ECUtune Stage2Av1 and Stage2Av1F

[longassname]

The main thing you will get affecting your afr at idle is the coolant temp based fuel enrichment. If your coolant temp is cold the ECU will richen the afr up substantially. As the coolant temp reading increases the enrichment decreases. At operating temp the ECU switches to using the o2 sensors to rapidly fluctuate afr around stoichiometric.

[Tapani]

Yes, all my observations have been when fully warmed up. It actually goes into closed loop very quickly even after a cold (35F) start up - just a few miles is required - just like it did before. The only thing was the low idle richness. Let's see how it goes :-). Driveability is excellent, no hickups and tons of torque (relatively speaking, of course).

For some reason I even get the full throttle up shifts at around 6800 rpm. This was hard to investigate when I hit the fuel cut off at five grand before the stage 2. Seems to work now, at least with the stock TCU (with incorrect gearing parameters).

Tapani

[immortal_suby]

Stage 2 update: just drove 1700+ miles (from SC to NY and back) on Stage2Av1 and got the best mileage I have ever done in my 193k miles of svx ownership. High tank was 27mpg. Averaged 26mpg. This was on my 92 svx which flipped 293,000 miles during the trip. Speeds were in the 70-80 range with gps average for the entire trip at ~70mph. This wasn't easy highway mileage, this was up over the mountains through west virginia, virginia, PA mileage. Car was full of my deer hunting gear as well.

The amazing part to me is that I wasn't trying to do good on mileage. I was moving swiftly throughout the trip trying to make good time. I don't slow down going up big hills, in fact I usually get up to around 80 so the engine is making enough power to go right up without unlocking the TC or losing speed.

Great software! Thanks LAN!

[longassname]

I guess this is as good a place as any to post this: The SVX ECU is programmed with a slow idle and a fast idle. It uses the fast idle when the AC is on and the pressure switch is activated. If the AC isn't on or the pressure switch isn't active like when it's colder than the ac is set to it uses the slow idle. A lot of camshaft profiles/combinations that perform very well in the SVX give it a really surgy slow idle. I've been able to fix this with some modifications to the data thresholds used for the slow idle in combination with adjustments to the idle stop screw on the throttle body; however, this has proven difficult to impossible for a lot of others.

Every cam profile I've made or has been made by others who communicate with me still idle well at fast idle (when the ac is on and the ac pressure switch is activated). This gave me the idea to just force the ECU into fast idle whether the ac is on or not. This should enable anyone with cams to have a good idle without having to make adjustments to the idle stop (which can't even be done right without either the ECUtuner software/interface or a select monitor).

While my explanation of slow idle vs fast idle is simple and straight forward the actual implementation of it in the firmware is lengthy and hopelessly entertwined with lots of stuff. The most straight forward way to modify the code to accomplish the goal was to set the bits which indicate the ac is on and the ac pressure switch is on: bits 2h and 20h of fa0 which is stored in memory at 105a. This modification is available as a special order in my stage1av1 or stage2av1 but I'm going to give you the technical details here so it's public in case I get hit by a bus or something.

The ECU writes 105a as a whole byte. The location of the code will vary depending on the version of firmware your ECU has but the code will be the same and will only occur at one location so you can easily search it out. It is:

8D5A10 <-that means store acl A to memory location 105a

I replace that code with the following:

20F08F <-that means jump to sub routine at 8FF0

8FF0 is just a blank space where I could store my code. My code does an or with the accumulator contents which sets the bits for the ac and ac pressure switch if they aren't already set, then it writes the acl contents to 105a and returns. It is, of course, placed at 8ff0 and reads as follows:

0922 <-that means or acl a with 22
8d5a10 <-that means store acl a to 105a
60 <-that means return to sender


To make a long story short it works as planned so with this modifcation we can make SVXs with performance camshafts idle well without having to make complicated adjustments.

[icingdeath88]

If I send you my stage 2 can you do this for me?

[longassname]

Originally Posted by icingdeath88

If I send you my stage 2 can you do this for me?

Ya I can do that.

[svxfiles]

BTW, I have two ECUTune 1AV1 upgrade chips that I will be bringing to Reading, so if youse Guys want some better performance and gas milage, maybe I can install them at Reading, justdon't tell Di!

[pearlm30]

I might be interested. PM you for details

Originally Posted by svxfiles

BTW, I have two ECUTune 1AV1 upgrade chips that I will be bringing to Reading, so if youse Guys want some better performance and gas milage, maybe I can install them at Reading, justdon't tell Di!

[Freeman]

Bring a few lol.

[THE NEW GUY]

Originally Posted by svxfiles

BTW, I have two ECUTune 1AV1 upgrade chips that I will be bringing to Reading, so if youse Guys want some better performance and gas milage, maybe I can install them at Reading, justdon't tell Di!

just some question: where is Reading? What is a PM?
will a second stage chip change (2av1) improve the mileage compared with a firts stage chip change (1av1)?
thanks

[svxfiles]

Originally Posted by THE NEW GUY

just some question:
1)where is Reading?
2)What is a PM?
3)will a second stage chip change (2av1) improve the mileage compared with a firts stage chip change (1av1)?
thanks

1) Reading, is the/an anual SVX get together held in Morgantown Pennsylvania, USA.
2) A PM is a "Private Message" as used by people on The Network.
3) The Stage 2, version Agressive, is to allow more power from our engines if they have been modified to make more power.
So the answer is no, they are not for better gas milage.

[THE NEW GUY]

Originally Posted by svxfiles

1) Reading, is the/an anual SVX get together held in Morgantown Pennsylvania, USA.
2) A PM is a "Private Message" as used by people on The Network.
3) The Stage 2, version Agressive, is to allow more power from our engines if they have been modified to make more power.
So the answer is no, they are not for better gas milage.

as always, you have the direct answers I´m looking for. Thanks SVXFILES.
two more questions,
1.- is the 1av1 capable of extract more power from my car compared with an old version of stage 2 (2v6) and changing the injectors and MAF? which configuration is better despite the cost?
2.- how to send a PM to somebody?
thanks again.