’90 R20 Suburban 4L80e swap

[JCampbell]

’90 R20 Suburban. TBI 454/TH400.

I’d like to swap out the TH400 for a 4L80e. What’s all involved in something like this? I’ve already got the electronic speedo seeing as how the Sub is a ’90. Do I just need a harness/ECM out of a ’91?

Anyone done this before?

[Jonboy]

If it were me, I would get an aftermarket harness, and run a later model ECM for a 4L80E (like 92-95).

[manimal]

watching this......as I would like the same for my '89 R2500 Suburban.

[JCampbell]

Originally Posted by Jonboy

If it were me, I would get an aftermarket harness, and run a later model ECM for a 4L80E (like 92-95).

Any leads on where one can get an aftermarket harness? I'm picking up the TBI harness from Howell, but I'm not sure who sells a trans harness.

[Jonboy]

Originally Posted by JCampbell

Any leads on where one can get an aftermarket harness? I'm picking up the TBI harness from Howell, but I'm not sure who sells a trans harness.

Howell should be able to make a later model TBI harness run a 4L80E. If not, try Fuel Injection Connection ( www.fuelinjectionconnection.com ). I am pretty sure Robert offers a later model harness.

[Rich84]

Howell should be able to make a later model TBI harness run a 4L80E. If not, try Fuel Injection Connection ( www.fuelinjectionconnection.com ). I am pretty sure Robert offers a later model harness.[/QUOTE]

I don't know what happened to his website...It's been gone for a while.

[Jonboy]

That link just worked for me. Then again, I like to call.

[manimal]

Hey Campy, here ya go...
http://www.chevroletperformance.com/...SuperMatic.jsp
and this
http://www.jakesperformance.com/4L80E_Components.html
and this.....
https://www.hgmelectronics.com/display/hgm/Home

[Firebirdjones]

There are alot of ways to go about it, none of them are cheap however.

The stand alone controllers are the easiest way to set one up and tune it/optimize it.

I've used Howell in the past, actually running their computer and custom made harness in the 6.0/4L60 swap I did in my blazer among other things, and they make a top notch product with great customer service.

Other avenues would be Baumann Electronics that makes the Optishift....

Bowler Transmissions makes the Simple Shift....

And my personal favorite is the TCI EZ TCU controller from TCI.....

The TCI seems to get the best reviews as far as easy installation and very easy tunability, and it's priced as one of the cheapest (around ~$600).

[JCampbell]

I'd really like to get away from running a stand alone controller. I'm already swapping this entire drivetrain into my C30 so it's really no problem to swap out the ECM for a late-model version.

Just seems like a simple, less cluttered way to go about it.

[JCampbell]

Originally Posted by Jonboy

Howell should be able to make a later model TBI harness run a 4L80E.

Just noticed that Howell offers the option for adding leads for the 700r4. I suppose it wouldn't be too difficult to add the leads for a 4L80e then.

Good lookin out...thanks.

[Firebirdjones]

Then I'd do a complete Howell harness if it were me.

I've used them for four retro swaps and have always been pleased with the results.

[JCampbell]

So it's really that simple? Howell harness and the proper ECM and I'm off to the races?

[BigBlocksRule]

Tagging along... I have a '91 'burb that I'm converting to 4WD and 4L80E. It was initially a TBI of course, I'm looking to find someone who can add the 4L80E pigtail to my current harness, wiring is still very pliable and I want to keep the ECM in the correct location. I have plenty of ECM's that I've scavenged from trucks when I part 'em out.
I found a retro-fit harness for a TBI engine and 4L80E for $305 from fuelinjectionconnection, might be something to think about, last one on this page:

http://www.fuelinjectionconnection.c...s-catalog.html

[Jonboy]

Originally Posted by JCampbell

So it's really that simple? Howell harness and the proper ECM and I'm off to the races?

Pretty much. I don't think the vendor matters so much. If you were going to go with Howell, I would stick with that. Either way, I wouldn't use two controllers.

Originally Posted by BigBlocksRule

Tagging along... I have a '91 'burb that I'm converting to 4WD and 4L80E. It was initially a TBI of course, I'm looking to find someone who can add the 4L80E pigtail to my current harness, wiring is still very pliable and I want to keep the ECM in the correct location. I have plenty of ECM's that I've scavenged from trucks when I part 'em out.
I found a retro-fit harness for a TBI engine and 4L80E for $305 from fuelinjectionconnection, might be something to think about, last one on this page:

http://www.fuelinjectionconnection.c...s-catalog.html

This harness is exactly the one I had in mind.

[BigBlocksRule]

I did a lot of searching, that one is the best price I found as well.

[Firebirdjones]

Originally Posted by JCampbell

So it's really that simple? Howell harness and the proper ECM and I'm off to the races?

You would have to call Howell and see if they even offer TBI stuff, but if they do that would be the route I'd go. I've always liked dealing with them.

I don't mess with TBI stuff anymore (been many years) so I'm not up to speed with what Howell might offer for that.

I have pictures of the last harness and computer I bought from them when I did my 6.0/4L60 swap. All factory weather packs, labeled, and any unnecessary stuff removed, made to custom lengths per vehicle and according to where I told them I'd mount the computer. Simple plug and play with no worries about crossed up wires or hacked factory harnesses from the junk yard. It's all brand new stuff with correct OEM wire colors so trouble shooting anything can be done with a factory schematic. Excellent quality and great people to deal with.