2000 V70 NA - Coil misfire on all cylinders?

Post by **scot850** » 02 Mar 2022, 16:14

My buddy who bought my old V70 NA 4 years or so ago is having an issue with the car. Since he bought it he had an ignition coil fail on one cylinder which was disappointing as they were replaced before selling the car. It has maybe done 25,000 miles since then.

I have a hard time believing that all cylinders are showing the same error, so assuming they are not all failing at the same time then what else can it possibly be:

1) Cam position sensor
2) Crank position sensor
3) If I recall the car has a cam vvt on either the intake of exhaust side but I can't recall which.

Are any of these likely to be culprits or would/should they throw their own codes?

I have a bunch of good used coils I can lone him to swap them all out to see if they are the issue but I doubt it.

I will get the codes that he gets tonight when I see him and post them. He says that although the CEL is on, the car runs just fine otherwise.

Thanks,

Neil.

Post by **abscate** » 02 Mar 2022, 17:04

The coils get a common 12 volt supply and get fired by individual triggers in the ground side , from the ECU

It’s probably getting a 12v supply fault wiping out the coils. This also is supply for the VVT solenoid , purge valve , and other stuff.

2000 Na will have intake side VVT

Post by **scot850** » 02 Mar 2022, 17:45

Thanks abscate. I thought it was intake but wasn't going to guess wrongly or you would mock me!!

Like you say, there are a multitude of possible issues or sources. The only common fault occurring seems to be the coils. Ig it was a 12V issue then would it not throw other codes?

Neil.

Post by **foggydogg** » 02 Mar 2022, 18:03

Since the trigger is on the ground side, could it be just that, a ground issue ?
I recall reading elsewhere that an ETM issue could make the ignition do odd things.

Oly850 · Post by **Oly850** » 02 Mar 2022, 18:40

Definitely check the ground points for the coil packs, the only other thing common to all is the intake vvt solenoid position sensor, if it was one coil pack you’d know what to do, etc.

Post by **abscate** » 02 Mar 2022, 19:20

I think I got that wrong. 12 volt supply to the coils is common to….

Checking…….

Post by **scot850** » 02 Mar 2022, 20:08

Looks like we are on the same plain here in terms of it is probably un-likely the coils are the issue. I have given him a bunch of used coils he can try and worst case a set of new ones from the stash. Having discussed with the owner he agrees it is un-likely but is going to work his way through the swap and try process t try to eliminate potential causes.

I've loaned him my Autel 802 so he can see if it shows anything else. He was less keen to try my steam powered laptop and Vida, but we may have to resort to that eventually.

I have told him to look at the grounds around the engine as well as all the power cables to battery, B+ and the like as well as the VVT, cam sensor and crank sensor. He says he has a bunch of used spare parts he can swap in if needed.

Thanks guys. I'll update as he lets me know where he gets on this.

Neil.

Post by **scot850** » 18 Mar 2022, 19:15

Well I for one was wrong. My buddy went to PnP on another parts errand which included the intake CVVT solenoid. I'd identified potential source cars and part numbers (2 up-changes) and while pulling that from a 2000 S70 NA he found it had what looked like a recent set of Bosch coils.

When he got home he pulled the coils and while fitting the replacement ones, he found the spring contact on cylinder #3 coil was badly corroded with copper verde gris. From his picture we also saw the ground area and bolt base of the thread area was also green. The weird thing here is this is a NAPA supplied coil he fitted last year!! No idea how or why the corrosion. He said when he fitted it the weather was dry and in the summer.

Early days, but so far so good and hopefully the check light will stay off!

Can only think the car had a slight misfire on that cylinder but was enough for the ECU to say all coils were bad??

Neil.

Post by **abscate** » 19 Mar 2022, 03:13

The car uses the crank sensor yo determine acceleration on each firing if the coil to detect a misfire on a given cylinder. It Isn’t perfect and can give the wrong cylinder assignment in my experience. If it’s more than one cylinder, or really running rough, all bets are off on cylinder assignment.

Post by **scot850** » 20 Mar 2022, 15:56

Got pictures from my friend of the coil pack corrosion. Added them below:

: Coil pack corrosion (2); Coil pack corrosion 2.jpg (247.99 KiB) Viewed 614 times

: Coil pack corrosion; Coil pack corrosion.jpg (236.77 KiB) Viewed 614 times

Still cannot explain how this can happen especially in cylinder #3 in the middle of the engine? Doesn't explain the base of the threaded section of the bolt either. Got to believe it is aliens messing with his car...........!

Neil.