Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Greenbay packer]

I have various dis pack related questions and would much appreciate any help and advice people are able to give.

My 2.5 V6 has recently started to run really roughly, like its not firing on all cylinders.  This began not long after I found loads of rainwater sitting around all the plug leads after the car had been left on a slope. As this has happened before I thought it would be ok after drying and running but its still running badly so today I started to have a closer look at things.  I removed the easy to get to leads from the plugs on the drivers side and used an inline HT tester to check whether power was getting to the plugs - this showed the centre and rear plugs were receiving high tension spark potential, but the front one, no.1, wasn't. I took this front plug out and it was oily (or wet, though it seemed more oily), cleaned it, dried it, refitted it and tried again but the tester still wasn't flashing so no HT potential.  I took the plug out and tested it on another vehicle and it was working fine, so I refitted it to the V6, tried the tester again and still no power.  I haven't had a chance to look at the other side yet, but so far is it reasonable to conclude that the fault must lie with either the HT lead or Dis pack?

I've just looked at the Dis pack renewal guide in the maintenance section on here, which seems to show the same version of the pack as is fitted to my car so I assume the vehicle used for that is a 2.5 or 3.0 V6 http://www.omegaowners.com/forum/index.php?topic=109316.0, and I can see that it will be an absolute joy to replace!  From what I can find out there seems to be three units inside the pack, each of which supply two cylinders - would I be right to think that if one of these units fails the supply to both cylinders will be affected, so if I find another cylinder not working on the passenger side the fault can only be with the dis pack and not the HT lead.  If correct, looking at the diagram on the maintenance guide would I be right to assume that the centre, no. 4, cylinder is the one most likely to be not sparking? 

I've removed the windscreen scuttle and had a nose down towards the dis pack but was horrified to find I could only see part of one of the four bolts that secure it (I assume all 4 bolt holes are used, not just the two on the bulkhead side which will be easiest to get at) - I can't even get my hand in and feel the others!    I was amazed that I could actually see and read a Bosch part number on one corner of the pack though some small consolation.  When I refit a replacement unit, assuming this one is knackered, will just a couple of bolts be adequate to secure it?  Also, I've seen people on here and another forum mention relocating their replacement dis pack, but is this possible without cutting into the wiring loom and will it require a set of longer HT leads?

Two final questions, for now at least. Firstly, my lovely Haynes manual and some of the posts on here indicate that the dis pack can be replaced after just removing the scuttle and wiper motor, but the maintenance guide say's to remove the scuttle and plenum - which is the easiest/ best method please.  As I've yet to remove a plenum I'm a bit dubious of touching that.  Secondly, its obviously not ideal, but how harmful is it to drive the car on 4 or 5 cylinders if I have to use it before I can get the job done - I'm thinking mainly about unburnt fuel getting to the cats, etc, but there may be other issues too.

May thanks for any help given.

[Doctor Gollum]

Leave the scuttle and remove the plenum and inlet manifold. You will then be able to get both hands and a foot onto the dis pack.

Remove, throw in the bin and fit the new one

[Lincs Robert]

I removed the scuttle & wiper assembly.

Either way you will get back-ache afterwards!

[Lizzie Zoom]

When I did mine, as in the Guide quoted, it was on a 3.0.

I did not remove the wiper motor, but certainly the wipers and scuttle need to be lifted out of the way  If you take it steady it is all very doable, but expect scratched hands, arms, and a bad back!  The four bolts on the dis pack can be a sod as you are working blind.  But take it easy and you will soon have the new one in place. A complete new unit is the only way to go

Ignore the Haynes manual, and follow the guide.  Do not attempt to use the car whilst only running on 4/5 cylinders.  You will kill the cats and put strain on the engine.

[terry paget]

I have changed several, removing wiper arms and scuttle. You can see the rear fixing bolts, the front ones you can feel. You need a slim socket and extension to access and remove them. You may break one or two off, not to worry, three will hold it all right. I removed leads first, then bolts, then raised the pack and unplugged the plug.

Not too bad a job, but be prepared for several hand grazes and a stiff back.

[Lincs Robert]

Just for the avoidance of doubt - you will end up with back ache! 

