any way to test ignition coil

wijcc · 11 Sep 2015 at 18:42

Is there anyway to test the ignition coil without having to get a new one and trying the new one?. The engine fault light is on my car, I think it is the engine coil that is causing the engine to misfire every so often as the car occasionally hesitates on acceleration/power delivery?
The car in question is a 2001 1.6 petrol ford focus, thanks in advance guys

pepsilol · 11 Sep 2015 at 19:06

Read the codes?

Either do a bench test with multimeter or spark plug test. This is really easy and a common thing to do. You should have googled or youtubed this.

wijcc · 11 Sep 2015 at 20:26

Thanks, I don't have a code reader unfortunately

pepsilol · 11 Sep 2015 at 20:33

I'd accept that as an excuse if bluetooth code readers didn't cost a fiver and a basic hand held one a tenner

red eye · 11 Sep 2015 at 20:39

engine running pull cylinder 1 ignition lead, put it back and move on to 2,3 and then 4.
What your looking for is the cylinder that does not do anything.

Use something insulated to pull the leads or pull them with the engine off

danza · 11 Sep 2015 at 20:41

Get a cheap reader, find out which cylinder is misfiring and if it's actually a coil. Swap dodgy coil around to check that the misfire moves with the coil, which will confirm that coil is dying.

Or the above. That's actually what I did before I had a reader.

red eye · 11 Sep 2015 at 20:47

it's a single coil pack on those
But a code reader will only tell you which cylinder is missing it could be anything from plug to a hole in the piston

dholdi · 11 Sep 2015 at 20:50

A holed piston would be more than occasional.

BigglesPiP · 11 Sep 2015 at 20:56

dholdi said:
A holed piston would be more than occasional.

1 in 4 is pretty occasional, right?

dholdi · 11 Sep 2015 at 20:59

BigglesPiP said:
1 in 4 is pretty occasional, right?

I presume you are not serious, right ?

pepsilol · 11 Sep 2015 at 21:02

dholdi said:
I presume you are not serious, right ?

Indeed, it got me stumped also.

Orionaut · 11 Sep 2015 at 21:13

Coilpack failure is common on fords. As has already been said, all a code reader will tell you is that a cylinder is misfiring not necessarily why. There is no way for the ECU to monitor HT output.

Lead pulling will indicate which cylinder is weak but be careful, do not pull the leads completely off. you do not want to go full open circuit on a "Good" coil as you can damage the ecu.

Just pull it up far enough to establish that the spark is jumping to the plug across a significant gap (Loud tick,tick,tick noise)

The bad cylinder will not generate a tick tick tick noise.

Get a decent Bosch, or similar, coil (Not Intermotor!) and change the leads and plugs at the same time.

red eye · 11 Sep 2015 at 21:20

dholdi said:
A holed piston would be more than occasional.

I missed that part, so if it's not missing on idle pulling plug leads won't show any anything unless hang out the window while accelerating.

I would replace the plugs and leads first, plugs are cheap and the leads are probably as old as the car

Clarkey · 11 Sep 2015 at 22:35

So common. I would just put a new coil on probably cost the same as a reader.

rodenal · 11 Sep 2015 at 23:58

Indeed - and as above make sure its a good quality one if not from Ford themselves. A £25 effort is no good to you

wijcc · 14 Sep 2015 at 00:26

The engine fault light went off on its own. But the hesitation in the acceleration/delivery of power is still there... but it is not happening all the time.

BigglesPiP · 14 Sep 2015 at 09:48

wijcc said:
The engine fault light went off on its own. But the hesitation in the acceleration/delivery of power is still there... but it is not happening all the time.

I'd wager the fault logged was a misfire detected. Typically these get logged in such a way as they clear after - for example - 40 ignition cycles.

I'd do what others have said and just replace the coil, if you get an OBD adapter (which in itself is not a bad move), it's not going to tell you "Yep, defiantly the coil, replace that thing."

Nodiggidy123 · 14 Sep 2015 at 10:39

My old focus did this. turned out the ht leads had become worn and didnt grasp the spark plugs properly.

could be worth checking.

wijcc · 16 Sep 2015 at 13:05

It seems like it was the HT leads... lead for spark plug no 4 to be specific.. I brought both a new ignition coil and HT leads. Thought I would try just changing the leads first one by one and it seems to have rectified the problem, by replacing just lead no 4. I will drive around for a few days and if it still working normally i will return the unopened ignition coil.
Thanks for the help guys

Enfield · 16 Sep 2015 at 16:01

Hi mate,

Pick up a code reader, pretty handy. I got mine for I think £13 or so. My scooby had a misfire on cylinder 3. Tried swapping the coil pack to another cylinder hoping the fault would move cylinders. It didn't. Moved the plugs over too, still same cylinder. Compression checked the cylinder, no compression.