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      QUADZILLA TUNE REPOSITORY - There is now a Quadzilla tune download area. When you submit a tune file to the download area it will automatically create a forum topic that allows discussion of your tune. So export your tune and upload it to the site. Then we all can help out in building better tunes. Check it out gang...
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      911 Support Group   06/22/2017

      Hey Gang, I've got the 911 support group database back up and running once again. It's listed in the 911 support category. It will allow members to list their contact information and location so other have a listed of members to call upon in the time of need. So if you wish to support other member please stop by and add your listing into the database. https://mopar1973man.com/cummins/911-support.html/contacts/
Mopar1973Man

OBDLink

100 posts in this topic

9 minutes ago, Me78569 said:

That's not what I am finding.  

 

When I read boost from the ECM I see it come off "bottom" right away.  It might send boost over obd differenly, but canbus at least seems to read boost at 0+ at idle regardless of altitude,  same is true when I take my truck to sea level.  My truck is a 00 tho so maybe there is a ambient pressure sensor being used where as 98-99 dont?

 

late trucks however seem to read boost differently and I cannot explain it yet. I will know more in the summer when temps come up again.

 

That's very interesting because I see the opposite. My truck will read 100-102 for a long time before it starts picking up. That might be the difference between the early sensors and the late sensors. It seems I might have bought the wrong truck for high altitude operation lol. But after 9 years I guess I'm stuck with it.

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My truck uses a early sensor though....  

 

All I can say is our trucks electronics are very much a testing groudn for dodge /cummins to figure out the Electic injection control system on a diesel.  

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Well, since I've taken it upon myself today to solve the mystery of my truck's poor performance on 2-stroke oil (see cumminsforum), as a side effect I solved the mystery of the boost formula.

 

The correct boost formula that works 100% accurately at any elevation is: (A/6.8947)-14.6

 

This means that in any OBD software, you need to add a custom PID for boost. For the mode and pid, enter 010b or 01 0b (depending on your software's format). For the minimum value enter 0, for maximum value enter 100 or 60 or whatever you want (22 suffices for my stock truck lol). For equation, enter the above formula: (A/6.8947)-14.6

Then for decimal point precision, just use 1 decimal point.

 

This formula does not depend on atmospheric pressure at all. And in fact, the whole discussion about atmospheric pressure is completely overblown because it really only concerns our trucks when they are at idle. You have to keep in mind the function of a turbocharger. It is by it's nature a perfect altitude compensator and will always try to achieve a certain equilibrium within it's mechanical limits. This means that as soon as we begin applying fuel with a press of the throttle, intake pressure comes up above standard atmospheric pressure anyway. It just takes slightly longer at 10,000 feet than it does at 2,000 feet.

 

For the above reason, and since I'm at 9,240 feet, I see my boost sit at 0.0 for a little while before it starts coming up. That time where it's at 0.0 is when the turbo is reaching 14.6psi. It's a very short period of time, but it is noticeable at my elevation (lasts about 2 seconds after applying throttle). My mechanical boost gauge shows the same thing.

 

Hopefully that clears up some of the issues that have been bubbling in this thread for a while. Just keep in mind that my truck is a 98.5, I don't know if the newer trucks report a different data format on 010b, but I can't see why they would.

Edited by SpaceHiker
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Intersting to say the least.  The ecm reports boost as 2 bytes per kpa over canbus not 1 byte per kpa.  Good work.  

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Oh yes, then there's that conversation. I forgot to mention that one. The people who were discussing that were making some important mistakes at various points in that conversation:

 

1. Some were thinking the ECM handles boost as psi rather than kpa.

2. Pretty much everyone assumed the ECM handles map readings as an integer, when it is almost certainly floating point.

3. People were confusing the canbus with obd.

 

So on the canbus, the ecm is taking raw voltage readings from the output of the map sensor and converting them to a floating point (decimal) number in kpa. What we see on obd is the rounded output, because decimal precision is not necessary and the obd spec doesn't have the space for it.

 

Logically then you would need 2 bytes on the canbus for the floating point value and 1 byte on the obd for the rounded integer.

