Speedometer reads correct but log speed is doubled

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08-23-2015
Brendang2000

2 Attachment(s)

Speedometer reads correct but log speed is doubled

Attachment 52933
Attachment 52934

1998 S10 running a stock to truck 4l60 and a 2000 silverado 6.0, ecu and harness.

Not sure whats going on here, but I did my tire/ratio calculations following the instructions by EC_Tune, (found here http://www.hptuners.com/forum/showth...iameter-Change ) and my speedometer is spot on, verified with GPS. However, any logs I capture the speed shown in the log is double what the truck is actually going. So if the log shows 70mph, actual is 35mph. Is there something I'm missing in setting up the table/chart? As always, any help is greatly appreciated!!
08-25-2015
Brendang2000

Anybody? I've contacted Tuning School, which I've purchased one of their seminars and able to access their support, and they were unable to help. They recommended I contact HPT support, but all I got there was the "Unfortunately we do not perform any in house tuning or calibration work". I'll try connecting to another vehicle to see if it's strictly this one project that has an issue. Also, the ecm is set as a 5.3, but I copied all engine parameters for the 6.0, tranny files are stock except ratio/tire. Hope someone can help here......
08-25-2015
Markmx6

I don't remember which of the settings does that off hand, but there is one. I will look it up when I get home from work and let you know. Or you can post up your specs and a screenshot of the tire ratio settings and we'll see where the discrepancy is.
08-25-2015
Brendang2000

2 Attachment(s)

Quote:

Originally Posted by Markmx6

I don't remember which of the settings does that off hand, but there is one. I will look it up when I get home from work and let you know. Or you can post up your specs and a screenshot of the tire ratio settings and we'll see where the discrepancy is.

Thanks for the reply Markmx6! Attached are the ratio settings, is there other specs that I need to post? Thanks again!!!

Attachment 52967 Attachment 52968
08-25-2015
Markmx6

Ok, your numbers look like they are calculated spot on.

Now if you change your vss pulses (the 4,000, and your 128,000) settings. If I remember correctly changing those numbers will change your log speed, but not your speedometer reading. I know it makes no sense, but it seems to work that way.

I would double one of the numbers (take your pick) and log, see what difference it makes. If no difference then set it back and double the other one. (I think the 128,000 is the one you will need, but I don't remember)
08-25-2015
Brendang2000

Quote:

Originally Posted by Markmx6

Ok, your numbers look like they are calculated spot on.

Now if you change your vss pulses (the 4,000, and your 128,000) settings. If I remember correctly changing those numbers will change your log speed, but not your speedometer reading. I know it makes no sense, but it seems to work that way.

I would double one of the numbers (take your pick) and log, see what difference it makes. If no difference then set it back and double the other one. (I think the 128,000 is the one you will need, but I don't remember)

I'll be able to give that a try tomorrow and let you know what I come up with. Appreciate the help!
08-26-2015
Brendang2000

I tried changing the vss pulses. The "mile-ABS" did nothing (threw an ABS light when I changed it the first time per Tuning School) and the "mile" made the speedometer in the vehicle double. So this matched the scanner, but was double actual speed. As a test, I connected up to my '06 silverado and the scanner was spot on with the truck, so that's telling me it's something in the s10 tune. Is there anywhere in the program to set speed settings that's not in the "Speedo" section? I could live with the scanner reading incorrect, but I'm worried the ecm is also seeing this double actual speed. Any other ideas? Thanks!!
08-26-2015
Markmx6

I would set things up so that the log and speedometer share the same speed, and then maybe double your transmission revs/mile which should cut everything back in half making it closer to accurate. It may take some playing to get it correct
08-26-2015
Brendang2000

Quote:

Originally Posted by Markmx6

I would set things up so that the log and speedometer share the same speed, and then maybe double your transmission revs/mile which should cut everything back in half making it closer to accurate. It may take some playing to get it correct

Thanks! I'm leaving town for a few weeks, so will have to give this a try when I return. Also be nice not to think about this problem...
09-15-2015
Brendang2000

Got back into town and did a little more testing. First, I set the Speed Limiter to 100 mph and drove up the road, the limiter kicked in at 50 mph showing on the speedometer (100 mph in the log). So at least I knew the program was seeing double the speed. Then I changed parameters in the Speedometer/General to almost min values and it still read double the speed. I changed some values to almost max and it still read double the speed. Then I was going to change all values to just under max to see what would happen and it killed the pcm, I can no longer talk to it. Great. After that I had to put in my other pcm that has a 4L80 in the stock tune, changed most things over to my tune, set tranny type to 4L60 (I know this is not correct and needs a segment swap) and drove up the road. Speedometer and log read the same speed! So, maybe that other pcm was bad? Now, if only I can find a file to do a segment swap on my other pcm. OS 9381344 that has a V8/4l60 Anybody?