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3.7 to 3.9 o

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eadb1

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Have a 06 Dakota.. it came with a 3.7 V6 and a 42re trans... Well long story short the trans was bad when I got the truck and when I blew the engine up I found older 3.9 with a 46re trans.. I have the motor in the truck and can get turnin over from a battery with a jump wire from the starter.. the key won't turn the motor over.. what would I need to make this thing run the 3.7 has coil pack wherever theb3.9 has a distributor.. have all the cool packs in the cylinder tubes
Any help would be appreciated
 
Would not have come with a 42re trans. They were discontinued with the 3.9 around 03.
And though I put a 46RH behind a 3.9 they wouldn't have come that way. You're probably dealing with a 545 RFE trans in a truck that new
 
No one comes from a ram 1500 and the new one was the 3.9 so I got no connections for the distributor cam and crank shaft sensor etc etc.. I don't know enough to know if I wire the coil and dIZZY to a one hot and one a switched pole should it then produce the fire.. or if I put the coil packs which go on the engine and run wires to the cylinder should it spark... Like it's what I said or at least what Google said that they were
 
The 545rfe on the harness is there like 3-8 pin connectors to it on the harness. The transmission I got I spliced the 8 pin off the other transmission then color code the rubber and number on the PCM as diagramed on the plug from that transmission. Apologies
 
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eadb1 said:
Have a 06 Dakota.. it came with a 3.7 V6 and a 42re trans... Well long story short the trans was bad when I got the truck and when I blew the engine up I found older 3.9 with a 46re trans.. I have the motor in the truck and can get turnin over from a battery with a jump wire from the starter.. the key won't turn the motor over.. what would I need to make this thing run the 3.7 has coil pack wherever theb3.9 has a distributor.. have all the cool packs in the cylinder tubes
Any help would be appreciated
Click to expand...
They have Compltely different ECU and wiring harnesses for the engines AND transmissions.
 
........... around 2006 dodge started something like remember all before programming or some shit where they put a 4th plug to the PCM .. that's when the PCM went from 3 to 4 sqaure connector boxes... And the pcm you just find the same color as the plug on the engine (,green orange blue and red) the plug also has number rows and match color n numbers then Master reset computer (,turn key on 10bmins x3);and that then resets the PCM and you can let it self learn it says .
 
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I wasn't trying to talk down to you about being over your head. It's just that if you don't have the knowledge to do that swap without dropping big bucks for a custom harness your going to go crazy.
To do what you want you need every thing from the donor vehicle, down to the evap. equipment and post cat O2 sensors and the anti theft from the ignition switch. You can't use the distributor engine with the coil pack harness or the other way around without major mods to it.
I've done EFI swaps at my shop before. Before painless wiring harnesses were around. I ran a 1996 5.9L magnum EFI in my 87 D250 that was originally carbureted.
Nobody was making any harnesses after market for it. I couldn't use the 96 harness and PCM because it wouldn't run after bolting all in, anti theft disabled injector pulse and fuel pump enable and starter enable. The PCM controls all of that and more.
That's why you get nothing when you turn the key.
Remember 96 and up was already OBD 2.
The way only way I got it running and drove it for 100K with EFI was to completely open up the harness and adapt a GM ECM from a third gen Camaro and run it batch fire with a GM module for spark and timing control. Then burn a custom prom to tune it
The prom for the 5.7L Camaro was close in tuning and ran but not real good. And I didn't have the electronic controlled trans like you, that's a whole new ball game.
I'm not saying you can't do it, but its not a bolt in type deal. I don't know you or you knowledge level. In your original post your asking asking about wiring a coil pack ignition to an engine with no crank sensor or cam sensor and thinking it will fire, not going to happen.
That's why I said your over your head and I stand by it.
Again Good Luck+++++6666666666666
 
You need to find a tuner that understand Ram ecu's. Some one that is prive to information us mear mortals are blocked from.
 
If the 3.9 is a magnum 3.9, find a donor truck to get the computer, harness, and any other little parts for the swap. Then your going to need wiring diagrams for the donor system and for your 06. This will get the engine to start, you will have to look further into the wiring to see about the gauges. Keep the sensors from the 3.7, oil pressure and coolant.
 
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