Air/Fuel Controller Installed

[89Vette]

So as you ?walk? the earth perhaps you should consider ?walking? this site with the same philosophy

(Sounds like you're expecting too much from "Mr. Turd in the punchbowl". After all...He says he's doing the best he can! LOL)

Though I'm skeptical that the VX is programmed too rich from the factory, I will be interested to see how the OP's modifications work. If it does help, I'll wonder if this mod is compensating for another issue (like O2 or MAF).

I think the bigger issue with going lean is to the converters. They die first. Engines can tolerate leaner than stoich burn ratios as lower loads. At WOT, it's a bad idea.

How is this much different than the IAT trick?

[Robbomaz]

(Sounds like you're expecting too much from "Mr. Turd in the punchbowl". After all...He says he's doing the best he can! LOL)

Though I'm skeptical that the VX is programmed too rich from the factory, I will be interested to see how the OP's modifications work. If it does help, I'll wonder if this mod is compensating for another issue (like O2 or MAF).

I think the bigger issue with going lean is to the converters. They die first. Engines can tolerate leaner than stoich burn ratios as lower loads. At WOT, it's a bad idea.

How is this much different than the IAT trick?

Speaking for OUR ECU, which is probably programmed a little differently, when you hook up a bank of sensors and watch behavior you can see where the poor fuel consumption is coming from.
At 20% TPS ign was +40 and A/F was 14.2, At 25% the ign was +12 and A/F was 12:1.......ANY kind of load saw these numbers, with the A/F dipping into the mid 11's at WOT. The system stays in closed loop a lot of the time and has knock sensing so the setup is odd to say the least.

So a lot of the time they are rich and retarded, and thirsty

We are nerdy enough to have got access to the tables in the ECU, but not nerdy enough as to read them & know what they mean.....

[89Vette]

Speaking for OUR ECU, which is probably programmed a little differently, when you hook up a bank of sensors and watch behavior you can see where the poor fuel consumption is coming from.
At 20% TPS ign was +40 and A/F was 14.2, At 25% the ign was +12 and A/F was 12:1.......ANY kind of load saw these numbers, with the A/F dipping into the mid 11's at WOT. The system stays in closed loop a lot of the time and has knock sensing so the setup is odd to say the least.

Wow...Are you sure that's "normal" for the fleet of VX units? If so, it shows that the WOT circuit must be set to engage at 25% TPS. That's certainly possible -- as it's a "trick" for tuners to do this to make a performance tune/motor seem snappier. It also shows why the people getting the best MPG drive (and I quote) like a tennis ball is under the gas pedal.

Running in closed loop is normal. That's what all motors (should) do after open-loop warm-up. Closed loop means the O2 sensor is providing feedback to the ECM for correction of the fuel trim data.

14.2 is the correct stoic ratio for ethanol (E10). So, that part would be correct -- unless you were running 100% gasoline.

[Robbomaz]

Wow...Are you sure that's "normal" for the fleet of VX units? If so, it shows that the WOT circuit must be set to engage at 25% TPS. That's certainly possible -- as it's a "trick" for tuners to do this to make a performance tune/motor seem snappier. It also shows why the people getting the best MPG drive (and I quote) like a tennis ball is under the gas pedal.

Running in closed loop is normal. That's what all motors (should) do after open-loop warm-up. Closed loop means the O2 sensor is providing feedback to the ECM for correction of the fuel trim data.

14.2 is the correct stoic ratio for ethanol (E10). So, that part would be correct -- unless you were running 100% gasoline.

Not a VX - hence 'our' ECU - Jackaroos. Four 3.5 manuals behave the same way.
Well aware of it as a tuner trick - have done it - but not usually seen on OEM setups. Pretty much ditches everything from 25% TPS upwards.
With O² and knock sensors it could be much leaner & more advanced a lot of the time
The supercharged units are returning much better fuel economy than the stockers despite being driven with somewhat more *cough* enthusiasm

[89Vette]

Matador.... Good one! But, it's more like a bunch of bull....

