New Coil - Tachometer Jumpy affecting TCU

[Bigrig]

Ok kids, here goes. Put a new Crane Cams high performance coil in the truck and subsequently, the tacho is now all the shop. As per other posts, it appears the Transmission Control Unit relies on the tacho feed in 'some' way for use of the torque converter (apparently and ohm or two either way of incorrect reading, it won't lock up - which mine now isn't). I took advice from a range of people an ended up going today and buying a new coil with inbuilt resistor to try and reduce the 'feedback' through the wiring and hopefully resolve the issue. Nope - still does the same thing. I swapped the dizzy module also, but it should have no affect at all.

Sooooo ... can anybody offer suggestion of what needs to happen? I've got a mechanical Scorcher dizzy that was sort of ok with the original coil (it was a bit jumpy also but the TC was working), and apart from that, nothing has changed - new valve body should have nothing to do it as it went in after the coil and the TC not locking up problem.

Thoughts?? Pleeeeaaase!!! Now I've tried 2 different coils (tried an EB falcon V8 coil also with the same effect).

Would like my tacho working again properly, but moreso does anyone understand how it affects the TCU as I would prefer to have the TC working again even more so.

Thanks a million in advance one and all ...

Not overly keen to drive another 2400klms down to Victoria and back with it in its current condition.

[Yendor]

I was just speaking with Scotty.

I think the problem might be the resistance of his replacement coils, does anyone have the workshop manual for a 1995 onwards model GQ that can look up the resistance value of the coil for us? or has one and can measure the value of their coil?

Thanks Rodney

[patch697]

I was just speaking with Scotty.

I think the problem might be the resistance of his replacement coils, does anyone have the workshop manual for a 1995 onwards model GQ that can look up the resistance value of the coil for us? or has one and can measure the value of their coil?

Thanks Rodney

If thats the issue then why was it having the same issue on the STD coil?

[NissanGQ4.2]

Considering your not at my place drinking beers / bourbons I have no sympathy for you or TANK what so ever.....On that note.........think I might just go poor myself another bourbon now

[NissanGQ4.2]

If thats the issue then why was it having the same issue on the STD coil?

agree with Paul on this one

[Yendor]

If thats the issue then why was it having the same issue on the STD coil?

The tacho and TC problem only started after he replaced the coil.

[Yendor]

He is not currently running a standard coil.

[NissanGQ4.2]

The tacho and TC problem only started after he replaced the coil.

I've got a mechanical Scorcher dizzy that was sort of ok with the original coil (it was a bit jumpy also but the TC was working).

Ok the TC was locking with original coil but sounds like there where problems 2 begin with

[patch697]

.4 to 2 ohms Primary & 6k to 16k ohms secondary

[NissanGQ4.2]

Scotty, I assume the tacho you are talking about is the Rev Tacho?

Is it just the Tacho doing crazy things or is the the revs of the motor itself?