Canadian Hummer Club Forums

Anybody know if I can just change the calibration of my speedometer with an OBD2 programmer or if I actually have to physically remove and program the ECU/PCM in my truck?



I like the idea of a PCM-Tune, but I doubt it will make the much difference for a manual tranny unless I ask for timing changes on a higher octane tune.

I haven't been able to find a handheld programmer that officially supports the H3 3.7 but the laptop style tuners (HP Tuners for instance) can adjust the speedo calibration. A little pricey though at $500!



Or I can make you a great deal on a Scan Gauge... Super easy to correct your speedo and a fraction of the price!

I thought scanguage can only read, not write to the ECU?



If it can change it can I just borrow yours for a few minutes <img src='http://www.canadianhummerclub.com/forum ... rgreen.gif' class='bbc_emoticon' alt=':mrgreen:' />



I keep coming back to this "PCM for less", although I am skeptical of the gains they claim.

I'm skeptical of the canned tunes, especially claiming more power from 87 octane with no other modifications... You could probably go to any tuning shop in Calgary and just get them to recalibrate the speedo for you since they'd have 'real' programmers like the HP Tuners. I had my Mustang dyno tuned at Tecmotion, but he does all makes/models and I bet he could do the speedo for you no problem.



Scan Gauge just has a spot to enter a correction value for the speedo, so while the stock speedo will still show the erroneous speed the digital speedo on the Scan Gauge will be accurate. That's how I'm doing it in my H3 anyway! Not a 'perfect' solution but definitely it gets the job done.

I have a similar OBD2 device from innovate I could do that with as well, I just want the dash guages to ready correctly both for speed and so my odometer is more accurate.



Yeah that is the thing with these PCM tunes, you can fool a lot of people into thinking it has more power just by modifying the throttle responce... which is what I think is going on with this PCM tune. Everybody keeps mentioning the "off the line" power increase, but then says it doesn't really have more power on the highway.



Really the only way to get more power out of a stock engine is to lean out any built in tolerance for the fuel and timing... which is better left to tuners and people with AFR guages.

Bah, I will just put up with it for now. I am so freaking broke from that Road Armor nonesense for a while.

Yeah I think you got it just right and I totally agree, leave the tuning to the experts and when you're going for more power get on a dyno with all the proper equipment!

I plan on buying the Diablo Sport Trinity as it does both.



Now bear in mind that a tune on a gas engine does not give a tremendous increase in horsepower. It does give some, for example on my 6.2 it only offers 22 more horsepower and a smidgen more for torque, which is ok - but more importantly it improves the overall performance, mileage, and shift timing. This one is more pricy but I like the fact that it tunes, but also stays plugged in and monitors your rig for you. Has diagnostics, recalibrates for tires, scans and clears error codes....

Don't forget though.... mess with the PCM - voids your warranty.



The Trinity will restore your original settings if you need to take it back in...... Can the dealer track that.... don't know...

Hey if I buy one of these, anybody else want to pitch in?



http://www.jegs.com/i/Superchips/848/28 ... tId=837887



I also sent an e-mail to Hypertech today asking if thier "speedometer recalibration" will work for an 09' H3T.