Smokeless ATT Tune

[Big T]

After my California smog travails, I'm interested in a "smokeless" tune for the ATT. I currently have a Heath tune and it belches smoke on start up, especially while towing or at altitude. We all know black smoke is I burnt fuel, so the tune must be dumping too much fuel before the ATT spools up. I need a tune that is near NA fuel delivery levels prior to the ATT spooling up. This should provide better fuel economy, while cleaning up my exhaust.

My son has a position tuner for his OBD II. Honestly, we run that on the economy setting most of the time and turn on the tow and race settings only when we need them. I would like an OBD II tune that would do the same, either have switchable positions (ideal) or have a fuel delivery curve that's economy my when you're not heavy into the boost and full performance when you are.

Is this possible with OBD II?

 

[Jorge6.5]

From my understanding there are no selectable tunes available for obdII, only obdI

 

[JayTheCPA]

My son has a position tuner for his OBD II.

That is a new one to me . . . Details and or pictures, please?


My Burb started to belch at startup the instant I installed the marine injectors; currently increasing their pop from 1800 (per the injector shop's original recommendation) to 2200.

Toward a better tune for the ATT, after talking with Dennis, I am putting my faith in his work and switching over to his tune (available through Leroy). Basically, it does a fair amount of re-mapping of different data curves to better play with the ATT; also, it is a product of actual data. Do not have any results at the moment as the Burb is still in the shop for a motor replacement.

My understanding of the 6.5's ECM is that it 'implies' boost pressure, rather than actually reading it, which in turn causes the smoke when the data curves do not match what the ATT is actually doing. Again, Dennis' tune should do a lot to match the ATT's characteristics to the ECM's data curves.

In terms of switchable tuning for the OBD II, I am on the hunt for it as well, but seems the barrier is that the 6.5 community is too small in numbers for anybody to R&D a product. Not helping is that I cannot find any sources who know fine details about the 6.5's ECM or wiring diagrams.

At the risk of straying into OT territory, based on descriptions of your CA snap test experiences, not convinced that CA actually performed the engineering standard that CA 'claimed' it followed as I did not read details which included six idle-to-max rpm cycles. In terms of the snap's engineering standard, there is a clause that States may adapt it to their own use. But that is another issue and I'm not looking to keep that experience alive in anybody's current memories . . .

 

[ak diesel driver]

pretty sure that was a typo as he says obd2 twice on different rigs

 

[WarWagon]

That is a new one to me . . . Details and or pictures, please?


My Burb started to belch at startup the instant I installed the marine injectors; currently increasing their pop from 1800 (per the injector shop's original recommendation) to 2200.

Toward a better tune for the ATT, after talking with Dennis, I am putting my faith in his work and switching over to his tune (available through Leroy). Basically, it does a fair amount of re-mapping of different data curves to better play with the ATT; also, it is a product of actual data. Do not have any results at the moment as the Burb is still in the shop for a motor replacement.

My understanding of the 6.5's ECM is that it 'implies' boost pressure, rather than actually reading it, which in turn causes the smoke when the data curves do not match what the ATT is actually doing. Again, Dennis' tune should do a lot to match the ATT's characteristics to the ECM's data curves.

In terms of switchable tuning for the OBD II, I am on the hunt for it as well, but seems the barrier is that the 6.5 community is too small in numbers for anybody to R&D a product. Not helping is that I cannot find any sources who know fine details about the 6.5's ECM or wiring diagrams.

At the risk of straying into OT territory, based on descriptions of your CA snap test experiences, not convinced that CA actually performed the engineering standard that CA 'claimed' it followed as I did not read details which included six idle-to-max rpm cycles. In terms of the snap's engineering standard, there is a clause that States may adapt it to their own use. But that is another issue and I'm not looking to keep that experience alive in anybody's current memories . . .

:hammer: Yup, we are small.

His son's is a 1994 OBDI burb.

 

[Chevypoor]

I was expecting a lot of smoke with Larry after installing the ATT and surprisingly it smokes less the the gm-5 with a turbomaster. It blows no smoke on start up and the only time I get smoke at is when I really get on it and then it is a medium grey puff most of the time.

Maybe Jay is onto something with the injectors. I am running stock Bosch injectors with a Heath Tune. Interestingly it smoked more on Gertie with the same tune but I was running high pops from Kennedy Diesel and when I took the motor out I discovered the turbo was leaking at the manifold. Went with standard injectors and I triple checked the turbo to flange bolts and now under 95% of my driving I have almost zero smoke. Have not had a chance to pull with her yet and I have not ran her at altitude so I cannot comment there.

