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Testing Ignition Coil Packs?

21K views 14 replies 5 participants last post by  John Gaunt 
#1 ·
I have an E230 (4 cylinder) W210 1997 that seems to be running on only 1 or 2 cylinders.
I have tested the spark plugs with a meggar and they seem OK. Now I suspect the coil packs.
There are 2 coil packs each serving 2 cylinders.

Can I test the coil packs using a basic model Fluke multimeter? How can I do that.
I have measured the resistance (about 0.7 Ohms) between the two conductors that the primary cable plugs into. I don't seem to be able to find a circuit between either of the 2 Secondarys that go to the spark plugs and the Ground connection on the Coil Pack.

Any ideas would be appreciated.
John Gaunt.
 
#3 ·
Hi John ,
Check all battery and ignition system and coil wiring and connections.
Normally,coils are checked using a calibrated ignition spark tester (which flashes) which is connected in line between the coil and the plug,after removing a fuse to disable the fuel pump.
If you know which cylinders are mis -firing,try swapping the positions of the coils and see if the fault follows the coil.
If all that fails and you still suspect a coil,try replacing just one at a time.
 
#4 ·
if the coil packs can be swapped between cylinders and you are getting CEL with a misfire code, the easiest way to check them is to swap the coil pack for the misfiring cylinder and another cylinder and see if the misfire codes swaps as well. If so, the coil pack is bad.
 
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#5 ·
In your particular system, the outputs of the secondary coil feed two spark plugs (one each), and the discharge is to the ground which is the engine metal, so it is important not to use anti-seize compound which would reduce the spark.

I use spark plugs that have anti-seize properties on the metal that contact the engine metal.

You can think of the secondary ignition as two spark plug gaps in series, with ground in between.
 
#6 ·
Thanks to all posters,
Mrboca, I was going to use some nickel anti seize compound on the spark plugs which I assumed would be conductive. Surely the secondary ignition is two spark plugs in parallel with ground being the engine metal that is connected to the coil pack ground.

Now I am wondering about the MAF sensor. The plastic air pipe that runs over the motor which I removed seems
to have a coating of light coloured compound inside. Would a dirty MAF sensor cause the engine to be hard to start and run badly?

Thanks............John Gaunt.
 
#8 ·
Thanks mrboca,
Your mention of fuel delivery rang a bell. The car has not run for 12 months and been out in the sun.
It had just over 1/4 tank of fuel but I added half a jerry can of petrol and it started straight away and runs well.
I think it was an air lock issue presumably at the fuel pump. Possibly just opening the fill cap would have been enough.
I bought the car (actually 1997 C200 but similar engine as my E230's) as a parts car. It was not running as the Electronic Key was faulty. I sent the key away and they repaired it and re-programmed it.
The car is very clean and straight so I will use it once I fix a few little things and get it registered.

The key repair and re-programming cost A$165 (about US$125) including postage.
I guess there are equivalent places in North America but the place I used is in Sydney.
Australian ECU Repair You can check their website Australian ECU Repair ? Mercedes Benz ECU Repairs

Their service was fast but I had to send them the Electronic Ignition Switch (they said to obtain the key code) although I gave them the VIN Vehicle Identification Number.

Anyway, Thanks again for the advice................John Gaunt.
 
#10 ·
Thanks mrboca,
We can get E10 petrol here but I don't use it. Of course I don't know what the previous owner used.
I will just get a couple of jerry cans of unleaded and put that in the car to dilute the remaining old fuel.

You asked about a scanner. I don't have that. For some reason Mercedes didn't start fitting the ODB connector for Australia until after year 2000. So my cars just have the large round multipin connector under the bonnet (hood). Also the instrument panel is not so high tech either.

Can I get and use a scanner with the round connector?

I think in some ways not having access to codes and needing to reset them is an advantage. With the couple of problems I have had with my daily drive E230 once the problem is fixed the car is automatically back to normal.
Still, if possible I would like to use a scanner for diagnostics.

Regards...........................John Gaunt.
 
#11 ·
Now I have been looking at scanners etc. on the internet.
It is a bit confusing and I don't know what I should buy.
I see I can get a cable to plug into my round multipin (about 40 pins, most not used) connector that has
an OBD2 connector.
I use a Samsung (Android) smart phone so think I should buy a scanner that uses Bluetooth with an App on my phone.

Any recommendations would be appreciated.
 
#12 ·
The 38 pin adapter you get typically has 3 wires between the plugs (power/ground/ k-line).. The K-line interface using one of those bluetooth scanners (BAFX, Vgate, etc) will allow you to read mostly the engine codes, and live data which could be very hand in troubleshooting.

I have one of those with my ahroid phone app TorquePro, and it is great. Mine is permanently plugged in to the 16 pin connector that we have inside the car in the US.

What I am currently looking for is some scanner that will scan the codes from the Transmission, Traction system , Airbag, Clima, Body controls, EIS, Instrument Panel.

I am building my own adapter cable with up to 16 pins between the connectors, so I can access the specific pins (functions) of the 38 pin MB socket.

I bought a multiplexer system and once I have the cable built, it will be interesting how much information I can access / reset adjust.

But for your basic system I recommend a genuine BAFX bluetooth scanner with TorquePro that you can download and (pay about $5 for the Pro version, free for the lite)

I tried the other smaller ones but they tend to overheat when used all the time.
 
#14 ·
The torquepro can give you some sensors data, but that will be pretty limited on W210.
For some reasons the fuel consumption data I was getting was very corrupted.
For real troubleshooting you will need better scanner than that.
Still I found the $12 Bluetooth adapter a lot of fun.
I like observe the sensors data from back seat when wife is driving.
 
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