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Post by Letitroll98 on Mar 30, 2005 14:01:29 GMT -6
What's the latest word on flashing the post '97 4.0L V8 PCM (OBD II) for improved performance. Is there a program available? Has anyone done it? Do you need to supercharge or radically mod to get any benefit?
I'm thinking about going for some stealth performance mods, i.e. less on noisy cat backs or whiny intake guts and more on quiet power. Already priced up some Delta 50's and Turbo Flows that are more rumble than shout. Enlarged throttle body assembly is possible. Wondering if a PCM flash alone would be more effective or concurrent with other mods. Thoughts?
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Post by Marc on Mar 30, 2005 19:09:21 GMT -6
So far as I know, only the dealers can flash the OBD II computer. Shift points can be increased & the top speed limiter can be taken off. Some dealers will do this, others won't. _________________ GM!!! BRING BACK OLDS!!!  |
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Post by JimW on Mar 31, 2005 9:16:03 GMT -6
Only in GM cars built after 2000 using the TECH 2 system. Dealers will flash the PCM and change things like rolling diameters for bigger rims etc.
You can also personalize your cars' Driver Information Center. I've seen a 2000 SSEi with a custom greeting display on the DIC when the car is started
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Post by stonecoldcrazy663 on Mar 31, 2005 14:28:23 GMT -6
i have a 98, and your saying that you can only flash a 2000+ car? how much do they charge to reflash roughly if i can do it to mine
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Post by Aurora40 on Mar 31, 2005 14:57:43 GMT -6
I'm pretty sure by the time they went to OBD-II, all GM cars had flashable PCM's. In fact, by the early 1990's many GM's had this.
However, the thing is getting a program to flash it with. Some things are configurable via a Tech-2 or similar device, and some things are in the actual program. I'm not sure you could raise the redline via a Tech-2 unless you had a program with that raised redline to flash it with. I think for the speed limit adjustment, you'd need a program to use, like if you had a non-autobahn, you'd need an autobahn program (which would mess up other stuff probably due to the different final drive ratio).
On a car like an STS that had several speed limits based on the tire option you picked initially, you could probably take the program for a car just like yours, but with the tire option, and use that to get the higher speed limit.
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Post by Letitroll98 on Mar 31, 2005 17:51:01 GMT -6
However, the thing is getting a program to flash it with. Exactly what I was asking. I would imagine you'd run a dyno and adjust timing advance curves, shift points, and add a bit of richness to the fuel mix. They do this with or without mods, like superchargers and cat back exhausts, for OBD II Cameros and Vettes all the time. Can't find a thing on any Premium V8 engines. I guess there's no market for anyone to invest the time. |
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Post by Aurora40 on Mar 31, 2005 18:09:29 GMT -6
Exactly what I was asking. I would imagine you'd run a dyno and adjust timing advance curves, shift points, and add a bit of richness to the fuel mix. They do this with or without mods, like superchargers and cat back exhausts, for OBD II Cameros and Vettes all the time. Can't find a thing on any Premium V8 engines. I guess there's no market for anyone to invest the time. I think you'd have to decode the program first. I suspect that's the real challenge. I don't think you can just set fuel and timing points via the Tech-2 or similar programmer. |
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Post by Marc on Mar 31, 2005 18:51:12 GMT -6
The procedure goes like this: You download the programming changes from the GM site noted below to the scan tool. Then you connect the scan tool to the OBD II port and then reflash the PCM. The catch: you have to get a user name & password from GM to get to the site noted below. I don't know whether or not GM would give those to DIYs. www.gmtcny.com/links.htm Click on "GM Techline" _________________ GM!!! BRING BACK OLDS!!! |
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