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tach signal
Posted: Sun Mar 05, 2017 11:32 am
by gto66
I have a MS2 v3.0 with b&g firmware and 2.92 code. I have it setup for hall effect sensor. I can get a tach signal on my stim but not in the vehicle.
Using a MSD ready to run distributor and a Crane CD box. When using a CD box the manual stated to jumper D14 to IGN.. Would I also use the JS10 to IGN jumper?
I have the jumpers connected like this:
XG1 to XG2
option to tachselect
tsel to optoout
JS10 to IGN
should I be using the IGBT high current driver circuit? I do have r43 and Q16 installed. I cannot seem to find anything about my problem.
Thanks for the help.
Re: tach signal
Posted: Mon Mar 06, 2017 5:11 am
by trakkies
You need to separate this into two different questions.
MS needs a tach signal regardless of the type of ignition. Without it, MS won't inject.
If you get a tach signal from your Stim but not distributor, it likely means the signal from the dizzy is a different polarity or voltage. The Opto circuit contains diodes, so won't work if the polarity is reversed.
I dunno your dizzy - can you give a link to the spec to determine what signal it puts out?
The same would apply to your Crane CD box.
If you use the BIP high current ignition driver supplied with MS, you don't need any external box to drive a single coil.
Re: tach signal
Posted: Mon Mar 06, 2017 9:36 am
by gto66
Here is a link to my dizzy
https://www.msdperformance.com/products ... parts/8528 I am new to linking at this site. If this is not correct please let me know. Thanks for your help Rod
Re: tach signal
Posted: Mon Mar 06, 2017 9:43 am
by gto66
Re: tach signal
Posted: Tue Mar 07, 2017 1:57 am
by trakkies
That appears to be just a modern P&P replacement for an original dizzy, designed to work with one coil directly. So a stand alone ignition system that you'd normally derive the tach signal to MS from the coil, with MS controlling fuel only.
The modern way is to provide a simple tach signal from the engine, and have MS determine the advance curve, etc. Programmable ignition.
Since the dizzy is controlling the advance curve, there's no much point in involving MS at all on the spark side. So if using an additional CD driver, that would be driven from the dizzy, not MS. But I've no experience of that - it seems a very expensive way of getting an inferior result.
There are lots of good reasons not to use distributor ignition - which is why you'll not find it being used for about 20 years.
The easiest other method which MS will control fully is wasted spark.