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[joshwyatt]

Wasn't really sure if it'd be better to post in this section or electrical...apologies if it's felt to be in the wrong section.
Vehicle; 3.2 manual (OY02 VTL)
Issue;
When started from cold and on enrichment it's fine, but off enrichement there's a missfire on the 1-3-5 bank.
James has looked at it, previously and tonight.
Not coil pack, not plugs...known good lambda sensor fitted tonight and no change.
So that really only leaves wiring from ECU to the 1-3-5 bank. Does anyone happen to have a wiring diagram of this? James thinks if the wiring is checked and replaced this would most likely cure the issue. As James' excellent process of elimination only really leaves wiring left. Is there any area prone to issues? Through breakdown from heat etc?

[Kevin Wood]

Any codes stored? I would expect a code if a coil circuit went open or short circuit.

What about coolant temperature sensor? Could be that the ECU thinks it has a cold engine all the time, so keeps the enrichment on, causing poor running as it gets hot.

Kevin

[joshwyatt]

James used his code reader, that gave 0300, 0301, 0303 and 0305. Those codes were cleared, but they returned after a while.
Your second point is most interesting, that is something neither James or I had considered. Would a live data test be able to establish if that were the cause? Thank you for your assistance Kevin 

[Entwood]

Any codes stored? I would expect a code if a coil circuit went open or short circuit.

What about coolant temperature sensor? Could be that the ECU thinks it has a cold engine all the time, so keeps the enrichment on, causing poor running as it gets hot.

Kevin

Wouldn't that affect both banks I wonder if the lambda is not going "closed loop" on that bank ?? Live data would show that I think

[JamesV6CDX]

Your second point is most interesting,  that is something neither James or I had considered.

Sorry Josh - Wrong  - this was one of the first things i considered and looked at

Would a live data test be able to establish if that were the cause?

It would indeed - and the CTS values were totally normal

I will post up a bit more background, and my reasoning, on here tomorrow 

[Kevin Wood]

Any codes stored? I would expect a code if a coil circuit went open or short circuit.

What about coolant temperature sensor? Could be that the ECU thinks it has a cold engine all the time, so keeps the enrichment on, causing poor running as it gets hot.

Kevin

Wouldn't that affect both banks I wonder if the lambda is not going "closed loop" on that bank ?? Live data would show that I think

Yes, it would be interesting to see the live data. Would prove the temperature sensor and might show up something else (excessive fuel trim on that bank, perhaps?).

I will have a look at the wiring diagrams but, IIRC, there's just a positive feed to the coil pack and the negative side of each coil goes back to a pin on the ECU. I guess the insulation could be breaking down when hot but not something I've ever seen before. Worth checking how the wires look at the coil pack and ECU connectors, though, as that's where the problem is most likely to be.

It is also possible that it's the coil driver(s) in the ECU. They could well have a failure mode where they play up when hot. Again, though, an extremely uncommon fault.

Kevin

Kevin

[joshwyatt]

Your second point is most interesting,  that is something neither James or I had considered.

Sorry Josh - Wrong  - this was one of the first things i considered and looked at

Would a live data test be able to establish if that were the cause?

It would indeed - and the CTS values were totally normal

I will post up a bit more background, and my reasoning, on here tomorrow 

  sorry James 

That'll teach me to pretend to know what's going on 

[JamesV6CDX]

Yes, it would be interesting to see the live data. Would prove the temperature sensor and might show up something else (excessive fuel trim on that bank, perhaps?).

Kev - The CTS values on the live data were normal.

I don't pretend to understand fuel trims to much extent - but, the values were the same across both banks, so nothing struck me as being unusual?

[JamesV6CDX]

Once we get this sorted out Josh, we'll have to pick a nice warm day to remove the gearbox and find out what's going on in there, too.

Either the clutch thrust bearing, or the input shaft bearings, are making a RACKET 

[Marks DTM Calib]

Hmmm.....I dont buy a wiring issue.

An ecu fault as a remote outsider possibly.

1-3-5 bank feeds off the same side as the brake servo pipe so air leak is a possible.

A weak coil pack is a possible, really needs testing with a test plug.

[david_omega]

when it was here, we changed ecu, made no difference, and tried other coil packs, no difference.

not saying dont check, but just to say, we ruled that out

[JamesV6CDX]

Plugs brand new, and coil pack is known good..  :-/

[Kevin Wood]

Does it misfire constantly, at idle, only at higher revs, only under load?

I'm sure it's been asked before, but can't remember.

If you unplug the lambda sensor to force it open-loop does it still misfire?

Kevin

[TheBoy]

When I saw it, lamda was non responsive, thus that was my initial recommendation, with a visual wiring check of the 1/3/5 coilpack (as thats free to do).

[TheBoy]

B1S1 lamda I should add