Edited by SpaceHiker

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sorry typing to fast thinking too slow.

 

The ecm reports it in as 1 byte, but the ECM reports it as 1 = .5 kpa  or A = .5 kpa in the obdlink stuff.  Still only 1 byte.   The conversion I have for the quad is (A * 2) / 7 = psi

 

I would have figured that the ecm would report values the same, but every time I assume something the ecm proves to not follow that.  

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Mine clearly reports A as 1 kpa. I've confirmed it with quite a bit of driving around with live data. I guess other years report differently?

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On 2/3/2017 at 5:38 PM, SpaceHiker said:

Well, since I've taken it upon myself today to solve the mystery of my truck's poor performance on 2-stroke oil (see cumminsforum), as a side effect I solved the mystery of the boost formula.

 

The correct boost formula that works 100% accurately at any elevation is: (A/6.8947)-14.6

 

This means that in any OBD software, you need to add a custom PID for boost. For the mode and pid, enter 010b or 01 0b (depending on your software's format). For the minimum value enter 0, for maximum value enter 100 or 60 or whatever you want (22 suffices for my stock truck lol). For equation, enter the above formula: (A/6.8947)-14.6

Then for decimal point precision, just use 1 decimal point.

 

This formula does not depend on atmospheric pressure at all. And in fact, the whole discussion about atmospheric pressure is completely overblown because it really only concerns our trucks when they are at idle. You have to keep in mind the function of a turbocharger. It is by it's nature a perfect altitude compensator and will always try to achieve a certain equilibrium within it's mechanical limits. This means that as soon as we begin applying fuel with a press of the throttle, intake pressure comes up above standard atmospheric pressure anyway. It just takes slightly longer at 10,000 feet than it does at 2,000 feet.

 

For the above reason, and since I'm at 9,240 feet, I see my boost sit at 0.0 for a little while before it starts coming up. That time where it's at 0.0 is when the turbo is reaching 14.6psi. It's a very short period of time, but it is noticeable at my elevation (lasts about 2 seconds after applying throttle). My mechanical boost gauge shows the same thing.

 

Hopefully that clears up some of the issues that have been bubbling in this thread for a while. Just keep in mind that my truck is a 98.5, I don't know if the newer trucks report a different data format on 010b, but I can't see why they would.

I'll give this a try next time I'm in my 02 and see if it works. Thanks! 

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You are reading boost over the sci bus I am reading it over the canbus port under the hood.  

 

The canbus port under the hood reports boost as .5 kpa per A 

 

It's interesting to me that the sci bus reports it differently. 

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(A/6.8947)-14.6  tried this formula and at idle, my gage was sitting at 14.6. So I subtracted another 14.6 and it set it on 0 but seemed to kind of track with my gage up to about 15-20 psi and it wouldn't go any higher. not sure what's up with that.

 

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boost fooling from the ez.  Remember the obdlink is showing you what the ECM is seeing, the Edge is limiting what hte ecm sees.

Edited by Me78569
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Little change of direction here. I would like to use my obdlink dongle on  my 3 vehicles. Is there any way to save a vehicle in the vehicle editor so I don't have to re-enter everything every time I switch cars? Like download the app 3 times and have one for each car or something like that?

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1 hour ago, Mopar1973Man said:

No need. The app will reconize the vehicle and rehook to its own profile. I've got my 96 and 02 Dodge.

Is there something special that needs to be turned on? Mine doesn't do that.

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As far as I've seen between my two trucks once you've saved the first profile for each one it automatically picks up the profile the truck and uses it. I'll double check again and see if there is a bug or something changed. I'll be a few days before I can test this. 

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MIne also remembers the vehicle.  I didn't have to turn anything on.  The only time I had to re-enter my vehicles information is when I removed and then reinstalled the app on my phone.

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Hmmmm. Today I took it out of the Tahoe and put it in my 300M. No VIN or anything came up for the 300M. It knew I changed vehicles because it told me to edit my vehicle in the editor, but did not display the VIN or fill in any of the info that comes along with it like it did the Tahoe. When I put it in there it had most of the info filled out just by reading the vin. like engine size etc. I'll have to put it back min the Tahoe and see if it changes but it appears I must be missing something.

