7MGTE Starts, But Stalls Shortly After....Update July 17

[CajunKenny]

Maybe it isn't vac...? You're asking for ideas so...

Codes are your road map. Get those to stay cleared and work from there.

Were you able to swap out AFM's yet?

 

[IBoughtASupra]

No, I took a summer class and I had a lot of homeowork to do. I will try and swap them out tomorrow. I have three. One gave a Code 31, the other I cleaned with brake cleaner, and the other has a inch hole on the top covered with electrical tape. 2/3 are bad, I am going to try the last one and see. :-/

 

[whitemike]

If It's throwing 31's I'd say It's apparent that your AFM is bad, with 20 year old electronics It's not unlikely that 2/3 are bad. Or even all three. If you get a *known* working AFM, and it still throws 31.. It's your wiring or ECU I'd say.

 

[IBoughtASupra]

I know code 31 is the AFM, that is why I am changing it. What are the chanced that my wiring harness from Toyota is defective....brand new. I am the first owner for it. ECU, I have not seen a lot of them go bad but I have a spare to try.

 

[jetjock]

˙˙˙ƃuoɹʍ ʇı ƃuıop ǝɹ,noʎ

 

[IBoughtASupra]

˙˙˙ƃuoɹʍ ʇı ƃuıop ǝɹ,noʎ

What am I doing wrong? Codes, AFM?

 

[jetjock]

Well, for starters you should be checking the AFMs the right way, which is under power while on the car...

 

[IBoughtASupra]

The TSRM says to disconnect it. How am I supposed to test it on the car? I read that testing it on the car wil test the ECU's resisitors. It was on the here.

http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=FI&P=96

Do I still use the TSRM's specs then?

 

[jetjock]

Ohming it isn't a reliable check of the AFM and it doesn't check the wiring at all. Nor does it verify if Vc and ground are present. You should check those first and once verified follow by checking Ks....preferably at the ECU connector. Use the voltage and frequency functions on your meter for those things.

That said *how* did you ohm it? What readings did you get and on what terminals? Maybe you're measuring only the air sensor, something many here do. Simply saying you tested it is meaningless. It implies we're supposed to trust you know what you're doing when, frankly, for all we know you don't.

Edit: As I suspected. THA only. Ah well, you certainly aren't the first...

 

[IBoughtASupra]

Well Jetjock, if I have a code 31 on one AFM and a code 24 on another one. Your telling me that they both can be good?

Going to swap out my last one today. My wires should be fine since it is a new Toyota harness I got, but I am still going to check the AFM plug's terminals with my voltmeter and ignition on.

 

[whitemike]

Isn't 24 the internal iat?

 

[IBoughtASupra]

Yes, and the IAT is in the AFM so it needs to be changed.

 

[jetjock]

Your telling me that they both can be good?

I never said that. For all I know they are bad. For sure the one you cleaned likely is.

The only things I told you is 1) you were testing them wrong and 2) when you test something it's important to tell us how you did it. In this case you were testing part of the AFM that has no bearing on code 31.

It's a lot better to *know* something is bad than guess it is and the best way to do that is dynamically measure the signal leaving the device or, better still, measure what the ECU is receiving.

Btw you can check everything at the AFM connector with the key on except for Ks. The engine needs to be running for that. Or you can test the AFM off the car by flowing air through it using other means. A muffin fan or vacuum cleaner works well.

Short of being broken off it's unlikely the IAT sensor would fail. Possible but unlikely. Code 24 doesn't condemn the AFM. Far from it. As with all codes it indicates only a problem in the circuit.

Lastly, I didn't read if you tried it but the engine should start and idle with the AFM unplugged. It should also rev fine up to 3000 rpm. If it doesn't you have other problems...

 

[CajunKenny]

jetjock is the man!

 

[IBoughtASupra]

I never said that. For all I know they are bad. For sure the one you cleaned likely is.

The only things I told you is 1) you were testing them wrong and 2) when you test something it's important to tell us how you did it. In this case you were testing part of the AFM that has no bearing on code 31.

It's a lot better to *know* something is bad than guess it is and the best way to do that is dynamically measure the signal leaving the device or, better still, measure what the ECU is receiving.

Btw you can check everything at the AFM connector with the key on except for Ks. The engine needs to be running for that. Or you can test the AFM off the car by flowing air through it using other means. A muffin fan or vacuum cleaner works well.

Short of being broken off it's unlikely the IAT sensor would fail. Possible but unlikely. Code 24 doesn't condemn the AFM. Far from it. As with all codes it indicates only a problem in the circuit.

Lastly, I didn't read if you tried it but the engine should start and idle with the AFM unplugged. It should also rev fine up to 3000 rpm. If it doesn't you have other problems...

Ok, I am going to try it. it rained all day today here in New York, so I did not get a chance to do anything. Tomorrow I will, better weather and no class on Friday. Ok, so what I am understanding is 1) I should test the AFM at the terminals of the ECU and 2) It should idle fine without the AFM. Without the AFM would it idle good or bad, surging or anything like that?

Now if it does not idle with the AFM unplugged, then I should check the TPS calibration and see if it is in spec. I changed the Idle Control valve, the one that was on their was stuck and would not move at all. No click or movement at all.