Who's humor is like junior high school

Not a VX - hence 'our' ECU - Jackaroos. Four 3.5 manuals behave the same way.

Does this mean other Isuzu's are set up the same way? Is Jackaroos your slang for ECU hacks?

Well aware of it as a tuner trick - have done it - but not usually seen on OEM setups. Pretty much ditches everything from 25% TPS upwards.

In terms of MPG, yes. But, you've still got increasing throttle openings and variable power.

With O? and knock sensors it could be much leaner & more advanced a lot of the time

And, that's what you hope to accomplish....right?

[Ldub]

Is Jackaroos your slang for ECU hacks?

Jackaroo is what they call the Troop? in Oz...I think...

[Robbomaz]

Jackaroo is what they call the Troop? in Oz...I think...

Not quite. Put correctly, Jackaroo is what you lot erroneously call the Trooper

And I see you fixed your spelin...

[Robbomaz]

Matador.... Good one! But, it's more like a bunch of bull....

Who's humor is like junior high school

Growing up is overated

Does this mean other Isuzu's are set up the same way? Is Jackaroos your slang for ECU hacks?

Its actually the guys that round up livestock here, and the proper name for your Trooper. The girls are Jillaroos. I cant comment on the other Isuzus, cos we havent put anything but Jacks on the dyno, but given the uniformly woeful fuel consumption, probably. Seems silly to me that I can get more power, torque AND economy from an LS2.....

And, that's what you hope to accomplish....right?

Not me, JDM. Although I wouldnt mind. Nor anyone else with one of this engines I'm sure. My response was in regard to your comment regarding running rich OEM - here in OZ, they do, at least on our four Jackatroopers

We have a Rodeo ECU (Rodeo here is a pickup, not a wagon) that we are going to try. Rodeo 3.5s dont have knock sensing, EGR or variable intake runners but they do have the highest quoted factory torque/power of all the 6VE1's sold here so weez thinking maybe the Hitachi ECU has better mapping than the Delphi, plus its a completely sealed unit.

[89Vette]

Growing up is overated

FWIW, my comment wasn't directed to you...

Seems silly to me that I can get more power, torque AND economy from an LS2.....

true, but it's probably in a lighter vehicle, has 2wd, and possibly a 6-spd.

Not me, JDM. Although I wouldnt mind. Nor anyone else with one of this engines I'm sure. My response was in regard to your comment regarding running rich OEM - here in OZ, they do, at least on our four Jackatroopers

Jacka-what? Sorry, I forgot you weren't the OP.

We have a Rodeo ECU (Rodeo here is a pickup, not a wagon) that we are going to try. Rodeo 3.5s dont have knock sensing, EGR or variable intake runners but they do have the highest quoted factory torque/power of all the 6VE1's sold here so weez thinking maybe the Hitachi ECU has better mapping than the Delphi, plus its a completely sealed unit.

great idea!

[89Vette]

We have a Rodeo ECU (Rodeo here is a pickup, not a wagon) that we are going to try. Rodeo 3.5s dont have knock sensing, EGR or variable intake runners but they do have the highest quoted factory torque/power of all the 6VE1's sold here so weez thinking maybe the Hitachi ECU has better mapping than the Delphi, plus its a completely sealed unit.

BTW...Are you certain the cam's are the same? Even within SBC's their can be cam differences which would account for rating's differences.

I'd be surprised if Isuzu left any timing on the table. OTOH, raising PE from 25% to 50-60% could be worth 1-2mpgs.

I'd bet a good 2wd/4wd switching system (or even gear box) would make as much or more difference. (maybe combine the two?) FWIW, any Jeep I've ever seen rated (and/or owned) did much better in 2WD vs 4WD mode. I could feel a difference in power as well. Just seems to be way less drivetrain loss.

Look at the difference in the 2wd vs 4wd Ford Escape's MPGs. Fairly significant in my book. (I wonder if there's any other changes in gearing, etc between these.)