Autronics Gm Propane Processor.

[thergen at svn.net]

If the Autotronics unit is supplying 5v and ground to the three wire
sensor (tps and/or map), I'd think you'd have a good chance of getting the
two controllers to run off the sensor in parallel.  The ecms likely have
relatively high impedance inputs for these types of sensors and two ecms
connected in parallel would not affect each other.

Two wire sensors or one wire that use the block as a 2nd conductor
probably would not be useable in parallel with two controllers.  These
type of sensors usually have pullup resistors in the ecm driving them. 
Two pullup resistors in parallel would cause both ecms to see incorrect
sensor values.

I haven't seen either controller you mentioned, so keep that in mind when
considering the opinion above.

HTH,
Tom


On Sun, 8 Aug 1999, Peter Fenske wrote:

> 
> 
> Howday All
> 
> I was wondering if anyone is familiar with or has any documentation
> on a GM Integrated Processor Fuel Management system made
> by Autotronics Control Corp Part # 5920.
> 
> It is giving me a problem in a commercial Van application.
> The unit appears to control a propane mixer using closed
> ?? loop operation..
> 
> It plugs in a 350 tbi using a 8747 C3 ecm.
> 
> Now the problem. The Autotronics unit plugs into the TPS and Map
> sensor. The original ecm connectors plug into the autronics unit
> I would presume the signals are processed and then sent to
> the ecm..
> 
> Big SES lite is on. Scan shows the TPS and Map signal are NOT
> going to the ecm. No timing, TCC ect..
> 
> So I was gonna use an extra map and plug the stock ecm into
> that. Not sure bout TPS.. Wonder if the signal output can be
> run in parallel.. At least the ecm would be happy.
> 
> Thank you for any help anyone can give
> 
> :peter
> 
>