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Done? It's never done!
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Discussion Starter · #1 · (Edited)
After getting the 550cc PT injectors installed, the car idled fine on both cold/warm conditions using the stock afm. After switching in the lexus afm into place and plugging back in the sensor, it idles poorly, though it does improve somewhat by tuning the adjustment screw. What puzzles me is that it's tossing a code 31 at me. Additionally, the car seems to fuel cut, or something that feels close to it when it start passing roughly 25% throttle. Does anyone have any clue what might be happening here? I'm thinking about getting a wideband soon, but it's a pain in the ass to drive it around bogging all the time.

Oh yeah, forgot to mention that the stock fuel pump (has been replaced 30,000 miles ago) is still in place.
 

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JZS161 Aristo TT
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tsupraspeed said:
tossing a code 31 at me..
Replace the AFM electrics and enjoy the stable idle and 17psi fuel cut

Check the plug conection first clear codes then replace if code repeats MMMM'kay
 

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Discussion Starter · #3 · (Edited)
do you mean replacing that black sensor box that sits on top of the lex afm housing if unplugging and replugging back in the harness clip fails to correct the situation. The afm sensor is relatively new, about 1 year old. There is some stuff that looks like grease on the afm sensor. The funny thing is that I've never used any oil type filter. I only have the Apexi one. Should I try cleaning down that section? If so, with what? Thanks for the previous reply. I'm hoping that the afm sensor isn't bad already.
 

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JZS161 Aristo TT
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Just the black box on the AFM is were your drama will be

If 100% operational before more like replug will fix check that all the wires are secure into the plug

The crap that builds up on the AFM sensor is normal just wipe off but dont spray the electrics with any type of cleaner or you will be loking for a spare
 

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me me me me me me!!!
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get a maf conversion. once i installed mine after my lex-afm blew i was stunned at how much smoother it was. that's if you don't get the lex prob. solved, then the conversion is a good mod.
 

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my shit bogs to after i did the lex/550's. pisses me off. cant figure it out. my injectors are working fine. but i know my afm is good. i mean, it worked just fine before i did the 550's.

does yours like sputter when you press the gas and the exhaust is kinda poppy?
does it sound like a cylinder isnt firing? this is what mine sounds/acts like. just wondering
 

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The AFM electronics could be 10 min old and still be bad. Time doens't matter. DO NOT touch the screen or the element on the AFM though. You will surely toast it if you do that.

Reset the ECU and see if it will relearn. I had to do that on a few people's cars. Putting the bigger AFM on there freaks it out. Reset it and make it relearn and see what happens. If that doesnt' fix it, then you have bad electronics and the black box needs to be replaced.

Did you put new electronics on with this AFM or did you use yoru factory one? In other words, did you replace the AFM body and electronics or just the body?
 

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for me i have the lexus afm with the electronics but i used the lexus electronics on my stock afm housing for a good 4 months before i put the electronics on the lexus afm with the 550's.
 

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Done? It's never done!
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Discussion Starter · #9 ·
I currently have the stock afm black box on the lexus afm, so I don't think the bad reading would be from a different black box. The lexus afm btw, is the SS replica one, if that helps any.
 

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Project:: Reaper
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i have the lexus AFM with RC 550's and no problems here. i think it could be the electronics, but i would try to reset the ECU first.
 

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Madd Tyte JDM yo ®
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trent has a good point. if you are delicate w/ the black box, it shouldnt be bad... but i mean, treating it like its a Bouncing Betty land mine. if you bump that triangular vortex generator, you could severely screw up the optical mirror inside the black housing and the electronics will officially be Fucked.

there seems to be a common misconception that the electronics are in that triangular vortex generator and covering them with oil and grime ruins the electronics. this is not the case. the black triangluar piece is just plastic. on the top of it is a Mirror, sealed inside the black square housing that the harness plugs into. when air passes around it, it causes the triangular piece to deflect as vortexes are generated behind it. the optical sensor bounces light off this mirror. depending on how much this mirror moves, is a direct correlation to how many vortecies are being created as a result of volumetric airflow... if the vortex generator gets grimey, carefully spray it off with Electrical contact cleaner. Do not damage the honeycomb grid on the front of the housing. this straightens the air out to ensure an laminar airflow across the body of the Meter housing, and thus, across the vortex generator.

hope that helps.
 

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so clean the thing that hang down into the afm?
ive reset my ecu a lot and it still does it.

on some days it will be worse, and others it wont be so bad at all. like when its hot outside it works pretty good or when i get the motor nice and hot after a long drive.
 

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Done? It's never done!
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Discussion Starter · #14 ·
The car idles fine now along with everything in vaccuum. Boost is still rough, but not as bad as before. I did not have any hexagonal metal screen in the front of the afm and I just borrowed one off of another supra afm that I had lying in the garage (I knew one of those would come in handy some day). The code 31 is pretty much gone, although it will toss it occasionally. I'd say the overall drive is 95% better now. There still is the issue of a slightly shakey rev once I start boosting, but everything else seems fine. Also, the hex screen that I put in from a junked supra seems to have some rock dings and dirt/oil on it. I rinsed off most of the debris, but there are two small bends on the hex screen. Would that cause any of the rough acceleration while under boost?

Other than that, the 550s and lex afm are working great, though it probably could use some adjustment on the screw.
 

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Madd Tyte JDM yo ®
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yeah, feel free to clean the Vortex Generator (thing that hangs down). its sealed off from the outside with an O-ring at the top of the housing. just dont hold it upside down when you spray it off... let the solvent drip Down. we dont want it seeping past the upper O-ring and into the electronics themselves. that would surely be a bad thing.

If you have an upgraded fuel pump, stock J-tube restrction, 550's and the lex... youre definitly running richer than you should be. if you bypass/drill out the J-tube restrictor, youll even out and should run stronger/crisper w/o the over-rich condition. having No honeycomb in there is worse than a honeycomb w/ a few dings in it. there is supposed to be a metal grate that mounts on top of the honey comb to prevent big things from coming into contact w/ the grid... such as hands and tools.

my setup was a modified stock Filter housing, bored out to accomodate the larger Lexus AFM. i had a drop-in K&N filter mounted in the air box, it was a pretty nice setup... even sneaky.
 

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which tube is it down there and how would i take it off?
 

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Madd Tyte JDM yo ®
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its the metal tube, kinda shaped like a J. the fuel return comes from the fuel rail, into the top of that J tube. then it goes thru that and into a rubber line again. its welded to the metal flange held on w/ 2 nuts to the side of the block. if you take off the lower rubber line, youll see that the end of the J-tube is closed off to about 4mm or so rather than the 10mm that the J-tube should be.
 

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Done? It's never done!
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Discussion Starter · #18 ·
Ok, so I turned the tuning screw to open the unmetered airflow up some more and it seems a bit better at WOT while boosting. Lower gears seems jerky, but 5th gear seems alright. Same thing happens at about 75% throttle as well.
 

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Madd Tyte JDM yo ®
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well, do you have an upgraded fuel pump w/ the stock J-tube in place or not?

its possible you are loading up w/ fuel too much and its breaking up. you really should pick up a Wideband and an SAFC. you can have both for less than $500 if you are a resourceful shopper. and itll really tell you whats going wrong too. otherwise, we are flying blind and cant diagnose anything.
 

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Done? It's never done!
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Discussion Starter · #20 ·
actually, that's the next set of mods that i'm getting within the month. The wideband will probably be within the next week or so. We'll see what turns up.
 
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