Howdy! I am just finishing a 94 5.2 Magnum swap into a 70 W200 PowerWagon, with a 93 46RH.
I have been down the same road and many of the same thoughts that are mentioned here. Before 94 there was a external regulator on the fuel rail, in 94 the switched to the in tank regulator. I really liked the in tank idea. I kicked it around a dozen different ways, but never could come up with a reasonable solution. I ended up using the Auromotive regulator and Summit inline pump, which I believe is identical to the MSD. They are both mounted on the frame rail, and the return runs to a tee in the line, at the back of the frame. So no return to the tank. I had to turn the regulator up to about 48 psi to make everything happy. The pump is a bit noisy.
You can use a 96+ (OBDII) barrel intake and manifolds on the 92-95 (OBDI) engines and ditch the EGR and canister. The PCM will record a code if you check them, but it will not turn on the light. I am using a 98 intake and the Pacesetter headers, with the EGR bung welded up. The OBDII barrels don't have the EGR ports, or you can plug them.
I highly recommend you use the PDC (power distribution). It will make life a lot easier! You need most of the relays anyway. You can then also re purpose the ones you don't. I reused the 2 ABS for my headlights. It also makes dealing with the alternator much easier. It does the MAD electrical mod for you basically. The EFI harness is pretty self contained, it all connects to 3 main plugs (assuming Ram donor), those 3 plugs are on the PDC also.
The wiring was a bit intimidating at first, but the 94 Service Manual was a real life saver! I knew I would never remember all the changes I made, so I began documenting them and creating my own, new wiring diagram. It isn't quite done, but here is the current state.
http://cbodydrydock.com/misc_images/Truck_Wiring.pdfThe engineers were geniuses in my opinion! It was like they engineered the whole drive train to be easily swapped into older vehicles. It only took 4 wires between the EFI harness and the bulkhead to start the motor!
http://www.youtube.com/watch?v=BevgW7RRx30There was a lot of spaghetti, as I rerouted the harness to mount the PCM on the fender, near the core support, instead of the firewall. The main harness also runs across the front of the engine now, instead of the rear.
I am also using the 94 cruise control. The cruise control buttons unbolt out of the steering wheel in a nice, neat little 4 button pod, perfect mounting under the dash.
The brake light switch is a little different, specially if using cruise. It has 2 circuits, 3 if cruise. 1 is normally open for the lights. 2 are normally closed, one for the PCM and one for cruise. Rather than jerry rig the 94 switch, I used the stock switch and 3 relays mounted just above it. My wiring diagram shows them. Only down side is I can here them click sometimes when braking.
Currently I am using the big Ram air cleaner box, only because it is self contained. But I am working on a way to use the smaller Dakota/Durango air hat and a TRUE cold air system.
I am still working out a couple minor bugs, only 22 miles on it so far! Just got the exhaust installed Friday. The Overdrive isn't kicking in, but I think that is related to the VSS error code I am getting. I am using the 2 wire VSS with the cable pass through from an 89, the 94 Ram used the 3 wire. Anyone got a fix for this? I used PCM# 7 and #47, The 8 volt line and the VSS line, and omitted the sensor return ground.
If anyone wants to kill some time, there is a 17 page thread on Sweptline.org documenting my adventure with this truck.
http://www.sweptline.org/forums/viewtopic.php?f=3&t=14030&start=0Happy to contribute any lessons and insights from my experience if I can!!
-Scott
