Bad AFM electronics or something else?
- Thread starter suprafanatic
- Start date
ok, not sure if this is bad or not but doesn't seem right to me. VC is only seeing 1.41 volts. KS is seeing 3.23, and THA is seeing 5 volts. Isn't VC suppose to be 5 volts?
So would that lack of volts to the VC terminal cause a problem like this? Should I test the VC terminal at the ECU and see if its even putting out 5 volts? And if so there's a problem between the ECU and the AFM plug? And if the ECU isn't putting out the 5 volts to the AFM plug then would there be a problem with the ECU or a problem with the ECU getting enough power? ugh this electrical stuff confuses me! lol
Ok, I feel like an idiot. I was reading the AFM plug wires backwards. My VC wire IS seeing 5 volts, the THA is seeing 1.41 and the KS is still seeing 3.23
Ok, JJ since I don't know much about electrical stuff how do I go about testing the KS for Hz? I'm gonna try and get my hands on a multimeter that can test for that. Does the car have to be just turned on or does the car have to be running to test the Hz? And what kind of number am I looking for?
Editing this post: I just read on Supraforums that if you don't really know what your doing you shouldn't test your AFM frequency? They were saying you could really mess something up. Is this true? And if so what am I suppose to do, just try another AFM?
Editing this post: I just read on Supraforums that if you don't really know what your doing you shouldn't test your AFM frequency? They were saying you could really mess something up. Is this true? And if so what am I suppose to do, just try another AFM?
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Not true. Set the DVM on Hz, and with everything plugged in get your meter probes on E2 and Ks. Back probing the connectors at the ECU is probably your best bet.
At idle, should be 20 to 30 Hz, and under load can go much higher (3 kHz or so).
If it were my car, I'd be thinking very hard about what Nick said. He's probably got the most experience working on Toyota's of anyone here.
Here's a datalog. Look at the cyan trace ("air flow" 4th from the top) to see AFM frequency during idle and light load.
[video=youtube;sXZJ9JVT3bY]http://www.youtube.com/watch?v=sXZJ9JVT3bY[/video]
At idle, should be 20 to 30 Hz, and under load can go much higher (3 kHz or so).
If it were my car, I'd be thinking very hard about what Nick said. He's probably got the most experience working on Toyota's of anyone here.
Here's a datalog. Look at the cyan trace ("air flow" 4th from the top) to see AFM frequency during idle and light load.
[video=youtube;sXZJ9JVT3bY]http://www.youtube.com/watch?v=sXZJ9JVT3bY[/video]
Nick M;1837765 said:
Are you talking about when he said this? My only question is if it was the fuel pump then why would it keep throwing a code for the AFM? Also, if it had a lack of fuel enrichment then why is it running pig rich in low RPM's? Or am I just crazy and not actually seeing and smelling an insane amount of gas being burnt/not burnt? When I first go out and try to start the car up when it actually stays running on its own its putting out a decent amount of smoke, and it smells like straight gasoline. After the car has ran for a bit and gets warmed up the smoke starts to go away.
But I understand what he is saying about seems like a lack of fuel enrichment, because most of the time when I try and start it up it dies right after it fires up. Like it ran out of gas. But other times its really rich. So maybe the fuel enrichment is just jumping all over the place? Again, I would think that points more toward the AFM than anything else cause if its messed up it could be sending the computer mixed up signals making it lean one second and really rich the next. Does that make any sense, or am I wrong about my assumption?
Also, it seems like the car is seeing a bigger load being put on it than it actually is at lower RPM's. At least it sounds like its got a bigger load on it than it actually does. Like I said before it sounds like the car is being brake boosted, it sounds like that untill about 1500-2000 RPM. And during that time the check engine light is on for the AFM. Once I break through that weird wall, the brake boosting affect goes away, the CEL goes off, and the car runs smooth. But when the RPM's drop back into that low RPM range the brake boosting affect comes back and so does the CEL.
I find it really strange how the day before the car wouldn't even go over 1500 RPM with out bogging down. Then the next day its the exact opposite and drove smooth in higher RPM, and horrible in lower RPM.
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suprafanatic;1838739 said:
3.23 Hz?
suprafanatic;1838780 said:
Get "boost" out of your mind. Most cars don't have a turbocharger, and they can suffer the exact same problem. An intake leak after the airflow meter and before the throttle body. If there is a split in the hose, the car will struggle to idle, if it idles at all. Forget boost, you can't drive it.
Nick M;1838828 said:
I understand that, I still just call it a boost leak, vacuum leak, whatever. Anyway, there are no leaks so why are we still going on about that part? I've tested the whole system for any leaks and there are none. I would still like to know the answer to this question: What else could cause the car to throw a code for the AFM "31" other than a the AFM, its wiring or the ECU?
I believe a intake adapter that does not fit properly or is not on correctly can trigger it and also cause bucking.
But othen then that there is nothing that would cause it other then wiring or ecu and the afm it self.
But othen then that there is nothing that would cause it other then wiring or ecu and the afm it self.
Ya well there's nothing wrong with my intake/intercooler system. I've taken the whole system off the car and visually inspected it, after that I ran several leak tests and found nothing wrong with the system. So intake leaks Ruled out, Fuel pump I would rule out because it wont throw a code 31. So is it safe to say its down to the problem having to be with the ECU, Wiring, or The AFM based on what we know this far?
I was not talking about a leak..
I was talking about the adapter that people use to put on a aftermarket intake Filter on the AFM
I was talking about the adapter that people use to put on a aftermarket intake Filter on the AFM
Again nothing wrong with that. Its a K&N kit. And I don't see how that would cause it to throw code 31 either, that kit has been on the car ever since I got it.
I haven't cleaned it, but that's not the issue either because I had the filter off for a while and it still acted the same. So its the same with or without the filter.
So things just keep getting more and more confusing. I just took the car for another test drive and it seems like its just getting better on its own. Its driving a little bit better than it did yesterday. Higher RPM's it drives like a charm, but still bogging/hesitating in low RPM's and check engine light is still on it lower RPM's. But the car didn't die on me once today when I took a drive. Yesterday it died like twice on me. And start up seems to have gotten easier than the day before.
I really wish someone on here could help me make sense of whats happening with my car lol.
I really wish someone on here could help me make sense of whats happening with my car lol.
suprafanatic;1838925 said:
Nick M;1837167 said:
jetjock;1833202 said:
jetjock;1833653 said:
Check the cirucit. The code says open or short in AFM circuit. As a side note, you also said;
suprafanatic;1833978 said:
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=FI&P=57
31 and 24 have something in common. You might look into it.
http://www.cygnusx1.net/Supra/Library/TEWD/MK3/manual.aspx?S=Main&P=49
Ignore the ohms if you forgot. Unless it showed open "OL" on the display.