i have an upgraded ct26, full 3in exhaust, 550cc injectors, lexus afm, aeromotive afpr, aem uego wideband. the wideband at an idle is around 14.8-15.2, no matter what i set the fuel pressure to that does not change. also when wide open under boost the wideband reads 13.3 then goes leaner from there so i let off. it doesnt matter how high i put the fuel pressure on that it still does the same thing. i do have vacuum going to the regulator anybody else have any suggestions?
lean question?
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ya sorry i forgot to mention that i got a walbro in which ive already changed out to one that i know worked in my cousins 240sx. and the aeromotive was from driftmotion i got there kit, it does go up when you unplug vacuum
boostaddict;1294176 said:
get a volt meter to test for the Vf signal.
That way you can see what happens (what your ecu does) when you alter your fuel pressure.
Also, when the vac.line is on and you rev the car, does the needle of the fpr show an increase in fuel pressure?
Did you also remove the restriction of the J-tube or not?
you need to test your FP as you gain boost. My guess is your FP gain is not 1:1 or just not working properly. You should have an SAFC anyway.......get one immediately for at least some security.
FYOB-do not boost.
FYOB-do not boost.
thevork;1295637 said:
the vf signal is at 5 which from my understanding is at full rich. what actally is that reading off of? could it be something as simple as a cooling temp sensor thats giving a bad reading so my car is compensating for it? maybe a lazy 02 sensor thats not kicking a code? bad or not fully working afm? any of these sound like common problem?
the Vf signal is created by the ecu and calculated using the O2 signal, water signal, HAC signal and probably one or more sensor that I forgot. 5 is full rich indeed. increase your fuel pressure to about 40psi (with the vacuum hose off) and see what happens. please allow 5 minutes or so for the ecu to detect your change and act accordingly.
Do you have the lexus afm with the screw so you can ajust it? you can try to open the gap on the afm a little more to allow more unmetered air to enter your car. But do that only when you find that increasing your fuel pressure does not work.
About your O2 sensor:
Under boost you are (most likely) in open loop which means that your O2 sensor is not used to calculate fuel needs and fuel maps are used instead. So your O2 sensor will not be responsible for your lean condition under boost. You can swap it out for another and see what happens in closed loop but it won't solve your lean-on-boost condition.
I'm curious on how you got the vacuum for the FP hooked up. You did connect the vacuum on the AFPR to the VSV below the intake manifold right?
And when you rev your engine @ idle, does the needle indicate that fuel pressure goes up? That's very important.
To answer your last question:
Yes, a faulty water sensor, faulty wiring and a bad afm are common causes of lean conditions on our cars.
The water sensor does not fail often, but the wiring does. it gets old and breaks.
However since we don't know if you ran this setup succesfully for some time or just got in installed we assume that most of the upgrades are recent and we also assume the car was running just fine before the upgrades.
That's why we're pointing at the upgraded parts first. Of course things can go bad but it's more likely that there is something wrong with the upgraded parts.
Do you have the lexus afm with the screw so you can ajust it? you can try to open the gap on the afm a little more to allow more unmetered air to enter your car. But do that only when you find that increasing your fuel pressure does not work.
About your O2 sensor:
Under boost you are (most likely) in open loop which means that your O2 sensor is not used to calculate fuel needs and fuel maps are used instead. So your O2 sensor will not be responsible for your lean condition under boost. You can swap it out for another and see what happens in closed loop but it won't solve your lean-on-boost condition.
I'm curious on how you got the vacuum for the FP hooked up. You did connect the vacuum on the AFPR to the VSV below the intake manifold right?
And when you rev your engine @ idle, does the needle indicate that fuel pressure goes up? That's very important.
To answer your last question:
Yes, a faulty water sensor, faulty wiring and a bad afm are common causes of lean conditions on our cars.
The water sensor does not fail often, but the wiring does. it gets old and breaks.
However since we don't know if you ran this setup succesfully for some time or just got in installed we assume that most of the upgrades are recent and we also assume the car was running just fine before the upgrades.
That's why we're pointing at the upgraded parts first. Of course things can go bad but it's more likely that there is something wrong with the upgraded parts.
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My sensor for my wideband does the same thing. I must have fried it on the dyno because it's too close to the turbo. It reads perfect at idle, but reads lean at wot. I switched it with my wife's new sensor and it reads 11.4 @ wot without changing anything but the sensor. If someone has already suggested this then disregard this message. It will self destruct in three.......two................
right now it developed a new problem, where it has code 31 and 24 and it runs like the afm is unplugged.thevork;1298075 said:
The lexus afm i have does not have the screw but it appears pretty easy to make it a screw.
i tried chasing as many wires as i could find for as long as i could see and came up with nothing there.
thanks for all the other information its good to know.
it is connected to the vsv right under the the intake, and yes the fuel pressure does go up as soon as you hit the throttle.
well today the afm problem is fixed. thing runs fine check engine light is off. still no solution on the lean problem. i think im going to try to make the screw for the afm, has anybody attempted this themself? or you have somebody do it? if i make a slit in the top of it will i be able to use whats in there as a screw? or do you have to drill it out and retap the hole then find a new screw?
If you drill out the existing hole, CAREFULLY, you will discover a screw already in there. It's been set at the factory for the car it was originally on, then sealed to stop us from messing with it.
Personally, I'd be searching for a fuel line restriction. Crushed or plugged fuel hardline, plugged fuel filter, something that would affect your fuel delivery when it's supposed to be at high output.
Personally, I'd be searching for a fuel line restriction. Crushed or plugged fuel hardline, plugged fuel filter, something that would affect your fuel delivery when it's supposed to be at high output.
thanks for your input grim jack i will take a look see at that next chance i get and see what i come up with
well i just checked all my lines no kinks or anything. i know the fuel filters good i just did it 500 miles ago.i may take the lines apart and try blowing through them with air a little later. the fpr guage says ive got 30-32 psi of fuel so i doubt it could be restricted to much if it is.
If you had a restriction in there somewhere, you'll get the right pressure at idle, but it won't be able to keep up when you're under power - so your pressure drops off, and you run lean.
One of the guys here had a problem like this... turned out to be spiders nesting in the fuel line while he had the engine out or something, I don't recall exactly. He spent a LOT of time trying to track it down.
Another guy I know crushed his fuel hardline with a jack lifting the car. Again, it was fine at idle, but under load it couldn't squeeze enough fuel through the crushed section and it started going lean. Took a LONG time to track that one down too.
One of the guys here had a problem like this... turned out to be spiders nesting in the fuel line while he had the engine out or something, I don't recall exactly. He spent a LOT of time trying to track it down.
Another guy I know crushed his fuel hardline with a jack lifting the car. Again, it was fine at idle, but under load it couldn't squeeze enough fuel through the crushed section and it started going lean. Took a LONG time to track that one down too.
i traced the lines back and there not crushed so i guess my next step is to take them apart and blow or fish something threw there.
You're doing things the hard way. Remove the regulator vacuum line and while monitoring fuel pressure snap the throttle full open a few times. If pressure doesn't change more than a couple of psi with the vac line off the system is unrestricted...
thanks for the pointer on that one jet jock i was about to go get into it too. it appears that it only goes up 2 psi or so, so im assuming that there are no restrictions. time to start looking elsewhere