I had the same problem with a Predator on my last truck which was a 2000 5.3L. My current truck in a 2005 LLY. I corrected the tires to 285/75R16. DIC now reads 22mpg which we all know is false. Hand calculated I got 18.1(95% hwy) which is almost 1.5-2mpg better than any other tank and i have over 31k miles on my truck. When I filled up the gallons used use to be within 1-1.5 gallons but this time I put in over 27 gallons and it said I only used 21 something. I am running a mild tune courtesy of Trippin but am courious why is it that DIC is always off when using a programmer. I thought EFI would work better since you can change the parameters directly but I guess thats not the case :(

I am a little confused, someone may need to educate me here!.
Are you saying that altering the speedo settings to your tire size has thrown the MPG in the DIC out (how bizarre) or because the ECM now has a performance tune in it things have gone west?.

Cheers,
Ross

I can get 22 mpg. This tool will probably allow you to buid a very high economy tune. It won't have much power, but...

so we know the DIC is some fuel-speed-time algorithm. Inputs are likely VSS, and fuel. How does it interpret fuel usage? I mean, there is no turbine meter, correct?

Flashscan, with tep programmer, it throws off the fuel consumptiom algorithm. Mine currently reads 20.5 avg mpg, my actual best was 18.69 hand calc. The gallons used is way off. May be the cluster can be reprogrammed, or when programmed with the tuner, something is inadvertently changed. I haven't tried efilive yet, but would be curious as to what the pcm inputs to the DIC for info.

Mike

If you alter the pulse tables you alter the data that the ECM uses to calculate economy. You are essentially sliding fuel into the cylinders "under the table" and this will skew the calculations. Additionally, you will run with less pedal position at the same load which pushes your typical operating range in the timing, boost etc tables. Lots of cause/effect going on here...

Boy, do I have a lot to learn.

My wife hates you all.

Dont mean to hijack here, but I have noticed when proggramming the truck the DIC says UNknown Driver. I am wondering if you could program it to say Hello Waid or something like that?

If you alter the pulse tables you alter the data that the ECM uses to calculate economy. You are essentially sliding fuel into the cylinders "under the table" and this will skew the calculations.

Spot on John, I never even thought of that :o:

Cheers,
Ross

Wouldn't the calculations be made using the "altered data" thereby displaying the correct value?

Dont mean to hijack here, but I have noticed when proggramming the truck the DIC says UNknown Driver. I am wondering if you could program it to say Hello Waid or something like that?

That is because there is no communication between the modules when it is programming. If you wanted to change that message you would likely need to be able to reprogram the BCM and/or instrument cluster. As much as I've tried to convince the EFI guys to give us BCM programming, it doesn't sound like it will ever happen.

Boy, do I have a lot to learn.

My wife hates you all.

:muahaha:

Dont mean to hijack here, but I have noticed when proggramming the truck the DIC says UNknown Driver. I am wondering if you could program it to say Hello Waid or something like that?

Although it would serve no purpose, that would be sweet. :cool2:

Quote:
Originally Posted by Wolford http://www.dieselplace.com/forum/images/misc/backlink.gif (http://www.dieselplace.com/forum/showthread.php?p=871859#871859)
Dont mean to hijack here, but I have noticed when proggramming the truck the DIC says UNknown Driver. I am wondering if you could program it to say Hello Waid or something like that?


Although it would serve no purpose, that would be sweet. :cool2:

Could I program my truck not to lock my doors at all, when in gear, It seems most of the programing concerns engine parimeters, I was just curious if I could completly turn off the "automatic in gear" lock my door feature.

Dont mean to hijack here, but I have noticed when proggramming the truck the DIC says UNknown Driver. I am wondering if you could program it to say Hello Waid or something like that?

How about a red light and the message "Hello Dave"

:muahaha:

Could I program my truck not to lock my doors at all, when in gear, It seems most of the programing concerns engine parimeters, I was just curious if I could completly turn off the "automatic in gear" lock my door feature.

It should tell you how to do this in the owners manual of your truck.

How about a red light and the message "Hello Dave"

:muahaha:
That wouldn't work! My name ain't Dave;)

It would work for me, but it would be creepy.:eek2:

Quote:
Originally Posted by Wolford http://www.dieselplace.com/forum/images/misc/backlink.gif (http://www.dieselplace.com/forum/showthread.php?p=871859#871859)
Dont mean to hijack here, but I have noticed when proggramming the truck the DIC says UNknown Driver. I am wondering if you could program it to say Hello Waid or something like that?




