I started having a very odd problem. While boosting, the AFR will swing totally lean for no reason at all. As you can see in the graph above, the afr will peg lean at which point I take my foot off the gas. Starting the car, idle and cruise are all perfectly normal.
The fuel pump installed is about a 2 year old walbro unit.
I verified the vac line to the fuel pressure regulator, and that seems to have no problems.
Seeing as how this is a Toyota 3sgte engine, I have no easy way to take a fuel pressure reading.
Any ideas on whats going on here?
Log attached below.
Fuel cuts out under boost.
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slow_hemi6
- Super MS/Extra'er
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Re: Fuel cuts out under boost.
Did you know that full lean on most wide bands is also the reading for rich beyond its measuring range.
Find the Manuals up top under Quick links: Manuals. 
Cheers Luke
Cheers Luke
Re: Fuel cuts out under boost.
No, I did not. However having owned the same gauge for so many years, I have never seen it do this.slow_hemi6 wrote:Did you know that full lean on most wide bands is also the reading for rich beyond its measuring range.
I also noticed this happening when I was holding the boost at a 11.5 afr. It would hold for a moment, and then swing fully lean.
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nathanhardy
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Re: Fuel cuts out under boost.
I wonder if you're blowing the spark out and that causing the lean mixture on the wide band... check your plug gap too
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Re: Fuel cuts out under boost.
That, I've never heard of. What I *have* read about is that a misfire (for whatever reason) shows as dead lean because all the O2 is unconsumed.slow_hemi6 wrote:Did you know that full lean on most wide bands is also the reading for rich beyond its measuring range.
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QuadraMAP Sensor Module -- PWM-to-Stepper Controller -- Dual Coil Driver
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QuadraMAP Sensor Module -- PWM-to-Stepper Controller -- Dual Coil Driver
Coming soon: OctoMAP Sensor Module
TTR Ignition Systems
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racingmini_mtl
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Re: Fuel cuts out under boost.
I also have never seen that for any WBO2 controller. I'm not saying it's not correct but I'd like to have a link to some manufacturer information on this.slow_hemi6 wrote:Did you know that full lean on most wide bands is also the reading for rich beyond its measuring range.
Jean
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slow_hemi6
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Re: Fuel cuts out under boost.
That's what I am talking about, being so rich it suffocates the sensor. I have had it happen on mine without any noticeable miss. You always see it go extremely rich first then dart up to full lean yet there is no associated change in PW. Took me ages to work out I needed less fuel to get rid of the "lean out".
Find the Manuals up top under Quick links: Manuals.
Cheers Luke
Cheers Luke
Re: Fuel cuts out under boost.
I'm not sure if thats exactly what is happening in my situation, but I do think that you are onto something. I remember seeing videos that show the wideband peg lean on a sensor that is failing. My sensor is only about 2 months old, but failure is possible.slow_hemi6 wrote:That's what I am talking about, being so rich it suffocates the sensor. I have had it happen on mine without any noticeable miss. You always see it go extremely rich first then dart up to full lean yet there is no associated change in PW. Took me ages to work out I needed less fuel to get rid of the "lean out".
I will also change out the plugs to see if thats an issue.