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VQ Throttle Body Re-Learn

17K views 51 replies 10 participants last post by  Pfbspecv 
#1 ·
I just installed a VQ throttle body and can't get the re-learn to work. I've done this many times with the QR TB and am very familiar with the process. You are supposed to wait 3 seconds after the CEL stops blinking, turn off the ignition, and start the car for the learning to begin. Each time the engine revs up and down around 1200 rpm but never becomes steady.

I know that the dealer can do this with Consult II but I was wondering if anyone has come up with a variation of the "gas pedal dance" to make it work. I flash my ECU ROM often with UpRev and fear that I may have to go to the dealer each time I re-flash the ROM.
 
#2 ·
i dont remember in which post it was but someone here said that he used a safc2 to get the idle down to 800 or 900 rpms and make it steady, it should be in a post somewhere :thinking: so maybe you can use your uprev to get them down and steady? btw any noticeable gains?
 
#5 ·
The issue is not "setting" the idle rpm - I can do that easily with UpRev. The problem is in "learning" the idle air mixture volume. It seems that the ECU is attempting to learn this, without success, as evidenced by the continuous fluctuation in idle rpm.


btw any noticeable gains?
That's funny; there's no way to tell just by driving. I expect the gains to be around 5 whp (Big Al said he got 25, but that's turbo). All area tracks are closed so I'll wait to dyno the car after installing my new header.
 
#3 ·
IIRC Cupit said it can only be done with the Consult II. He has a "friend" at the stealership so they do it cheep for him. around here its like 90 bucks @ Stealer.

Let us know if it works out well and what HP gains you made (i would love to do this mod to mine)
Good Luck!!
 
#4 ·
Its very tricky. The car temp has to between 190-202, the steering wheel has to be straight, no power should be on when doing the relearn not even the fans. If the CEL is on you have to clear the code first.
 
#8 ·
here is the link for the idle relearn. Also you have to put ur idle back to stock setting for it to take.
This post should be a "Stickie" in the Maintenance Forum. Great link!

I just tried your suggestion in your previous post. I cleared the DTC code (but it is still stored in the ECU as a pending code), and warmed up the car to 190-195° before doing the entire re-learn procedure (pedal position, throttle closed position and idle air volume). I did it three times with the same results.

I guess I'll take it to the dealer on Monday and have him do it. He charges $50. That's not bad but I don't wand to do this each time I re-flash my ROM.
 
#17 ·
Stock Idle is about 700-725 if I remember correctly get your hands on Consult-II let the car warm up, go into Engine then go into Work Support after that scroll down to the Idle Air option and drop it down as much as it would go, I won't drop lower than the factory setting, select update and it should be saved, turn the car off, then turn it on without Consult to confirm the update took, after you're sure it took go about your regular Idle learn procedures Good Luck :)
 
#18 ·
he has UpRev and cipher............. cipher is a consult

i think there was a difference between the early and later VQ TB's, like a couple of wires are swapped.

you could check the Spec V wiring, and then check an early and later VQ TB schematic to see.

BTW, what is the code you are getting?
 
#21 ·
I do suggest getting the Idle re-learn done with Consult because that code P0507 you posted is the common one that we see whenever we change a throttle chamber and the pedal dance only works about 25% of the time for us, as far as the Value I would say it is static but it alos depends on your re-flash because I know some software allows you to adjust the idle of the vehicle (I don't know if yours works the same way nor do I know too many details about tuning software) but I know that the Idle saves to the ECU after it's changed, so chances are if you haven't lost the idle with your first reflash you won't lose it after you do your second re-flash, I hope this helps I was kinda confusing myself in my own words
 
#22 ·
UpRev allows you to change the idle rpm but not the idle air volume. These 2 values are stored in separate locations in ROM. I'm guessing that once Consult II changes the idle air volume parameter, it will remain in ROM even after an UpRev re-flash.
 
