2000 V70R - Bench testing on-plug ignition coils?

Post by **scot850** » 22 Oct 2014, 23:11

Is there any way to bench test on-plug ignition coils? I picked up a set of used ones from a 2000 V70 at a pick n' pull, and don't really want to pull the cover on my car and check each one.

I'm guessing some sort of resistance check, but how and which pins to check. Is this a reliable what to check these, or do you really have to run them to be sure they don't break down under load? I know you can buy a tool to check these, but for something I am unlikely to use very often, I can't see the point investing in one.

Any input, as usual, greatly appreciated.

Neil.

Post by **precopster** » 23 Oct 2014, 04:17

Many of them arc to the sides of the plug wells through the rubber boot.

The boots are the number one problem followed by total breakdown. IPD sell the boots separately for around $8 each.

Post by **abscate** » 23 Oct 2014, 04:31

I made a series

of ohmmeter measurements on my 1999 and wrote a thread on this in the past year..will find link..

https://www.matthewsvolvosite.com/forums ... il#p325109

Post by **scot850** » 23 Oct 2014, 20:17

Thanks guys. Had a look at the 5 coils and the rubber boots look in really good shape, but based on advice, I'll look even closer to double check. The rubber does feel soft and supple.

abscate, saw your note, and appreciate the info, but as a Mech. Eng. can you clarify for the un-initiated what you actually measured.

1) Is the only important measurement the pin 1 to 3 ohm check? ?If not, what did/do you do for measuring the other pins, and do you check 1-2, 1-3, 1-4, 2-1, 2-3, 2-4, etc, and if so what are you measuring, only ohms (resistance values) or do you measure continuity?

2) If 1-3 pins are all that is important, is there a 'range' they need to be in to be good/acceptable?

3) I can return these to Pick n' pull if they are faulty, so I guess I may have to run them in turn to make sure they are all good, but no point trying they if there is a basic test to see if it is worth trying at all.

4) Can you explain what : 'I measured all pins INF Ohms on MOHM scale except pins 1-3 (852ohms)' means for me. Don't recognise the terms used.

Many thanks,

Neil.

Post by **abscate** » 24 Oct 2014, 04:15

Yeah, that was a comm fail...

In short, the resistance between pins 1 and 3 measured at 850 ohms on good, in-service coils

All the other pins showed infinite resistance.

I don't have a tolerance on this measurement but if it varied more than 20 % I think I would replace it or at least suspect it.

Post by **precopster** » 24 Oct 2014, 06:48

Now we need a comparative measurement off a coil that doesn't fire at all. Cylinder 1 on our XC70 misfired last week so I swapped the boot only with cylinder 2. The fault code stayed on cylinder 1. I replaced it with another. So now I have a falied coil pack to measure. Will report in......

Post by **scot850** » 24 Oct 2014, 11:28

Thanks Mike and abscate! Once I get a chance to check my 5 spare units I`ll add that to this thread also.

Neil.

Post by **scot850** » 24 Oct 2014, 21:14

I tested the 5 units as promised. They tested as 851, 854, 858 858, 859 ohms. Not enough difference to concern about. Hope this helps.

Neil.

Post by **precopster** » 28 Oct 2014, 18:40

I hot 866 ohms on a faulty unit. Obviously not a conclusive method of measurement.