AFM Issue?

[Jonnymkiii]

I was going for a quick drive the other night and was boosting around 12 psi, then all of sudden the car would not boost and it was running very rich. If I give it constant gas it spits and sputters and will stall if the car is not moving. I was only a short distance from my house and was able to get it home by pressing the gas pedal in quick, short bursts. Vacuum appears normal, but as I mentioned previously, it will not boost.
I checked vacuum lines and the intake path, and couldn't find any evidence of any kind of leak. I am thinking that it is the AFM, but have not tested it yet. Would you agree this is the probable problem, or could it be something else? How much do used AFMs go for in the Supra community?

I left for Vienna the day after this happened, so I can't do anything about it now, but I would like to have a game plan for when I return.

 

[mcpcola]

Damn sounds like Muffler Bearing







Just Joking :naughty:

 

[shaeff]

check your codes first:http://www.cygnusx1.net/supra/techtip/engineerrorcodes.html

codes can tell us alot of what's going on.

sounds to me like you have a boost leak. the most common culprit is the pipe off the bottom of the turbo. it tends to crack and split due to the heat from the turbo and manifold. check that. boost leaks cause you to run rich because you're leaking out air that is already accounted for (read: metered) and the ECU is putting in enough fuel to compensate for it. when you lose that air, there's still that same amout of fuel going in, so you run rich.

 

[westonboege]

i was gonna say a charge pipe popped too...

 

[siman]

Charge pipes dont throw CEL's though....

I think your AFM or TPS might of went out.....but you need to get the code or see what code its throwing!

 

[Jonnymkiii]

Thanks for the feedback! Once I get back I'll investigate further.

I did a top side check before I left of the pipe connecting to the turbo, and it appeared fine, but then again, it was a top side check. I'll jack it up and inspect further. I wish I would have had time to check the codes too, but unfortunately I didn't. It sucks having something break right before I leave for 3 weeks.

 

[tlo86]

all you need is a piece of wire to check the code. if i remember right the code is either 11 or 21. check that air filter too.. i have a hunch the sensor is dirty because of the infamous k&n air filter you have (the oil gets all over the Mass airflow sensor and screws it's ability to detect the amount of air)

if you can get it to idle right hit the mas lightly with a hammer or wrench and it should do the same thing when it stalls.

..but anyways i sprayed it with electrical cleaner/carbeurator cleaner (a non-wet non-combustible cleaner, never use anything else or your sensor is really screwed) and it workes fine for me now and i hope it is the same prob you had, i plan to replace it though with a map ecu from powerhouse racing.

a new one for a turbo will cost $500, or at least that i found. and the non turbo is like 20 - 60$.

if it was a boost leak he wouldn't be running 12 psi. i have that same prob right now, it happens on and off and sounds like an exhaust leak. i lose a lot of boost though, runs at 4 - 5 psi max.

 

[shaeff]

dont spray anything on your sensor unless you want to toast it...

-shaeff

 

[tlo86]

(a non-wet non-combustible cleaner, never use anything else or your sensor is really screwed)

maybe i didn't make it clear enough, you do need a special cleaner, i used electrical cleaner, used to clean open wires and computers.. it sprays on and dries itself. you are right though most cleaners will toast the sensor. but i say again.. a special cleaner spacifically designed to clean it :icon_bigg 8 - 12$ at a parts store, double check with someone if you are unsure

 

[siman]

Radioshack has the cleaner for like $5.

My family uses it on our keyboards and my brother uses it on his computer rebuilds....

I used alchohol on my TPS, it evaporates and leaves no residue...it cleaned the TPS signal up like a charm. My tps is going out...but dirt and grime hindered the signal so I cleaned it and prolonged the life of it.

I am sure it can do the same with the AFM connections.

 

[tlo86]

do not use alcohol on the sensor. thats asking for trouble... do NOT use anything combustible (anything that can catch on fire) or you will not be driving your car for a while... what i am talking about is the sensor itself not the connections

also...

http://www.cygnusx1.net/supra/techtip/engineerrorcodes.html

connect the red squares with a wire check the code.. just to make sure.

 

[siman]

The sensors are air tight you know.

Cleaning with alchohol steps:

Get you a bottle of rubbing al.
Get some QUE TIPS.
Get a rag to wipe away excess al.

Un plug connectors.
Dip que tips in al.

Clean silver/goldish color connectors male/female with que tips....you will be amazed at how much dirt comes off of them.

Hook back up and go. I assure you that you will notice a difference.

Like I said, do not douse your plugs/connectors in al. Just keep it simple and let them dry then plug them back up!

All electrical cleaning spray has some base of alcohol in it.....

 

[tlo86]

ahh ok i was about to grab a bottle of vodka and goto work.. i'll do what you said maybe it will help the trouble i have had lately

im sure both can contribute to the prob he is having