Could I program my truck not to lock my doors at all, when in gear, It seems most of the programing concerns engine parimeters, I was just curious if I could completly turn off the "automatic in gear" lock my door feature.

Again, that is a BCM function, we can only program the PCM.

I am a little confused, someone may need to educate me here!.
Are you saying that altering the speedo settings to your tire size has thrown the MPG in the DIC out (how bizarre) or because the ECM now has a performance tune in it things have gone west?.
Part of it may be the tune but most of it is in the programming I believe. Here are a couple examples:

1. My truck is a 3500SRW so it is programmed with 265/75R16 tires. Using EFI I changed that to my current tire size 285/75R16 and now my speedometer is 4-5mph faster. When I didn't change the tire size it was only 1.5-2mph faster. I used my Garmin GPS for comparrison purposes.

2. I fill up just under 1/4 tank. The DIC Gallons used when using the stock tune would be less than 1 gallon different than the amount of diesel it actually took to fill the truck. With the current tune the DIC Gallons used now reads 4-6 gallons more than it actually takes to fill up.

3. Using the stock tune I average between 15-16.5mpg according to the DIC. Hand calculated it was approx. 1/2-1mpg less. Using the current tune the DIC mpg reads over 22mpg but hand calculated it's 4 mpg less minimum.

4. Heres the one that really concerns me. On my way back from San Jose I tracked my mileage and over a course of approx 275 miles my DIC showed than I had driven 11 miles more compared to my Garmin GPS. I recently got back from another trip to Idaho and using the stock tune my DIC was spot on when compared to my GPS.

There are some other things that are off but I think this gives you an idea of what I'm referring to.

Just out of interest.
Your stock file is of course the one read from your truck right, the file you are programming in that is your 'tuned' file, is that modified from your stock file or is that one that has been passed on to you to try that was not originally from your truck?.

Cheers,
Ross

My truck is a 3500SRW so it is programmed with 265/75R16 tires. Using EFI I changed that to my current tire size 285/75R16 and now my speedometer is 4-5mph faster. When I didn't change the tire size it was only 1.5-2mph faster. I used my Garmin GPS for comparrison purposes.

I noticed the same results. After trying to return tire size back to 245/75/16 tire last night, but the calculator was off even on that. I had to bring up the stock tune I downloaded from the PCM to get the value again. I also had the same problem with the speedo being 4 mph faster than GPS readings. I made a post about it on the EFI Live forum and recived some insight from Kennedy and others over there.

Have you actually measured the tire diamater and used that figure or are you using the Width/Profile/Rim settings to calcualte the tire diameter.

The Width/Profile/Rim settings are an estimate, measuring the tire diameter is more accurate.

The most accurate way is to adjust {H0101} so that your speedo and odo are correct when compared to your gps unit.

If you gps said you travelled "G" miles and the odo said you had travelled "O" miles then adjust the {H0101} like this:

{New H0101} = O/G*{Current H0101}

i.e.
If you travelled 275 miles (G) by GPS and the odo recorded 286 (O) and assume that {H0101} was 101008 then the new {H0101} value should be:

{New H0101} = 286/275*101008 = 105048

Regards
Paul

Thanx max that was what I was wondering

i.e.
If you travelled 275 miles (G) by GPS and the odo recorded 286 (O) and assume that {H0101} was 101008 then the new {H0101} value should be:

{New H0101} = 286/275*101008 = 105048
Paul I ran a complete tank on the modified tune and this is what I got.

odo 420
gps 407

Speedo was consistantly 3-4mph off and at higher speeds 5-6mph off. I know you did the equation above but did you multiply or divide those numbers? Sorry I still don't understand how to figure this out. My modified tune shows H0101 value 91410. For anyone has upgraded from 245s to 265s my stock tune since I originally have 265s and upgraded to 285s show a value of 97277.

Bryan,

Your stock tune shows 97277. EFILives estimate of what it should be based on your tires are is 91410.

Using Paul's formula.................

420 divided by 407 multiply the answer by 91410 to get the new H0101 value.

94329

Another option without a GPS would be to actually measure the diameter of the tire and use that in EFILive's calculator. EFILive provides those measurements as an estimate. The actual sizes vary from manufacturer to manufacturer.

Thanks Guy that clears up the formula for me. I've only put about 50 miles on this tank so I'm modify the H0101 table and see if that corrects the problem. Not sure if it will correct the gallons used issue but we'll see.