Coil Pack Tester?

[Jonj1]

Sorry if this the wrong section, search bought up various non specific results.

So what is the best way to test a coil pack? Without expensive diagnostics, I have seen it done with a volt meter and one of those coil on plug tools(are the cheap chinese ones any good)

What would someone recommend?

[Richard-D]

What's the car/ignition system? Could have an impact on the best way to test.

[Jonj1]

Mk2 Focus ST, standard coilpacks

[finlo]

Cheapest way is probably acquire a known good one and swap them about to see if that cures your problem, assuming you have a problem that is?

[Jonj1]

My problem is hesitation, its when accelerating, like gently acceleration the car blips like its lost power then continues again. Coil packs are not cheap on these cars so don't really want to spend £60 on the chance one maybe faulty and I am struggling to find anything to say it has Mode 6 in the UK so can't see the misfires with Forscan, hopefully someone will correct me on that.

There are so many things it could be, map, maf, booster solenoid, coil pack just trying to rule things out before getting into more expensive options

[Richard-D]

These look to have a 'coil on plug' system with 4 wires per coil. Please let me know if that isn't the case. I would expect each of the coils to have a constant 12v (with the ignition on) and a constant ground. Without an oscilloscope your best bet would be to ensure the +12v and ground is there for each coil. Once you've checked that then if you have a fault code reader your car's ECU will have a 'misfire counter' that tells you which cylinder has an issue. Then it's swaptronics time as suggested above. Just need to see if the fault moves with the coil.

[stevieturbo]

Really a scope is the best way...some scopes can be bought cheaply. Interpreting any results can take a more experienced eye though.

And for coil packs, I'd always try and get OEM coils...sometimes aftermarket ones are just crap.

But as others have said, is the ecu even reporting the misfires and if so, which cylinder ? Simple free test is to swap coils from a different cylinder to see if the problem moves.

Ensure plugs etc are all in good order first.

This is a "relatively" cheap, and more dedicated ignition tool to be easier to use than say a full scope.

https://gtc.ca/product/ta500-smartachcop-multisyst...

[Wombat3]

Jonj1 said:

My problem is hesitation, its when accelerating, like gently acceleration the car blips like its lost power then continues again. Coil packs are not cheap on these cars so don't really want to spend £60 on the chance one maybe faulty and I am struggling to find anything to say it has Mode 6 in the UK so can't see the misfires with Forscan, hopefully someone will correct me on that.

There are so many things it could be, map, maf, booster solenoid, coil pack just trying to rule things out before getting into more expensive options

Sounds very like a coil pack. I had one fail recently & it did exactly that - misfire under acceleration.

However, that was the 2nd time I had this fault, first time it turned out to be knackered spark plugs which (according to the BMW iDrive in the car) had only been replaced 10K miles earlier by a BMW main dealer (prior to my ownership). My trusted Indy laughed at that idea, he reckoned they were the originals (at nearly 40K).

2nd time around, knowing the plugs were nearly new, I bought a coil pack & sure enough #3 was the culprit.

So suggest pull the plugs & check the state of them & if they are OK (or you know they were recently replaced) then buy a coil pack. They are a common failure on lots of cars - its generally a matter of when, not if.

[Jonj1]

Many thanks for the replies.

The plugs I changed myself a couple of thousand miles ago however I have recently had a lot of work done on the head tracking down an oil leak which turned out to be a pin sized hole so they coils have been in and out so possible for one to have been damaged.

I am changing the intercooler this weekend and have new cold and hot side hoses and also a brand new Bosch map sensor so if its the same after that will definitely be looking at the coilpacks.