Any 6l80 experts around?

[67Steven]

I am working on my l92/6L80 combo trying to get the trans to stop whining, and I may have tracked the culprit down, but need someone to verify I am reading it correctly.

According to this diagram http://www.lt1swap.com/pictures/6Lx0...p%20Signal.gif

1. The red/white wire 1840 should be hot at all times, correct?

2. Orange and black 6399 should be controlled by the ECM?

(Pin 59 I believe since I am not running a BCM and not a manual trans) If I do not connect this to the ECM, I get a CEL P2534 with 'lost trans signal' every time I start the truck and I have to clear it every time. I originally had the OG/BK wired to switched 12v, but kept getting the P2534 CEL.

I researched and found this video:http://youtu.be/SLGXIJNUwJ4 from this thread:https://forum.efilive.com/showthread...n-engine-swaps which led to the conclusion above. No more CEL.

Right now, the wires are reversed, OG/BK hot all times and RD/WH switched by ECM at the trans pigtail. Which leads me to believe that this is keeping the trans solenoid pack powered at all times when it shouldn't be, thus producing the whine.

I am wondering if by manually turning off (by battery or removing the trans pigtail) the trans signal to stop the whine, if it is not allowing it to do the adaptive learning for shifting?

Or, am I completely off base?

Thanks for any help!

[67Steven]

Since I cannot edit my post for some reason-

It is actually the pink wire 2139 that is currently switched by the relay, and the red/white wire has no power at any time. Is this correct?

[BR3W CITY]

Steven, take a look out for threads from Hart Rod and JorgenSC, I believe both are running a 6l80e. Hart has been awesome about breaking down his experience with setting up and tuning the setup.

[67Steven]

Okay, I will do more research on there builds, thanks.

[raic65]

I had the same problems as you do. This was suggested to me on another site. I used EFILive to ignore the code, but if you look at the end of the thread, there is a link to LS1tech that involves how some have wired up the transmission.
http://www.pro-touring.com/threads/7...wap?highlight=

[67Steven]

Originally Posted by raic65

I had the same problems as you do. This was suggested to me on another site. I used EFILive to ignore the code, but if you look at the end of the thread, there is a link to LS1tech that involves how some have wired up the transmission.
http://www.pro-touring.com/threads/7...wap?highlight=

Thanks, I have read that that one before, I think all the posts about this issue are pointing to one another, like an endless loop, heh!

I do not have power on the red/white wire where according to the diagram I should. This leaves me perplexed as it is the stock harness that came with the engine/trans.

[clinebarger]

Originally Posted by 67Steven

Since I cannot edit my post for some reason-

It is actually the pink wire 2139 that is currently switched by the relay, and the red/white wire has no power at any time. Is this correct?

Circuit # 1840 Red/White should have constant battery power.

[67Steven]

Success!

I sat under the Blazer and verified the pin-outs to the transmission. When I had the harness modified, they swapped OG/BK and RD/WH. The wires perform correctly in the pins, just the wrong color. I was reading other threads on this transmission, and went through the torque converter lock-up thread here: http://67-72chevytrucks.com/vboard/s...d.php?t=604032 and discovered to my dismay I had wired the brake switch incorrectly (in my defense, I wired it as I was informed it needed to be from the harness guy, which is backwards)

I changed it around and went for a test run. WOW! What a difference, it has a lot more power and just wants to go. No more funny shifting or banging at slow speeds, it feels like it shifts smoother and more consistently, exceedingly fun to drive!

Also- no more whine at shut-off. A very satisfying day, to say the least.

[Hart_Rod]

If you turn your key on and don't start the truck can you hear a "humming" coming from the transmission?

[Hart_Rod]

Some good info on the 6L80:

https://forum.efilive.com/showthread...rence-Material

[67Steven]

Originally Posted by Hart_Rod

If you turn your key on and don't start the truck can you hear a "humming" coming from the transmission?

I hear a slight hum. As I understand, that is normal, as well as a short hum after shut down, that is the solenoids equalizing. My transmission hummed all day if I let it go. Now I think it was the torque converter power staying on?

[67Steven]

Originally Posted by Hart_Rod

Some good info on the 6L80:

https://forum.efilive.com/showthread...rence-Material

Thanks for the link. I will try to read that today.

