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Neon DOHC swap

Discussion in 'Other Vehicle Discussions' started by Celerity, Sep 12, 2005.

  1. Celerity

    Celerity Well-Known Member

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    I've got this 98 ECU and the 98 DOHC wiring harness. Underneath the fuse box is a clip that holds two pretty major connectors (One is 10 pin, the other is 10 pin (on the 95 harness) and 11 pins (on the 98 harness)). I traced the wires down and I'm left with one wire - A green wire with yellow stripe.

    Here is what I've found: In the 98 harness, it seems it handles the radiator fan signal and fuse in the ENGINE harness, while in the 95 SOHC harness, it handles the radiator fan in the CHASSIS harness. using the 95 radiator - I think I'm ok just tossing the green wire out of the equation (It goes to pin #23 on the new harness, and the older harness doesn't have a pin #23)

    Do you have access to either an ECU pin-out, 98 Harness wire-out, or the accurate wiring diagrams for the engine harness ?

    Thanks !

    -> Steve

    The ECU is broken out into two entire harnesses. The first harness is the engine connector, the second one is for the chassis controlled stuff. Things like Cruise control, A/C switches and ABS is contained in the second one. The first one is for the engine - And all will work on the 98 engine, but the harness needs to talk to the fuse block without issues. This green wire looks like it belonged to something in the 98 fuse block.

    I need either detailed source for wiring diagram / schematics or the ECU pin-outs for the first gen Neon. Any help ?
     
  2. neonmike

    neonmike Senior Member VIP

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    what year is the car and what r you tryin to do swap ecus from one year to another? i don't have my wiring guide with me cause i am at work but i can get what you need when i get home if you give me some more info. like year car, year ecu, year engine, and what not. i have done it all to a neon so i can get ya an answer if ya get me that stuff.
     
  3. Smonkeyboy

    Smonkeyboy Senior Member

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    umm... looks like he is trying to swap a 98 engine/ecu into his 95 chassis
     
  4. Celerity

    Celerity Well-Known Member

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    Bingo !

    the 95 is a Plymouth highline, sans A/C. It was originally an automatic car, but has been successfully swapped to 5 speed. Now the SOHC motor is out and the DOHC is going in. The harness I got was new Mopar, and I only needed to switch around one connector - the connector that is attached underneath the fuse box. (The two connectors under there are similar, and on the 98, they are different)

    After swapping out the connectors, the 98 had 11 connections, and the 95 had 10. There is only room in the harness for 10, so I'm one out. The one that's out is this green wire with a yellow stripe, and it's #18 on the PCM harness connector. So either the wiring or the ECU pin-out chart will help tell me what it is.

    Also, if you're really into Neons you might be interested in the project.

    -> Steve
     
  5. CoreyR

    CoreyR Senior Member

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    so why are you not using the 95 harness?

    you dont need to use a 98 harness just because your using a 98 motor. or is there another reason your using the 98 harness?

    maybe i missed the point :)
     
  6. TurboMirage

    TurboMirage YEEAAAHHH VIP

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    i think the only people who build neons exist in new england. :)
     
  7. phyregod

    phyregod !!YTINASNI

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    **EDITED**

    nevermind.. If you cant say nothin' nice, don't say nothin' at all....
     
  8. Celerity

    Celerity Well-Known Member

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    Because I could change one connector with the 98 harness (Because it's a 98 Motor) or I could find myself changing ALL connectors but one. I'm not keen on that.

    Also, do the 98 DOHCs use a dwell fuel injector ? Tha'ts another thing I have to work on.
     
  9. jamesA

    jamesA Well known pissed off telephone guy VIP

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  10. TurboMirage

    TurboMirage YEEAAAHHH VIP

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    hah! i thought not.
     
  11. CoreyR

    CoreyR Senior Member

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    the only things you would need to change on the 98 motor to use the 95 harness is the 98 motor has a combined IAT/MAP sensor and the 95 has a seperate MAP and IAT sensor you would use the sensors off the SOHC manifold and theres a spot on the DOHC manifold to tap for the IAT. also the IAC and TPS have diff conectors that you would have to cut and splice in the 98+ connectors. when i did my DOHC swap in my old 95 SOHC i used a 97 motor but kept the 95 SOHC harness and just modified it to work. it ended up being easier for me but you have your mind set on using the 98 so have fun. :D

    also you might have some trouble with emmissions cause 95 wasnt really OBD2 and 98 is.
     
  12. TurboMirage

    TurboMirage YEEAAAHHH VIP

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    the intake manifold still plastic on the 98? you could always punch a hole in it with a screwdriver. ;)
     
  13. CoreyR

    CoreyR Senior Member

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    no DOHC's had plastic mani's
     
  14. Celerity

    Celerity Well-Known Member

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    NO WAIT ! !!! DON'T LEAVE ME !!!!!!!!!

    I was also wrong on the case - It's a 96 car with the 98 motor. Both are OBDII as I could see.

    But let us talk more about this swap... that you did... successfully :) You actually installed sensors in the 98 motor from the 95 ?
     
  15. CoreyR

    CoreyR Senior Member

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    yes. if you look at the DOHC manifold where the map/iat sensor is look to the right you will see a little round flat spot casted into the mani. on a 95 DOHC mani thats tapped to i forget what size thread and has a IAT threaded into it and the map is to the left like it is now.

    now that you say its a 96 your really wasting your time swaping harnesses. 96 has everything identical to the rest of the years up to 99 EXCEPT the fan switch wiring and you can use the 98 ECU with the 96 harness but you just need to reverse 2 wires on the ECU for the fan to work properly (instructions can easily be found on neons.org). the only thing you would need to to do with the single cam harness for on the DOHC is to extend the coolant temp sensor wire cause its in a different spot on the DOHC.
     
  16. Celerity

    Celerity Well-Known Member

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    Harness has the same connection types and the same runs, etc - But the end of the harness is different and the connectors are mostly different (Males where the old ones were female, etc).

    Thats what I meant by "I could switch this one connector, or I could leave it alone and switch all the rest".

    -> Steve
     
  17. Seany-izzle

    Seany-izzle New Member

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    neons.org search or ask about the shop manual that they can send you as a file. My ex-roommate has a copy of it, he got it from a guy on neons.org and i guess its pretty popular on there. id get it from him for you, but i dont talk to him anymore cuz he is a piece of fucking shit.
     
  18. Battle Pope

    Battle Pope New Member

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    Pretty good reason...
     
  19. CoreyR

    CoreyR Senior Member

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    yes FSM's own.
     
  20. jamesA

    jamesA Well known pissed off telephone guy VIP

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    :thumbsup:
     
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