Magnum swap EFI wiring

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moparman9

moparman9

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Considering a magnum swap into my 71 Dart. I have access to a complete running 1992 Dakota with a 5.2 MFI. Looking at the wiring diagrams, it appears that all the MFI system needs to use most of the Dakota's underhood wiring is to splice a power wiring from the ignition switch that is hot in run and start, a fused power lead hot at all times, and ground from the Dart to the Dakota wiring. I would use the original wiring in the Dart for lights, wipers, etc. Is this pretty much it or have I missed something? I know I will need an electric fuel pump and also need to notch my 727 bell housing for the crank sensor , change the flex plate, and install an o2 sensor, but it seems pretty simple. Is there any thing I am missing?
 
Don't know. Does the Dakota have whatever the "security" features in the column switch? This integrates with the ECU
 
The only OBD I that I have ever seen with alarm, not SKIM was a grand cherokee and it was defeated by unplugging security module from harness. Dakotas never had it, until you got into RT trucks in 98.
OBD I is easy to hook up , it just doesnt have any real tuning ability without spending a bunch of $$$
 
I saw a new one recently- before the latest non-alarm I'd seen was an '04 Dakota 3.7 and pretty sure the '06 Durango 3.7 I saw didn't have it. SKIM has the thumbprint key.

Yeah, you can upgrade to OBD-II later. You may even be able to keep many of your sensors, looks like there was more interchange with OBD-Is and '96s than there was with many of the later years.
 
Infecteddog said:
I saw a new one recently- before the latest non-alarm I'd seen was an '04 Dakota 3.7 and pretty sure the '06 Durango 3.7 I saw didn't have it. SKIM has the thumbprint key.

Yeah, you can upgrade to OBD-II later. You may even be able to keep many of your sensors, looks like there was more interchange with OBD-Is and '96s than there was with many of the later years.
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Many Dodge and Jeep vehicles could be ordered with the factory alarm, mostly Durangos 98-2000 and Grand Cherokees 96-01 but there are a few Rams and Dakotas with factory alarm. Its easy to figure out if they have it. As far as SKIM, othe wise known as security key, most Dakota RT's have it, 98-03, Durangos and Grand Cherokees with convenience package 75-85% of them by my estimation. This system does not use a thumb print key, it is a RF transmitter embedded in the plastic key fob(grey in color instead of black) that transmits a signal to the receiver located next to ignition switch which in turn compares key codes to match ones stored in PCM. If it gets correct code, it allows pcm to send ASD relay latching signal. If it doesn't get correct/no signal, it will fire and die.
Not sure what a 3.7 has to do with anything associated to SKIM in a magnum other than that after 06 most Dodge and Jeep vehicles have it. It can be easily defeated with a flash or correct pcm replacement.
 
moparman9 said:
Considering a magnum swap into my 71 Dart. I have access to a complete running 1992 Dakota with a 5.2 MFI. Looking at the wiring diagrams, it appears that all the MFI system needs to use most of the Dakota's underhood wiring is to splice a power wiring from the ignition switch that is hot in run and start, a fused power lead hot at all times, and ground from the Dart to the Dakota wiring. I would use the original wiring in the Dart for lights, wipers, etc. Is this pretty much it or have I missed something? I know I will need an electric fuel pump and also need to notch my 727 bell housing for the crank sensor , change the flex plate, and install an o2 sensor, but it seems pretty simple. Is there any thing I am missing?
Click to expand...

So....back to my original question???
 
Would I need the instrument cluster or some portion of it to run an OBDII setup? Or can I just wire up a CEL and use the diagnostic port by itself? Would you recommend Dakota or Ram wiring for best fit in an A--body?
 
moparman9 said:
Would I need the instrument cluster or some portion of it to run an OBDII setup? Or can I just wire up a CEL and use the diagnostic port by itself? Would you recommend Dakota or Ram wiring for best fit in an A--body?
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No, yes, whichever.
 
OP a 96-97 ram didnt have ccd buss so it still has tach signal wire, oil pressure and coolant temp wire that will work with factory A body stuff. They also have a MIL driver (cel) and have OBD II ALDL so you can still scan and get live data.
 
magmunmopar: If I use a 96-97 ram harness and pcm for my A727 equipped Dart, will I have any engine performance issues due to the PCM not "seeing" the 46RE trans, or will it just have a nuisance CEL? Or do I need a manual trans PCM?
 
magnummopar said:
OP a 96-97 ram didnt have ccd buss so it still has tach signal wire, oil pressure and coolant temp wire that will work with factory A body stuff. They also have a MIL driver (cel) and have OBD II ALDL so you can still scan and get live data.
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Would the same apply to the 96-97 Dakota/Durango?
 
moparman9 said:
Would the same apply to the 96-97 Dakota/Durango?
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a 96 Dakota is an odd duck but I think its ccd, not near my FSM's right now so I cant check. Not a 97 Dakota, its ccd and they didnt make the Durango until 98 which is ccd.
I would not shy away from a later set up, they will work just fine, they just work better with a flash which if you plan on adding performance upgrades, you will want to do anyway.
 
Thanks everybody for all the good info, it gives me a lot to think about and will probably save me lots of time and $$!
 
magnummopar said:
a 96 Dakota is an odd duck but I think its ccd, not near my FSM's right now so I cant check. Not a 97 Dakota, its ccd and they didnt make the Durango until 98 which is ccd.
I would not shy away from a later set up, they will work just fine, they just work better with a flash which if you plan on adding performance upgrades, you will want to do anyway.
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Vans ccd those years? Know they did 318/727 vans with OBD-II.

Of course all OBD-IIs can be flashed, just some will easier to use with your old guages not like the others will be horrendously hard.
 
Infecteddog said:
Vans ccd those years? Know they did 318/727 vans with OBD-II.
I believe they are.

Of course all OBD-IIs can be flashed, just some will easier to use with your old guages not like the others will be horrendously hard.
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As previously mentioned, the ONLY OBD II harness and pcm that works with factory gauges would be the 96-97 Ram as it had the senders and wiring for Oil, Tach and Temp. It is also the least intrusive pcm coding of all OBD II's. In other words, it wont run in limp home mode if you dont have evap etc. The later model pcm's will run in open loop limp mode if you dont have everything hooked up or flashed out. If by "horrendously hard" you mean running two wires for oil & temp along with drilling hole for CTS in intake manifold, then yes its horrendously hard, We can do it in about 20-30 min here.
 
magnummopar said:
harness can be either MT or AT but pcm either needs to be flashed to remove trans or locate a MT pcm
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To avoid reflashing, could I use an AT pcm and just connect "dummy" od and tcc solenoids to fool the pcm into thinking there is a transmission present?
 
No the pcm is much smarter than that. It doesnt just measure ohms load across pins, it has 8 wires going to trans, 4 are returns from sensors that if they read out of spec for more than a minute or two will set code and most likely put pcm in limp mode. Gov pressure needs to be seen, out put speed sensor too as well as trans temp and gov solenoid. Just find a 5 speed pcm in u pull it yard for $50 or less depending on location. It will play nice with your 727.
 
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