Thread: Future Aztec L67 swap?

Title about says it all.

I know, I know, they're not the easiest cars on the eyes and most of you are probably screaming WHY???? at me right now, but hear me out...

Well, the car my wife is driving is getting quite old and I don't want to keep sinking money in a car I don't like, so I started asking her what car she wanted... and she chose the aztek.... funny thing is that she had never seen this car before and I jokingly was like: "what about this car??" and she's in love with it now... lol

Idk, maybe it's growing on me. Futuristic, and well, it's a pontiac so it has that going for it, and supercharging can't hurt anything right?

The good news:
-this swap has been done a few times successfully on both the pontiac montana and the chevy venture
-the only thing different from the engine and cradle is the power steering rack and things like fuel connectors and cooling/ac lines
-the axles, mounts, subframe etc is directly swap-able so there's really no hardware fabrication necessary

As some background, I am currently studying to be an electrical engineer and work in a research lab so vehicle schematics and wiring are not an issue at all.

The biggest issue is the computer. Fortunately it's a very similar pcm to the grand prix (namely it's the same as the 3.1L 01 gp pcm)

The bad is I've heard it uses class 2 communication so I'd have to use the harness from a regal or century and adapt it if I'm not mistaken.

Anyone done something like this? I've seen a few on youtube, but no one has actually put out a how-to that I've seen.

Originally Posted by WarStryker13

I would suggest looking into finding a few examples of an 01 GP 3.1L swapping to an L67, that should give you most of the wiring info and what adapters/hardware you'll need to procure. You'll also need a tuner that can change VIN numbers, because you might need to use a different PCM than the original Aztec PCM.

Second, I would look for an AWD Aztec. If she ends up not liking it after all, you can put some bigger tires on it and go offroading in a Pontiac. lol

Yeah. I'm hoping someone has some of the information left over from old websites like motorswap.org which apparently used to be the bomb, but it's offline so no dice.

Fortunately I do have someone who can program the pcm for me for the vin number. I'd have to keep the harness basically completely in-tact. I'd probably keep everything stock up to the fuse box and then just figure out how to adapt that.

Unfortunately the "AWD Aztec" uses the 4T65E with an extremely weak differential that turns at a right angle to a drive shaft that goes to the rear, but it isn't a true AWD as it apparently only engages when the wheels loose traction so in my opinion, it's kind of pointless. Plus I've heard a lot of people have issues with the rear differential and end up swapping to just fwd anyhow! lol I really wish it actually was AWD

From what I can gather, the guy who did the montana swap just used everything up to the fuse block from a regal and just changed the vin and spliced a few wires.

Looks like the radiator hoses will work from a gp, as well as the heater hoses. AC lines might be a bit tricky but the power steering lines should swap right out no problem too. Fuel lines can just be spliced with a repair kit so not worried about that. Might have to upgrade the fuel pump.

Basically I'd probably buy both an Aztek with a blown engine or transmission and a grand prix that's been in a bad rear end collision and force them to inbreed to some very strange result! haha

Well, finally got a hold of the wiring schematics for both vehicles and they're not that different. I have everything mapped out and I know the engine would start and run fine with the grand prix pcm.

The problem however, is that I highly doubt the class2 data is compatable between the vehicles, meaning even if it runs and drives, most of the bcm features and almost all the instrument cluster controls won't work.

Since probably no one is following this post, I might have to post in the tuning section for this, but my question is whether there is any way to modify the stock pcm programming to support the L67 so that I could keep factory controls.

Option 2 is running two separate pcms, one stock, and the other from a gp. Basically I'd wire everything for the engine only off the gp pcm, and everything for the body off the stock pcm. Despite this sounding crazy, it's been done before and this method works, but I'm just not a big fan of running two separate pcms espcially because I'd have to wire another dtc connector and a custom mil indicator since obviously you'd have no way of knowing what's going on with the gp pcm. Other issue would be the gp pcm throwing a bunch of codes because a lot of sensors would be disconnected.

Any help or ideas would be much appreciated! I do know some programming, but I have no idea how the code for our pcms work or are even programmed in the first place? Is it assembler language? lol

Originally Posted by Bronco Boy

Did you look here?
MotorSwap

Dude! I have no idea how your link is working but thank you! Doesn't look like there's a direct thread on Azteks, but I'm hoping I'll be able to find what I need there. I'll try to post the updates here as I go.

However, if anyone knows how to reprogram the pcm from the aztek to support the L67, I would be willing to pay! Wiring is the easy part. Getting the software to communicate is where I'm out of my league. I'm not big on assembler language.

Well, no dice. Looks like everyone who swaps from a 3.4 or 3.1 has just adapted the wiring and used the gp pcm with the new vin. Plus, anyone who has done a swap on class 2 data systems like the Aztek aren't spilling the're secrets either...

