1996 Silverado -- sent for an ecm programmer

[vteco]

Just sent for an ECM programmer/tuner:

The one I ordered was a JET Performance Dynamic Spectrum Tuner Programmer

Beforehand, I watched this video about tuning for fuel economy, though the guy did some (to me) questionable and/or unexplained choices. Also he completely omitted test results, which was highly irritating. Nevertheless I thought the video was interesting stuff.

https://www.youtube.com/watch?v=kVTNq6qbUpc

The Hp Tuners programmer he used does not work with '96 K1500 trucks, but the above mentioned JET programmer does so that's why I ordered it. The user interface is a lot more primitive, but I think it will program whatever is available on a '96.

My main first interest in programming will be transmission shifting points, since so much of my driving relates to hilly twisty roads in the 35 to 45 mph speed limit range.

I'm not going to jump into engine mixture games at this point.

[vteco]

The Jet-14005 DST Flash Tuner has arrived, and I've installed the software and spent a lot of time looking at tuning videos. Very few and not much detail on this particular brand tuner.

I got it from Summit Racing, which had a good discount.

There are several YT videos on a different model Jet sells with very limited tuning parameter choices. That one has a self-contained LCD display.

But this one is a full-fledged tune programmer version, working through a laptop with a GUI. You can adjust seemingly every parameter an ECM supports. Mine is specific to older GM vehicles.

I haven't yet been able to use it with the '96 Silverado because that's awaiting work on the fuel system. But I am now trying to learn what would be best to try as an initial change. I'm thinking transmission shift points.

You are allowed to tune only 4 different ECMs before having to purchase additional licenses, so I haven't wanted to try it out on the Subaru in advance. The Silverado is the main target.

[freebeard]

Can you tune each of the four multiple times?

Here's hoping for good luck.

[vteco]

O yes, definitely you can, freebeard.

[vteco]

I was able to briefly test the new Jet DST tuner/programmer today by reading the Silverado's VCM. This creates a file on your laptop that you can look at using the software they provide, and you can change parameters.

If you do change them, you can write that out to a modified computer file. And if you want to write that new configuration to the VCM, you can do that with a second included JET program.

Right now I'm just studying the original settings on my laptop. I've noticed something I think is a program error, so I've written to JET about that. It relates to pulses per revolution of a speed sensor.

I also noticed that my tank size is listed as 16.7 gallons, when everything I can find on the internet says that a 1996 Silverado K1500 has a 26 gallon stock fuel tank.

I also see that the tire diameter shown in the VCM is a little off, which might (or might not) account for my speedometer reading about 3mph low @35 mph (as measured by local radar speed signs).

There is a ton of information to learn from the settings data I can see now. I'm not anxious to change anything yet, but very interested to understand the parameters I'm seeing. There are hundreds, maybe thousands, including the tables.

It's really interesting!

[Logic]

This is going to be interesting!
I assume you planning to change gear at higher rpms on your hilly roads?

[vteco]

Not sure yet about anything -- I need to understand a lot more than I do so far.

Any thoughts?

[Piotrsko]

Speedo could be correct strange as that sounds. How far offset is the radar gun from your position on the road? We have one here that I pass frequently on a curve that varies as you drive by but is always couple miles per hour higher than what the car indicates.

[vteco]

Could be, Piotrsko.

Sorry, missed the other question about speed difference...

Two radar speed signs agree that when I am reading 38 mph on my dash's speedometer, I'm actually going 35 (the posted speed limit). One of the signs is shortly after a curve in the road. The other is on a long straight slight grade.

Of course they both could be wrong -- they're on the same road, not far apart, and likely from the same manufacturer.

I guess once I get the truck back from the fuel tank replacement (today or possibly tomorrow) I can try checking the odometer accuracy on a measuerd length of highway, and also check speed against GPS in Torque app on the phone.

[vteco]

If interested, I'll post a few screen captures fromf my '96 Silverdo's PCM, as presented by the Jet-14005 DST Flash Tuner.