#23 ·
it would only make sense to me that it does since it doesn't alter the configurations for idle air volume but if that's the case you shouldn't need the throttle open or throttle closed learn you need an Idle air volume learn so that the car can adjust it's volume parameters at idle for the new TB, the flap since it's computer controlled is gonna have to be closed a little bit more than the QR TB to maintain a steady idle volume since there's a difference in the air flow so I don't think the pedal dance will work cuz to my knowledge thats only for TB open and TB closed positions everything in between is different with the new TB
 
#33 · (Edited)
That's very interesting but I don't get it. Those pins are supposed to actuate the TB motor either to open or close and are reversed in the two TB's. That would imply that if I step on the gas, the VQ TB motor should close the flap with the QR connector as wired. That's the part I don't get because the gas pedal operates normally. Before I start cutting and splicing the connector wires, I will PM some people who already did this mod and how they got it to work. Besides, when you do the TB pedal dance, the TB open and TB closed are "learned", aren't they?

Thanks Big J. Not that many people would put in so much effort to be helpful.
 
#34 ·
everything else is the same, voltages, TPS wiring, etc.

checking the 2002-2003 stuff now.


It is weird that the TB would open like it's supposed to with the wires swapped, but, it's in black and white in the FSM, idk. It would be a quick cut and twist to check it.
 
#35 ·
Just got a PM reply from someone who did the swap:
"i was told i had to swap wires around and i tried swaping some wires and mine wouldnt even start. i just left the wires the same and it would start fine but it would run real bad, so i took it up to nissan and got it relearned from them and raised my idle. it runs fine now with that all done.
***************

I think it might be a good idea to try shortcut10's suggestion of first doing the Consult II idle air volume re-learn.
 
#41 ·
see the lock nut and set screw..... It will adjust how far the TB is closed when unpowered.

If you adjust it you will need to do a closed position relearn, which is basically just turing the key on and off several times with a long enough pause for the ECU to power down.

It might let you do a relearn. Just remember how many turns you go, kinda like adjusting an idle mixture screw.
 
#42 · (Edited)
Big J, you might be absolutely right. I checked the QR TB and it doesn't have a corresponding adjustment screw and lock nut, but the throttle is not fully closed either. That may be why the idle air volume can only be adjusted with Consult II on a QR TB. Consult can probably tweak the "closed" position in either direction.

With your vast treasure trove of knowledge I am assuming this may be one nugget you have not yet totally mastered. Together we might arrive at a solution that will encourage others to this mod without fears.



Since I don't know in which direction to turn the screw and how many turns it takes to get an approximately correct opening, I will remove the intake hose connection and visually observe and measure the throttle opening and closing while turning the set screw. I think the measurement can be done with a feeler gauge slid into the opening. The opening on the QR TB is .016". If the set screw does affect the throttle closed position, then I will adjust it to about 2/3 of the present opening as a starting point. I will let you know how it turns out.



12/12/2010
The locking nut backed out easily but the adjusting screw won't budge. I've poured Liquid Wrench on the threads and tapped it with a hammer while trying to turn it in either direction - no luck. I'll do this for a couple of hours and then quit. I don't want to use a pair of vise grips yet because there is a chance that this is not the adjustment screw for the throttle and I don't want to damage it. I will get one or two junked VQ TB's and experiment on them.


12/14/2010
Got pissed off and grabbed a couple of vise grips to pry that setscrew loose. The vise grips bit but the damn screw still wouldn't budge with moderate force. Shortcut10 got in touch with a local Nissan parts manager who agreed to let me look at a couple of VQ TB's. Neither TB's setscrew could be turned with a Phillips screwdriver. I think this is the end of this experiment for me.

While I was there, I had my idle air re-learn done with Consult II. It took about 20 minutes (everyone was coming over to look at the car) and cost about $55. I just hope that I won't have to back when my ECU resets.
 
#43 ·
I just wanna say this is a verrrry interesting thread!! this is a mod i want to do but have the fear of not working.

Great job and thanks Westner, Cupit and Big J !!!
 
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