HPP3 Power Tune, and Gas

[EquatorHeat00]

Does the power tuning of the HPP3 drink up more gas then the stock setting. If, so by how much? I heard it makes the car run richer, and it already runs rich right. I know the improvement of the programming is minimal to , but if I'm losing gas mileage I might switch back to stock.

[Joe 1320]

The program will not make the car run richer. Will mileage suffer? yes if you don't keep your foot out of it. You need to compare with and without programming. Doubtful the program is going to affect mixture and mileage to any measurable degree. it is most helpful in changing fan settings, setting automatic trans shift points, correcting for gear swaps, etc. There really isn't much to the engine tuning portion.

[Jeff_in_Atl]

From my research I think the HPP3 power program leans out the WOT over rich condition from the factory. I guess in theory that should make it better on gas. In reality it feels so much better you'll probably do it more so it may make it worse. LOL I also think that I read about it advancing the timing more. That should help the mileage too.

On another note, in my research for how to reprogram my car for the M6 conversion, I ran across many many cases of the HPP failing to complete the programming cycle and the car failing to start afterwards. I know a lot of people have used it successfully but let me give you some options.

The HPP3 cost about $350. I decided it was more cost effective and safer to buy an interface cable from AKM cable for $90 and get www.PCMforless.com to do the programming for me. He has an e-mail program where he will fix anything in the computer and can add his version of a "power tune" for $50. That's $140 vs $350. And I now have the cable and can use free scan and any other PC based software on my car. I'm thinking about buying tunercat for $90 just to be able to mess with it myself.

[Injuneer]

The little bit of tuning that is actually added by the "power program" is only for WOT operation. As long as you keep your right foot off the floor it isn't going to affect your gas mileage in any way. They can't really alter the "closed loop" (part load) portion of the tuning, and still get it approved by CARB and other emissions authorities.