How to trouble shoot an ignition coil

[lucky_lager]

Hey guys, so the other day I was driving up a small incline and my car died. (almost like i ran out of fuel) I tried turning it over, it was having a tough time cranking and it wouldn't start.. Evenutally smoke came out of my starter. So I took out my starter, bench tested it and it was no good.

So I replaced my starter, now it cranks fine but I don't think I have a spark. And I'm pretty sure I'm getting fuel. With all my Leeds connected I pulled my spark plug and couldn't see a spark. So I tried connecting my spark plug and one of the Leeds directly to the ignition coil and I was told that I would definitely see something if my coil was fine, but I didn't.

So I'm curious, without actually replacing the ignition coil how can I test it, or see if it's getting power. Also is there a fuse I should be checking? Any feedback would be appreciated because I'm dead in the water at the moment. Thanks in advance! Cheers

[lucky_lager]

Actually I had an idea, if I could meter out the resistance on my primary and secondary coils while the coil is off the car I could probably get a for sure answer.. I'm just not entirely sure what resistance values I should be looking for, and I don't have a good coil or a service manual to check! If anyone could help I would be forever grateful haha. Cheers!

[kjopen]

I had a very similar problem however, it was intermittent - sometimes it would just die and refuse to start no matter what, then start after a while and run perfectly - sometimes days. It turned out to be the CPS (crank position sensor), this is located behind the front engine mounting.

[lucky_lager]

oh thanks! is there anyway you could provide a picture? ive tried to find it with no luck. i've been cruising forums and this doesnt seem to be an uncommon problem. thanks in advance

[lucky_lager]

also! i mean i've searched everywhere for this thing. i have a 95 golf cl with a 1.8. what did you have?

[SammoVWT]

I would say you have pretty much diagnosed it already. if youre not getting a spark at all with the car on, i would say the coils probably dead (especially straight from the King lead itself).

The only thing stopping it from there would either be A) Broken ignition Leads, B) Dead battery, C) Broken power in cable to coil, D) Immobiliser?

If you can find a part number for your coil, you can probably find the coil resistances on the manufacturers website/google etc.

[lucky_lager]

The only thing about the coil is I found a service manual online that gave me all the resistance values of the primary and secondary coils and they all within factory spec. I have voltage at the harness going to my coil too so at least I know it's not a problem further down the line. My real question now I guess is what could be preventing my coil from sending a spark to my distributor. Maybe it's what kjopen said and it's the CPS but I can't seem to find it anywhere.

[lucky_lager]

And I have continuity in all my leads, battery has 12.5 volts, I have 12.3 volts at the harness going into the coil. I don't have an immobilized either. Resistance at the coils are 0.7 ohms and 3000 ohms respectively.

[kjopen]

its right next to the oil filter and engine mounting just around the bumper level of the car. I have a 2.0L gl - I think the engines are virtually the same. By the way, I had no spark when I had the problem. The CPS didn't know where it was so it the ECM would not provide a spark...

[SammoVWT]

Not all mk3 engines have a CPS, some are in the distributor (hall sender)

The only sure way to find out is by getting the engine model code, it should either be on the block somewhere, or you may be lucky and find a code in the boot under the boot lining or maybe one in one of the door pillars etc.

Should be a long code with 3 letters in, showing the chassis number/engine model iirc. I think they all start with A for mk3, im not 100% on this though, mine is AEE for example.

If you have the original documents, it may show it on them

(Its worth making sure the earthpoint is good, sometimes they work loose/rust a bit - failing that it always worth scanning for fault codes incase something else is stopping it or if any cylinder missfires have been logged, also make sure the battery terminals are clean, this can stop coils from functioning too in some cases)

[lucky_lager]

well anyways problem solved. turns out it was the ignition module inside the ignition coil that was the problem.. coils themselves were fine which is why they metered out within spec. transistors in the ignition module self destructed.. thanks for all the help.. now onto suspension issues..

[kjopen]

thanks for reporting back - great when people do that.