ls 400 afm

hvyman

Dang Dude! No Way Man.
Staff member
Apr 17, 2007
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Fullerton,CA
The plugs are the same. So you dont need that plug unless yours is messed up and you trying to fix it.

Electronics are the same too.
 

Green7mgte

New Member
Dec 30, 2009
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North Canton, Ohio, United States
the issue is Im having hard starts with code 31
Im able to start the car and the idle is good. When I give it gass I bog down around 2k. Problem goes away when the car reaches normal operating temp tho and I am able to drive normally. wich leads me to it being a wire problem.
 

theprodigy79

Irish Cream
Mar 5, 2007
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Centreville, VA
Isn't it recommended to use your stock electronics with the 1UZ AFM, or does it make a difference?

Did you upgrade your injectors (this doesn't have anything to do with Code 31, but just curious)?
 

Green7mgte

New Member
Dec 30, 2009
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North Canton, Ohio, United States
no compleatly stock engine.
Im to understand the wires going into the 7m afm are the vc / afm -tps . ks / afm . e2 / ground and Tha / air temp sensor
I am compleatly clueless on how to test the continuation on these using a multimeter, first time having to.
I dont really want to buy a new AFM if its a wire problem. would rather just splice in a new connector and about 6 inches of wire.

---------- Post added at 05:07 PM ---------- Previous post was at 04:53 PM ----------

I dont think it makes a difference about the afm itself. just the honeycomb wich allows 15% more air to enter. I have one of those allready just not putting it on untill I aquire a wideband.

---------- Post added at 05:17 PM ---------- Previous post was at 05:07 PM ----------

any suggestions? think replacing the afm and connector is a good idea? any helpfull links with more indepth info on testing ? thanks guys
 

jonahs_supra

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May 17, 2011
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best way to find out if its a wire problem is to do a resistance check on your wires from afm plug to ecu plug
gets a multimeter thats has a ohms selection
i prefer the type with a audible beep so that way i know when there is resistance
next find and print out a ecu pinout for your year supra
find and print out a engine wiring diagram
get a gator clip and about 6 ft of wire(smaller wire is fine)
disconnet battery ground
strip about 1/2" of wire on both sides of 6ft wire
on 1 end of gator clip you can crimp or tighten down wire using a screw
the other end of your 6ft wire your going to insert it into 1 of the afm harness pins at the afm plug
connect the gator clip jaws to either you black or red wire(doesnt matter which 1 you choose)
remove glove compartment
unbolt ecu
remove ecu harness plugs(make sure you disconnected battery 1st)
look at engine wiring diagram to chase down what color/name of the 5 afm wires you will be chasing down
lets say you chose E2 on the afm plug
look at ecu pinout and find where E2 wire is on ecu plug(BTW when looking at a ecu pinout...its as if your looking at the ecu so you will need to reverse the order of wires or just find what the colors are lol)
IIRC E2 is the main sensor ground for all sensors
depending on which multimeter you have then you will want to set it to the lowest ohms setting

IMO no wires should have more then 2ohms of resistance

---------- Post added at 07:26 PM ---------- Previous post was at 07:21 PM ----------

here is how to test a afm
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=FI&P=96

also i bought a lexus afm for mine about 6 months ago
bought just the electronis...
worked great for a month or 2 then it went out lol
 

Green7mgte

New Member
Dec 30, 2009
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North Canton, Ohio, United States
I went out for a moment and d/c the afm plug. Put one multimetere pin on the brown plug and the other on the other wires with the IGN on. got some numbers that way. tsrm says its 4-6 is legit. I got about 4.99 to 5. yea I know about the ecu being reversed. Found that out when I hooked up my safc for the first time and went.. wtf? I found a afm at a local import yard for like 70 bucks and the wires for an additional 20.. bit much for a connector piece. Thank you for the lecture, I really appreciate it.
 

hvyman

Dang Dude! No Way Man.
Staff member
Apr 17, 2007
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Fullerton,CA
Your afm is bad. The air temp sensor is not reading right. Unless your wiring is shot which is a possibility. Just replacing the connector is not going to cut it tho.

Take the lex housing off until you have the rest of the supporting mods unless you like rebuilding engine for the hell of it.
 

Green7mgte

New Member
Dec 30, 2009
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North Canton, Ohio, United States
agreed on the honeycomb housing. I have never installed it, just have it sitting around. Im going to purchase the afm tomorrow. Just a question, Since my 7m is a 92. A ls 400, 92 afm should be compatible correct? I would hate to spend the money and have it not work.
thanks for all the advice.

---------- Post added at 09:56 PM ---------- Previous post was at 09:45 PM ----------

and johnas keep me posted on your afm. Guess its good to have spares.
 

Green7mgte

New Member
Dec 30, 2009
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North Canton, Ohio, United States
just an update. I went to the import place today and had them pull it for me when they opened. Came home and installed it.. they sold me the housing and electronics as one unit.. w/e for 75 bucks ill sell the housing and make my money back =). the screws holding the afm were pretty old and brittle so I had to extract them. secured the afm in my stock engine and fired it up.. took it around the block and got it to op temp, seems to work normally.
thanks for the imput / advice.
oh hey, what removes greese pencil markings? gass? goo gone? any suggestions?
 

Green7mgte

New Member
Dec 30, 2009
65
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North Canton, Ohio, United States
After I put on my new to me afm all was well.. this morning when I got up it was about 60 degrees and the car went back into its same old habits. so Im going to pick up the new clip and wire, just wanted to know if there was anything special I had to do for wiring the new set in. Also is there any other place I could look. I read the thread in titled "Code 31 help" and that has some pretty useful tips in it. Altho I experience no other symptoms except for when its cold out.. or below 60 F. Hoping the new clip solves my problems.