Yup, the Lex AFM that everyone likes to use is from the V8 equipped, 400 series. I suspect you just had some bad luck.
7mgte AFM issues, please help!
- Thread starter BoostedRunner87
- Start date
alright guys thanks alot for the info. I will do some more checking into the HAC sensor tomorrow. as far as testing VC goes, i have tested both AFM's with the ohmmeter multiple times and it seems to me that they are within spec
I wasn't suggesting you test the meter yet again... I meant you might want to test the voltage at the VC pin on the harnes, it's where the AFM gets its power.
CRE;1459933 said:
ok that makes more sense! that was the nest thing i want to check into, is how to check all the wiring going to the AFM. so the VC pin should have 12v to it? or just a power signal?
I dont see how the hac sensor could be the problem... yes I know the computer tells you the code for a reason but runner said this is a 5 year old swap.
now im no expert by far but if he didnt take the sensor out,it probably hasnt been there the whole time. I had CPS sensor go out but didnt throw any codes and it acted similar to what he org. posted. I would test that the cps just for giggles.
if his IC piping is aluminum and his couplers arent split, probably go lookin for a preturbo boost leak. just my 2 cents.
now im no expert by far but if he didnt take the sensor out,it probably hasnt been there the whole time. I had CPS sensor go out but didnt throw any codes and it acted similar to what he org. posted. I would test that the cps just for giggles.
if his IC piping is aluminum and his couplers arent split, probably go lookin for a preturbo boost leak. just my 2 cents.
We've already discussed the fact that the HAC won't cause this kind of trouble. The HAC just happens to share some wiring with the other piece of hardware for which a code is present and with which he has had previous trouble.
I do hope he checked the intake piping already... but yeah, people forget the little things when frustrated.
Runner, you really should check all of the wiring for the AFM and remove the patched in portion (if it's not connected to anything, if it is post the details). Test Ks in particular too, that's the signal line.
I do hope he checked the intake piping already... but yeah, people forget the little things when frustrated.
Runner, you really should check all of the wiring for the AFM and remove the patched in portion (if it's not connected to anything, if it is post the details). Test Ks in particular too, that's the signal line.
CRE;1460241 said:
ok thats good to know, i will check tomorrow. also i dont believe the patched in piece is causing any problems. basically it looks like they might have broken the female plug that connects to the AFM, so they just wired in a new one. the wires are the same color and they are soldered together. I will double check tomorrow for any kind of pre turbo leaks. As far as the HAC goes, i am not concerned with that. It was never installed with the swap and has ran fine for five years without it.
Well, if it is actually not present then any relationship between it and the AFM is a moot point. Looking back at the TEWD it appears that the KV meter portion of the AFM uses E1 brown wire) for the ground and E2 is for the temp sensor. So, test Vc, Vs and E1.
well i checked all the pins on the female side of the connector (side with the wiring connected to it) you told me to check Vc, Vs, E1. according to my Haynes manual mine has a Ks pin but no Vs pin. i'm assuming Ks is the same as Vs. Ks must be my signal pin. Looking at the connector my pins go in this order from left to right: E1 Vc Ks THA E2.
i turned the key on and i have 5 volts power at Vc Ks and THA. I tested E1 and E2 and they both appear to be grounds.
now here is the very strange part that has me all screwed up. With the key off THA works as a ground. With the key ON it still works as a ground, but like i said above, with the key ON THA has 5 volts power. So this is my question. how can the THA pin have 5 volts power and also act as a ground at the same time while the key is on? does that indicate i may have a short somewhere in the wiring? i would think that if i did have a short then i would be popping a fuse somewhere. I have checked all the fuses in the vehicle multiple times on both sides with a test light and they all are good.
i turned the key on and i have 5 volts power at Vc Ks and THA. I tested E1 and E2 and they both appear to be grounds.
now here is the very strange part that has me all screwed up. With the key off THA works as a ground. With the key ON it still works as a ground, but like i said above, with the key ON THA has 5 volts power. So this is my question. how can the THA pin have 5 volts power and also act as a ground at the same time while the key is on? does that indicate i may have a short somewhere in the wiring? i would think that if i did have a short then i would be popping a fuse somewhere. I have checked all the fuses in the vehicle multiple times on both sides with a test light and they all are good.
