PCM re-program for 97 3.8L w/3.42...

[Texas4ever]

I just got an appointment at the GM dealer to get my PCM re-programmed on Tuesday. I am going from a 3.08 open diff to a LSD/3.42 rearend combo on Monday on an A4. I was going to try the SCU2000 or maybe the SLP product, but it looks like good 'ol GM is going to come thru for me...!!

Let you know how it goes next week...
getting faster and faster....!!! [img]graemlins/toto.gif[/img] [img]graemlins/toto.gif[/img]

[Dirty8-un-Dreds]

FYI: many people here have had problems trying to do this through GM. The techs at gm largely ddo not know how to re-program a PCM. They know how to look for a way to change a setting to 3:42's (but there is none) the dealership that i went to accomplished nothing in two hours of work and then tried to charge me for not doing anything. Be careful you may be getting burned.

[DrFix2Fly]

My dealer told me they could do it and then scratched their heads like monkeys when I actually got there. I now have the Jet calibrator installed.

[Texas4ever]

Thanks for the input... I will probably still take to the dealer because the mech SOUNDEDlike he knew what he was talking about.

DrFix2Fly, how do you like the Jet SCU...?? I have heard mixed results from these units. I heard it helps the speedo and odometer but the shift points are not as easy to reclaibrate. Has this been your experience as well...???

I am just looking for a good way to get the new gears to show the correct speed and shift at the right time.

thanks... :rolleyes: :rolleyes: :rolleyes:

[SLOWBRAEATER]

Sounding like you know what your talking about and actually knowing are two completely different things.

[Texas4ever]

I agree, maybe the mech does not know what he is talking about, but I will know in just a few minutes of talking to him if he does or not. If he does not, I will walk away...

thx

[99redcamaro]

any updates??

[DrFix2Fly]

I like the SCU 2000. It was easy to install and calibrate. If you want to make sure your speedometer is accurate after installing one, either pace another car with a buddy or use the mile markers on the highways. Zero your tripometer at the first on and see if your tripometer reaches next mile as you pass the signs. The reason I say to use ten mile markers is because they aren't accurate from one to the next but if it seems to average out after ten, you are all set.

[Texas4ever]

The GM tech would not/could not do it. My speedo is off by a factor of 1.11%. So if I am running 50 exactly my speedo will show 55(50mph x 1.11 = 55.5. This 1.11 factor is going from 3.08 gears to 3.42's. So, it is really off by around 10 or 11 percent. For example if I am running 100 (100 x 1.11 = 111) my speedo will read 111. This is why you hit the speed limiter faster.

I have not had this fixed yet. I am still trying to decide which way to go to correct the problem. A buddy of mine has an S-10 with and LT1 in it with a 95 ODB-I PCM in it. He showed me the program, Autotap, all the shifts are based on MPH and throttle position. So my 1-2 shift is around 5600, it is only off by around 200RPM's which is really not that bad. The problem lies when it does shift the RPM's drop lower than they should, which puts me slightly out of my power band in the next gear.

I need to get this fixed, but I am not sure if I should use PCMforless, not because of the money, but because I do not want him to just change the program and it could make the engine run to lean/rich and I have no way to montior this.

Any suggestions would be appreciated.

Someone needs to write LSI Edit for the V6 guys.

For now I can live with it, but for the track I will need to change the PCM in some way to correct the speedo and shift points.

thanks...

:rolleyes: :rolleyes: :rolleyes:

[speedy-v6-camaro]

<blockquote>quote:</font><hr>My speedo is off by a factor of 1.11%. <hr></blockquote>

11%

[Texas4ever]

you are correct.... but if you multiple

50mph (actual speed) x 1.11 = 55.5mph(speedo shows)

but yes it is 11%...

another way to look at it would be

(55.5mph(speedo shows) x 11%) = 6.105(delta off in mph)

55.5mph - 6.105mph = 49.395 or 50mph (actual speed)

This will work for any speed, to make it easy let's look at 100mph.

(100mph(speedo shows) x 11%) = 11mph (delta) duh..

100mph(speedo shows) - 11mph = 89mph(actual speed)

Because this is a percetage error the faster you go, as you can see the worse the speedo will be off.


just everyone remember this is going from 3.08's to 3.42's. The precentage or factor will be different if you have different gears. Tire height will also effect ratio. If you change the tire height the formula would have to change to take that into account as well.

thanks...

if ya think about it, it is just really easy math.....

[img]graemlins/burnout.gif[/img] [img]graemlins/burnout.gif[/img] [img]graemlins/burnout.gif[/img]

[Redsix]

Texas4ever,

Houston huh? Make a quick trip to College Station and you can go to the dealership here and ask for a Paul Costa. He has done it for many people down here. Just a thought. ;)

[ March 02, 2003: Message edited by: Redsix ]</p>

[SLOWBRAEATER]

i told you the guy was blowing smoke up your rear