I want to eco-tune my 95 GM ODBI PCM

[GasSavers_backslash]

Hello Everyone,

I know I don't post alot, but I do read abunch here. Anyway, I notice that many of you are forunate enough to own 1996+ cars that have the abilty to be tuned with a programmer and be read with an SCII. However my issue is because of school, I'm stuck with the car I own which is a 1995 Buick Park Avenue Ultra (Which means it's supercharged unforunatly and only gets 23 MPG ).

Because of the year it has a OBDI, which so far I found to be useless. However I've been Google-ing lately, and have found multiple websites that say sell a special OBDI programmer for sale. The price is very steep and they don't show my car, but rather show 1995-era sports cars such as the Corvette (I guess they don't think people use these things for eco-modding ) .

Now I'm wondering two things, one, Is any proven possable method that I can alter my car's pcm values?, and two, Is the cost of doing so affordable enougth that you won't be losing money in the end?

Thank You So Much!
Keep on Hypermilling!

[theholycow]

I suspect that those don't let you manually tweak much, but rather upload a whole pre-set bunch of tweaks made for power.

I wonder if it's possible to remove the supercharger belt without hurting anything?

[kamesama980]

I don't remember if you have a seperate belt for the SC but regardless, without the SC spinning, you have a rather large blockage in the inlet tract.

If you car isn't specifically listed on the ODB1 programmer site, I really really doubt it can do anyhting for your car. many of those cars you have to remove and replace the main chip. Either way, you won't find an aftermarket chip for economy I guarantee. My advice is the same as with any GM... good tune up, high tire pressure, light throttle, low speed.

[GasSavers_backslash]

What about running an underdrive pulley and a new belt, for the sc and alternator?

[DRW]

If you have electronic ignition, a programmer might let you add timing in the part of the map that's used during light throttle/ low rpm cruise.
I'd check what can be changed, then find out if those things might help economy.
As far as cost vs. benefit, you might gain 1-3mpg, which won't save much.

[GasSavers_backslash]

DRW: I noticed you had a custom EPROM for your laser, what has that done for you? Just wondering.

[DRW]

Originally Posted by backslash

DRW: I noticed you had a custom EPROM for your laser, what has that done for you? Just wondering.

It's given me many hours of enjoyment and a superiority complex.
It's hard to say how much mpg I got solely from programming the ecu since I also started hypermiling around the same time. I can say this for sure, everytime I extend the ecu's lean burn range I see a small jump in FE. My Gaslog has some interesting reading if you can spare the time to read it. I've kept track of the ecu changes over the years.