 

[Big T]

Sorry about the typo; my son has a 4 position tuner (by an unmentionable vendor) on his '94.

On the snap test, they snapped it twice and definitely not to redline RPM.

I have the marine injectors with about 50k miles on them. In addition to the noted smoke, my experience is that the fuel economy is less with them. I'll be looking for a source that reubilds injectors with German Bosch nozzles.

My post was really aimed at the apparent fuel inefficiency of the available tunes while running an ATT. We need a tune with less duke delivery for the range prior to the ATT spooling up, then ramp up the fuel when it starts to spool up. Effectively naturally aspirated level of fuel delivery, then boosted fuel delivery. Otherwise, there's a lot of raw fuel being dumped out the exhaust.

I only mention my son's OBD I tuner because 90% of the time we run it on economy, only using tow or race for those time we need it. His fuel economy is better (German Bosch nozzles) and it barely smokes during normal driving.

 

[6.5L]

Got to have a little bit of extra fuel to help with spool up. At least in my case it helps

 

[Will L.]

Is it possible to have 2 units in the truck on a switch? Key off only situation, but an option. Most of the time run soft, then when you hook up to a trailer, or whatever you just hit the switch before starting.

Build a harness that ties in all the control wires, but power to the unit goes through a switch that in position #1 powers up unit #1, then shut of ignition move switch to position #2 that diverts the power to unit #2 cutting off power supply to #1.

 

[JayTheCPA]

On the snap test, they snapped it twice and definitely not to redline RPM.

Does not look like the spec California stated they followed, so appeared that they decided to just go their own way. At least now we know.

We need a tune with less duke delivery for the range prior to the ATT spooling up, then ramp up the fuel when it starts to spool up.

What we are lacking is actual boost measurements going into the ECM. IIRC, WW had touched on this by way of pondering whether / how a MAF would benefit the 6.5.

Is it possible to have 2 units in the truck on a switch? Key off only situation, but an option. Most of the time run soft, then when you hook up to a trailer, or whatever you just hit the switch before starting.

Build a harness that ties in all the control wires, but power to the unit goes through a switch that in position #1 powers up unit #1, then shut of ignition move switch to position #2 that diverts the power to unit #2 cutting off power supply to #1.

Had thought of this as an option as well. A potential nit is that in addition to making it a key-off solution, it will also force a 'Theft Deterrent' reset on some platforms.

If going the route of adding a multi switch to select ECM's with separate tunes on them; I'd consider adding a 3'rd ECM for either valet or no-start :hihi:

 

[Will L.]

The no start could be a 3 position switch that has nothing in 1 position. You would really want a protected switch so it does not get moved on accident while driving.

 

[Big T]

Had thought of this as an option as well. A potential nit is that in addition to making it a key-off solution, it will also force a 'Theft Deterrent' reset on some platforms.

If going the route of adding a multi switch to select ECM's with separate tunes on them; I'd consider adding a 3'rd ECM for either valet or no-start :hihi:

The Security light is always lit on the '99. I talked with Bill Heath on this and he said that it's usually a switch located on top the HVAC controls that goes out. Like the ABS light, I've chosen to ignore it.

While we're dreaming, maybe a tune that deactivates cylinders to improve economy?

This post came about as I was reading about the Ford Ecoboost not meeting the claimed EPA mileage. Couple points learned or confirmed from that.

1) Turbos do not improve fuel economy. Engines run on a specific fuel:air ratio, so when you force more air in with a turbo, you also must increase the fuel. So more boost = more fuel = less fuel economy. Granted the power and torque are increased, but if your into the boost, economy goes down.

2) Apparently, Ford has gamed the EPA mileage tests with the Ecoboost. The test is 12 minutes long on a Dyno. Certain number of minutes at 60 mph to reflect highway speed and a certain number of minutes at 46 mph to reflect all around speed. Problem is, no one drives like that. Once that they feel the acceleration and torque, they're heavy into the pedal. To get the EPA rated mileage, you'd have to be very soft I to the pedal to achieve almostmnaturally aspirated driving conditions.

3) Independent towing tests comparing the 3.5 liter Ecoboost to the 5.0 liter V8 showed the Ecoboost getting a pathetic e 7.5 mpg vs 9.4 mpg for the V8. Presumably, this is due to the Ecoboost being in heavy boost mode, whereas the V8 was always in NA mode.

