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Alternate 4l80e controler idea.

y5mgisi

y5mgisi

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Why cant we just take a computer from say, a 91 burb with a 4l80e, and re write a chip for it, and use it to control the trans? I mean, im guessing it needs to see tps, map, maybe tach? Seems like it would be easy enough to rig those things up to work and "talk to the computer to tell the 80 what to do? No? Why not? Seems super simple, but i still cant even burn my own chips... But if we could get it to work, it would be an ultra cheap way of controlling it as opposed to the TCI unit!
 
What you're describing is most of what the trans needs I think, other than the VSS (James and Stephen know this stuff way better than me, a call to us may help a bunch).

Can you delete everything but those components from a '91 PCM? I would think no, the computer wouldn't let you delete some core pieces of the fuel injection system (which I assume you want to replace with a carb or some other injection system).

And maybe you can but maybe it's way more time and hassle than it's worth. 4L80's have been around a long time, I doubt there is an easy way to use one that everyone has been overlooking for the last 20 years but who knows...
 
like i have said in the past. there is a few small shops that do this.

i have a stand alone harnness that does this with a custom chip.

needs coolent temp / vss input - output off tranny / raw tack signal / map signal / brake light switch / power and ground. and gives you aldl cable to plug in scanner for problems and check engine light wire.

custom burnt chip. and the shift program was great in this thing. drive like grandpa and it shifted like grandpa. drive like you stole it and wow :eek1: she was a full on shift kit.

my only problem is for the life of me i cant recall th name of the place i got it from. :doah: and harnness and chip was around 700-750
 
You can use a Megasquirt GPIO board as a "Megashift" which can operate many transmissions, including 4L80E: http://www.msgpio.com/manuals/mshift/index.html It works best with a Megasquirt engine controller, but can be configured as a stand-alone, as well with a few key input signals. The kit is like $250 and the software to tune it all with is free.
 
If you want to run a tbi350 in front of the 4l80 you could get the engine/trans harness from a '91 burb with that setup. You could also use the computer/harness from a '91 or newew c/k that had the tbi350/80 combo

I put in a '92 tbi454 and a '94 4l80e with a '91 np241 and an electronic speedo from a '91.

My setup is controlled by the computer and harness from the '92 suburban engine donor. I had to enlarge the firewall hole for the harness and do some wire splicing. The computer sits in the '7747 bracket. It is the exact same size.

If you want a gm computer to control the engine and transmission and be able to use 4 lo BE CERTAIN that the transmission you want to use has the reluctor ring on the output shaft. Mine doesnt, dammit.

You can also use the trans controller from a 6.5 diesel for the 4l80 from what i hear. I have never tried this though.
 
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I dont see the need for flashing if your motor is a tbi motor. Just use the computer and harness from a vehicle with a 4l80e.
 
i have heard the best harnness to find easy and modify cheep and easy is from 3/4 or 1ton van with tbi and 4l80-e .
 
Yah, no need to "re-write" the PCM. I have seen a pin-out diagram for the correct wiring, but I could not find it now after a quick search. I recall it being on the Dynamic EFI site if that helps.
 
Yea, mostly i was talking about using the original wire harness and computer off something with the 4l80e and addapting it to work on whatever. Anything from a carbed blazer to a 4.3l s-10.
 
explain to me, cause i'm stupid, why the 4l80e can't be made to work without electronics like th400...the older 700rs do not need a computer.

i'm still being stubborn and don't really want a confuser in the truck if i don't have to...
 
They do not operate using a valve body like the old automatic transmissions do. They used hydraulic pressure vs springs to switch gears, the new transmissions use electric solenoids to move the pistons in the valve body.
 
COCHEV said:
explain to me, cause i'm stupid, why the 4l80e can't be made to work without electronics like th400...the older 700rs do not need a computer.

i'm still being stubborn and don't really want a confuser in the truck if i don't have to...
Click to expand...
I don't know how much it is but I heard if you use a manual valve body, then no need for the comp stuff.
But I also was reading on another website about people who build a controler from a certain ECM from GM with a regular harness from a TBI, none that have to do with 4l80e either, just programed after that.
I will try and find the thread.
 
COCHEV said:
explain to me, cause i'm stupid, why the 4l80e can't be made to work without electronics like th400...the older 700rs do not need a computer.

i'm still being stubborn and don't really want a confuser in the truck if i don't have to...
Click to expand...

A computer takes in info like vacuum and throttle position and input and out put speeds to then decide when to activate solenoids to shift the gears. As the other guy said, you can use a manual valve body but that takes away some of the "automatic" from the trans.
 
y5mgisi said:
A computer takes in info like vacuum and throttle position and input and out put speeds to then decide when to activate solenoids to shift the gears. As the other guy said, you can use a manual valve body but that takes away some of the "automatic" from the trans.
Click to expand...

With the manual valve body, all you get is no clutch.
It's manual otherwise.
It's the route I would go if I get another auto no matter what auto it is.
Now all I have is manuals in all my trucks and the one I am building.
 
if i'm going to have an automatic, then i want it to shift itself. I just don't want an auto that has a bunch of electronics attached to it.

I though i read on here that someone was developing a 4l80e, without the e... but that could have just been my wishfull thinking
 
I believe you can get a kit from transgo that installs a vacuum modulator and eliminates the computer. It's # 48-MOD

Or you can get the manual wiring harness on the same page as the link I posted above and go full manual with no computer as well.
 
Transgo 48MOD converts line pressure control from computer control to vacuum control.

There is no automatic shifting of a 4L80E without a computer. The valve body doesn't have fluid pathways for shift "logic". All shifts are controlled by electrically activating solenoids.

If you don't want a computer, you only get full manual shifts with a full manual valve body on a 4L80E.
 
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