very ls newbe. please help advise opinions options?

[boostedc10]

Travlinman most of the standard sensors are left alone in the harness. What you eliminate is typically down stream o2s, the EVAP stuff and if no a/c that can go to. The link Br3w shared from LT1 swap also shows you have to wire in an obd port and a check engine light so you can make sure everything is ok and check for codes.

Most people keep at least the upstream o2s so they can put the vehicle into closed loop and let the ecm make fuel corrections as needed.

Running without them or just a wideband eliminates this feature.

[BR3W CITY]

Originally Posted by travlinman

Br3w..would like to keep the system intact and use steering and braking if possible.

I have some pictures of my setup in my build. All thats really required is getting the HB unit and master bolted to the firewall, modding the pedal linkage to be the right stroke, and hooking up all the lines. It seems like a bunch of folks (myself included) get over-touchy steering from lack of residual pressure valves. It still works fine, its just 1-finger cadillac steering. We're working on figuring out exactly what the problem is, but the braking aspect works great from the onset.

I did an internal rebuild on mine, which isn't hard, but also not needed on most units.


I don't like the stock style 02 sensors because of the different plugs and the cost to replace them. I' just rewire with the Bosch 13444, which is the cheapest and easiest-to-wire heated 02. You'll want to have them unless you switch to SD tuning (ditching the MAF and 02's), and running a wideband/logging. That way is much more time and tune-intensive but makes a touch more power and is often how the sandrail/boat/pull truck setups are built.

[boostedc10]

You want the O2 with sd tuning too. It makes no sense for a street car to run open loop unless you tune yourself and even then I still don't see the point in leaving it open.

[BR3W CITY]

Originally Posted by boostedc10

You want the O2 with sd tuning too. It makes no sense for a street car to run open loop unless you tune yourself and even then I still don't see the point in leaving it open.

I guess thats a preference thing. We've had my truck running on pretty much every different way just to see what we like. Right now its set with a wideband on one bank and the regular front 02 on the other (takes ~3minutes to take my other 02 out of the toolbox and put it in). We do a significant amount of street logging and live-tuning which makes that fairly practical. We don't have to leave it open loop, but we can and have before. My truck runs very nicely at the moment, significantly better than it did before my switch to SD. All it takes is the press of a button to re enable it.

Other reason would be running race gas or another alt fuel, and then we start to play around with "street car". And your right in the fact that if your not doing your own tuning, or at least logging and updating with a pro tuner, it could be a little frustrating.

[travlinman]

Ok fellas been really busy with work now the rain is gone. My donor was delivered and have already pulled the motor and trans from it. Fuel lines and tank pedal/wiring and tac module.
Do I really need any of the underdash harness? Hope not looks like a pain to pull all of that out. What besides the main motor harness I unplugged to pull the motor what all do I need? Fuse block? Extra wiring fuel pump etc..?
I ordered a set of dingo mounts for it already.
I also read I might not be able to use my older 4l80e trans with the newer computer something about older electronics in the trans not meshing with the newer electronics? Will the newer harness connect to the trans? Will they have the same type sensors?
Was hoping I wouldn't have to touch the trans in my truck and just drop the motor and bolt it up.
My donor will be gone by this weekend so anything I need needs to come off now.
Thanks for all the help here guys.

[clinebarger]

Originally Posted by travlinman

.
I also read I might not be able to use my older 4l80e trans with the newer computer something about older electronics in the trans not meshing with the newer electronics? Will the newer harness connect to the trans? Will they have the same type sensors?
Was hoping I wouldn't have to touch the trans in my truck and just drop the motor and bolt it up.
My donor will be gone by this weekend so anything I need needs to come off now.
Thanks for all the help here guys.

Your "Early" 4L80E can be made to work by updating the Internal Harness, EPC solenoid, & Shift Solenoids.......The Shift Solenoids are not mandatory but were updated 3 times, So I recommend using the most current replacements.
The '94 & up EPC is absolutely required!