[cam.in.head]

and then once you have checked / replaced all the plugs and know they are fine its time to check or replace the leads. if there is any doubt or they are originals or have been on for years then best to replace but if not they can be tested.assuming they do not feel crunchy and brittle on the part of the rubber boot above the plug(the heat realy gets them there)you can test them with a meter. on a 20k range expect a continuity of approx 16k on the longer ones coming down to a lesser / around 9k on the short ones.the leads are resistive hence the longer ones being higher.no reading on a 20k scale indicates a break or bad connection .and yes the coil is a bugger to get out but worth looking at.they can crack and cause ht leaks to earth.any cracks should be obvious .if you replace ive been told best to replace with a genuine bosch .cannot comment of pattern items .

[Lincs Robert]

One advantage of taking the scuttle/wipers off is that you can test it without putting those parts back on. 

[Greenbay packer]

Thanks for all of the replies - looks like I've got some back ache to look forward to then!  Think I'll leave the plenum for now and try with wipers and scuttle removed as I like the idea of being able to run the engine and test the replacement and the leads before putting everything back together.  Thanks again 

[TheBoy]

Thanks for all of the replies - looks like I've got some back ache to look forward to then!  Think I'll leave the plenum for now and try with wipers and scuttle removed as I like the idea of being able to run the engine and test the replacement and the leads before putting everything back together.  Thanks again 

Brave.

I wouldn't.

[Lizzie Zoom]

Thanks for all of the replies - looks like I've got some back ache to look forward to then!  Think I'll leave the plenum for now and try with wipers and scuttle removed as I like the idea of being able to run the engine and test the replacement and the leads before putting everything back together.  Thanks again 

Brave.

I wouldn't.

.................yes, because without the plenum removed the task cannot be done...........that is what I have experienced anyway!

[Migv6 le Frog Fan]

It can be done, but its not worth the hassle - from memory.

[Nick W]

It can be done, but its not worth the hassle - from memory.

That was my experience too.

[Greenbay packer]

Thanks for all of the replies - looks like I've got some back ache to look forward to then!  Think I'll leave the plenum for now and try with wipers and scuttle removed as I like the idea of being able to run the engine and test the replacement and the leads before putting everything back together.  Thanks again 

Brave.

I wouldn't.

Ok, guess I was just being ultra hopeful and thinking 'there's only four bolts, how hard can it be?' - very by the sound of it! Not had the plenum off before so am a bit wary but if it has to come off I'm hoping its one of those jobs that once its done I'll be wondering what I was fussing about. I'm still half hoping it might just be an HT lead as I seem to have a spark at 5 out of 6 but nothing at the front right, but that is probably wishful thinking.  Thanks again.

[cam.in.head]

can you manage to remove the offending lead or for that matter all the leads with plenum still on. i did it a few weeks back but with it removed. cant recall if you can.lets say you can. and you have access to a meter it might be worth checking the leads first. water and heat does seem to kill them.

[Nick W]

can you manage to remove the offending lead or for that matter all the leads with plenum still on. i did it a few weeks back but with it removed. cant recall if you can.lets say you can. and you have access to a meter it might be worth checking the leads first. water and heat does seem to kill them.

It's fiddly, but possible to replace the leads with the plenum in place. With that in mind, a quick visual inspection of them should be enough to condemn them, or not. A new set isn't expensive, and the faffing about doesn't really justify checking them with a meter. After all, you won't need to change them again.

[Andy H]

can you manage to remove the offending lead or for that matter all the leads with plenum still on. i did it a few weeks back but with it removed. cant recall if you can.lets say you can. and you have access to a meter it might be worth checking the leads first. water and heat does seem to kill them.

It's fiddly, but possible to replace the leads with the plenum in place. With that in mind, a quick visual inspection of them should be enough to condemn them, or not. A new set isn't expensive, and the faffing about doesn't really justify checking them with a meter. After all, you won't need to change them again.

When I changed the leads on my 1994 V6 about 15 years ago the leads from Vauxhall cost £75 per side. I thought that was expensive.......

[cam.in.head]

Yes new is always better .i just thought he may want to test leads then at least he would hopefully have found a fault if 1 or more were showing open circuit.

[Nick W]

It's fiddly, but possible to replace the leads with the plenum in place. With that in mind, a quick visual inspection of them should be enough to condemn them, or not. A new set isn't expensive, and the faffing about doesn't really justify checking them with a meter. After all, you won't need to change them again.

When I changed the leads on my 1994 V6 about 15 years ago the leads from Vauxhall cost £75 per side. I thought that was expensive.......