Tomorrow:
1) Unplug AFM and see if car starts and idles
2) Check TPS to see if in spec and adjust if needed
3) Changed out my injectors which I believe are GE high impedeance injectors. (OHM to see if I get anything besides 2.0 to 3.8) Have A GTE Set That OHM'ed 3.4-3.5

4)I hope not, but if all fails, whats next?

It revs fine just bogs down when it tries to idle. Aaron at DriftMotion suggested the TPS too. Lastly, when you say a problem in the circuit, you mean the wiring. So there could be a problem with the internal circuit of the AFM or in my new Toyota harness?

Did some searching and the pins for the AFM at the ECU are the following, 24 pin plug, pins 8,9,10 on the top. Correct?

Jetjock, I was reading an old thread on this stuff on MKIIITech when JDub was having this problem. You guys were talking about the brake booster leaking. I am going to cap off the fitting too and see, I doubt it though since my vaccum is at 21 on my boost gauge.

 

[IBoughtASupra]

I checked today but could not do much, it started to rain really hard. I had a -6 AN oil feed line going to my turbo. I was supposed to use a -4 AN, so I had to change it out. Car was smoking and the turbo is brand new from Aaron at DriftMotion. That is good now. Then I see the housing for the thermostat is leaking, so I believe the O-Ring is bad there. I put a new Stant one with the O-Ring gasket there but looks like it was defective since it is slowly leaking there. Anyone put a bead of silicone there to help? This is the first one that has leaked there out of three 7M's I have built....This is the first one not to idle as well. :nono:

What thermostat do you normally use Jetjock, I usually use a Stant 180F but the parts store sent out shop a Stant 195F, I will have to call and check on that tomorrow.

I unplugged the AFM and the car still starts and revs up to about 500 RPM and then comes back down and stalls out. I was going to calibrate the TPS but it started to rain, so I could not do anything else. Going to be 80 tomorrow.

The TPS is working because if I pull the throttle it does show a Code 51, so I know the switch is good. If the TPS is not throwing a code 51, the car should be in idle mod, right? I know with a Code 51, the idle system will not be active, but if it is not throwing a Code 51, will it tell the TCCS to be in idle mode?

Going to try and calibrate the TPS tomorrow and see what happens.

 

[whitemike]

jetjock is the man!

That's how I feel after every time he posts a few hints in someones thread, then finally comes out with the big reveal!

 

[IBoughtASupra]

That's how I feel after every time he posts a few hints in someones thread, then finally comes out with the big reveal!

He gives hints, makes you wonder and then finally give the full answer. It is the reason why a lot of people get an attitude with him, but I figured that it is his way of helping:dunno:. It is the reason I am not acting like a douchebag like most people would.

 

[CajunKenny]

That's how I feel after every time he posts a few hints in someones thread, then finally comes out with the big reveal!

He gives hints, makes you wonder and then finally give the full answer. It is the reason why a lot of people get an attitude with him, but I figured that it is his way of helping:dunno:. It is the reason I am not acting like a douchebag like most people would.

I think it's the whole "Teach a man to fish..." mentality.

 

[IBoughtASupra]

Today I finally got the chance to test the TPS and other things. I Used A New Snap-On Multimeter With Aligator Clips And A TPS Pigtail I Got From A Old Horrible Harness I Had Laying Around. Here is what I found.

Testing The TPS According To TSRM

Incase It Makes A Difference, Since "E2" Is Common, I Put The Black(Ground) Lead To It.

Contacts Resistance Result Meter Setting
VTA - E2 .861 ohm 2k
IDL - E2 .046 ohm-Closed 1ohm- .5mm Feeler Gauge 2k
IDL - E2 1 ohm-.9mm Feeler Gauge 2k

VTA - E2 4.46 ohm Throttle Fully Opened 20K
VC - E2 5.79 Throttle Closed/Opened Gives Same Reading 20K

I know VTA-E2 is in spec and VTA-E2 with the throttle opened is in spec. If I try to get IDL-E2 in spec with the .5mm feeler gauge, the lowest it gets is .058 with the meter set at 2k. Is VC-E2 supposed to give the same reading with the throttle opened and closed? I took pictures to show you guys how I was doing everything. With these settings I don't get a Code 51 and the car revs without any misfires when holding a steady RPM in any range(When I Plug In AFM.)

It does smell rich,which is weird since I OHM'ed the injectors and they are 13.4-13.6 which are GE injectors, shit I mixed them up. Tomorrow I am going to get a new sensor for my wideband and what the AFR's are. I did not touch the AFM since Jetjock said the car should start and idle without the AFM plugged in but only be able to rev to 3,000 RPM.

Picture 1 - Boost Gauge Showing Reading
Picture 2- TPS And Pigtail Used
Picture 3- TPS Upclose
Picture 4- IDL-E2 Gets .046ohm Closed.....5mm Feeler Gauge Shows A 1

---------- Post added at 08:38 PM ---------- Previous post was at 08:33 PM ----------

I think it's the whole "Teach a man to fish..." mentality.

I agree, learn someone to fish, they can feed themselves. Learn them how to fix something, they will learn from that. Building this car has thought me a lot about engines.