not have caused this!!!! I have spoken to them and they have asked me to get evidence that this procedure could have caused the coils to get fried.

They said their tech dept had told them not possible. However I have no doubt the tech are not aware it was started from the engine block.

If anyone could direct me to literature, or supporting evidence that I can send to the AA in pursuit of this claim I would be most grateful. Equally if they are correct in their analysis I would like to be aware of that too.

Thanks
 

television

Always remembered RIP
Joined
Mar 14, 2005
Messages
164,073
Reaction score
331
Age
86
Location
Daventry
Your Mercedes
2002 SL500, 216 CL500, all fully loaded
Hello and welcome.

This is not an easy thing to prove, yes there are the correct jumping points on a 208.

If the jumper pack had a output of well over 14 volts,,,this could knock out the coil packs,,it would not be possible to damage sparking plugs with any form of jump starting.

The trouble is I cannot see where he could have jumped it from other than the terminals provided.

Now if the battery on the car was dead flat, then the resistance of the battery would be very high. The effect of this is the the jumping source could put out over 20 volts if the ignition was turned on without allowing the battery to recover, then the coil packs could fail under that loading.

Normally just leaving the jump starter joined up for a few mins, puts sufficient voltage in the battery, so that it starts to recover, the internal resistance drops, the charge rate goes up, and this pulls the voltage from the jumping device to a safe level to enable you to turn on the ignition safely..
 

Miffy

Senior Member
Joined
Sep 6, 2008
Messages
7,356
Reaction score
3
Location
Bromley, London
Your Mercedes
CLK 320 CAB Elegance C208
are there any pictures that can be put up of the "scorched plugs" ? as Like malcolm, I am stuggling to see how they could be damaged in this way
 

television

Always remembered RIP
Joined
Mar 14, 2005
Messages
164,073
Reaction score
331
Age
86
Location
Daventry
Your Mercedes
2002 SL500, 216 CL500, all fully loaded
are there any pictures that can be put up of the "scorched plugs" ? as Like malcolm, I am stuggling to see how they could be damaged in this way

You are right ,,nothing could do that.

Just thinking a little more while I have been out.

A car that the AA would normally would jump start, would be a car where the battery was too low to start the car, but the residual voltage in that battery would not allow the jump starter to put much more than the 14 volts through it, and the cars system.

When a battery has been emptied completely as in this case, you must always wait until the voltage has fallen to a safe level, that is no more than 14 volts before you turn on the ignition.
 
OP
S

Shannon

New Member
Joined
Jul 29, 2009
Messages
4
Reaction score
0
  • Thread Starter
  • Thread starter
  • #5
The AA told me that their vehicles are limited to 12 volt batteries as they are aware higher voltage can knock out sensitive electrical components.

As for the scorched spark plugs, I called the garage and they said that the plugs looked as though they had not been changed in a long tome and were showing sign or wear and tear, and used the word 'scorched', so I must have made the wrong assumption. However there is no doubt before jump, the engine was running fine, after, two ignition coils were burnt out.

I was there when the AA chap hooked up the cables and he did not use the points I have since sen. He took the plastic cover off the top of the engine and was struggling to get purchase, with the cable grips.

As for being difficult to prove I think the chain of events would indicate it was not random. To lose one coil to age and wear is possible to lose two at the same time , there must be a common source.
 
OP
S

Shannon

New Member
Joined
Jul 29, 2009
Messages
4
Reaction score
0
  • Thread Starter
  • Thread starter
  • #6
One final thing , like the parrot in the Monty Python Sketch, the battery was dead flat.
 

television

Always remembered RIP
Joined
Mar 14, 2005
Messages
164,073
Reaction score
331
Age
86
Location
Daventry
Your Mercedes
2002 SL500, 216 CL500, all fully loaded
The thing is,,did he use his van or a portable jump pack
 

turbopete

Senior Member
Joined
Feb 4, 2009
Messages
14,204
Reaction score
328
Age
46
Location
Spennymoor
Your Mercedes
2010 '60' Ford Mondeo 2.0TDCi Zetec (sorry)
they once put BOTH on mine! 1 on the battery and 1 on the jump start point under the bonnet! would thet give 24 volts or just be like connecting 2 extra batteries in series instead of the usual 1?
 

