Jeep 4.0 Liter MPI (circa 1987-1991)

[Programmer]

James,

These things used to have problem with oil contamination of the sensor
(rearward of the engine) responsible for cam position to the ECU. Causes
extended cranking, and eventually ends up as a no start. Another fault of
these things was cranking speed. Hall effect sensors can run low speed
sensing quite well--AC output type need a higher RPM to get the signal high
enough for reference.

If you're 100% sure on the fuel pressure, fuel filter and ignition
secondary--check out that sensor.

Lyndon
IP TECH
-----Original Message-----
From: Simpson, James H <James.Simpson at Unisys.Com>
To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
Date: Tuesday, May 04, 1999 5:13 PM
Subject: Jeep 4.0 Liter MPI (circa 1987-1991)


>Hi,
>
>I have a 1987 Jeep Cherokee 4.0 Liter MPI engine installed in a 1982 Jeep
>CJ7.  I have discovered that AMC used a Renault (Renix?) computer system in
>the 1987-1991 Cherokees, and that information on this computer system is,
so
>far, impossible to obtain.  I'm having some troubles starting the engine;
it
>cranks for several seconds (15-30) before it starts, if it starts at all.
>I've been through all of the static tests (sensor resistance/function, fuel
>pressure, etc.) and everything looks OK.  I've been looking for information
>on computer codes and commands with no success.
>
>Q. Does anyone have information on the Renix computer system?
>
>Q. Is it possible to retrofit a different computer system to this engine?
>Has anyone done this?  I guess GM would be my first choice.
>
>Thanks for any help you might be able to give!
>
>Jim Simpson
>
>