No VF signal during operating or Idle.

jetjock

creepy-ass cracka
Jul 11, 2005
9,439
0
0
Redacted per Title 18 USC Section 798
Ok, I see. You were trying to check emulated cross counts, which is what I was alluding to. Fair nuff. I still don't see where it says to short Vf to ground though. Although it's unlikely to hurt anything you should still try and avoid doing that.
 

supraguy31

New Member
May 10, 2005
626
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Pembroke, NC
Actually the entire Process is a little strange. States #2 to connect the Positive terminal of volt meter to VF and Neg to Term E1 and do following steps.

Second block states to connect terminals TE and E1. Maybe Im reading into it a little but regardless I didnt get anything other than a 0.09v reading at any given time. Might be doing this wrong but I went by what the book states to do.
 

3.0 GT

2JZ Holset Mafia
Nov 30, 2008
381
1
0
Franklin, Tn
whats weird is this only happens, as far as i know, to maft pro users using a map sensor and no afm. what would cause this???? i hate it.
 

supraguy31

New Member
May 10, 2005
626
0
0
Pembroke, NC
3.0 GT;1647813 said:
whats weird is this only happens, as far as i know, to maft pro users using a map sensor and no afm. what would cause this???? i hate it.

I hope to get this figured out. Ive finally said the hell with dealing with Numberous Bad harnesses and bought my Christmas Present. Brand New Shiny 89 Supra Manual tranny engine harness. Merry Christmas to me. Will be here in Monday. Now to Diagnose a No voltage Between STA and ST1 which is part of the Ignition switch. No cold start or starter signal and its not the harness because Its been this way for atleast 2 Years and 4 different harnesses. I have to use the MK2 starter wire and tap it into the MK3 starter wire to get the car to start.
 

3.0 GT

2JZ Holset Mafia
Nov 30, 2008
381
1
0
Franklin, Tn
supraguy31;1647823 said:
I hope to get this figured out. Ive finally said the hell with dealing with Numberous Bad harnesses and bought my Christmas Present. Brand New Shiny 89 Supra Manual tranny engine harness. Merry Christmas to me. Will be here in Monday. Now to Diagnose a No voltage Between STA and ST1 which is part of the Ignition switch. No cold start or starter signal and its not the harness because Its been this way for atleast 2 Years and 4 different harnesses. I have to use the MK2 starter wire and tap it into the MK3 starter wire to get the car to start.

do you think a new harness will fix this problem? how much $ did that cost you anyway?
 

supraguy31

New Member
May 10, 2005
626
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Pembroke, NC
Yes it will. I have had other harnesses in the car after this one and as soon as I got them installed this VF issue went away. Problem was that the replacement harnesses had issues that were not brought fourth before I bought it. Solve one issue and another one or two come up. Just tried of buying used harnesses and not getting anywhere but running down other issues.

Brand New toyota Harness from the Dealership.. $540 Shipped
 

3.0 GT

2JZ Holset Mafia
Nov 30, 2008
381
1
0
Franklin, Tn
maybe i can rewire my stock harness because no way in hell am i paying that much for a harness. id rather go standalone lol
 

gottadiesel

Flyin Low
Feb 16, 2009
459
0
0
Vancouver, Washington
3.0 GT;1647851 said:
maybe i can rewire my stock harness because no way in hell am i paying that much for a harness. id rather go standalone lol

Of course sometimes we have to look at what our time is worth... At my billing rate for my business, I could pay for the harness in 10 hours, so as soon as I spend 10 hours dickin around with an old harness that has numerous issues, plus is 22 years old, depending on what part of the country it came from, may be cracked, maybe corroded... In the OPs particular situation, I would consider making the same decision... Of course not say that someday I will not go stand-alone, as I am sure we will only be able to get sensors for the 7M for so long before they become nearly impossible to come by...

To OP - Good luck either way and I'm sure we will catch up with each other in the area one of these days...
 

jetjock

creepy-ass cracka
Jul 11, 2005
9,439
0
0
Redacted per Title 18 USC Section 798
supraguy31;1647812 said:
Actually the entire Process is a little strange....

It's not strange if one understands what the flow chart is trying to accomplish in each step. It's basically a troubleshooting methodology for finding out why the engine isn't in fuel control when under conditions where it should be.

The test is used to determine:

1) Whether the O2 sensor is cross counting at all.

2) If it's not is the sensor itself at fault or is it because the system is unbalanced full lean or rich and if so in which direction.

3) Will the O2 sensor (and thus Vf) respond to enrichment using the coolant sensor signal (the chart should read "another cooled water temp sensor" btw, not "coded"). If not the system is either lean from other causes or the O2 sensor is bad.

