Nj ignition leads amd coils

[Trevortsmith]

Gemster. All leads now seperated fine bit ill do the conduit too as it seems like a good idea to be safe in future.

[erad]

Yes eng is idling but tacho is on 3000rmp. I can axcept tacho driver is us bit what of the running problem.are they connected?

I doubt that the tacho reading high would affect the running of the engine, BUT, IF the engine is running at 600 R/min and the ECU thinks it is running at 3000 R/min, it is possible that you are getting a few extra sparks in between when the spark should occur ie on the intake stroke as well as the power stroke. That could cause popping in the intake manifold for sure. Can you disconnect the tacho and se if the problem goes away? I doubt that it will if the problem lies in the power transistor which is driving the tacho as well, but who knows? All I can say is that I am glad it is you and not me who has this problem....

[disco stu]

I had the same thought Erad, if tacho is reading when it is actually trying to spark then that could be causing the backfires and missing. Have you got access to a timing light or similar you could check if the problem if actually in the coils firing at the wrong time?

[erad]

I had the same thought Erad, if tacho is reading when it is actually trying to spark then that could be causing the backfires and missing. Have you got access to a timing light or similar you could check if the problem if actually in the coils firing at the wrong time?

Stu: If the beast is firing 5 or 6 tomes per rev, you probably won't see the 'extra firing because it would be out of the range on the crankshaft pulley. But it would be worth trying. When I stuffed my Crank Angle Sensor, the timing flashes were all over the place. Maybe the OP should check this - it may be his CAS which is crook??? But my Tacho never went to 3000 R/min like this....

[disco stu]

Is there any other way of checking the firing?

[nj swb]

Is there any other way of checking the firing?

Put the magnetic pickup on the lead for cylinder 2. It should be firing when the timing mark is out of sight - if you can see the timing mark at any stage then the firing has a problem.

[erad]

Put the magnetic pickup on the lead for cylinder 2. It should be firing when the timing mark is out of sight - if you can see the timing mark at any stage then the firing has a problem.

Not quite - firing will occur at 120 degrees, and you may still miss seeing it. Same for No 3 cylinder - that fires at 240 degrees crank rotation. If the timing light fires at 6 times the rate (500 R/min idle, showing 3000 R/min on the tacho) or even 6 times (600/3000 R/min), I would expect to see a flash somewhere within the scope of the crankshaft pulley. I am beginning to suspect the Crank Angle Sensor...

[nj swb]

Not quite - firing will occur at 120 degrees, and you may still miss seeing it. Same for No 3 cylinder - that fires at 240 degrees crank rotation. If the timing light fires at 6 times the rate (500 R/min idle, showing 3000 R/min on the tacho) or even 6 times (600/3000 R/min), I would expect to see a flash somewhere within the scope of the crankshaft pulley. I am beginning to suspect the Crank Angle Sensor...

Read my post.

Seeing the mark would be confirmation of an ignition firing problem.

I didn't say that not seeing the mark doesn't mean there isn't a problem.

Subtle difference. I forgot this is the internet.

[Trevortsmith]

Hi all. Had a go at it this weelend and pulled all leads off fitted split conduit and taped both ends and problem sorted. Runs great now. Still gotta sort tacho and other lights on dash but at least it runs. Thanks all for your help.
Thanks Trevor smith

[erad]

You say that you taped both ends of the HT leads. Depending on what tape you use, this may break down at a later date. You are probably better off without tape at the ends because the tape is now a weal point in the insulation. Try it, but check at night (in total darkness) and see if you can see any sparks where the tape is. If you see anything, remove th tape and then check again.

Once a HT led breaks down, it will always break down at that point (the insulation is weakest at that point). SO if you see sparks, try to fis it ASAP ie before it gets too bad at that point. Try moving the lead so that the weak point is further away from the earth point.

[disco stu]

Good to hear it's running alright and you find the source of that issue

[erad]

Regarding the tachometer issue, maybe somehow, somewhere, someone has connected the tacho signal to some other part o the system and it is now picking up every spark instead of maybe just No 1 spark pulse? As long as the beast runs, that is the main thing. Hope it keeps on running.

[gemster]

Glad it's all sorted, well kind of anyhow...

The split conduit was done on the whole engine harness and Leads on mine when I bought Her...
Best bloody idea ever.... Thanks Geopaj...
And I think the bit of tape at the ends may give you trouble later on... So I just used a small cable-tie and cut it when I have had to 'open' them...
Most brands of Elect tape contains Lead... And being a Metal, may give you issues down the track...

Gemster....