[67Steven]

Okay, I have yet another transmission issue. When driving, the transmission feels like it is 'binding' up. I have to give it more and more fuel just to keep a steady speed on flat ground. It has happened twice so far- I had a bad experience of it today- so much so that I had to pull over and didn't need to brake to a stop. When I tried to go, forward or reverse, it felt like the parking brake was on (it wasn't). I shut off the truck, unplugged the connector at the back of the transmission and plugged it back in. Started and drove just fine.

Most of my trips are short, say less than 20 miles one way, as I get the bugs worked out and get a feel for how it drives. It seems that the longer drives are what causes the 'binding'.

Fluid (dex synthetic) is full and does not smell burnt, but it is new (600~ miles) so I guess it shouldn't. No CEL at anytime, any thoughts?

I know a bad tune be the cause of this, but could there be something mechanical that would not throw a CEL?

[BR3W CITY]

what kind of stall is in the convertor?

That still sort of sounds like its trying to stay locked up (the decel issue).

When your at a stop, does it feel more like your actually trying to "overcome" something (like how it feels to do a brake stand, or launch of the foot)? OR does it feel more like the engine is free-spinning more than it should (1500rpm and your barely moving?).

[67Steven]

Originally Posted by BR3W CITY

what kind of stall is in the convertor?

That still sort of sounds like its trying to stay locked up (the decel issue).

When your at a stop, does it feel more like your actually trying to "overcome" something (like how it feels to do a brake stand, or launch of the foot)? OR does it feel more like the engine is free-spinning more than it should (1500rpm and your barely moving?).

Stock stall converter. I don't know if it is staying locked or not, but I did have my brake wire incorrect (+12v when brake not applied) now it is 12v with brake applied and it has occurred with both wiring arrangements.

At a stop sign, the truck takes off like it should. If you let off the brakes, it will roll forward (or back if in reverse) like a normal automatic.

When the 'binding' occurs, it starts to gradually need more fuel to go the same speed on flat ground. When I pull over, and stop and try to go again, it feels like you have one foot on the brake, and one on the gas (Hey!) at the same time and if you give more gas, it feels like more braking, also- but it will move begrudgingly. No grinding, no popping, no noise or fluid puking out anywhere and no CEL.

What makes me wonder if it is in the tune, is the fact that I can disconnect the electrical to the transmission for a split second, fire up the truck and drive like there was never an issue. Almost like it turned off whatever was at fault. I think it would still be binding if it was a mechanical issue.

Thanks for the help!

[Hart_Rod]

Any updates?

[Houston Ben]

This is how my 6L80 feels sometimes. I feel like I have to give it more pedal than needed to speed up just a little. It also feels like it wants to slow down for no reason while I am keeping at a steady speed ( I don't know how to explain this). When I first start the truck after it has been sitting for a while (after work/first thing in the morning) first and second gear seem to not want to shift and feels very weird. Once it warms up it shifts fine with no more problems.

[BR3W CITY]

I'm gonna toss a tune issue into the ring....I know you guys love it when I say the problem is in the Magic Box. This is my experience from the 4l80e

Going down the road at 65 at like 1800rpm, all of a sudden, it seems like your giving 5% more throttle, a few hundred rpm's, but the SAME speed.

This is actually caused by a few things, one of which is the lockup speeds/settings, another is "abuse protection" (bet you've never heard it referenced before), and the last is issues related to pedal postion %. Its gonna be hard to articulate, but I'll try.

Basically, the gear changes/lockup can be adjusted on a table of speeds. If any of the speeds fall out of a reasonable range, it can attempt "permanent lockup" in which the VSS will never see its "top" speed. The pedal position comes in when you have issues like IAC-crutching. This is using dbw throttle % to give a smoother idle, after you've maxed the IAC setting. You also tend to see really "bumpy" power graphs. Both are signs of lazy/inexperienced tuning. We are currently battling some major tune issues, and I'll be able to give you a better idea of how it can be handled next week*

*we've pretty much given up an allowing anyone to tune my truck, aside from a few very special individuals. Call me an elitist, but when I have the guy who designed the LS1, along with another guy who designed MAST's tuning system, telling me I'm doing it wrong...I listen. Those two have nearly 65years experience, and are working with my a friend and I on a few projects. They are also helping us offer tuning on the side, so I'll be able to offer more to you guys here as time goes on.

[Houston Ben]

Interesting Brew, I'm excited to see the results! I guess I might just have to buy HPtuners and do things myself, not that I know anything about HPtuners or tuning in general...

[BR3W CITY]

I'll let you know what we end up with. Also, are you SURE your dipstick is locking and staying in? You wouldn't believe how BAD gm o/d trannies can work when the stick pops out.

