Compression Testing

[WallerZ]

Yeah sorry, just to fill in some gaps.

Its running a Ford Edis6 set up with a coil pack. At Stoneleigh we put new plugs in, swapped HT leads around for firing order, checking HT leads ok, coil pack was ok and spark plugs sparking. When out the block, plugs sparked and HT leads arced when pulled during running. Injectors were pulled and fired fuel, swapped and even wiring swapped but the problem remained. So from Stoneleigh we confirmed the plugs, injectors, HT leads, firing order and associated wiring were correct and working. The coil pack was brand new from trigger wheels. I have a spare but with 3 cylinders down (left bank cylinder 1-3-5 right bank 2-4-6 with 1 & 2 at the front) which were 1 (125psi) 2 (140psi) and 3 (120psi), it didn't seem right the coil pack was down as the plugs were also sparking still.

Overall, no matter what we tried, we could not move the problem and each component seemed to be working when tested.

I know you guys said it seemed to be running on 6 cylinders and with the change down to a proper idle, its hard to say but surely would be noticeable loosing half your cylinders? I have watched some videos back and there doesn't seem to be a major difference in it running.

[theduck]

I think it's valvetrain, it explains the chirping noise and why the more the engine has been run the worse it has caused the problem to get.

[Guest lotusPaul]

Ok.so im getting one complete bank is not firing. Id get another coil pack in there to see if it acts the same. At least it will eliminate that. Please ensure first tho that the non firing leads are actually fitted 100% correctly. I had a mis fire from my lotus and was down to a wrongly fitted lead.

Yes i slapped my self silly.

Also while your at the coil pack ensure the wire loom conections are good.

 

Your pressures are a bit low admittedly but should still fire

 

What are the condition of tbe plugs in the non firing side. Dry or wet after turning over?

[brumster]

Yeah sorry, just to fill in some gaps.

...snip...

I know you guys said it seemed to be running on 6 cylinders and with the change down to a proper idle, its hard to say but surely would be noticeable loosing half your cylinders? I have watched some videos back and there doesn't seem to be a major difference in it running.

Cool, useful info, so I agree you seem to have been clinical about working through it. That's fair enough, just wanted to make sure!

 

Still confuses me how the 3 down cylinders are not firing at all, given there's spark and fuel - even with slightly low compression I would still expect there to be a bang, even if it's going the wrong way up out the throttle body! Unless the inlet valves have completely snapped and you're just squirting fuel onto the back of a closed valve but I think you'd have noticed something that bad

 

Bore scope?

Leakdown test?

Cam covers off and turn the engine over by hand and watch?

Do a dance and sacrifice 3 chickens to the V6 gods?

 

I'll duck out now, I'm out of ideas

[Guest lotusPaul]

Ive been looking on the net on this system and it appears to me that it fires in pairs. Top and bottom as a group of 3 pairs. So if your getting a bank not firing is that all the top row or all the bottom?

Im begining to think your main issue may be that anoying thing of electrickery, but id ensure all conections are tight and earths in correct place. Id also swap to the spare coilpack as it may confirm my thoughts.

 

2nd idea,

Whether its sparking or not tho id still expect the plugs to be wet with the unburned fuel thats supposedly been injected. So forget the first idea for now and confirm the non firing bank has fuel being injected by having a shot at starting and inspecting the plugs after. If thier dry, im leaning to no fuel being injected, as that would also give the impression of no spark.

Again if no fuel being injected check that electrickery.

 

3rd idea.

 

????????????????????( hope ecu is not buggered)

[WallerZ]

Its 2 cylinders on 1 bank and 1 cylinder on the other Paul. All the connections have been tried and tested and no problems moved. All sparking and all fueling. This was all confirmed at Stoneleigh.

 

I'm thinking test the other engine, if compression is good then swap that in (like for like is easy and done in an afternoon... with help pretty please? Lol) and then strip the engine slowly and figure out the problem. If the other engine doesn't work then I've got bigger issues to find. At least the better engine is in then lol.

