Coil Testing Confusion....

[irishkeet]

Hello

I have been following the Brickwerks guide to test the coil on my Doka (1.9 DG) and I'm confused.

According to the guide this is the readings I should be getting....




Firstly my coil (Part Number - 1220522016) is not on the list.


I can just make out a little bit of green on the label


My reading are the exact same each side at 2.97




I had a spare coil in a box of bits (same part number) but the remains of the label looks grey



and this coil also tested the exact same each side at 7.50




I tried re-testing with another multimeter, same results. Can anyone shed some light on my confusion please

cheers
irishkeet

[Stesaw]

A quick google search says 220522016 is a golf jetta mk2 coil.

If youve followed the brickwerks testing info correctly I would have though though if the primary and secondariers are within spec for a T25 then it's fine to use.. but again I dunno if that could damage other parts of the ignition system..

[aec]

The primary coil runs between the two spade terminals. So if you measure the resistance across these you should get something very low, less than 1 ohm.

The secondary coil runs from the negative spade terminal to the centre HT terminal.

So from centre to negative you've got just the secondary coil, i.e. 2970 ohms
When you measure from positive to centre, you're measuring both coils in series, but:

2970 + ~0.5 = near as damn it 2970, so the readings look the same, i.e. 2.97K

 

[irishkeet]

The primary coil runs between the two spade terminals. So if you measure the resistance across these you should get something very low, less than 1 ohm.

The secondary coil runs from the negative spade terminal to the centre HT terminal.

So from centre to negative you've got just the secondary coil, i.e. 2970 ohms
When you measure from positive to centre, you're measuring both coils in series, but:

2970 + ~0.5 = near as damn it 2970, so the readings look the same, i.e. 2.97K

 

DOH! so I was measuring the primary incorrect (I was measuring from centre to 15), I have remeasured from terminals 1 to 15 and I get a quick display that disappears to a reading of zero. Does this mean the coil needs changing?

[DoubleOSeven]

20k setting on MM is too high to read such a low value, maybe.

[Oldiebut goodie]

Most probably your multimeter cannot read the low of 0.5 ohm - if you are down my way I can test it with my 4 wire meter which measures in milliohms.

[aec]

It's most probably fine.  If it was reading several ohms or open circuit you'd know for sure it was duff, but a dead short across the primary seems unlikely. Reading 0 ohms on basic meter is probably good enough.  But try your lowest setting (200 ohms?)

[Aidan]

our coils are interchangeable, no other parts were changed in the ignition system so it doesn't matter which one you use; the VW part number is on the sticky label

Grey one is a Golf numbered part that VW fitted to T25T3 for a while, probably due to supply chain
211 parts were originally Bay, but the suffix changed for the T25/T3 versions

The new ones from Hella aren't even same form but are functionally the same

[irishkeet]

many thanks for all the help and knowledge