piggyback an E40 PCM onto a WK grand cherokee computer

[rumblebox]

story: i want to swap my 6.0 into my wife's 2005 WK grand cherokee without sacrificing much of the options. the PCM/TCM have to be there for the rest of the modules to communicate and work properly. so i have to piggyback my LS1 computer onto the factory computer to keep all my vehicle functions.

i've done swaps before, but i've never had to do this. i really have no idea how i would make the 2 computers work together.

[ScarabEpic22]

So E40 6.0L, Im guessing its an LS2 then? And being an E40, means its a 24x/1x engine. Id honestly ditch the E40/T42 setup myself, not sure if you want to keep DBW or use DBC. If you want to use DBC, run an LS1 PCM.

What you need to do is figure out what the Jeep PCM/ECM wants for input signals (ie if a PWM signal what Hz are the pulses at, ground this to activate 4WD, etc) then convert the GM PCM/ECM signals to what the Jeep wants to see.

What options would you lose by ditching the Jeep stuff? You should be able to control the engine, trans, and transfer case standalone (GM electronics but not sure about xfer case). Gauge cluster can be done by feeding the Jeep ECM or by setting up the GM ECM/PCM output to being what the Jeep does in EFILive.

[rumblebox]

i just saw a thread where a guy did the swap and let the jeep computer control the cluster and just tapped the jeep's temp and oil sensors into the LS1. but i'll probably just build a cluster with autometer gauges so i can actually calibrate them with EFIlive instead of having to buy diablo sport for the jeep computer.... plus the cluster would probably light up like a christmas tree once i start cutting signals to the jeep computer. he couldnt get the tach to work either. apparently everything on his jeep still works too. A/C, lights, wipers, door locks, windows.... everything. i'm fairly certain i would sacrifice ABS though.... which is fine.

this may be even easier than i thought.

also that was my bad on the PCM number. it's a 99 ls1 computer.

[rumblebox]

ok what if i did this? basically just run everything engine and gauge related from the LS1 computer and just leave power going to the factory jeep PCM/TCM so it can just communicate with the other's. is it that simple?

[ScarabEpic22]

Should work, as I said before just have to figure out what the Jeep cluster wants to see for a data signal to run the gauges.