CoilX and a 4l80e tranny

Marco · Post by **Marco** » Sun Jun 28, 2015 5:56 pm

Hello from Netherland,
I have been fighting a problem for over 2 years until I found this great place.
So here is a short story, I have this truck with a electronic od transmission that was controlled trough the stock ecm that also controlledthe tbi injection.
I upgraded to a standalone injection system with aftermarket distributor, but the stock ecm needs a clean 5Volt Vref signal to know wat rpm the engine makes to get the lockup to work.
I then put a wire from the negative coil side to the 5Volt vref and that fried my ecm to the death.
I replaced the ecm and now manualy use the lockup with a switch.

So I ran into the CoilX that should do the trick to get me a clean signal, but I have questions to where to put the +5Volt wire, output wire and the negative that goes to the "raceCapturePro" that I obviously do not have.
Here is a wiring diagram of a stock Chevy tbi distributor where you can see the inputs of my ecm:

I hope some of you could help me out, I allready have ordered the CoilX that should do the trick.
Someone told me the B5 conection on the ECM Reference high should need a square 5volt signal, but he was not sure.
Thanks

Marco · Post by **Marco** » Wed Jul 08, 2015 10:16 am

Anyone ?
I found out that indeed B5 refference high needs a square 5volt signal, but what do I do with the other 2 wire from the coilx ?

Post by **brentp** » Fri Jul 17, 2015 6:04 pm

Hi,

I'm sure you've seen the documentation here on CoilX: http://autosportlabs.net/CoilX

It needs a 5v power supply, so it's designed to work with the 5v vref output of the RaceCapture/Pro.

To use it in your case, you will need a 12v to 5v voltage regulator circuit to power the CoilX. Then it should work for you.

Please keep us updated on what you find out!

Marco · Post by **Marco** » Fri Jul 17, 2015 6:37 pm

Hi,
I understand that the CoilX is not designed for my purposes, but I was hoping it does.

I see now what you mean, so it may work.
Does the 5Volt ref signal needs to be exacley 5Volt ?
Becouse the altenator gives me between 12.5-14-5 I can use the output wire for my reference high input of my ecm that needs a max of 5Volt.
But what do I do with the ground wire beside the output wire ?

Thanks for your help, it is much apreciated.
Marco

Post by **brentp** » Fri Jul 17, 2015 6:48 pm

it should be exactly 5v, about 1% tolerance. You can also tie the grounds together, or the coil side close to where you're getting the high voltage signal.

Marco · Post by **Marco** » Sun Oct 25, 2015 5:46 pm

It works !
I am very happy !
thanks