Sorry, yes, Ks for a KVAFM (7M-GTE) Vs for a Vane AFM (7M-GE) sorry... 
THA is a simple thermistor, ground on one end and ECU on the other. Simply put, the ECU uses a pullup resistor on the other end to create a readable signal between the two. So a ground when the ECU is off and voltage when the car is running is normal.
Not all shorts blow fuses. AFAIK, none of the wires in that harness would blow a fuse when shorted across each other... they may blow other things though (in the ECU perhaps, I don't know how much abuse it can take).
So, check list:
Have you checked for intake leaks (after the AFM)?
Have you checked the ignition timing and the timing belt?
Have you tested for shorts in the harness (you know, is there continuity across Ks and Vc, I would unplug the harness at both ends and then test for continuity across Ks, Vc and E1.)?
You didn't try to clean the new AFM, right (don't if you haven't)?
Did you wash behind your ears?
Do you have access to another ECU?
You said it's barely running.... what precisely is it doing?
I think you need to go through the test procedure in the Toyota Service and Repair Manual (aka TSRM) and test everything... Haynes isn't the greatest.
Here's an online version of the TSRM for a later year Supra, the ECU pinout is different, but the data is mostly the same.
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=FI&P=49
That's literally everything I can think of...
THA is a simple thermistor, ground on one end and ECU on the other. Simply put, the ECU uses a pullup resistor on the other end to create a readable signal between the two. So a ground when the ECU is off and voltage when the car is running is normal.
Not all shorts blow fuses. AFAIK, none of the wires in that harness would blow a fuse when shorted across each other... they may blow other things though (in the ECU perhaps, I don't know how much abuse it can take).
So, check list:
Have you checked for intake leaks (after the AFM)?
Have you checked the ignition timing and the timing belt?
Have you tested for shorts in the harness (you know, is there continuity across Ks and Vc, I would unplug the harness at both ends and then test for continuity across Ks, Vc and E1.)?
You didn't try to clean the new AFM, right (don't if you haven't)?
Did you wash behind your ears?
Do you have access to another ECU?
You said it's barely running.... what precisely is it doing?
I think you need to go through the test procedure in the Toyota Service and Repair Manual (aka TSRM) and test everything... Haynes isn't the greatest.
Here's an online version of the TSRM for a later year Supra, the ECU pinout is different, but the data is mostly the same.
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=FI&P=49
That's literally everything I can think of...
CRE;1460617 said:Sorry, yes, Ks for a KVAFM (7M-GTE) Vs for a Vane AFM (7M-GE) sorry...
THA is a simple thermistor, ground on one end and ECU on the other. Simply put, the ECU uses a pullup resistor on the other end to create a readable signal between the two. So a ground when the ECU is off and voltage when the car is running is normal.
Not all shorts blow fuses. AFAIK, none of the wires in that harness would blow a fuse when shorted across each other... they may blow other things though (in the ECU perhaps, I don't know how much abuse it can take).
So, check list:
Have you checked for intake leaks (after the AFM)?
Have you checked the ignition timing and the timing belt?
Have you tested for shorts in the harness (you know, is there continuity across Ks and Vc, I would unplug the harness at both ends and then test for continuity across Ks, Vc and E1.)?
You didn't try to clean the new AFM, right (don't if you haven't)?
Did you wash behind your ears?
Do you have access to another ECU?
You said it's barely running.... what precisely is it doing?
I think you need to go through the test procedure in the Toyota Service and Repair Manual (aka TSRM) and test everything... Haynes isn't the greatest.
Here's an online version of the TSRM for a later year Supra, the ECU pinout is different, but the data is mostly the same.
