Xcal question

[SuperHO]

this is mostly aimed at Paul, but if anyone else knows and wants to chime in, feel free. my wife's 98 is getting truly craptastic fuel economy, and i'm pretty sure it's primarly due to trans programming and fuel maps due to the amount of carbon on the back of the car. what i'm wondering is if there's a tune you could do to jean out the fuel mixture and firm up shifts while locking the converter sooner at light and part throttle and tin fatten up when it reads more voltage from the TPS?

 

[slowshow]

I, too, am curious to the limits of the XCal...

 

[bacernate]

Paul's a magician. He can do whatever ya want.

 

[SHOZ123]

You can't practically lean it out much beyond closed loop, ~14.6 A/F ratio. You can move the WOT fuel maps around based on load and the WOT trigger TPS position.

 

[SuperHO]

would that improve steady state cruising fuel economy at all? i.e. highway travelling?

 

[SHOZ123]

Not really. If you are in closed loop then it is more a maintenance condition question.

FWIW I got ~27 mpg on a long Interstate 75-80 mph cruise. Around 22 average in my normal driving.

 

[hawkeye18]

ooooh, I think he just told you to fix your shit!

 

[SHOZ123]

HA...

I would say if you have the standard OEM TC lock/unlock BS then the economy at cruising speeds will be better when the TC stays locked.

 

[SuperHO]

i'd say you're right, since the tach's hovering around 3k at 75mph. looks like it's time to start pricing R&R of the trans so i can throw in a new TC and shift kit...

 

[SHO Dude]

Just jumping in here...

There are not many limitations to the programming power of the SCT products. The limitations are on the side of the Dealer (the guy doing the programming). Some know what they are doing, some don't. SCT puts the power in our hands (the hands of each SCT dealer). I doubt very seriously if there is anyone in the country that has more experience with tuning these cars than Paul or myself.

What I tell my customers is that it's not a question of "if" we can change something, it's "how do you want it changed".

Back to the original poster, I'd recommend cleaning the MAF before you do anything else. If you pull the MAF and don't find a Chia-Pet hanging onto the wires, you might look somewhere else.

That said, fine tuning the computer and getting everything out of it will help the fuel mileage a ton.

Call us after you talk to Paul and make your choice on which one to use.

 

[SuperHO]

if you really loved me, Doug, you wouldn't make me choose...

I'm guessin that the first thing I need to address is the torque converter, as I know that thing's almost never locking up. doing that I imagine would seriously increase fuel economy from the 18ish mpg I'm seeing right now. I'll check the MAF when the wife gets home. I'm pretty sure I've got a can of MAF cleaner lurking about somewhere in my garage.