[YungNwrenchin44]

After several days of dead end research, With no specific answers, Im reaching out to the experts, In hopes of getting my car back on the road. I drive a 2004 Buick lasabre custom which came with the l36 series 2, after 240,000 miles she gave out and I happened to get a steal on a low mileage l67 series 2 with trans, which come to find out was a direct swap.

the engine unfortunately didn’t come with the pcm, and The guy I bought it from said it came from a bonneville as for the year, was never able to figure that out, eitherway, so here’s my questions, I haVe the l36 wiring harness and so far everything is almost plug and play, except for 1. the injector connectors, which I’ve done for the 36lbers,

ok I don’t mean to get off track, but my original car the ect sensor was a 2 wire deal and the one that I obtained because my original broke upon removal, and the one I got from a 97 regal gs is 3 wire, so I either need to find out how to splice my harness to allow my sensor to work.

I went ahead and got the wiring harness from the regal gs, in case, because I thought I needed it, but I don’t want to go through the hassle of removing everything again, and this project has taken so much longer than expected and I been without a vehicle to long.

Also I have the 04 pcm and the pcm from the 97 regal gs which is factory supercharged, need help knowing what is compatible, do I jus get my stock pcm tuned which I found someone from Lansing that was able to tune it for me, but if I can use the l67 pcm and save a 100 plus dollar I’d rather do that cause money is tight with not having a vehicle to get to work.

All help is much appreciated

 

[dezldave961]

Yep, injector connection changed on L36's around 2000, and the ECT harness is 2 or 3 wire in random cars. Harness or sensor swap will be fine, or just grab a fresh one from RockAuto (or the junkyard).

Might want to go for the tweaking of the car's file, to keep things simple. Dunno who your "guy from Lansing" is, but I haven't been around SE Michigan since ~'06 so who knows who found some tuning habits since then.

 

[YungNwrenchin44]

Thanks dezldave, I’m jus gunna grab the new sensor, but since I got the down time, I really wanted to try the regal pcm and try to wire the 3 wire sensor into 2 either it will work or it won’t, because the difference between the two sensors is the 3 wire uses the extra wire to do the same thing the 2 does right? As long as it’s not goin to mess anything up by me plugging in the pcm. The tuner is Chris wilfong btw

 

[dezldave961]

From what I see in the service manuals (finally got time to look it up)...
2-wire just has Pin A) black ground, and Pin B) yellow ECT signal
3-wire were Pin A) black ground, Pin B) yellow ECT signal, and Pin C) green signal to gauge cluster

I think this was a feature in some older OBD2 cars, before everything got on the serial data line, but various models had this randomly until ~2005 as the new canbus system became more integrated in GM's.

I'd stick with whatever sensor and wire type the car has, because only the dash (not pcm) will care if there is or isn't a 3rd wire. Swapping entire harnesses is very unnecessary and even counter-productive in some cases. If it's a 3800 car, 95% of it is already correct, and you'll have maybe 2-3 things to adapt/extend/delete as you get it routed back onto the engine. Most L36 cars I've converted to L67 (usually just via top-swap) only require removing tape for the MAP sensor location, adapting injector connectors for '00+, and possibly re-positioning the EVAP solenoid to suit the harness (boost solenoid is always deleted from the valve, with top port still connected to s/c tree & bottom port left open to air, since it's just a traction control add-on anyway... a DTC will need to be turned off).

- Dave

 

[YungNwrenchin44]

Dave can I ask a trans question here? I finally got her running was so excited, but short lived, car sounds rather good for running on stock pcm, but trans will not shift into any gear, it’s stuck in park, is this from the pcm not matching gear ratio to new trans I tried to dig in and research but not finding much besides I need it tuned probably but I figured it would shift atleast. Oh and it did shift correctly before being connected to electronics.

 

[dezldave961]

It might be a year to year issue. Your 2004 car trying to operate a 1997.5 transmission isn't a direct swap, even though the harness plugs in. The shift controls moved inside, from the external mode switch on the shifter post that older 4t65e's have. Also, 2003+ transmissions had a completely different wiring/signal change than 1997-2002 transmissions, which I forget the details of, but maybe James can chime in.

I've run a 2002 GS transmission in my 1998 GTP and still have it on-hand, but I'll hesitate to use it in my 2004 GS unless we dig up what was required for that swap. (A.K.A. I will also benefit from the info that resurfaces about this.)