I paid about £30 over the counter at a local motor factor, just before they closed for the day. They're a standard service part for any dispack equipped Vauxhall V6, so I don't see any reason to buy them from a dealer.

[Diamond Black Geezer]

Mine are Bosch Vectra (B) V6, different part numbers to Omega, but they do fit/reach, if you see a cheap set for Veccy.

Definitely worth changing the HTs when you do the DIS pack 

[cam.in.head]

Not sure about not needing to touch them again thou.depends how long your keeping the car. My brothers 2.5 was bought in 2005 and didn't have its original leads on then. We replaced them approx 2009 with new Bosch.they failed this year due to heat with a bad misfire.5 of the 6 leads were open circuit .all the failures were where the lead crimps into the plug end due to heat . Also comparing to an original lead found in the boot the Bosch leads didn't fit as well as the original.could have been wrong type but the newer Bosch leads bought also didn't fit perfect although still worked perfect. They were taller ,and slightly thinner. Surprisingly number 6 was the OK lead

[terry paget]

I once bought a set of V6 plugs from a factor, nicely boxed up, for about £12. Put it on the car, ran fine, no misfires, but some radio unterference. I replaced them with an old set from my parts heap, interference cured.they were fine. Clearly Omega leads need to be resistive.

[Greenbay packer]

Yes new is always better .i just thought he may want to test leads then at least he would hopefully have found a fault if 1 or more were showing open circuit.

Starting to hope (or kid myself) that it may just be a lead that's at fault. Using an inline tester I have now confirmed that I have HT power getting to 5 out of 6 cylinders but nothing is getting to the front drivers side (no.1) spark plug. I'm sure I've read somewhere that the dis pack module has three sections inside, each of which covers 2 cylinders. Can anyone confirm this?  I was thinking (or hoping!) that if this is the case and the unit is faulty I would be most likely to lose two cylinders rather than just one.  Or can did pack failure just affect one pot?

[Kevin Wood]

The coil pack fires plug 1 and 4 from the same coil internally. It's not impossible for the output on no.1 to fail while no.4 is still fine (short to ground on the no.1 end of the coil would do it).

Also, an open circuit lead on no.1 would likely cause a weak or missing spark on no. 4.

Could try swapping the connectors at the coil pack for no. 1 and no. 4 and see if the spark moves to no. 1 and no. 4 is thereafter faulty?

[Greenbay packer]

The coil pack fires plug 1 and 4 from the same coil internally. It's not impossible for the output on no.1 to fail while no.4 is still fine (short to ground on the no.1 end of the coil would do it).

Also, an open circuit lead on no.1 would likely cause a weak or missing spark on no. 4.

Could try swapping the connectors at the coil pack for no. 1 and no. 4 and see if the spark moves to no. 1 and no. 4 is thereafter faulty?

Thanks for confirming that, it was what I was hoping to hear. Definitely going to concentrate on eliminating a lead issue now before looking at the dis pack.

[cam.in.head]

Gottabe worth a try especially if car was running well before the water issue and you have found a missing spark at 1 plug.

[Greenbay packer]

Gottabe worth a try especially if car was running well before the water issue and you have found a missing spark at 1 plug.

Definitely, thanks.

[Greenbay packer]

Just to complete the tale, I tried a new lead on no.1 but still got no spark despite no. 4 seeming to be ok (perhaps my tester was a bit misleading but the flash looked as good here as on the others that were working), so concluded the fault must be with the dis pack.  Decided to remove the unit the hard way so whipped out the wiper motor and undid the four bolts - it was fiddly, but I have a pretty useful 1/4' drive socket set with various extensions so was able to get it out fairly easily.  Couldn't see any sign of a fault or shorting on the outside of the unit, in fact it appeared to be in such good condition I began to doubt my diagnosis so I connected the leads up again with the unit lose on top of the plenum and tried the car again with new and old HT leads.  Same result, it still seemed to be firing on 5 cylinders.

Bought a new Bosch unit from autovaux on eBay for £70, tried it on top of the engine again and started the car.  Success!, running on six again and sounding nice and smooth.  Fitted the unit back on its shelf, which was more of a pain than getting it out, started the car again and all was still fine.  Tried the car on a short run, then took it away for the weekend and 450 miles later I'm still happy.

Thanks for all of your replies they were a big help, this forum is great.

[BazaJT]

Good to hear you've got a result