SMEC to 87 rewire.

so recently i rewired my 87 harness that i have in my reliant (87 H body lebaron harness) to use 88/89 smec connectors and run the 88/89 smec boards.

it was pretty much a continuation of this thread. http://www.turbo-mopar.com/forums/sh...wiring-the-car

i edited A.J.'s SMEC to 85 LM document to account for my changes.

one change that i thought was beneficial was to connect the SMEC 14 way connector pin 2 wire (K5, BK/WT Ground) wire to a 14 gauge wire and connect it directly to the fuel rail ground.

my car is running pretty well so far.

Attachment 62831

Brian

oh and btw, unlike A.J., i decided to forgo the connector swaps and just cut each wire individually, slide a piece of marine grade heat shrink over the wire, solder and heat up the heatshrink.

i didnt want additional 30 year old connectors with their potential resistance to cause problems.

not a knock on A.J., he decided he didnt want to cut and splice and hack up the harness. he also made this beautiful spreadsheet to guide me.

thanks A.J.!!

Brian

Brian,
I was thinking of doing this as well. How much time would you allocate for this task?

Thanks for working through this and sharing your experiences!
This will undoubtedly be the way to go that others should follow (converting to SMEC boards) to update from the LM. The SMEC has much improved capabilities, especially in the flashable configuration!

That does look like a nice conversion. I'm wondering why the power module still though? Wouldn't it be easy enough to just pull the LM harness across the firewall, and install the 60 way pins on everything that needed it?

ETA: I now see where doing the 60 way pins which are needed at the LM location would be just as easy if not easier.

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Originally Posted by chromguy

Brian,
I was thinking of doing this as well. How much time would you allocate for this task?

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hmmmmm. i soldered 5 wires or so an evening here and there for around 3 weeks to do the SMEC 60 way end of things. then i took an afternoon to do all the underhood stuff.

if you are super organized and had uninterrupted time, you could probably do it in a day. it would be a good weekend project.

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Originally Posted by cordes

That does look like a nice conversion. I'm wondering why the power module still though? Wouldn't it be easy enough to just pull the LM harness across the firewall, and install the 60 way pins on everything that needed it?

ETA: I now see where doing the 60 way pins which are needed at the LM location would be just as easy if not easier.

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are you wondering why i kept them separate? or are you thinking i kept the 87 power module? i didnt. i swapped to the 89 power board under the hood and the 89 logic board where the LM went. you cant keep the 87 power module unless you do stuff to the injector signals. i believe they are inverted from 87 to 89.

i kinda wanted to keep the 89 logic board in the car too. keeps the chip area from getting wet and then you dont have to worry about waterproofing it as much.

my battery temp will be off but if im fussy, i can solder wires where the thermistor goes and extend it to under the hood by the battery. some guys say they accidentally knock that thermistor off the board when socketing the smec and the system still works ok afterwards so im not super concerned.

Brian

Thanks for that info Brian. That makes a lot more sense now. I to have run the board without a thermistor for a time, and there was no trouble with anything from what I could tell.

That sounds like a lot of work! That's not a jab at all....I can appreciate it - the time and effort involved. With these cars there are so many ways to "skin a cat". I once converted an '88 Omni TBI harness to what was a close approximation of a Mopar Super 60 harness and people thought I was crazy. Lots of splicing, but it fit like a glove. My SL was originally LM/PM, then SBEC ('91 Lebaron GTC harness), and now SMEC (TC harness). Anymore I just like to adapt everything at the bulkhead.

If I ever do a TIII Omni I have a '90 Omni SBEC harness to base it on. Kudos.

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Originally Posted by iTurbo

That sounds like a lot of work! That's not a jab at all....I can appreciate it - the time and effort involved. With these cars there are so many ways to "skin a cat". I once converted an '88 Omni TBI harness to what was a close approximation of a Mopar Super 60 harness and people thought I was crazy. Lots of splicing, but it fit like a glove. My SL was originally LM/PM, then SBEC ('91 Lebaron GTC harness), and now SMEC (TC harness). Anymore I just like to adapt everything at the bulkhead.

If I ever do a TIII Omni I have a '90 Omni SBEC harness to base it on. Kudos.

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It was alot of work. Had I planned it out better, I would have taken the 89 gtc harness I had and spliced it at the firewall connector. That is less wires.

That said, I like the smec logic board being in the car.

Brian

This is the route I will likely go in my lancer. Just have to find some smec connectors. I actually enjoy doing wiring.

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Originally Posted by Aries_Turbo

one change that i thought was beneficial was to connect the SMEC 14 way connector pin 2 wire (K5, BK/WT Ground) wire to a 14 gauge wire and connect it directly to the fuel rail ground.
Brian

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did that on my omni dragcar
I also flipped and re-pinned the injector harness so the connector is on the driver's side
and across the trans
seemed to cleanup more of the engine bay, shortened the run (less weight too hehehe)

that ground is a joke , up the fender well, across the firewall, down the other fender, jump across through a connector to the fuel rail harness, ground to the fuel rail and back to the firewall
or out the computer and to the rail ????? where was the penny counters on this one

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Originally Posted by "Top Fuel" Bender

did that on my omni dragcar
I also flipped and re-pinned the injector harness so the connector is on the driver's side
and across the trans
seemed to cleanup more of the engine bay, shortened the run (less weight too hehehe)

that ground is a joke , up the fender well, across the firewall, down the other fender, jump across through a connector to the fuel rail harness, ground to the fuel rail and back to the firewall
or out the computer and to the rail ????? where was the penny counters on this one

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Yeah that ground path was a bit crazy.

I was more concerned with multiple 30 year old connectors messing up that ground signal. Lol.

Tangent coming.... Thought of you when I moved some vac hoses around on my cnc machined vac distribution block.... :-)

Brian

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Originally Posted by Aries_Turbo

Tangent coming.... Thought of you when I moved some vac hoses around on my cnc machined vac distribution block.... :-)

Brian

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thanks !! I sold a ton of those but never see them on anyones car

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Originally Posted by "Top Fuel" Bender

thanks !! I sold a ton of those but never see them on anyones car

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i remember you hooting and hollering about that lol. mine is on my car hehe. :)

Brian