DIY_EFI Digest V4 #613

[CSH-HQ]

Just hook it all up per the factory.  The "tough"part is the VSS and just 
read the archives for that.
  All the sensors?. TPS, CTS, VSS, MAP, how much simplier do you want?.
The ecm powers the fuel pump for about 2 sec when you turn the key on to 
prime the system, from then on it's the oil pressure switch that powers it.
In a roll over it serves as a saftey item, since inverted there is no oil 
pressure.
  Don't try just running in limp home mode, or just start it that way, do it 
right once, and limp home mode will probably get ya home if needed.
Grumpy

>
>From: Mike Comai <comai at expert.cc.purdue.edu>
>Subject: Limp home mode on GM systems
>I'm putting a GM '747 system into a 1979 CJ5.  I was curious if anyone new
>what sensors/systems the ECM uses when it enters limp home mode.  I
>noticed that on the schematics it looks like the fuel pump is running all
>the time when the oil pressure switch is closed(i.e. bypasses the relay) 
>and the only reason I can think for that would be if the ECM fails or
>enters L.H.M., or the relay fails.  I just wanted to make sure that I
>think of all the angles when I do the install, and I'd appreciate any
>more info on L.H.M. or any other odities that aren't easy to see.  Thanks,
>Mike Comai