E55 Coil Pack vs HT Leads Question

[mlsports]

Hi Guys

This may e the most stupid question, but I really have no idea so thought I'd ask.

Cylinder 3 on my 1999 E55 was misfiring, so I have the coil pack and HT leads replaced - and WOW! What a difference! Smoother acceleration, smoother idle, quieter. Quite amazing really!

I'd like to do the other 7 cylinders as the other leads must be pretty worn too.

However, at £122 per coil pack, plus £20 per HT lead and two leads per cylinder - it's £1,134 just in parts!

Now, here's my stupid question. Is the coil pack used only when starting the car - or is it used whilst the car is driving as well?

I'm think that replacing just the HT leads could give a great result as they are what carries the charge from the spark plugs etc. So that make sense.

So, coil pack - only for starting the car, or also used when driving?

Thanks guys!!!

 

[television]

Yes the coil pack are in use all of the time and provide the spark for that plug that they are connected to

Just replace the leads, that could prevent some damage to the others.

A coil pack either works or it does not,no in the middle

 

[Blobcat]

As an aside IIRC that is how Maranello Concessionaires became the official Ferrari importer in the UK. The noticed severe misfiring and replaced plug leads with Spitfire ones. Sent the mod to Ferrari and the rest is history.

 

[mattkh]

Hi Guys
Cylinder 3 on my 1999 E55 was misfiring,
I'd like to do the other 7 cylinders as the other leads must be pretty worn too.

Hi
How did you pinpoint it to cyl 3 ?
Why change the other 7 if they are not misfiring.

 

[television]

Hi
How did you pinpoint it to cyl 3 ?
Why change the other 7 if they are not misfiring.

You can just take the plug lead off until you come to the one that makes no difference or use a spare sparking plug on the lead and ground the plug.

you can buy cheap meters now for this

 

[type49]

Get your garage to do a "smooth running" test. This acurately measures each spark line duration & will show up any breakdowns in other leads. Don't fix it if it aint broken!

 

[mlsports]

Cylinder 3

Hi
How did you pinpoint it to cyl 3 ?
Why change the other 7 if they are not misfiring.

The car had a problem misfiring and would lose a LOT of power when accelerating. So we replaced all of the spark plugs. Made a small difference.

Then it finally came up on the diagnostic that cylinder 3 had a problem. So replaced the leads and coil pack for that cylinder.

Wow - what a difference! Smoother start, quieter start and idle, smoother acceleration, more power, not as 'grunty' sounding etc.

However, I'm certain that it's still not 100% and I believe that the leads age in a fairly uniform way, so if these are gone then the others won't be far away. I think anyway?

 

[mlsports]

Sounds good!

You can just take the plug lead off until you come to the one that makes no difference or use a spare sparking plug on the lead and ground the plug.

you can buy cheap meters now for this

When taking the lead off of the plug, what difference should I notice, and what would this difference means (worn/perfectly ok)?

With regards to the meter, that sounds ideal! What are they called? I assume I could buy one on eBay? And how do I use it?

I'm excited about the meter idea as this could solve my issues and save me a lot of money!

 

[television]

Type 49's post does make sense though

 

[mlsports]

Coil Pack

Yes the coil pack are in use all of the time and provide the spark for that plug that they are connected to

Just replace the leads, that could prevent some damage to the others.

A coil pack either works or it does not,no in the middle

That's great news and exactly what I needed to hear!

How will I know if it's working or not? I'm guessing if I get a meter and test it then it will give a reading of zero if the coil pack has gone?

 

[jberks]

The problem with twin spark is that you can't always tell if it's misfiring. If the leads are original, I'd change the lot. My experience with a 2000 car was that MB leads start to degrade after 3 years or so. I changed all of mine twice over the 6 years I had it. The idle deteriorated, not massively but certainly noticable. A new set and she was like new again.

I believe there are excellent after market leads at a fraction of MB ones and given the lifespan I experienced, I can't say MB originals were particularly high quality.

 

[mlsports]

Great!

Sounds good!

What brands of 3rd party leads would you recommend? Also, do they make them specifically for each vehicle (i.e. all different lengths depending on which cylinder is being replaced).

Also, does anyone know the name of the spark plug meters, or where I could buy one from?

Thanks guys!

 

[rmt6668]

Hi

Can any 1 please advice, I notice on my C220 W202 1994 vehicle, the HT lead going into the coil, number 2 & 3 are interchanged. An I right to assume they both share the same coil ?

If not whats the sympton caused?

Thanks

 

[television]

No you cant interchange them the car will miss fire, the switching is done by the ECU

 

[230K]

Hi

I will go out on a limb here but looking at the diagram 2 and 3 could be interchanged if they go to a single coil pack. If that is the case 1 & 4 spark simultaneously and 2 & 3 would spark simultaneously and either could be swapped without a difference in the running of the engine.

Some makes of car have 2 coils for 4 cylinders, some have one coil for 4 cylinders, and some have 4 coils for 4 cylinders. Not sure what way your 220 is.

230K

 

[Aussie Nick]

Mls ports I agree With your suspicion that "the others are not far away." My experience is that the Bosch coil packs,through attrition eventually develop tiny cracks (Sometimes almost invisible).This will lead to earthing of the respective cylinder ignition charge thereby robbing that particular cylinder of some of the charge necessary to properly ignite the fuel air mixture. A correct and substantial amount of charge is necessary in these modern motors to ignite the combustion process. My view is that if you have experienced the problem with one of youir ignition coils it is more than likely that the others will soon follow . Replacing all the coils and leads will greatly improve the power and smooth running of your motor. My view would be to replace all leads and charger coils now

 

[mlsports]

HT Leads

Hi guys

Thanks for the feedback!

I would consider replacing all the coil packs and HT leads except for the cost. £122 per coil pack x 7 (one is replaced already) = £854, then 14 HT leads @ £22 = £308. Grand Total: £1,162. Plus fitting of course.

It was mentioned here that generally the coil packs either work or don't work, whereas the HT leads can deteriorate and so the 'signal' does not pass through the lead as strongly as it should. So replacing just the HT leads *should* give the best result without going all-out and spending crazy money.

With regards to replacing the HT leads on my E55 AMG, is this a job that's easy to do myself? I've never taken the big plastic engine cover off yet myself, what's the access like to the leads once that's off? Is this something I should be able to easily do myself?

Thank you!

 

[television]

GSF charge £80 for the 113 coil packs

 

[mlsports]

Gsf?

H there

Sorry for my ignorance, but who are GSF?

And any advice on replacing the HT leads myself?

Thank you!

 

[rmt6668]

Yes my C220 has 2 coils for 4 cyclinder, 2 spark plug per coil. Attaches is a pic of that exact coil.

Hi

I will go out on a limb here but looking at the diagram 2 and 3 could be interchanged if they go to a single coil pack. If that is the case 1 & 4 spark simultaneously and 2 & 3 would spark simultaneously and either could be swapped without a difference in the running of the engine.

Some makes of car have 2 coils for 4 cylinders, some have one coil for 4 cylinders, and some have 4 coils for 4 cylinders. Not sure what way your 220 is.

230K