Continued problems with speedo calibration! Solution?

Using version 2.1.12 and latest updates from HPT. Vehicle is a 2005 LS2 C6 Corvette A4 w/ an upgraded 3.42 differential from the original 2.73. Stock tires. All relative speeds have been compared against our calibrated chassis dyno rollers and most test speeds are 60, 70 and 80 MPH.

We have been in contact with HPT *MANY* times over this re-occuring issue and absolutely *NONE* of the "fixes" they have supplied/suggested are working...period! This is getting very expensive and time consuming trying to hunt around for an answer to this problem and it's getting ridiculous, as this isn't the first time we've had problems with this product..

We have performed every-single possible combination to get the DIC, the dash speedo and the HUD to have all the same values in speed, but nothing has worked 100% yet.. If we input the "3.42" ratio number in any one of the four(4) differential ratio data entry areas of this calibration, select "Commit" and so on, one of the three speed reference gauges are not accurate.

1. Input the "3.42" accurately in data entry areas and select "Commit" as instructed- Dash and HUD speedo are correct, but DIC and PC speedo are off by 50 MPH or so and do not climb with the same linear rate as the dash speedo. Obviously, the cruise control does not work either...

2. If we take that same file that was "Commited" to a 3.42 ratio, (to maintain shift patterns/strategies, as they are correct) but input "1.00" in all data entry areas, the dash and HUD speedo are 3 MPH slow and the DIC & PC screen are dead accurate- Cruise control works properly.

3. If *ANY* of the gear ratio data entry areas have the "3.42" input anywhere, there will be a problem somewhere with accuracy of the dash & HUD speedo, as well as, the PC speedo and the DIC. There has been no way around it..

As a test, we have altered the PPM up and down by huge margins to see if we get any sort of change at all- nothing... We do have the shift points set exactly to target and they are right where we want them for this application- this has never been the issue.

When we first broght this to HPT's attention, the latest version out at that time was 2.2.0 we believe. Now that we have the latest version and was told that the problem was corrected, we find differently and this is unacceptable.. We're chasing our tails here and since HPT won't provide a phone number for professional tuners to call to sort out the problem in a quick, efficient manner, we have to invest more time and hassle in tryping all of this out, while waiting for a reply that may or may not come. Time is money and HPT has burned up a lot of both around here thus far because of this very issue. We've still yet to hear from HPT on our last email sent yesterday.. We've always been supporters of HPT and have waded through the bug fixes patiently in hopes of a better product, but our patience is wearing *VERY* thin here with these re-occuring problems time & time again.

Anyone ran into this before or has some kind of solution? Thank you for your time. :usa:


Best Regards,
DTE

Well, we've gotton no reply from HPT either by email or from anyone here as of today, so we had to put a customer in a rental car to get him home because of this on-going problem with this software.

He came back here today with his car from 3 1/2 hrs. away to get the problem taken care of, because we told him that that HPT had the corrective fix for the bug problem via the software based on what we were told, so we informed our customer to come on over and we would take care of it for him quickly. Well, so much for that and now it's 5 more hours of overtime pay to one of our employees to help today and another $214 for rental car expenses to get the customer home because of "bugs" that were supposed to be corrected this time around- not to mention the rental car expenses incurred to get our customer back over here to get his car! It's never ending, very expensive and quite frustrating to be "testing' for someone without any compensation in return...

Hopefully *someone* has an answer to this problem that we see is happening with a lot of different vehicle platforms all over the internet, not just the Corvette.

Regards,
DTE

i responded via email.

Thank you and file sent as requested.

DTE

Chris/Keith~
We changed the data entry values in every single table on the speedo page both high and low as per your instructions to see if it would make ANY difference at all one way or another...no good. The speedo on the dash and HUD are still 2.5 to 3 MPH slow, while the scanner and the DIC are dead-on accurate.

There have been 59 views to this thread and no one has any answers????


DTE

We've also uncovered another problem w/ the speedo operation, although it was partially hidden before...

When the vehicle is accelerated hard from a dead stop, right to the point of tire adhesion w/ the traction control button on, but the system not active, the speedo needle will read "Zero" until the throttle is lifted slightly. Then the speedo needle will wake up and "catch up" to the actual speed the car is going. It does not do this with the traction control button selected "off"- at least not that we can tell.

Since everyone that has read this thread doesn't seem to interested in helping or to even chime in with any sort of possible solution to where we have to answer all of our own questions- Chris, Ken or Keith??????????????? This is your product and we're still burning up the overtime hours here trying to sort out all of this ongoing issue for you folks......


DTE

Phil,

we are answering your emails via support. you emailed us only a few hours ago.

Chris...

In a nutshell~

When we made the gear changes in the respective gear ratio data entry areas and pressed the "Commit" button as it should be, the speedo and HUD will be dead-on accurate, but the scanner and the DIC are approx. 50 MPH slow making the cruise control inoperable.

When made changes to that very same file above, only making incorrect gear ratio data entry changes of the "wrong" 1.00 changes in each box just to make it "right", where the scanner and DIC are ow dead-on accurate, but the speedo and HUD are 3 MPH slow now....

Then of course there is the no speedo movement form hard aceleration from a dead stop until you lift.

Three issues and we'll bet they are all related somehow...


DTE

Problem is sorted out on all accounts w/ the help from HPT and some of our own custom speedo calcs. to get it within .391 of one MPH from being dead-on accurate.

Thanks Chris. :)


DTE

glad you got it all sorted out...care to share the stock/modified speedo tune to help out any others with this issue?

the issue is that the auto calculator couldn't handle the stock config on this vette. It seems GM, yet again, has made things a lot harder than they need be and also taken multiple ways to achieve the same thing on the same vehicles.

In future i think we will disable the auto calculator for this particular vette and folks will have to do it manually. It's not hard to calculate the tire revs/mile or the pulses/mile values.

In anycase i will be adding some detailed instuctions to the help file.

Chris...

Chris,

Is this issue apply to the LS7 PCM? I tried a few weeks ago changing the tire size parameter for 345 rear tires from 325 and found that after I made the changes, the dash speedo and the HUD where off greatly.

Howard
Redline Motorsports

yes some A4 corvettes have the problem. If you changed tire width i don't see why you would want to change anything.

I think his tires are 345/35/19, so they are ~.7 taller than the stock tires.

Russ Kemp

Sorry to revive an old thread but I have this exact same issue with my 05 4L65E corvette. I recently installed a rear diff out of an 09 vette going from 2.73 to 3.42. When I accelerate the speedometer stays at 0 until we let off and then it instantly jumps to the correct speed. We have tried not using the auto calculator for the gear swap and we still have the same issue, can anyone elaborate on the answer or upload a file of an 05 A4 corvette that has a tune that works with 3.42s? Thanks!