Seriously, if anyone has done this, please speak up! I've spent pretty much all day just searching through forums.

Looks like the main issue is with the instrument cluster and bcm. I pieced together the bcm wiring pinout from autozone. Found out why the montana swap is so simple and widely done, as it uses the same bcm as quite a few other L67 vehicles such as the grand prix.

Unfortunately for me, the only other vehicle that uses the exact bcm is the buick rendezvous (which makes sense because it's basically a cousin).

Strangely, the BCM in the 05 impala and monte carlo L67s uses three out of four identical connectors, and uses class2 data just like the Aztek for almost every system. I'm thinking best case scenario, the pcm from the impala will communicate with the gauge cluster and bcm and it'll be a simple swap. Worst case, I'm going to have to figure out how to swap the impala bcm in the Aztek and figure out what features I can save and what I have to give up.

Anyone have the BCM pinout to an 05 impala? Can't find them anywhere...

Well, looks like I'm drawing the short straw. I'm looking into how to piggyback two pcms and what that would mean. Looks like there's really three options I have here.

1. Pick a L67 pcm .bin and see if it works and keep trying tunes until I run out.

2. Piggyback the Aztek pcm and use it for instrument cluster and communication to bcm, and use the gp pcm for engine and other systems and run a secondary DLC connector for second pcm.

3. Bite the bullet and get an aftermarket instrument cluster made as long as everything else works.

4. I know, I said three options above, but I'm listing a fourth here and not mentioning it above because for me it's not an option, but according to the person who did this swap already, with the gp pcm, the speedometer works but nothing else on the gauge, so theoretically you could drive it like this. Don't think it would pass inspection though, and I'd kind of like to know when the fuel is getting low and things like that and I want my dic and hud to work too. I'm listing it because somebody might consider this as an option.

Bad news is although the physical connectors for the impala/monte carlo bcm are identical, the actual pinouts are entirely different. I'll post them elsewhere if anyone needs them.

Originally Posted by Scottydoggs

pretty sure you just need to re arrange the pcm plug pins to work with the new pcm. so you need the pcm pin outs for both cars pcm's.

Thanks Scotty. I have the pinouts for both and it doesn't look that difficult to switch. The main issue that the person I found who completed this swap back in 2010 (can't get a hold of him since it's been awhile) did exactly that with a gp pcm. Problem is that the gp pcm won't communicate with the instrument cluster since it's completely powered by class2 data. He didn't say if all the security functions and such worked, but I guess the main issue is that unlike the montana which has the same BCM as the gp, the Aztek has a unique BCM and a strange instrument cluster. I know a few other w-bodies that had L67s had class2 instrument cluster such as the regal, park avenue, 88, impala, monte carlo, and a few others. I think I might start with an impala or monte carlo PCM and hope for the best.... I want backup plans just in case

Originally Posted by Scottydoggs

theres a thread here where a guy did a 3800 in a old olds car that had obd1, so he did a bit more work and made it obd2 iirc he had to rewire to the cluster.

I'll try searching for that. Any chance you happen to know the link to that? Thanks scotty

Yeah. If I can get another instrument panel to fit, it wouldn't be that bad to wire it up at all. I'd prefer to keep the factory one if I could.

On a side note, it would be really cool to keep the AWD option, though that might not be a good idea since it's already way too weak for the platform, though admittedly, I drive like a grandma, so as long as the L67 was fairly stock, I don't think it would be an issue. Unfortunately, the only way at all of getting that to work is by running dual pcms since the rear drivetrain is completely run off the factory pcm and there is no tune available to add it, and unless I can program in assembly language, that's not going to happen. Only things I can see being an issue is the class2 data being hooked up to both will just confuse the entire system, whether the L67 pcm needs vss to calculate fuel trims etc. and if so, whether it can be run in parallel, but other than that it should work. I'd obviously have to tune out the various check engine lights for both separate systems accordingly.

All that being said, I think it'd obvious that I'd prefer to not have to do all that extra wiring and hoping it works. I think the phrase "keep it simple stupid" applies, but if I've tried every other option, it wouldn't be the worst experiment, and AWD would be fun!

Well, looks like this dream might be a reality build soon! Found a 2003 aztek with a blown engine but rust free and in great shape. Owner has had it posted for quite a while and I offered car work in exchange for the car and he accepted! Looking at probably $200 in parts to fix the suspension on his ford taurus and I'll be towing the Aztek home! Crossing my fingers this all goes through well.

You just can't leave anything alone lol

Originally Posted by selliott

You just can't leave anything alone lol

haha well my wife won't let me spend money on my gp, so I've got to have something to do 3800 related!