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=FI&P=49
That's literally everything I can think of...
ok i will go through and test for shorts and continuity. i do not have another ecu. i did not clean the other sensor i bought. yes it is barely running..... here are the symptoms:
I can start the vehicle and it will idle almost perfectly for a long time with no CEL. But as soon as i push on the accelerator it cuts out and stumbles horribly. If i continue to do this or rev it up a little bit multiple times the CEL will then come on. After i have started and ran the vehicle a number of times over the past couple days i decided to pull the spark plugs out and check them. The engine is obviously running rich because the plugs are black and smell like gas. Could it be running rich because i have the wrong spark plugs in it? Or is it just doing this because the AFM is not reading properly? I put new Bosch spark plugs in it. NAPA recommended those or NGK. I would have gotten NGK but they were out of them at the time. I still would not think the plugs are the issue though because it seems to idle smooth with no misfires.
^^^ I just found your thread. The AFM didn't do it for you I see To bad you are not closer to me, I have another one also sitting here.
Maybe ask / send pm to jetjock and ask him, when he gets time, if he could read this thread and insert his opinion. He's pretty good with the TCCS. Helped me out plenty of times last spring. He doesn't come around the forums much anymore, but he might have more light to shine on the subject.
To bad you are not closer to me, I have another one also sitting here.Maybe ask / send pm to jetjock and ask him, when he gets time, if he could read this thread and insert his opinion. He's pretty good with the TCCS. Helped me out plenty of times last spring. He doesn't come around the forums much anymore, but he might have more light to shine on the subject.
92nsx;1460663 said:^^^ I just found your thread. The AFM didn't do it for you I see
Maybe ask / send pm to jetjock and ask him, when he gets time, if he could read this thread and insert his opinion. He's pretty good with the TCCS. Helped me out plenty of times last spring. He doesn't come around the forums much anymore, but he might have more light to shine on the subject.
yeah unfortunately it didnt help. I am at a total loss as to what is wrong with this turd. I still wish i had a known good AFM i could test. I'm not saying the one you sent me is bad, i'm just thinking it would be nice to install both of the AFM's on a running supra and see if they both work with no issues.
I do know one thing, it runs alot better AFTER the CEL comes on. it idles smoother and i can rev it up farther until it starts to cut out.
BoostedRunner87;1460685 said:
This may simply be because it isn't until then that the ECU has decided the data is out of bounds and begins running on the fail safe maps (limp mode).... I'm not 100% sure of that though.
BoostedRunner87;1460685 said:
I know what you are saying, shit shipping alone could bounce the AFM out of shape. Is there any local supra owners around you? If so, have them stop by your place (before we get any more snow) and you could test with theirs and give them a couple beers for there time.
Another thing you can try / test is the continuity of the wires from the TCCS to the AFM wiring. You just need a 10' wire with gator clips on the end of the wire and test all 5 wires to make sure there isn't a brake in any of them.
If it won't go over 3000 rpm that'd confirm Fail Safe but CRE is likely right. It's exactly why I told the OP to unplug the AFM and try it.
Frankly I'm puzzled why this seems so hard to resolve. Ks is easily tested with any decent DMM and if it checks out the causes of code 34 are well known.
Frankly I'm puzzled why this seems so hard to resolve. Ks is easily tested with any decent DMM and if it checks out the causes of code 34 are well known.
I was just wondering you said that you took it off to clean it and then it started throwing codes. Im curious where it is a swap did you install it back the right way. I know people putting them upside down and it would act up because the air can't flow into it. Just some advice.
92nsx;1460663 said:
jetjock;1460709 said:
Opps!!! My fault, your already here :aigo:
I knew I should have read EVERY post.
You making a come back ? JK, good to see your aboard.
i installed everything the exact same way it was. i unplugged the AFM and it runs the same with it unplugged. IDK what that is supposed to mean for sure. and yeah it sounds like a fuel cut at about 3000 rpm, i'm sure thats because of fail safe mode. unfortunately i do not know anyone in my whole town that has a 3rd gen supra to test their AFM. also what exactly is the TCCS?