Running rich 12afr

[1989toyotasupraandpickup]

Ya i didn't want to start a new thread but no one was chiming in quick enough on the other one. I thank you for chiming in and helping when i need it. Your very knowledgeable on the supra. The wideband gauge goes to the gauge only and not to the ecu. Already checked. Will check the power and ground to the sensor and remove it to calibrate it to see if its malfunctioning. ECU temp sensor is new. My electric fan is probably turning on to early keeping the engine a little cooler.

Took the narrowband sensor out and it tested fine with the propane torch .988v with the flame and .012v with no flame. The on car diag Vf1 and e1 indicates the sensor is not working correctly. It does not fluctuate 8 times in 10 seconds. I will take pictures of the spark plugs and post them here. If you get time take a gander at the video. You will see where the a/f ratio sits. Even when i rev the engine. Does not move barely. Im going to take the manifold off today and seal it with copper rtv gasket sealer and see if that helps. The only thing i can think of that would cause my rich running condition. Does it act like a boost leak if the intake gasket has a leak? Its worth a shot and i am going to clean my injectors to make sure they are not leaking or clogged.

Saw on youtube a nice injector cleaner setup. Cant test the flow but you can clean the gunk out of them. Looks like it works good. i went to school for electronics and know how to diag electronics but the manual gives you nothing on how to diagnose the problems. like you said the manual is a broad repair method. My brother is a mechanic but he has no time to help me out. The AFM may even be toast but no code. Engine wont rev with
AFM unplugged but will idle. no code with oxygen sensor unplugged either. When i unplug the AFM i get a code along with the ecu temp sensor when thats unplugged.

Sorry to hear about the puppy. I hope he gets better. My puppy broke is back 2 legs when he ran out the door and into the main road. Doing good now all healed and happy to be alive. Thanks for the help i appreciate it.

[cre]

This isn't a high traffic forum. Responses come slowly from time to time and there is no paid staff, we volunteer our own time to help. Just bumping your original post if you haven't seen a response in a day is better form.

Please post the make and model of the wideband. The power source and grounding of the wideband are critical if you want to avoid false readings due to linear or (worse) logarithmic voltage offsets. Also remember that improper wiring or hardware placement will cause readings to shift as connectors, wires and or hardware are heated up... If any of the wideband's hardware sits in the engine bay you should consider moving it. The preferred ground would be to a stud near the one that the ECU is grounded to on the driver's side of the head.

The torch method of testing isn't the whole picture. The sensor doesn't report with a flat voltage signal, it's frequency must match the IGf signal (with an offset). This is what looking at Vf tells you but they don't explain it well or tell you how to read it even more accurately with a scope on both signals. Really, it's a cheap part an I'd just replace it if you still don't trust it after going through the diagnostics in the TSRM. EDIT: If the ecu doesn't see the correct frequency in the OX signal it will regard the O2 sensor as defective and go into full time open loop operation. The ECU gives the O2 sensor a set period of time to start providing a valid signal before it writes it off. No error code will be presented if I remember correctly.

Unfortunately, I don't know anyone at present who has Toyota's publication on testing the KVAFM with a scope... I really wish I did though. I'm going to have to start asking my friends from a couple dealerships if they can get me a copy.

You may also want to check the ECU for any signs of leaking caps.

I still have no reason to have any faith in your wideband. When cold all of your AFR readings should be on the rich side not stoich; 13.5:1 or so or lower.

I'll try to take a look at the video in a just a few minutes. I have some documents I need to finish working on before a courier arrives for them.

EDIT2: Yes, ANY intake leak between the turbo and the head will leak the most as the intake charge is at a higher pressure. It's just called a boost leak if it's leaking specifically while the system is pressurized. Check for any leaks in the intake and vacuum plumbing. Ok, gotta go. I'll try to get back in a bit.

EDIT3: Don't let me forget to give you a list of what AFR you should see and when. 10 to 12 while boosting is NOT a rich condition. 22 when coasting is NOT a lean condition. 17 while cruising IS a lean condition unless you're feathering the throttle, coasting down hill, etc.

[cre]

Okay, well, I figured it'd probably be a quickie so I watched the video now.

