Nj ignition leads amd coils

[Trevortsmith]

Ill try the airflow sensor this arv but how can i keep tje leads apart when they all sit so close together?

[erad]

You say 3 new leads. I don't know the NJ, but the NL had 3 coils and 6 separate leads, No 1 and No 4 leads coming from the one coil, No 2 and No 5 from another and No 3 and No 6 from the third coil.

The leads have to be kept separate from each other and there are little nylon spacers and supports which the leads clip into. It is possible that someone has been there before you and not put them back when they removed the intake manifold. my ever fading memory tells me that one of the supports was bolted to the power steering pump bracket. What is the diameter of the leads? The genuine leads are ridiculously small - 5 mm diameter from memory. And with such a high voltage, they break down easily. If you are getting backfires, you are probably getting crossover eg No 1 is trying to fire and No 4 inlet valve is open and it is firing instead because there is less resistance for the spark to jump on the lower compression cylinder. That suggests that your leads are arcing to each other. This is why I went to such lengths in my diatribe about running the HT leads - it is critical.

If you don't have any little nylon lead spacers, I suggest that you go to your local dealer and buy some. What brand leads did you get? I found that anything other than NGK were typically too long and they tended to touch each other or some point of earthing . NGK leads also have the cylinder numbers printed on them which makes getting the correct lead very easy. Again, from memory, running the leads eg from No 5 or 6, I think I had to run the lead at the inside side of No 3 or 4 plug and then the outside of No 2 or 1 plug before the leads climbed up towards the coils, if you get my meaning here. It was not a straight run to the appropriate plug.

Have you had the Intake Manifold off? If yes, how well sealed was it when you replaced it? If you get an air leak (when the throttle is closed, you have maximum vacuum), you will have a lean mixture and this can cause backfires because there is more resistance in a lean mixture than a proper 14.7:1 air/fuel mixture. You could try closing the gaps in the spark plugs from the 1.1 mm down to say 0.9 mm and thus will make it easier for the spark to jump at the plug electrode rather than at the easier path somewhere else.

It is not easy to get the leads laid out so that they do not cross each other or touch earth, but as you have found, it is critical to do so.

[stumagoo]

its my understanding the DOHC has 3 COP and 3 leads from those coils over to the other bank - at this stage I would check timing with luck it has not jumped a tooth and maybe the crank sensor wheel has spun

[Trevortsmith]

Ok so just ordered all the lead clips from Mitsubishi. My leads are ngk andyes i did have the intake off replaced the gasket but used no sealer as i was advised against it. Did think rhat was odd but hey ho ill do it again. Ill do all this then check timing. It is intermittent from 4 to 5 to 6 sometimes so i do think leads arcing is the problem.

[erad]

It is not often that I am right but I am wrong this time (again!). I wasn't aware that this model had that HT lead arrangement. You live and learn each day, although hopefully I won't need to apply that knowledge to any of my cars in the future.

[stumagoo]

Ok so just ordered all the lead clips from Mitsubishi. My leads are ngk andyes i did have the intake off replaced the gasket but used no sealer as i was advised against it. Did think rhat was odd but hey ho ill do it again. Ill do all this then check timing. It is intermittent from 4 to 5 to 6 sometimes so i do think leads arcing is the problem.

ahhh I made that mistake..... the metal intake gasket on mine was replaced 3 times while I was chasing a miss.... I eventually gave up and 90000kms later while replacing plugs I reused and sealed with a fine smear of gasket goo as well as the gasket and my miss totally dissapeared. that was the 3rd new set of plugs btw so it was not the plugs causing it I had replaced the gasket - then plugs and gasket then gasket again and finally plugs with a reused gasket with glue on it and the miss went- plugs were done as a maintenance factor no other reason

[Trevortsmith]

Right . Plug gaps altered. Plenum sealed. Leads separated and not earthing anywhere. Now it idles but still pops and bangs. On turning the key rev counter jumps to 750rpm and on starting it jumps to 3000rpm on engine idle.
Losing the will to live now . Considering making this immaculate pajero a boat anchor!

[disco stu]

Are you saying that while idling the taco shows 3000rpm?

If that's the case I'm wondering if there is something wrong with crank sensor, leading to ignition timing being out, leading to it not firing properly

[erad]

Is it just the tacho jumping to 3000 r/min or is the engine revving that high as well? I doubt that the Crank Angle Sensor would cause this sort of action, but, sorry, it has gone beyond my experience. The Oxygen sensor in the exhaust can cause problems but I doubt that it would cause this problem, but as said it has gone beyond my experience.

Poppng and banging seems as if you may sill have the HT leads connected to the wrong plugs. When I had my troubles, it would run but in retrospect only on 4 cylinders (maybe even only 2, I cannot remember. The engine certainly would not rev freely. When my wife pointed out my mistake (Oh the shame of it), the engine SPRANG into life like it had never done before.

[stumagoo]

rev counter signal is generated from the Power transisitor unit - yeah sure that is driven by the ecu and that is driven by the CAS but the rev counter gets no signal from the CAS.

also the Tacho signal and the ecu signal are paralell --- so the PTU sends it signal to both for their respective uses - it does not go to the ecu then on to the tacho or the other way around

[Trevortsmith]

Are you saying that while idling the taco shows 3000rpm?

If that's the case I'm wondering if there is something wrong with crank sensor, leading to ignition timing being out, leading to it not firing properly

Engine idling and the tacho shows 3000rpm. On revving tacho only moves 500ish rpm.

[Trevortsmith]

Engine idling and the tacho shows 3000rpm. On revving tacho only moves 500ish rpm.

Also on the dash cluster the front 2 wheels are flashing and the a/t light is on now could that mean anything

[gemster]

You can slip some split conduit over each lead.... 7mm fits well...

Saves stuffing around trying to fit those lead separators...

Gemster...

[erad]

Engine idling and the tacho shows 3000rpm. On revving tacho only moves 500ish rpm.

My reading of your post is that the engine is idling at something like normal speed, but the tacho is showing 3000 R/min. Is that correct? If this is so, obviously the tacho or its driver is U/S.

If it is running at a true 3000 R/min, then you probably have the throttle cable not seated properly when the sheath fits into place on the intake manifold.

[Trevortsmith]

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?