Re: Modifing pulses and analog signals to the PCM

From: Shane Moseley (smoseley@ix.netcom.com)
Date: Thu Mar 01 2001 - 15:00:07 EST


WOT or waiting at a Red wrote:

> I've been reading all the post, current and archive, to try to understand
> the PCM in my Dak better. The reason I am interested is I have been
> considering the possibility of using a small PLC (programmable logic
> controller) to interface key sensors to the PCM. Coupled with a simple OI
> (operator interface) you could take the incoming signals, buffer them (read
> change them) and send them on there way to the PCM.

While I do agree with the reasoning behind wanting to do this - I'm not so sure
if a PLC can make it easy to get there. I mostly say this because I am just
ignorant when it comes to PLCs. Don't they just map a set of inputs to a
selectable set of outputs? More importantly, what kind of speeds (of conversion
- or latency from in-to-output) can it achieve? Is this a 2D mapping because
you'll more than likely need at least a 3D-type mapping. If the speed is
adequate, what about after implementing a 3D (or greater) type of kludge - will
the speed still be there?

I personally have been working on a similiar solution - not with a PLC but a
full-blown custom-fabbed micro-based approach (see www.diy-efi.org section on
efi332). My reasoning is that I want TOTAL control.

Don't let me discourage you in any way as I have even heard of people having
success in fuel-injecting motors using not much more than a 555 timer IC...
(don't laugh - remember you can do EFI with only 1 input - TPS - called AlphaN -
I see it at the dragstrip all the time - winning most of the time!).

For a list of all sensors - check my writeup at the following URL:

http://home.netcom.com/~smoseley/DodgePCM.txt

Latr,

Shane

--
'96 IndyRam-HisIndy-MPI/TB/Pulleys/AccelCoil/MPComp/HookerSuperComps/CompTAs
'96 IndyRam-HerIndy-numbered(#142)"Track Truck"
'74 Triple-Black Dodge Challenger Rallye 360 home-brew EFI R&D vehicle
'68 Black Corvette Convertible 427 (For Sale)



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