There is something different between the smec power module and the LM power module concerning the injector drive signals. It has been tried in the past and has been unsuccessful.Originally Posted by thedon809
It's not to say that someone couldn't figure it out but it hasn't happened yet.
Brian.
Ah ok. Let me know how you make out with splitting up the smec. That might be the way I want to go considering the difficulty in finding a clean drop in h body harness.
i keep going back in forth though cause i have a clean 89 turbo van harness too. move 2 pins for the windshield wipers and it plugs into a k car. ive done it before with a 90 3.0L v6/604 harness into a 88 reliant.
Brian
The black/blue tracer is not connected directly to ground from factory, not on SBEC anyway and I'm pretty sure not on SMEC either. It connects to every sensor and runs to the computer, the computer grounds it through the black/white tracer wire.
i looked over the SMEC conversion PDF and my 87 turbo wiring diagrams and my 89 minivan turbo wiring diagram and the 1987 Y5 wire from the PM that is black/light blue (like the sensors ground wiring color) does connect to the K5 splice but it connects through the J9 circuit splice and through 2 terminals of the fuel injector harness connector and the crimped connection of the fuel rail bolt ground lug. and the Y5 wire is only 18ga where all the other ground wires are 16ga. it could effect the operation of the K5 connection from the SMEC to the rest of the harness.
so for pin 2 of the SMEC 14 way connector that A.J. was connecting K5 circuit to the Y5 on the 85-87 PM connector, id run a separate 16 gauge wire over to the K5 circuit somewhere near the diagnostic connector.
is it crucial? dunno. i suppose i could do current tests through that ground to see how much it is carrying.
Brian
This. In the LM Power Module, the injector drivers (and maybe coil) are source-driven (that is, the LM supplies 5v to the injector drivers). In the SMEC, the PM is sink driven (that is, the logic board supplies a ground to drive the injectors).
is it logic level stuff? could a 7404 be used to invert the signal?
Brian
Hmm, maybe. Is it fast enough?
Hmmm not sure.
it looks like the switching is typically less than 10 ns, which would be more than adequate.
89 Voyager LE, 2.5T2 - rest in peace
87 Charger Shelby T2 (2.4 conversion in process)
Not happy on how crappy the car ran, A.J. torn out the LM/PM with SMEC conversion and put a 88 SMEC wiring in there instead. He said it runs so much better.
http://www.turbo-mopar.com/forums/sh...=1#post1110642
I've separated my body harness and engine harness to install Microsquirt, it is surprisingly easy to do.
I think LM/PM to SMES conversion will be more troublesome than just convert straight to SMEC harness.
It is a lot easier to do than most folks think.
I went from an 83 carbed harness to 89 SMEC. I basically did the same thing. Kept the body wiring, eliminated the engine wiring, then mated up what was left of the 83 harness to the engine wiring part of the 89 SMEC harness to make a working TII harness.
I did make a couple of changes to even out electrical load on the system, but after doing some electrical checks, it fired right up with no issues...
there are too many variables to know what was wrong with that setup. there was also LM/PM connectors on top of SMEC connectors which can add resistance in areas where resistance shouldnt be added.
gary donovan didnt complain when he did the same thing (without added connectors) to his reliant years ago....
Brian
Right, old wires are not dependable. It would be a shame to did all the LM\PM to SMEC conversion work, then find out there are still issue.
I torn my 32 year old engine harness all out and put in Microsquirt and fresh harness, my ignition timing is dead on every time where I set it. No jumpy from 10 to 14 like every other stock turbo dodge I've seen.
Yeah old stuff doesn't help lol.
If mine sucks after that, i have a 89 van harness. If it still sucks, ms3.
Brian
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