V8 Plug to Coil pack order ?

[N1CERB]

http://www.tvr-cerbera.co.uk/WorkshopWiringDiagram...

In the plug order diagram above for the even side, would you agree that the order is correct?

When I removed my old leads to fix my dodgy running and idling troubles I see that my coil is wired the opposite way round for plugs 4 and 6. All my other leads are the same as in the diagram.

Does anyone know which order their leads go to the even side coil pack at all please?

Perhaps I have been running with two plugs on the even side being in the rong firing order. Just how rough would that sound and feel??

Chhers
Dave

[Tanguero]

The diagram is the way round that my car is wired. 1997 4.2

[N1CERB]

Mine is a 4.2 if they are any different to 4.5 ?

[N1CERB]

I wonder if I have just been driving about with two plug leads the wrong way round all this time?? What a difference its going to make!!

[SporttiJanne]

No worries, plugs 4 and 6 fires simultaneously. (Like 2&8, 1&7 and 5&3 do.) Ignition system in Cerbera V8 is wasted spark, not sequential.

[N1CERB]

Thanks for that confirmation. Its been on my mind all night and I just found a good write up on flat planed cranks that also answered the question.

I still cant understand how the connector plug to the coil tells which plug to fire though. I must be reading the wriring diagram wrong? I read it as two switched 12v + leads and then a coil control wire and a coil ground (GND) wire. There must be two control iginition wires and the pack be self grounding. I am just mis reading the meaning of GND on the diagram.

Only one way to find out!

Cheers

[crypto]

The 12V supply to the coil-packs are on Pin3+4. The ECU coil-driver stage (Pin19/20 and Pin40/55 on the ECU) switches to ground to "charge" the coils within the coilpacks. When the ground is released by the ECU, the coil-pair fires (one of them as a wasted spark as mentioned above). Pin 1+2 on the coilpack connector are not ground, they go to the coil-pairs.

[N1CERB]

Ahh makes sense now why there are just two control wires. It was the initials GND that threw me into thinking it was for a earth of some description. But with two plugs firing at the same time on each side you would only need two wires to control them.

I just hope I get them the right way round when I wire up the new connectors!!

Pins 3 and 4 I see should just be the switched 12V supply and so the red wires go to these on both sides. My odd and even coild have different feed wire colours though. That I assume go like this...

EVEN - Pin 1 = Pink. Pin 2 = White.

ODD - Pin 1 = Orange. Pin 2 = Yellow.

Speaking with Jim down in Auckland he has a Cerb in there with the same colour wires to both coils? These being oranage and yellow to both.

I wonder why mine is different??

Cheers

Dave

[crypto]

N1CERB said:

.... I wonder why mine is different?? ...

because its a TVR

[N1CERB]

Yep!

All sorted now, running sweet!

[pmessling]

This is what i have always referred to

http://tvrcerbera.co.uk/Gallery/displayimage.php?p...

[N1CERB]

Yes, used the same. Mine were the wrong way round on 4 and 6. But it makes no difference as they fire at same time. But in right order now anyway.

[N1CERB]

Hey Folks,

Blowing the dust off an oldie! I dont seem to be getting a spark on 3 and 5 cylinders.

Am I right in thinking that if I test the 4 pins of the coil drive connector, with ignition swtched on, they will all be + feed?

Is there any way to test if these switch to Ground as they are supposed to?

Also, I cant seem to find the wiring diagram for the engine that shows the coil packs. Anyone got a link please? Think its title is CEPD008C.

Thanks all

Dave

[Byker28i]

http://www.thetvrsite.com/cerbera/wiring-diagrams

[N1CERB]

Cheers for the link. That is where I already get diagrams from though, but not the one I am after. They dont seem tolist the ECU or engine loom diagrams other than the Excell one atthe bottom of course. I am sure I used to have one that had the full engine bay including coils?? Its listed as a continuation drawing on these diagrams but not listed.

I am hoping also that someone will know what output will be from the ECU with just ignition switched on. This being the feeds to pins 1 and 2 (From 19&20 and 40&55) before engine running. I am hoping these should be constant +ve feeds. Then when the ECU triggers it just grounds each of these pins n sequence to fire the relavent coil pack and corresponding two cylinders?

So in theory with my basic electronics knowledge, if I connect a circuit tester to each female connector 1 and 2 at the coil plug end, it should flash between + and - ve when I press the starter button??

Trying to work out where my fault is on no power to cylinders 3 and 5 still..!!

Cheers all
Dave

[ukkid35]

The simplest check is to connect up a spare coil pack (without fitting it), this takes no more than 20 mins. If that works you can fit it fairly quickly and easily. I somehow managed to test a replacement from a Saxo in a scrapyard (costing just €25) and fit it in two hours earlier this year, while I was at the Ring. Sadly too late to get back on track, but it can be done on a 4.5 without removing the fuel rail.

[N1CERB]

Cheers. Mine is a 4.2 so fuel rail and injector cables get in the way a bit. You know I didnt think about just pulling the cables off and having the coil remote on top! I could try my second spare one tonight and see. But I am going to try swap the cables and leads over from one coil to the other in situ without removing fuel rail tonight.

I am guessing a remote coil will need to be earthed via one of the bolt holes???

[ukkid35]

N1CERB said:

I am guessing a remote coil will need to be earthed via one of the bolt holes???

Nope - no earth connection there.

[N1CERB]

Cheers. I connected up a remote coil last night and still nothing on that side. Calling in the cavelry tomorrow!