94 LS400: AFM, Fuji Electric part # 22204-42011
My AFM experience did not go so swimmingly either.
Purchased the CRC MAF cleaner & showed up over at my mechanics to gently clean the AFM with q-tips as I had seen recommended.
I was screwing around w something else in the garage ( They are buddies & mechanics ) & was horrified to see that one of the shop employees was liberally dowsing the AFM with the spray at close range.
At that point I did not follow thru with the a compressed air follow up since protocol had been altered.
When I nervously re-installed the AFM I had a CEL light that would not clear. I did not check the code.
Car ran okay until you tried to more than moderately accelerate or if you turned off the AC, which would cause it to die immediately.
Easily my biggest screw up in LS maintenance history.
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Road to Repair:
Skowered Lexus parts Classifieds & came up with 2 used AFM's, 1 from a SC300 & one from an SC400 UZ-FE.
Currently using the SC-300 AFM since it got here first. Works great & I find it hard to believe there is a difference in these 2 units. The foremost expert that I could find on the subject ( Reg Reimer of RCTS Canada ) tells me there is so I defer.
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To clean or not to clean?
Found this quote at the Lextreme Forum:
"Do not clean that AFM. For starters, it is not a MAF or mass air flow sensor,it is an volume air flow meter. This one in particular is called a Karman Vortex meter".
"There is a piezoelectric reflector and a small LED inside. Do not spray anything in it ever. This usually ruins them. Ask all the kids with a first gen Supra (87-92) about their AFM after cleaning it, or installing a K&N and having it get wet".
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Altering the 1UZ-FE AFM with a Sonic Screw:
Note: This product was originally made for high horsepower 7mgte engines. The mod is of the AFM of a 1UZ-FE engine so the info here should be applicable those seeking higher performance from a UZ-FE engine.
Info & kit from RCTS Canada
Yes we still make these kits.
Screw alone is 110$ Cnd
The whole kit, injectors+clips,AFM and screw is 1708$ Cnd.
Thanks
Clyde
Installing the SONiC screw for the Lexus 1UZ-FE AFM upgrade
SONiC Tech Note Series:
Remove the factory alloy plug from the body of the air meter. This plug covers the chambers of the air screw port. When you have removed this plug it is not needed again. So don't feel bad when you have to drill a hole into it so you can pull it out .
The stock Lexus air screw is installed below this plug. The best way to remove the plug is to drill a good sized hole in the plug and then insert a large flat head screw driver to twist and =pull the plug loose from the Lexus AFM body. They come out quite easy, toss it away after you remove it. Be sure to remove and trace aluminum filings from the drilling process.
When the plug is removed you will see the gold colored stock air screw in the body. Donít toss this screw out, we may use it some day with 720 cc injectors, Iím working on that right now. There is a O-Ring on the stock screw that you will need to install on the SONiC screw before you thread it into the AFM body.
Install the O-Ring from the stock screw onto the SONiC screw. When you install the SONiC screw turn it in so that it is down as far down as it will go in the AFM body. Then back it out 1.25 turns. This is where you will need to have the screw set on most cars with stock fuel pumps and pressure.
Remember the further out you turn it the higher the fuel cut point will be, but the leaned value system {Vf data} will run in a higher % =of correction. I run my car with the screw turned all the way in then 1 turn.
Note; when the screw is fully bottomed out in the chamber there is still a small triangle shape of open space, this is the way it is =suppose to look.
Re-install the Lexus AFM, buy stretching the factory 7M-GTE rubber sausage hose around the Lexus AFM body. You will need a larger hose clamp as well as the Lexus AFM is larger in diameter than the 7M GTE AFM.
Install the 550 cc injectors and clips and injectors.
Reg Riemer
