New HPT User
I just picked up HPTuners (non-pro version) with 6 available credits off craigslist. Lots of research still to be done but thought I'd see what other, smarter, people think of the tune on my car. This is a generic bench tune that was loaded on when I sent my comp and harness out to be modded for my swap. Car has been running fine for the last 3 years but I always wondered about the tune that was put on the computer. Now that I can see the tune, there are a couple basic things that have me scratching my head but I'm also totally lost at this point on the more "heavy" aspects of fuel and spark. I've attached the tune file for the car for review if you care to take a peek. Any and all info. you are willing to provide will be greatly appreciated.
Car is 1987 Monte Carlo SS. 2004 5.3 (flex fuel from the PN of the injectors) and 2003 4L80E. 3.73 rear gear and only modification is Mid-length headers; bone stock everything else. Car has run 13.67@104 in the 1/4 on 87 octane gas. MPG is 18 no matter how I drive.
I'm hoping that other HPT users can see the tune. Like I said, totally new to this stuff...
Thanks,
The VE table looks smooth.
However the spark tables have the lowest advance #s I have ever seen at high throttle - 8 degrees at 3200 rpm and a max of 12 at 4800. And that is the high octane table!
Was this designed to run on cheap wine or something?

Also, the Injector Flow rate table has all equal values (33). That means the pressure regulator needs to be vacuum controlled. If yours is not, you need to change that table.
I'm still learning how to look at and diagnose other people's tunes.
Since this is swap into a (lighter) car, I suspect the OP wants to get more performance out of it and won't be towing with it.
Since swaps often change how the fuel system is plumbed and regulated, it is important to know how the type of pressure regulator affect the injector flow rate table (IFR).
Last edited by mrvedit; Apr 9, 2015 at 01:45 PM. Reason: typo
mrvedit is correct, I would like to optimize the system mostly for power but also would like to squeeze out more MPG. As he said, the car is lighter (stock is ~3800lbs) than the truck it originally came from and won't see the hauling/towing that it was tuned for.
2xLS1: thank you for checking the tune against a stock one. Did you find it on the repository or is it one you have saved to your computer? I'd like to see it too if it wouldn't be too much to ask you to upload it. Things that have me wondering about what they did are DFCO basically disabled as well as lean cruise. Are they set that way from the factory or did the tuner change the settings to cancel them out? Lean cruise would bump my MPG for sure because most of the time I'm on the highway with the car.
Some of the settings in the trans look a little weird too. Like why is 1-2 shift set to super hard at low and high RPM but soft in the middle?
Reading up on this stuff continues...
Thanks for the help,
And Lean Cruise can only be enabled with hex editing the file or some other tuning software than HP Tuners. There is one out there that lets it be enabled quite easily. Even if you populate the tables with HP Tuners they will not be used. It is an EPA thing that HP Tuners chose not to violate.
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And Lean Cruise can only be enabled with hex editing the file or some other tuning software than HP Tuners. There is one out there that lets it be enabled quite easily. Even if you populate the tables with HP Tuners they will not be used. It is an EPA thing that HP Tuners chose not to violate.
Neat little fact on the lean cruise, guess I'm stuck with 18mpg for a while
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Neat little fact on the lean cruise, guess I'm stuck with 18mpg for a while

Rather than enabling your lean cruise you can work on the O2 RL switch point tables & Mode vs Airflow table & lean your AFR mixture that way. Last edited by ctd; Apr 12, 2015 at 08:19 AM.