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I have run mine on 4 vehicles and it only recognized the VIN on my wife's Honda Odyssey van and my sister in laws Toyota Sienna van. All the others load up the vin blank. I have yet to fill them in but all the tools work and it will connect to each vehicle If you label each one. You should just plug it in, wifi should load up automatically although I check it first,then open app and push connect button at the bottom of app screen. I don't have it set up anymore automatic than that because I want physically see my vehicle profile load when I push connect. I am running on iphone7. It's a bit different than android I think. 

After you enter the stuff manually for the vehicle editor that doesn't load your vehicle for the first time, it should load from that point on when you switch vehicles. 

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On 2/23/2017 at 4:47 AM, woodtrucker said:

I have run mine on 4 vehicles and it only recognized the VIN on my wife's Honda Odyssey van and my sister in laws Toyota Sienna van. All the others load up the vin blank. I have yet to fill them in but all the tools work and it will connect to each vehicle If you label each one. You should just plug it in, wifi should load up automatically although I check it first,then open app and push connect button at the bottom of app screen. I don't have it set up anymore automatic than that because I want physically see my vehicle profile load when I push connect. I am running on iphone7. It's a bit different than android I think. 

After you enter the stuff manually for the vehicle editor that doesn't load your vehicle for the first time, it should load from that point on when you switch vehicles. 

 

It depends on the software you are using. If you are using the torque pro app for android, it allows you to create and save a custom live data profile for each vehicle. It does not automatically switch over based on the vehicle it's connected to. You have to change the profile manually, but the procedure is obvious. 

 

Other software will behave differently. You might need to switch to a different app.

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I think it's working now, but as said above it doesn't load the VIN for the truck but it recognizes each vehicle. I also noticed there are 3 pages of gauges and I will use 1 page for each vehicle so I don't have to change them every time I switch. What's this torque pro thing and where do you get it?

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Go out on google play you'll see the OBD apps available you can use any app you want for OBDlink if you wish but the other problem is you most likely going to have to pay for other apps. 

 

https://play.google.com/store/apps/details?id=org.prowl.torquefree&hl=en

 

https://play.google.com/store/apps/details?id=com.palmerperformance.DashCommand&hl=en

 

https://play.google.com/store/apps/developer?id=Palmer Performance Engineering&hl=en

 

https://play.google.com/store/apps/developer?id=Ian Hawkins&hl=en

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On ‎3‎/‎3‎/‎2017 at 8:41 AM, Mopar1973Man said:

Go out on google play you'll see the OBD apps available you can use any app you want for OBDlink if you wish but the other problem is you most likely going to have to pay for other apps. 

 

https://play.google.com/store/apps/details?id=org.prowl.torquefree&hl=en

 

https://play.google.com/store/apps/details?id=com.palmerperformance.DashCommand&hl=en

 

https://play.google.com/store/apps/developer?id=Palmer Performance Engineering&hl=en

 

https://play.google.com/store/apps/developer?id=Ian Hawkins&hl=en

Thank you. Hey Mike, can you post a screen shot again of what the values are supposed to be. I can't seem to find it. Also, how do you know what the values should be for other vehicles?

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3 hours ago, dave110 said:

Thank you. Hey Mike, can you post a screen shot again of what the values are supposed to be. I can't seem to find it. Also, how do you know what the values should be for other vehicles?

 

Here you go... My whole article on it.

 

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On ‎3‎/‎5‎/‎2017 at 4:26 PM, Mopar1973Man said:

 

Here you go... My whole article on it.

 

Great! One suggestion. Somewhere you posted a link for a nifty calculator to figure out the offset for the vol. efficiency. That would be a good addition to this article along with an explanation on which number goes where.

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1 hour ago, dave110 said:

Great! One suggestion. Somewhere you posted a link for a nifty calculator to figure out the offset for the vol. efficiency. That would be a good addition to this article along with an explanation on which number goes where.

 

I'll try to get the write up done... 

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