I noted that Honda dropped a 2.4 liter turbo charged engine in their SUVs for a 3.6 liter V6. The V6 gets 2 mpg better mileage across the board and has better up and torque.

Diesel do better on mileage when turbs are added because they're coming down from an already higher level of efficiency and the turbo is improving aceleration hp and an already superior level of torque torque.

 

[Will L.]

The way a turbo increases mpg is through its temporary application. By using a turbo in the power band to achieve the desired rate of acceleration pulling a determined load, a smaller engine is capable of producing enough work force to sufficiently get the task accomplished. Once the work load lessens such as finished accelerating so now only maintaining speed, the power supply can reduce there by saving fuel.

A comparison would be take a n/a truck towing a 5,000 lbs trailer up a long hill. Running it at near full throttle trying to obtain freeway speeds will burn less fuel than a turbo truck at exactly the same speed. However the added power from the turbo can cause the acceleration needed to get the truck up to speed much quicker allowing the operator to let up on the throttle sooner, consuming less fuel over all.

The more fuel efficient n/a vs turbo only occurs when the operator chooses to accelerate at the slower rate of the n/a vehicle. The same thing can be accomplished by simply using a smaller engine and not putting a large demand on it, drive a 2,000 lbs car instead of a 6,000 lbs truck. Or running the truck with the smaller engine by killing cylinders like you say, to replicate the smaller engine.

To kill cylinders for the 6.5 is a money pit. You need to not only kill fuel supply from the injector, but separately control the valves in order to stop an engine braking scenario from occurring. If you have an idea for that, I would enjoy hearing it. I have worked on several cylinder cancelling engines over the years, and all sacrificed a lot in order to obtain that feature.

 

[tanman_2006]

A variable timing cam might be easier done than cylinder shut off as mentioned and easier than that would likely be MAF install.

It sounds to me like the injectors could have been a lot of your emission issue coupled with tuning from an anti ATT tuner.

 

[JayTheCPA]

The Security light is always lit on the '99.

Scenario I had in mind was that the truck simply would not start until it went through the 6 minutes of key-on / key-off sequences due to a 'cold' wake-up of the ECM.

Probably can get around this by keeping all of the ECM's alive / 'warm' with a harness that supplies 12v to all of them.

Maybe the only answer to switchable tuning really is to stack multiple ECM's, figure out the creative wiring solution which supplies inputs to all of them, and only allow *one* of them to actually send outputs to the truck. . .??? Only question with the stack configuration is whether one of them will 'code' from not liking what the 'active' ECM is doing.

Naturally, I'd prefer to have one ECM do all the work to include reading air pressure / density and switching tunes. But without getting much traction in terms of details about the 6.5 and 6.6 ECM's, a stack solution is all I can think of at the moment . . .

 

[tanman_2006]

What about a 411 nbs ecm? They are swapped in gmt400 vortec trucks, they are used in boosted applications, and proven adaptable to get 400 chassis.

source unknown

 

[Will L.]

Teach me, I only had to mess with 1 ecm years ago. "cold wake up"?

I've dealt with trucks that had no battery in it for a couple years and had the truck fired up in two minutes after installing the new battery.

 

[Burning oil]

I am at the mercy of my brother on this, but its in the works. We plan to build an adaptor that would convert OBDII to OBDI.
You'll need a 94-95 ECM. Then throw whatever tune/multi tune you want at it.

There could be some bugs to work around with the theft deterent trucks (BTW what year did that start?) But on 96- 97 going to OBDI is doable.
The hold up right now is finding the 32 and 24 pin sockets for the ECM connections.

 

[ak diesel driver]

IIRC kojo said obd2 could be done but would require soldering . I assume he's talking about the prom.

Sent from my Studio 5.0s using Tapatalk

 

[JayTheCPA]

What about a 411 nbs ecm?

Looked into this: gasser only

. . . "cold wake up"?

Only have my rig as a reference, but it is very consistent where unplugging the ECM or disconnecting the batteries prevents the truck from starting. It will crank, but not start; also will not trigger the GP's IIRC. Getting it to run again requires the 'key-on' for 5 minutes and 'key-off' for 1 minute sequence.

For similar ECM's, the thought is to always keep the ECM 'warm' to avoid the lag time in switching units.

adaptor that would convert OBDII to OBDI.

Forgot about that as an option, and am sure that if anybody will get it to work, you will :hihi: