TBI to MPI swap

[twotirefryer]

ok guys, got a 92 pathy with bad motor, but it has MPI, so i'm gonna do a little write up on swapping the TBI to MPI. This will be a learning process since i've never done this, but i am armed with a FSM for 89 and FSM for 92. searching yields little info. i have LOTS of experience with nissan of this era, mainly se-r, 300zxTT and 240sx, so it shouldn't be a big deal. i will be using a stock ECU to get it going then going to the calum modified ECU that is completely laptop adjustable for bigger maf, injectors, whatever. there will be dyno numbers before and after. i'm expecting around 20 hp to the wheels with intake, headers and exhaust. this will hopefully be a fast deal because it's my snowboarding rig, with plans to have this done before christmas. LETS DO THIS.

 

 

to start, since i have not tore the 92 apart a few questions for you guys.

 

1. does the MPI harness go from the engine bay all the way up under the dash like the 89?

 

2. are the accessories, i.e. heater controls, stereo, rear hatch accessories plugs the same between the 89 and 92 or am i switching the dash and guage cluster out? something tells me i am.

[unccpathfinder]

theres some stuff on AC...i just dropped a 95 into an 87 but i did the entire wiring harness as well...i've heard of folks doing it that way but IMO it's a lot easier to rip it all out put the whole harness in and be done with it (but thats cuze i had it available and after comparing the 95 diagram to my 87 i found it easier to swap the whole thing but the 89 might be a lot closer) but like i said in the swap section on AC they'res some good info just takes some searching

 

depending on the options in ure hatch it might hook up...i know i did some splicing b/c they changed a lot of connectors but a lot stayed the same but the wires had the same colors...

 

i know everything on my steering column was the same, the heater and all the ac pull cables are the same and the resistor too and all that crap was the same, the stereo didnt matter to me b/c i have that hard wired in...the fuel pump was the same...

 

the gages ran straight down to the fuse block after splitting to the vent on the driver side that controlled cruise and something for the AT....the gages between 87 and 85 were completly different

 

i went auto harness to manual and just shorted (twisted together so they're always on) the inhibitors and run the auto ecu to the best of my knowledge the ecu just sees the accelerator being pushed and thinks the truck is always in park which isolates it from the transmission action

 

hope some of that helps

Edited September 18, 2006 by unccpathfinder

[GrimGreg]

The guages were changed in 90 and 94. The 90 change was a minor change, but still would require a lot of splicing since the connectors are completely different.

[88pathoffroad]

Yep. True dat.

[twotirefryer]

damn, didn't even think about that. the 92 pathy is an auto. anyone got a good 5 spd 90+ wiring harness? i'm not afraid to cut and splice, but the automatics are electronically controlled. meh....

 

Dustin