Alex Crow

Senior Member
Joined
Jul 9, 2009
Messages
10,677
Reaction score
40
Location
Super Suffolk
Your Mercedes
W169, W124, w202, W203, KTM 250 EXC, VW T25 camper and a Polo in a pear tree
have the coils been changed and the problem resolved? was the diagnosis carried out by MB experts? if not then it may be you have a different problem.

possibly........your air mass sensor is at the limit of its values and your ecu had adopted long term adaptations to suit. when the battery went flat these values would be wiped and the engine would run poorly, shutting down cylinders under load probably.

does the engine run `ok` on start up and run rough (dropping cylinder/s) after driving a shrt distance? yes the mil light will be on but if it runs smooth-ish at idle then think on.

the AA used the engine as an earth but where did he connect the live? the starter is hard to reach from above, he possibly used the live socket under the bonnet? he could actually be innocent.
 

turbopete

Senior Member
Joined
Feb 4, 2009
Messages
14,204
Reaction score
328
Age
46
Location
Spennymoor
Your Mercedes
2010 '60' Ford Mondeo 2.0TDCi Zetec (sorry)
thats what i was worried about! it does do strange things occasionally, but i try to ignore them!
 

Cole@MBS

Forum Supporter
Authorised Forum Supporter
Joined
Dec 1, 2008
Messages
13,625
Reaction score
764
Age
51
Location
Hedge End, Southampton
Website
www.mbssouthampton.co.uk
Your Mercedes
124 300 CE 24 Coupe, C220CDI, 1959:Morris Minor
The thing about this thread which puzzles me, is the 208 don't have a jump point under the bonnet!!!!

As A/P said, where did he put the positive???
 

turbopete

Senior Member
Joined
Feb 4, 2009
Messages
14,204
Reaction score
328
Age
46
Location
Spennymoor
Your Mercedes
2010 '60' Ford Mondeo 2.0TDCi Zetec (sorry)
i thought all mercs had jump points under the bonnet? only other place id think of trying to put it, if accessible would be the starter motor terminal
 

Cole@MBS

Forum Supporter
Authorised Forum Supporter
Joined
Dec 1, 2008
Messages
13,625
Reaction score
764
Age
51
Location
Hedge End, Southampton
Website
www.mbssouthampton.co.uk
Your Mercedes
124 300 CE 24 Coupe, C220CDI, 1959:Morris Minor
Trust me Pete, you have a hard time putting your finger tip on it, you would never get a crock clip from a jump pack on it!!
 

turbopete

Senior Member
Joined
Feb 4, 2009
Messages
14,204
Reaction score
328
Age
46
Location
Spennymoor
Your Mercedes
2010 '60' Ford Mondeo 2.0TDCi Zetec (sorry)
well im inclined to agree with you then since access is that tight, where was the positive lead put? im sure the cables and terminals at the rear of the alternator would be impossible to clip onto, and im really at a loss to where else has wires thick enough for the current draw required to start the car!
 

television

Always remembered RIP
Joined
Mar 14, 2005
Messages
164,073
Reaction score
331
Age
86
Location
Daventry
Your Mercedes
2002 SL500, 216 CL500, all fully loaded
on the firewall, like a 202
 

turbopete

Senior Member
Joined
Feb 4, 2009
Messages
14,204
Reaction score
328
Age
46
Location
Spennymoor
Your Mercedes
2010 '60' Ford Mondeo 2.0TDCi Zetec (sorry)
i thought my 202's had them on the inner wing, the same as my 210?
 

Cole@MBS

Forum Supporter
Authorised Forum Supporter
Joined
Dec 1, 2008
Messages
13,625
Reaction score
764
Age
51
Location
Hedge End, Southampton
Website
www.mbssouthampton.co.uk
Your Mercedes
124 300 CE 24 Coupe, C220CDI, 1959:Morris Minor
on the firewall, like a 202

That little box we advise people to shoot 12volt down to open there boot when they have taken there battery of and closed the boot is only 1,5mm wires,
I hope they didnt jump it of there!!
 


Over 100 branches Nationwide, More than 114,000 Parts in Stock, The UKs Largest, and Fastest Growing Parts Supplier,please see MBO Members’ Area for discount codeEuro Car Parts Ltd
Top Bottom