**Note** The Internal harness may have been updated in the past, If you had to un-bolt the trans connector....You still have the old harness & will need to be changed.
If it has a "Squeeze to disconnect" Trans connector....The Harness has already been undated.

EPC solenoid Part# 8684216
Shift solenoid "A" Part# 24201004
Shift solenoid "B" Part# 24201005
Internal harness Part# 24200161, Rostra Part# 350-0032.

The Yellow arrow in the pic is where the '91-'93 Temp Sensor is located, Just unhook when removing the old harness, The new harness Will Not have a connector for the Temp Sensor.....It is built into the harness. Leave the Temp Sensor in the Valve Body.....DO NOT remove it!

[travlinman]

cline..
seems like alot to me but i dont know transmissions.
is this something a trans shop would know about if i took it in to have done? would it just be easier to keep the newer 04 trans and just swap the tail housing out for a 2wd one?
what would either cost to have done. tailshaft i heard is around 100.00
what about the older unit?

[clinebarger]

Originally Posted by travlinman

cline..
seems like alot to me but i dont know transmissions.
is this something a trans shop would know about if i took it in to have done? would it just be easier to keep the newer 04 trans and just swap the tail housing out for a 2wd one?
what would either cost to have done. tailshaft i heard is around 100.00
what about the older unit?

It is not hard at all to do this, Drop the pan & filter & the Solenoids are right there! Unless your allergic to ATF....This is just above basic maintenance.

Your 4L80E is stronger than a 4L60E....I am a big 4L60E advocate, However a 1-ton dually is to much for them.

Actually changing the internal harness & solenoids on a 4L80E is easier than a 4L60E, And you have to have the Driveshaft reworked, different yoke installed, & move the crossmember on top of tearing the trans half way down to install the 2wd output shaft.

Basically, It would cost you more time & money to run a weaker transmission.

To change just the output shaft & Tailhousing on a 4L60E, I charge $200 plus parts. That's you bringing me the unit. 9 times out of 10 I find the 3-4's loose & it turns into a full rebuild

To change Solenoids in a 4L80E....In the truck, Would run $85 plus parts.

You need the following to keep your 4L80E...

Shift Solenoids
EPC Solenoid
Trans Harness
Pan Gasket
Filter
ATF
LS 4L80E flexplate
LS 4L80E Crank spacer
LS 4L80E Crank bolts
Do a simple mod to your 5.3/4L60E harness
4L80E ISS sensor connector (on your old harness)
4L80E segment swap performed on your PCM (You need the PCM tuned anyway)

[travlinman]

cline,
thank you sir. you've been a big help explaining this . i will keep my older thans in the truck and just bolt the ls up to it. keeping the drive shaft linkage etc.. where it is and wont have to worry about it. wheres a good place to order trans parts? rockauto?
now i know i wont need it i can post it on the local for 500. with transfer if thats fair and move it along and keep funding this build.
looks like i dont need any of the inside dash harness so that saves me a few hours not taking that out. the donor will be loaded up and gone this weekend my 78 will be mostly gone as well. so i can get rolling on the big stuff on my 91.

[clinebarger]

Originally Posted by travlinman

cline,
thank you sir. you've been a big help explaining this . i will keep my older thans in the truck and just bolt the ls up to it. keeping the drive shaft linkage etc.. where it is and wont have to worry about it. wheres a good place to order trans parts? rockauto?
now i know i wont need it i can post it on the local for 500. with transfer if thats fair and move it along and keep funding this build.
looks like i dont need any of the inside dash harness so that saves me a few hours not taking that out. the donor will be loaded up and gone this weekend my 78 will be mostly gone as well. so i can get rolling on the big stuff on my 91.

A GM dealer may be the easiest way for you to get quality parts, Rostra is another source.

A good used 300mm 4L60E retails for $600-$700, The Transfer can sell for another $300. A good price to get rid of both together...I would ask $750 as-is.