Tach problem with Mag

Hi Guys

We have a SuperMag III on our injected big block, with an autometer tach adapter to the Autometer ProComp tach but it's not getting any reading, it is all wired up as per the instructions and the tach worked fine previously with a SuperMag II that had a generator on the mag drive

is there something we're overlooking or is it just one of the few tachs that the adapter doesn't work with?

Thanks

 

Sounds like you need a battery,...??????
..... for the tach and shift light....

 

As I just said in the other thread... We had one of these adapters... Well, actually, make that 3 of them.

None of them worked properly. We were only, at best, able to get RPM up to about 2k before the tach went nuts.

Maybe others have had success, but we went to the resister core wires, moved the transformer to the furthest possible point away from the tach/adapter, braided all of the wires under the dash and ultimately foil coated the entire wiring harness.

The thing just plain didn't work.

Back to the inductive pickup and mag tach... Flawless.

-WJ

 

we've got an on board battery for the oil pressure warning light, tach/shift light, rear lights etc

sounds like an inductive pickup and mag tach is the way to go, any recommendations for particular models to go with? don't need anythign fancy, recall would be nice but not essential

 

We use the Auto Meter 6831: http://www.autometer.com/cat_gaugedetail.aspx?gid=2752&sid=9

We're using an external shift light which it appears Auto Meter has discontinued or, I can't find it, but it's part number 5342.
http://www.autometer.com/hp/instruction_download/instructions/397f.pdf

Maybe one of the more experienced guys here will have a better solution for ya.

-WJ

 

Make sure that you have good grounding expecially between both heads to the negative on the coil. Bad grounds can cause all kinds of interfernce that can drive you crazy.

 

the grounding is pretty good I think

It's not even interference problems, when the motor is ticking over the tach sits at 1500rpm wavering slightly, but when she's opened up and revving freely the tach needle just sits there on 1500

 

Same Issue

we had the same problem and an informed arm chair crew chief told us to ensure that our 12 volt battery was fully charged. He was right.........no problems since. Good ground and full charge was the answer for us.
Good Luck!
BRownman and the FNGs

 

I have been told the converter should be about 24" from the coil on a SM III.