Will any ECU work?

[Wagonator]

Hi,
I am new to the forum and new to the FSJ world. Bought my first 1990 Grand Waggy a couple weeks back and have already started getting the parts together for a 5.3/4L60E/NP241C swap. I have figured out the hard way that there is a huge difference between 4x2 and 4x4 with this tranny, so I am already on the hunt for a new one. I am still on the lookout for the t-case too. So my question is concerning the ECU. I grabbed the ECU out of a 2001 Silverado (same truck I took the motor and 4x2 trans from) and am wondering if I need to go find something else or if this will work. Any, and all, advice would be greatly appreciated seeing as how I don't know jack about these trucks.

[AwesomeJ10]

Welcome to the site.

I dunno too much about the later PCM's, but I do think you are better off running the one that came with the motor/tranny because it controls them both.

Now that being said, I also think you have to get the PCM 'flashed' by someone who has the equipment to do the later PCM's...

[FSJ Guy]

You will want an ECU from a vehicle that has/had the same motor/trans/transfer case as the parts you are actually using. Using a stock ECU with a transfer case when the ECU isn't programmed for a t-case will likely foul up the Vehicle Speed Sensor (VSS)

Best case scenario is to find a complete drivetrain (engine, trans,t-case) and the corresponding ECU.

Or you could look at programming it. But I'm not sure who has programmers for the "newer" ECUs.

[babywag]

PCM will work, but you will need to have it flashed w/ the right program and have VATS removed etc. or it'll never even run.
You need a matching program for the engine/trans./etc. that you will be using.
The harness you use/buy/modify will need to match as well.

Lots of info on the web, and people out there that can reflash it for you, and rework a harness if you're not up to that challenge.
Shop around the prices vary quite a bit.

[AwesomeJ10]

So I have a Moates autoprom and it can burn SF512 chips on a 7747/7427 ECM.

So what about the 'later' GM stuff? Does moates have a solution for that?

[babywag]

Yep, the roadrunner. NOT cheap though + need additional HW & SW.

http://www.moates.net/gm-1996present-ro ... 00_56.html

[nester]

If you're just looking to be able to edit the config on the PCM, I'd recommend HP Tuners. It's not cheap either, but it has the most functionality.

If you just need someone to update the tune for you, check out LT1Swap.com, he's cheap and you're bettering the community, as he provides all the wiring diagrams for free.

With the transmission, you can always swap the 2WD tail shaft for a 4WD. I bought a 2WD trans from a Trailblazer SS (4L70E) and had it swapped to 4WD. Granted I let the trans shop do it, during the rebuild.



VS

[Wagonator]

With the transmission, you can always swap the 2WD tail shaft for a 4WD. I bought a 2WD trans from a Trailblazer SS (4L70E) and had it swapped to 4WD. Granted I let the trans shop do it, during the rebuild.

I would do that, but the 4L60E 4x2 case is not as thick as the 4x4 case and would be more prone to failure under the torque right?

Thanks for all of the information everyone. I have heard of LT1swap before and read a writeup stating that he helped someone with their harness and reprogrammed the PCM for aroud $75 which isn't too shabby.

Also, lately I have been conflicted as to what t-case I want to go with. I hear good things about the 241, but also hear that they aren't very strong. I'm not building a crawler, just a DD with off road capabilities. I was looking into the 229 case too, does anyone have any insight on these?

[nester]

With the transmission, you can always swap the 2WD tail shaft for a 4WD. I bought a 2WD trans from a Trailblazer SS (4L70E) and had it swapped to 4WD. Granted I let the trans shop do it, during the rebuild.

I would do that, but the 4L60E 4x2 case is not as thick as the 4x4 case and would be more prone to failure under the torque right?

Thanks for all of the information everyone. I have heard of LT1swap before and read a writeup stating that he helped someone with their harness and reprogrammed the PCM for aroud $75 which isn't too shabby.

Also, lately I have been conflicted as to what t-case I want to go with. I hear good things about the 241, but also hear that they aren't very strong. I'm not building a crawler, just a DD with off road capabilities. I was looking into the 229 case too, does anyone have any insight on these?

Are the cases different?

My trans guy builds racing transmissions for a living, and said mine should be "bulletproof" for what I want to do. So I don't know. I wouldn't think there's a whole lot of difference there, I know my case came from a hot rod version of the Trailblazer, so it probably saw more abuse there than I will put on it...

[lobie]

Are the cases different?

2wd, 4wd 4l60e = same case. Different tail shaft. The later ones (~98+) have a removable bell housing.

ECU is not a big deal either. Preferably from the vehicle it came from but you can and will get it reprogrammed. The VATS has to be removed. Also a lot of people remove the downstream o2 sensors.

There are a lot of people that do programming. As stated above HP tuners is pretty popular. I have had HP Tunners and now use EFI Live. Whatever fits your budget and use.

[lobie]

Also, lately I have been conflicted as to what t-case I want to go with. I hear good things about the 241, but also hear that they aren't very strong. I'm not building a crawler, just a DD with off road capabilities. I was looking into the 229 case too, does anyone have any insight on these?

241 is a good case and stronger than the 229. There is a chart somewhere that tells what the numbers mean.
I beleive they are:
2= selectable 2/4 wheel high low (not positive on this one)
4= the torque rating. Higher number = higher torque
1= manual shift

EDIT: I was close. Read this:
http://www.socalultimate4x4.com/index.php?topic=4786.0

[Wagonator]

Ok, so upon further research it seems that its going to be more cost effective for me to return the tranny I bought and look for a 4x4 setup seeing as how I don't have the technical knowhow to swap the tailshaft myself nor the money to have it done for me. I have seen some in my area for $350-1000, the higher being fully rebuilt, and I should get around $300 back for what I have. Who knows, maybe the yard I picked it up at has since received a 4x4 K truck.

So a 241 it is then. The hunt continues...

[nester]

The 241's are fairly inexpensive. I gave 125 for mine.