Factory EFI A body conversion

Discussion in 'Magnum Engine Swaps' started by sport74, Dec 29, 2018.

  1. sport74

    sport74 Well-Known Member

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    I'm thinking about converting my 408 to factory EFI. It's got an estimated 400-450 HP. I know some folks are running the stock EFI on strokers and it doesn't really know what size the engine is.

    What have you done to make the EFI work? What is needed? I will list the parts I know will be needed, please chime in with things that tripped you up or parts I might not know I need.

    Throttle body
    Linkage
    Fuel rails
    Injectors
    Wiring harness
    Computer
    Distributor
    Coil
    Crank sensor
    Crank sensor reluctor wheel
     
  2. charles mill

    charles mill Wildman68 FABO Gold Member

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    good tlk to edelbrock . point all ? u ask they have pioneered this. cheap. and dam good help. they have up 2 1150 cfm..injected.
     
  3. 1994redram

    1994redram FABO Gold Member FABO Gold Member

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    You've got it all pretty much listed. Are you planning on going OBD1 or 2? OBD1 is very simple but you have to send the PCM off to be tuned, OBD2 requires some extra wiring but is easily tuned with a hand held tuner. You need to make sure your throttle body comes with the TPS, MAP and ICV. The intake has an intake air temp sensor, and 2 water temp sensors, one for the gauge and one for the PCM. The distributor holds the cam sensor it's usually called something else but I can't recall what.

    I swapped a 1995 OBD1 5.9 into a friends 1974 short wide dodge. Wiring was so simple and the motor bolted in easily since we replaced a 318 carb motor. Bolted the 727 up to the 5.9 to mark the location for the crank sensor. Cut the notch into the bellhousing and even used the rubber bushing/seal from the Magnum donor to seal dirt from the bellhousing notch. Used the stock harness, PCM, etc. The kickdown cable and brackets from the Magnum fit and work perfectly on a 727, so grab all that if you have an automatic. We even modified the Magnum throttle cable to fit his firewall to keep it all OE and it all fit the throttle body perfectly.

    I've also swapped an OBD1 truck to OBD2 so it could be tuned easier. That truck ended up having some butchered dash wiring and that project turned into a nightmare quick.
     
  4. Bobzilla

    Bobzilla Well-Known Member

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    Forget about OBD1 Dodge PCMs unless running a basically stock engine. The OBD1 PCM will have one single large harness connector plugged into it.
    The OBD2 systems can be easily tuned, are more plentiful in wrecking yards and used trucks, and just as easy to wire in. The OBD2 system will have three small harness connectors plugged into it.
    The biggest issue you'll want to consider is the factory systems use the flex plate for crank sensor trigger wheel, and they are the weakest link. With mostly street driving they are usually fine, but if you plan to hook up on slicks a lot at the dragstrip you may beat up that factory flex plate. Not sure if anyone makes a stronger flexplate that includes the crank sensor reluctor windows.
    What's the intended use? Which intake bolt pattern do you have, LA or Magnum? Do you want; a dual plane, single plane, or custom intake?
     
  5. Garry in AZ

    Garry in AZ Building a 9 second Valiant FABO Gold Member

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    I don't know much about the OEM EFI setups, but wouldn't you also need O2 sensors?
     
  6. Bobzilla

    Bobzilla Well-Known Member

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    Yes. All of the sensors used to run the engine properly are needed. Going by memory, that includes MAP, TPS, IAT, ECT, O2, cam synch (the factory EFI distributor), and crankshaft position sensor.
    Outputs needed are the IAC and injectors.
    Fuel pump relay can be controlled by PCM or separately from a wired ignition source if preferred.
    I'm sure I forgot something there, but it's most of the main items for a factory Magnum setup to run properly. Same stuff used on aftermarket systems that do not use throttle-by-wire or mass air flow metering.
     
    Last edited: Dec 30, 2018
  7. C130 Chief

    C130 Chief Mechanical Genius

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    If performance engine changes are a priority now or in the future, the factory ECU might not be the best way forward. And a 408 is pretty far from stock already. A universal aftermarket engine management computer like a Megasquirt will work better in the long run. You could use OEM components for just about everything, although a better intake manifold (Hughes does an EFI air gap) and higher flow injectors will be needed regardless of the ECU choice. Is your engine Magnum or LA?
     
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    • sport74

      sport74 Well-Known Member

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      I'm running a magnum, and was thinking that this would be a cost effective way to go fuel injection. My cam will likely change in the future, I already run a knock off air gap intake and thought about having it modified. It is beginning to look like cost wise it will be fairly close to, if not more expensive than a off the shelf self learning tbi unit. Had I done this from the get - go I would have bought a wrecked truck with everything. I had the space to store a donor vehicle for stripping then, but now I only have space for my car.
       
    • mopar65

      mopar65 Well-Known Member

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      SCT Tuning (96-03) If you are wanting to use the factory EFI. I would contact Ryan and he will get you set up with a tune for what ever you want.