Note the "repair over lean" and "repair over rich" decisions. Also note the "repair relevant diagnostic codes". One must understand what will unbalance the system to go beyond those levels.

supraguy31;1647765 said:
...Let the car warm up to Normal Operating temps, Jump the VF and E1...

Nowhere does the chart say to short Vf to ground and since it wouldn't make sense to do so I'm going to assume you're guilty of a typo.

Lastly, assuming everything else is working, the thing most likely to cause this is an incorrect load (AFM) signal.

Good luck. I'm guessing that unless your harness is really screwed up this is unlikely to be a wiring problem and even then it should be repairable. Hope I'm wrong but either way it'll be nice to have a new harness...
 

grimreaper

New Member
Jul 2, 2008
2,180
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0
Dallas
jetjock;1647963 said:
It's not strange if one understands what the flow chart is trying to accomplish in each step. It's basically a troubleshooting methodology for finding out why the engine isn't in fuel control when under conditions where it should be.

The test is used to determine:

1) Whether the O2 sensor is cross counting at all.

2) If it's not is the sensor itself at fault or is it because the system is unbalanced full lean or rich and if so in which direction.

3) Will the O2 sensor (and thus Vf) respond to enrichment using the coolant sensor signal (the chart should read "another cooled water temp sensor" btw, not "coded"). If not the system is either lean from other causes or the O2 sensor is bad.

Note the "repair over lean" and "repair over rich" decisions. Also note the "repair relevant diagnostic codes". One must understand what will unbalance the system to go beyond those levels.



Nowhere does the chart say to short Vf to ground and since it wouldn't make sense to do so I'm going to assume you're guilty of a typo.

Lastly, assuming everything else is working, the thing most likely to cause this is an incorrect load (AFM) signal.

Good luck. I'm guessing that unless your harness is really screwed up this is unlikely to be a wiring problem and even then it should be repairable. Hope I'm wrong but either way it'll be nice to have a new harness...

^ this, I've had a problem, like this before. Check the tuner pro settings in the BIN for the KPA range on the VE table. If your using the settings that lets you adjust the KPA range, It may be off. During a laptop to MP transfer it somehow got messed up. 1500rpms was 200kpa and 2000 rpms was 450kpa and so on. Massive overfuel that I initially thought was the ecu saying open loop. Af ratios where erratic, but I was driving it, not idling. Go through all your pro settings. Make sure your aware of any scalers that will effect the fuel %. Temp, main, Ve, user tune, AUX, etc..

---------- Post added at 09:56 AM ---------- Previous post was at 09:55 AM ----------
3.0 GT;1647813 said:
whats weird is this only happens, as far as i know, to maft pro users using a map sensor and no afm. what would cause this???? i hate it.

Piggy back lesson #1, you cant fight the stock ecu. Put the stock o2 sensor back in and let the computer take care of closed loop.
 

supraguy31

New Member
May 10, 2005
626
0
0
Pembroke, NC
Thanks for that Info JJ.

Let me make sure I clearify this. With the Previous harness that I had in the car, It had a KS issue along with a few other small issues but had Absolutely no Problem with VF signal picking up within the normal around of time. I put this harness in the car and this is the only problem that I have... No engine codes or anything. MAFT Pro is connected as it was the previous harness and no changes have been made to it.

If this Harness has a Incorrect AFM load which Im running Speed Density then what do I look for to fix that. I also want to point out that the A/F ratio does change from time to time. Drive the car at cruising when VF is working and its at 13.9 to 14.4 with a Average VF signal between 1.80 to 1.98 but nothing in the 2.5v and Higher range. Get out, Start the car back up and get back to cruising range, A/F is at 15.3 to 16 and VF is still at the 1.80 to 1.98v range. Basically, it never changes once it starts to read.

Maybe this is something to look at. Previous harness, readings would be 2.0 to 3.0v back and forth. I havent paid for the new harness yet, He just got one sent to the Dealership since there is only 3 left in the country. Good to have one on hand.

Robert

---------- Post added at 10:12 AM ---------- Previous post was at 10:08 AM ----------

grimreaper;1647980 said:
^ this, I've had a problem, like this before. Check the tuner pro settings in the BIN for the KPA range on the VE table. If your using the settings that lets you adjust the KPA range, It may be off. During a laptop to MP transfer it somehow got messed up. 1500rpms was 200kpa and 2000 rpms was 450kpa and so on. Massive overfuel that I initially thought was the ecu saying open loop. Af ratios where erratic, but I was driving it, not idling. Go through all your pro settings. Make sure your aware of any scalers that will effect the fuel %. Temp, main, Ve, user tune, AUX, etc..

---------- Post added at 09:56 AM ---------- Previous post was at 09:55 AM ----------


Piggy back lesson #1, you cant fight the stock ecu. Put the stock o2 sensor back in and let the computer take care of closed loop.