[Houston Ben]

I'll double check!

[Hart_Rod]

Originally Posted by BR3W CITY

I'm gonna toss a tune issue into the ring....I know you guys love it when I say the problem is in the Magic Box. This is my experience from the 4l80e

Going down the road at 65 at like 1800rpm, all of a sudden, it seems like your giving 5% more throttle, a few hundred rpm's, but the SAME speed.

This is actually caused by a few things, one of which is the lockup speeds/settings, another is "abuse protection" (bet you've never heard it referenced before), and the last is issues related to pedal postion %. Its gonna be hard to articulate, but I'll try.

Basically, the gear changes/lockup can be adjusted on a table of speeds. If any of the speeds fall out of a reasonable range, it can attempt "permanent lockup" in which the VSS will never see its "top" speed. The pedal position comes in when you have issues like IAC-crutching. This is using dbw throttle % to give a smoother idle, after you've maxed the IAC setting. You also tend to see really "bumpy" power graphs. Both are signs of lazy/inexperienced tuning. We are currently battling some major tune issues, and I'll be able to give you a better idea of how it can be handled next week*

*we've pretty much given up an allowing anyone to tune my truck, aside from a few very special individuals. Call me an elitist, but when I have the guy who designed the LS1, along with another guy who designed MAST's tuning system, telling me I'm doing it wrong...I listen. Those two have nearly 65years experience, and are working with my a friend and I on a few projects. They are also helping us offer tuning on the side, so I'll be able to offer more to you guys here as time goes on.

J - you've been holding out on me.......

[BR3W CITY]

Sh!t Rob, after our last conversation you had pretty much hit the ground running....you didn't need me

Its actually some newer knowledge to me as well, as its only been the past month or two I've had access to people this high up the food chain. I'm leaving my house in about 30 minutes to go meet with a GM design engineer and a commercial camshaft engineer to mess around with my tuning. I have learned SOOO Much from these guys its insane. The second fellow just finished building an "experiemental" BlueBird "shortbus" with a Twin Turbo 8.1L. Scariest bus ever.

[Hart_Rod]

Originally Posted by BR3W CITY

Sh!t Rob, after our last conversation you had pretty much hit the ground running....you didn't need me

Its actually some newer knowledge to me as well, as its only been the past month or two I've had access to people this high up the food chain. I'm leaving my house in about 30 minutes to go meet with a GM design engineer and a commercial camshaft engineer to mess around with my tuning. I have learned SOOO Much from these guys its insane. The second fellow just finished building an "experiemental" BlueBird "shortbus" with a Twin Turbo 8.1L. Scariest bus ever.

Sweet!! While you are there, ask them how I can get cruise control with a GEN IV and how I can make my paddle shifters work in Drive.............

[BR3W CITY]

Originally Posted by Hart_Rod

Sweet!! While you are there, ask them how I can get cruise control with a GEN IV and how I can make my paddle shifters work in Drive.............

I'll text him this afternoon and see what he says. (Turns out his family holds the patents to some very popular heads).

We just dumped my last tune in the garbage, peeled the tuners sticker off my truck, and started from scratch. We ended up going with the full custom SD-enhanced OS w/live tuning, and the fact that I can get 2-3 bar for free if needed.

A couple of things regarding Ben's post.
One of the things we noticed was that cam-surging was causing a ton of the "overcoming" problem while cruising under light load low throttle. Turns out, its a paradox....what you describe as "giving it more to go the same speed", is ACTUALLY the cam surging PAST the target speed. In other words, your riding the "high" and feeling the "low". This is exagerated with a big cam, but can happen on anything. This is largely related to bouncing AFR's 2 the front 02's (Even in SD), and makes stft's go wacky. It will look like a racing-heartbeat if you view the o2 signal on the interface.

IAT's reading wrong can also command a whole set of wrong tables, causing the vehicle to bounce between High and Low octane tables, effectively giving you a different map. Some tuners set these tables the same, because they run into this issue....which is the wrong way to do it.

Assuming the 6l80e has control similarities to the 4l80e, then looking at the lockup settings for Engage and Release might be a good idea. It almost sounds like its not releasing lockup, meaning your effectively engine-braking like a semi truck....thats not good for your crank shaft or input shaft on the tranny, should it happen after a WOT pull or something.

I'm not ignoring the possibility of a mechanical failure, but the fact that it changes with key-on-key-off makes me lean towards tune, or an electrical fault at one of the connectors.