3200 running rough...broken wire?

[macaroni]

My 3200 has been running intermittently rough for a while and now seems to be running on 7 cylinders all the time.

I had a look under the bonnet and before I did battle with the coil and plug covers, I noticed a broken wire in the loom going into the left hand bank of plugs.
I took the sheath off and there are 4 black wires intact, in addition to this broken one, so I wonder if it is just spare, or should be joined to something.
Thing is, I can't find the the broken end.

It could be a wild goose chase and I do need to look at the plugs/coils, but this seems an obvious place to start.

I have attached a picture to make this clearer, maybe.

Any help gratefully received.

Antony

 

[jluis]

I would say it's not a spare and given the location, it's probably related to one coil in that bank.

According to the wiring diagram, you should have 12 wires going into each plug bank, 4 of them being black and the others coloured.

 

[Contigo]

Too difficult to say but it is suspicious given your issues and the location of a broken wire to the Coil packs and injectors etc... Whip thr coil pack covers off and inspect each set of cables and compare.

I will check mine tomorrow and report back.

 

[macaroni]

Thanks Jorge, that's the 5th black wire though! Unless it is very dark blue.

Thanks Phil, I'll have another look tomorrow when it is lighter.

Cars...

 

[Contigo]

Oh and first thing I would do to eliminate the cables is unplug/plug each coil pack one at a time until the idle evens out.

 

[macaroni]

That's what I set out to do, but couldn't get the coil pack cover off and spotted the broken wire.

 

[jluis]

Coil pack cover should come out easily (only 2 screws), however you seem to have a an allen screw instead of the standard torx screw.
Is that why it's hard to remove?

 

[Contigo]

T11 I think, it is a Torx type that's for sure.

 

[macaroni]

I've got the correct tools for the job, but the left hand cover fouls a bolt poking out of the ABS ECU housing and the right hand cover is blocked by the coolant bottle.

I only had a quick look, to be honest, so I'll have a proper look in the rain tomorrow.

 

[macaroni]

The allen key is for the injector rail, the coil pack covers are held on by 10mm bolts (left hand) and a torx bolt (right hand).

 

[allandwf]

I've had a look at mine, and it's exactly the same! One black wire seems unused , unterminated.

 

[macaroni]

OK, so I've had the coil pack covers off and all the wires seem to be present and correct so I agree with allandwf, I think it is a red (black) herring.

Starting with the left bank (nearside) I unplugged all the coil packs and let it run on 4 cylinders (be more economical!) and plugged each one back in their was a discernible increase in engine speed, along with audible proof that the injectors were working. I used the time-honoured method of "listening" to a screwdriver resting on the injector body. A kind of DIY stethoscope.

Then I moved to the other bank (offside) and they all seemed to work OK too, although plugging each coil pack in didn't make as obvious an improvement as the other side. Again the injectors were silent until the coil pack was plugged in again.

Then, for fun, I did a throttle reset, to no avail.

So it definitely still idles lumpily and revs reluctantly, although there are no dashboard lights (thanks Jorge) and the SD2 throws up no codes, apparently.

Any more ideas?

I'd like to check the plugs, although they were apparently changed in January during a service.

Antony

 

[jluis]

Bad spark plugs?
Clogged injector?

 

[Contigo]

Same as mine mate and was duff fuel. Bang 30 quid of super unleaded in and retest.

 

[macaroni]

Ha, just done that too Phil. I only ever use Shell V+ Super Power Nitro awesomeness.
That should prevent the clogged injector so it may well be a bad spark plug, as it started misbehaving after the service.

 

[saintetienne]

Antony , If you are out for a road test down my way give me a shout .

 

[Contigo]

Check the spark plug gaps Ant, 0.65 if NGK......

 

[highlander]

Check the spark plug gaps Ant, 0.65 if NGK......

Given problem started after service, I'd go with this as issue....

 

[macaroni]

Right, up with the larks and under the bonnet.
I attacked the offside bank first, as that was the most suspect during yesterday's investigations and the front most plug was a) full of some liquid, b) loose and c) had a massive gap!
0.65mm is 25 thou in old money and I think I could have got the whole set of feeler gauges in there.
I checked all 4 of that 4 bank while I was there and they all had too large a gap.

Put it back together and it now runs as smoothly as it should!

I'll do the other bank at some point, but that seems to have been the problem.

Thanks for your input guys, much appreciated.

Antony

 

[allandwf]

Excellent! Good result, we'll all just ignore the black wire in the loom, or put it down to it's Italian roots