86 and 85 LM's interchange?

[daytonaturbo87]

Will an 85 T1 LM work in an 86 T1 harness? Running a G head and a 86 harness and would like to run an 85 LM to keep timing and fueling curves as the factory intended.

[iangoround]

not without swapping in a new HEP, distributor, and re-pinning the plugs at the LM. I did a similar thing in the opposite direction with my car (85 to 87 T1 LM). The post 85 computer will not work with the 85 HEP, period. You need the "new" style HEP and distributor for it to even think about running.


The simplest solution would be to get your 86 LM socketed and a chip burned for your setup. There are plenty of people on the board who can help you with that.

[mw6886]

Yup, and I am one of them.

If interested, send me an email - shelby22t at gmail.com

[iangoround]

Also, you might want to check out the Knowledge Center here. There's a big section on just this sort of thing.

http://www.turbo-mopar.com/forums/vb...y&categoryid=6

[daytonaturbo87]

I dunno, recalibrating seems like it might be more work than it's worth for now. Eventually I'd like to get the DC top intercooled log calibration for it, then fab up my own top intercooler setup for a log, but that's as far as we'll be going with this engine. For the immediate future it would just be easier and I would feel better if I could just drop in one of my known good 85 T1 LM's.

I'm sure I can easily find a 84-85 turbo distributor/hep if I knock up the yards around here a couple times. What are the wiring changes needed to put a 85 LM in a 86 harness? I'm sure the instructions for doing the opposite conversion are out there somewhere, I could easily back track it. I checked out minimopar and he doesn't have the LM pinout posted for the 85 LM.

So a different dist and some LM connector repinning? Is that it? No other harness changes needed???

[iangoround]

I just looked at my FSM and the minimopar site and the 85 and 86 LM pinouts seem to be the same. The only difference is that the 85 LM red pin 4 is the signal for the low fuel light that the 86 LM doesn't seem to have.

I guess I was mistaken. My swap went from 85 electronics to 87 electronics, and there were 4 or 5 pin changes I had to make.

So just find a 85 style dist and HEP and you should be good to go.

[daytonaturbo87]

Thanks Ian, I did some more reading/searching that's that's the conclusion I came to as well, but definitely nice to have the reinforcement from the FSM. 1985 turbo distributors aren't the most common things out there, but I don't forsee finding one to be too hard. Thanks.

[iangoround]

I was just browsing ebay and there is an 85 dist/HEP listed right now.

http://cgi.ebay.com/ebaymotors/Dodge...em130197248430