 

The only thing found with the ECU is the latest firmware. Easy fix but everything else is apparently looking ok...

Edited May 3, 2017 by WallerZ

[Jez Morton]

Zac, hold fire i may have worked it out. I have a scenario where 1 2 and 3 fire in the wrong place.

Basically the coils are reversed a b c is actually c b a. This means the wasted spark misses 1 2 and 3.

Try leads as follows cylinder to edis

 

1 to 3

2 to 1

3 to 2

4 to 4

5 to 5

6 to 6.

[theduck]

This image shows the normal layout for a Ford V6 firing order

 

 

So instead of Coil ABC its ACB, does that still fit your idea Jez?

Edited May 3, 2017 by theduck

[Jez Morton]

That sort of thing in your picture left to right coils are 2 3 1, my theory is its wired 1 3 2.

So if you look at the numbers on the edis as cylinder numbers connecting 1 to 1 and 2 to 2 etc as Zac did cylinders 1 2 and 3 dont get a spark.

[Jez Morton]

I think the numbers on the edis are cylinders not firing order, if you follow the ford firing order 142536 then this follows the coils as pairs 1/5 3/4 2/6 and repeat. If you swap 1/5 and 2/6 first spark is 3/4 second is 1/5 and third is 2/6 fourth is 3/4 fifth is 1/5 sixth is 2/6. So 1 2 and 3 dont fire.

[Guest lotusPaul]

https://www.google.co.uk/search?client=ms-android-samsung&biw=360&bih=278&ei=Mj4KWdvMMsWIgAax853IDw&q=edis+6+firing+order&oq=edis+6+firing&gs_l=mobile-gws-serp.1.0.0i22i30k1l2.7218.14364.0.15669.24.21.3.0.0.0.236.2789.2j17j2.21.0....0...1c.1j4.64.mobile-gws-serp..2.21.2462...0j41j33i160k1j0i67k1j0i13k1._c-PG0Ojl24#imgrc=By42XJNq78hM0M:

[Guest lotusPaul]

Ive found this. Well above. Are your leads in correct position

[Longboarder]

Have you got a definitive firing order? Is it this? 90s V sixes had a crossover in the dizzy cap according to my research and thus the actual numbering read round the cap was not the actual firing sequence.

 

Nigel

Edited May 3, 2017 by Longboarder

[WallerZ]

To be perfectly honest, I've no idea on the firing order. The V6 firing order is easy, its 123456. The issue is linking that up with the edis firing order and actual coil firing order.

The order Jez suggested worked and seemed a lot happier running (but not perfect) and on more cylinders, although a possible valvetrain issue plus varied compression might still be causing issues, means the engine is coming out and my spare going in with more consistent compression across all cylinders. Just gotta get over it being sat for 2 years lol

Edited May 5, 2017 by WallerZ

[Longboarder]

Good. So it is 123456. The triple coil wasted spark unit is very simple. It's three separate coils with a common 12v feed. Forget the numbers on the top. They are for ford v6 engines whose cylinders are numbered differently and fire in a different order. The V6 engine still has paired cylinders just like a four pot. When two are up two are 2/3 down and two are 1/3 up but the pairs move together. Of the two at TDC one will be firing and one will be exhausting and vice versa next time they come around but they are both given a spark so they both need to connect to the same coil. So 1 & 4 are a pair and must share a coil. 2 & 5 are a pair and must share a coil. 3 & 6 etc. The coils are laid out as shown above by the Duck but think of them as three coils for the three pairs of cylinders AND IGNORE FORDS NUMBERING. If your three coil driver wires can't be moved to suit my pic, ie coil driver 1 is positioned on coil 3 then just move plug leads 1 & 4 to position 3 etc.

 

Nigel

Edited May 5, 2017 by Longboarder