WOT voltage - car runs lean?? Gen2 w/ G chip

[breiter]

I just installed a Gen2, Extender Extreme G Chip, 3.5 Maf w/ 3.5 Maf Pipe and a Big Mouth Air system. I have 4.40 volts on my ScanMaster at WOT. I think this is enough voltage to trigger a WOT condtion but I only read 710 - 730 on my ScanMaster after a first and second gear pull. I adjusted the fuel pressure from 43 to 46 to 48 to 50 lbs and still can't get the readings above the 720's. I am trying to get to the 790 to 820 range.

The car absolutely flies and I don't have any spark knock. I am running 18lbs of boost on a fuel mixture of 2 gallons of 110 and 5 gallons of 93 octane. I run 60 lb Mototrons with a street chip setting. I have added 4% fuel increase to Low Gear WOT via the Extender Extreme G Chip and even tried adding 5% increase Main Scale from the Gen2 but no improvement. I have not changed the default values for the User Modes on the Gen2. I have a new throttle cable I plan to install it tonight because I think the old one is stretched. I should be able to get a little higher TPS reading at WOT but not sure this will help. The Extender Chip is set at 65% Dutycycle but I don't think that has anything to do with it. Any ideas?

 

[breiter]

Anybody have a suggestion?

ttt

 

[bilt2run]

I am experiencing the same thing

 

[D's GN]

Are you using the wideband correction input on the Gen 2?

 

[breiter]

Not on the car yet but I do have it. It is disabled on the Gen2.

thoughts?

 

[my1stgn]

Maybe you have a lazy O2 sensor? Could be going out. FYI (just incase you didnt know, not trying to be a smartazz) But O2 sensors are basically little "batteries" sort of. They produce voltage by comparing the diference in the exhuast oxygen and the outside oxygen. Once they get old, they end up producing less, and less voltage (causing your car to think its lean, then the car constantly adds fuel to try to achieve 14.7-1 AFR when in closed loop) So you end up wasting fuel and your economy takes a crap (thats why the recommend O2 sensor to improve fuel economy, ect) Well anyways, to keep it simple, it might just be your O2 sensor being crappy since you say your car is strong and you get no KR..... just a thought, hard to diagnose over the internet

 

[TurboBob]

It sounds like your car is running ok.

What did you set the settings to?

What spark advance are you running?

Do you know what your fuel pressure is doing at WOT?

What is your injector pulsewidth at WOT?

Did you add any fuel in the high load page or the airflow page?

Bob

 

[breiter]

To answer the O2 question - I have a heated O2 sensor but it could be bad. It has about 5k miles on it. Are you saying that the sensor could be giving me a lower reading than what is actually happening?

To answer Bob.

There are a lot of settings so I don't know how to answer your question. I did not add fuel to the high load but that is a good idea. I added fuel to the low and mid range but now that you mention it the high range seems to be the problem. I will add 5% and go up from there.

I did add 5% at the Main Scale page but nothing changed. I do not know how to answer your question about the injector pulsewidth? Again, the Gen2 is basically default to the stock settings other than the MAF settings.

I do not know my fuel pressure at WOT. The G Chip instructions state to set the fuel psi to 45. The Big Mouth air kit says to add a few pounds. I will adjust back to 46/47. The spark advance would have to be whatever the default of the G chip and the Gen2. I have not modified the spark in either the Gen2 or the Chip. Assuming the Main Scale 5% would increase all setting by 5% the spark may have been increased 5% but I don't understand the Gen2 well enough YET but I will figure it out.

thanks for you help in advance.

 

[Mike Licht]

Set your fuel pressure at 45 and NEVER move it. You no longer tune that way. Move the main scale back to "0" By adding 5 there and 5 in the low load area you have added 10% at idle which I am sure is driving the BLM down. Adjust the low load until the BLM comes into range. Go to the high load add about 5% at 3000 and 10% above that to 4000 and 15%$ above that. Make sure you set the timing for the type of fuel you have. go make a blast and see where you are. Let me know if need help
Mike

 

[breiter]

Thanks Mike. I will make the changes tonight.

 

[D's GN]

When I made my 10sec pass my scanmaster was reading 740mv...the car was not knocking and pulled hard picking up 24mph from the 1/8-1/4 with the torque converter unlocked. I datalogged my runs with my Zeitronix wideband and checked it thinking it was way lean at 740mv but the AFR was a steady 10.5-10.9 all the way through and EGTs were 1500s climbing to 1650 at the end pushing 6000rpm. I guess the low MV's on the Scanmaster aren't so scary afterall? Hope this helps

 

[my1stgn]

To answer the O2 question - I have a heated O2 sensor but it could be bad. It has about 5k miles on it. Are you saying that the sensor could be giving me a lower reading than what is actually happening?

Well if you have a bad or lazy O2 sensor then it might not be able to produce to high a voltage (ie it its around 750mv) If you can look at your crosscounts to see if the O2 sensor is pretty active @ around 2500 RPM. But I would think if your O2 sensor is only 5K miles old, it should be fine. Its a possiblity but best way to check your actual A/F is with a wideband.

 

[breiter]

thanks for the replies. I think I can resolve this with tuning the Gen2 and adjusting my G chip.