First, diagnostics mode should be engaged when the ECU is off.

I think I've mentioned it before, but if not the MKIII and other TCCS equipped Toyota's are notorious for rich or varying AFR at idle. It's very common. Typically 13 is the richest you'll see and around 15.5 the leanest. Also the ECU uses a richer open loop fuel map after a warm start than it does after a cold start. Temporarily inserting a 4.7K to 10K resistor in place of the ECU temp sensor will ensure that the ECU runs the cold start fuel map. Only do this for diagnostic purposes and only diagnose when the engine is running from the same initial state (ie after restarting once the car is warm).

Don't rely on the car's tach for an accurate RPM measurement. Get a calibrated gauge on it. I've seen the dash unit read hundreds of RPM high and low in the past. IMO, Vf diagnostics are rather worthless as there are many factors which can affect the results and it's really only good for diagnosing gross failures in that specific mode.

You'll find more detailed information here:
http://www.well.com/user/mosk/Vfsignal.htm

Feel free to replace the O2 sensor but until you're POSITIVE the wideband doesn't have a voltage offset, is properly calibrated, set for the correct fuel type and the sensor is good STOP RELYING ON IT... Hell, put tape over it. Once you're sure it is 100% you should seriously consider using it to emulate the narrowband signal to the ECU and ditching the actual narrowband sensor. Narrowband sensors aren't worth much when it comes to diagnosis they're a switch with no grey are or middle ground between results: RICH - Perfect (300mV window right in the middle) - LEAN

From what's shown in the video I'm inclined to believe the ECU isn't even entering "closed loop" operation. I've already detailed the main conditions under which it isn't in "closed loop" (or in other words when it is running "open loop").

There are no error codes present, correct?

Lastly, make sure the cold start injector isn't leaking.

[1989toyotasupraandpickup]

the wideband is an AEM 30-4100 gauge-type UEGO controller with the bosch LSU3.2 sensor. I believe i have to remove it to calibrate it to see if it bad or just slow. i can hook the sensor into the computer. there is a 0-5v analog output. there is also a serial output for data logging. would i be better off using the analog output on the wideband to make sure that the stock narrowband sensor is not bad. i mean why buy a part if i dont need it. Knock sensors should give a code if its detecting knock correct? AFM Bad? Cant find no vacuum leaks but i heard alot of people talking about the vsv's under the intake manifold go bad and cause a vacuum leak. i saw somewhere on the internet how to test the afm meter with the ossciliscope. however you spell that. i believe it is a square wave. thats all i know. caps dont look like they are bad. any specific ones that would leak. i mean you could tell if they were leaking by looking at the board.

[cre]

Originally Posted by 1989toyotasupraandpickup

I believe i have to remove it to calibrate it

For the most accurate calibration, yes. There are other ways but I'm not going to go into them as results vary and I want to be as sure as possible that yours is properly calibrated.

Originally Posted by 1989toyotasupraandpickup

would i be better off using the analog output on the wideband to make sure that the stock narrowband sensor is not bad.

As I said, if the wideband can emulate a narrowband output on the analog out then I would remove the stock narrowband and use the wideband to supply the ECU with the OX signal permanently.

Originally Posted by 1989toyotasupraandpickup

i heard alot of people talking about the vsv's under the intake manifold go bad and cause a vacuum leak.

If it's a concern then test them, it's simple.

Originally Posted by 1989toyotasupraandpickup

Knock sensors should give a code if its detecting knock correct?

No.

Originally Posted by 1989toyotasupraandpickup

I saw somewhere on the internet how to test the afm meter with the ossciliscope. however you spell that. i believe it is a square wave. thats all i know.

Oscilloscope. I don't know where that info has been posted online. If you find it please post a link.

Originally Posted by 1989toyotasupraandpickup

caps dont look like they are bad. any specific ones that would leak. i mean you could tell if they were leaking by looking at the board.

Yeah, they're often easily identified by the expanding casing and/or leaking electrolyte. I don't think this is your problem though.

First things first, check the wideband's power and ground points and recalibrate it. Then, if you have time, setup the narrowband emulation on the analog output and connect it to the ECU in place of the oem sensor's input. THEN post back.