Aloha! VERY lean low RPM, heavy load/boost...like 17:1 on my AFR gauge..any ideas?

[Skidmark]

So, here's the situation. While climbing a long hill...or even on a flat straight....if I'm at 2500-3000rpm in a higher gear and I accelerate the car to put it in a low rpm "boost" scenario, it gets scary lean (17-ish:1) and stays there.....until I lift.
If I'm accelerating briskly from a stop and rowing through gears, AFR is 11-12:1 ish like I'm assuming it should be.
Any ideas?

[Tobias22]

For what it's worth, I'm having the same issue. I'll let you know if I find a solution. After checking all the vacuum lines, the bypass actuator and the boost reference line, I am now onto changing the fuel pump.

[Tobias22]

No luck with the fuel pump. On to checking vacuum lines again.

[Tobias22]

Any progress? I'm still at a loss.

[Skidmark]

Still diagnosing .
stay tuned

[Skidmark]

So I double checked the tuning cards which the installer coiled and placed inside the area under the steering wheel. What I discovered seemed to fix my problem.
1. the boost reference line where it goes from small tubing to larger clear tubing and attaches to the sensor….the clear tubing is so soft it actually folded and I’m sure was giving an inaccurate reading.
2. the settings on my boost fuel card were lean on the green-blue setting. So I bumped it up a notch.
3. I also found a vacuum leak at the EGR valve.
4. ALL of the large 3/8”(10mm) vacuum hoses are WAY, WAY too soft and easily collaps. There is no way these hoses are vacuum rated. I had to replace several hoses related to the Vacuum hoses on the intake side of the motor.

Im now getting a 11:1 AFR at low rpm/high load situation….it gradually comes up to 12-12.5:1 as revs increase.

I have an autocross this weekend….I’ll update.
Skiddy

[Tobias22]

Thanks for reporting back. Still in progress on my issue. Let us know how the autox goes.

[Skidmark]

AutoX is great ! Now tires are the weak link…not motor..

Having new issues with the damn cards…..
Now at full throttle rowing through the gears AFR goes to 10:1
High load, 3-4k rpm full throttle and AFR has a mind of its own.
Sometimes it’s 10:1, other times it’s 11:1 others it’s 14:1 and SOMETIMES power drops instantly and the AFR is 18:1 !

Super frustrated.

Main issue is I have to do a sea level to 8k foot climb and back down to sea level to get to the track on the other side of the island…… super lean/rich AFR is bad.

Not sure what is going to make these dang cards more consistent…?
”Skiddy”

[Skidmark]

Aloha Tobias, any luck?

I have checked everything…and checked it again….
I have played with the cards incessantly only to not see a noticeable difference under our particular situation. I do have situations when accelerating briskly, the AFR will slam from 11:5 to 17:0+ with a noticeable loss of power when it does so….and stay there for several seconds, then richen back up without any changes in throttle position or loads. Dangerous stuff !

Yesterday, I fiddled with the cards for almost an hour while climbing a grade. Never really saw a difference in AFR’s in the high load, mid rpm range. 4th, 5th and 6th gears.
Boost Fuel Control :
I brought the red/blue as high as 7 lights
Green/Blue 7.5 lights
Yellow/blue 6 lights.

It appears as though the boost cards are registering boost (via their lights) but they are far from consistent or reliable.

My paperwork shows these as the “default settings” ??

Green/Blue = 4
Yellow/Blue = 6
Red/Blue = 3

They just don’t fix the problem, nor work consistently.

Any help is appreciated.
Skidmark

[Tom @ Fast Forward]

Skidmark, Do you have access to an OBD2 reader? If so, what is your long term fuel trim (LTFT)?

[Skidmark]

https://www.youtube.com/shorts/NpQdQIlgKtk

https://www.youtube.com/shorts/lTNf088zhfA

[Skidmark]

Aloha Tom,
I do not have a fancy OBD2…..mines like 10 years old.

[Skidmark]

Running out to get food/valentines card……be back shortly. 🤪

[Tom @ Fast Forward]

Hard to read the AFR on the video. Numbers are just blinking. Probably the syncronization between camera frame speed and AFR gauge? My guess is that the stock ECU likes your slow increase in boost and is not going open loop to let the cards do their job. If you put your foot flat on the floor, does it get rich?. AFR is based on three things. RPM, pressure (boost) and engine load. When you accelerate slow like that, engine load is low.