Understanding VF correction issue (maybe?)

[7M4EVR]

Overview: I seem to be having a weird little tuning issue that I am trying to wrap my head around. I have done lots of reading on the TCCS and particularly the learned value correction (vf), but I can't determine which inputs may be causing my symptoms. Maybe my symptom is not directly caused by the TCCS correction, but why the symptoms happen at the exact same time the vf changes is what I am trying to use to help narrow down the cause (could be on the completely wrong path though).

Related Mods: 3" turbo back exhaust, lexus/550/afpr, CT26 60-1 trim, FMIC, manual boost controller, 3 angle valve job on rebuilt head with NA cams. autolite double platinum plugs gapped at .32 (same symptoms with NGK's)
-Lexus screw turned all the way out, base FP set at 32 (with vac), running 10lbs of boost

Symptom: Upon first start up for the day my VF will be at 4.95. It will stay at 4.95 during cruise and will have a rough idle and will start bucking at low RPMs. It will stay like this all day long unless I shut the car off, pull the efi fuse and reset the TCCS. After resetting, I will restart the car, it will show 4.95 for a split second, then stay right at 2.75 all day for as long as I keep the car running. When it's at 2.75 the car runs great, no more bucking, lumpy idle, pulls much more smoothly in boost. But as soon as what seems to be me letting the car idle for a period of time or shutting the car off the car goes back to the same symptoms of lumpy idle and 4.95 vf. It's like my short term correction is perfect, but as soon as I shut the car off and it reverts to the long term (if I understand it correctly) it has issues until I reset the TCCS again. Does anyone have any suggestions on where to start looking?

What I have done: Boost leak tested entire system, turbo inlet up to 3000 pipe thoroughly. Took off throttle body and cleaned throttle plate, set throttle stop srew, and tested dashpot and IACV via TSRM. My TPS may need to be adjusted, but it does not set a code. I have no codes at any point in time, even after driving a couple days without resetting TCCS. Cam timing is lined up with marks when #1 at TDC. ign timing is spot on 10*.

Thanks for taking the time to read in advance...long post, but wanted to get it all out there. Just looking for suggestions on what to try next. I will always report back to the thread and give results of the diagnosis as any help is much appreciated! There is a very limited amount of import tuning help in my area.... : (

 

[IndigoMKII]

Just throwing this out there, could the NA cams be causing it? Haven't checked to see the pros/cons of running NA cams on a GTE.

 

[Suprapowaz!(2)]

What is your base fp vacuum disconnected? Do you have a wideband? Have you done the 12v mod? Stock fuel pump?

 

[IndigoMKII]

IIRC the TCCS only has 8 bits of memory so not much learning correction. If your TPS needs to be adjusted what it could be doing is this, it's telling the ECU that you're not leaving idle but you're really trying to accelerate. Too far out of adjustment either way is a bad thing, it's lying to the ECU and the o2 sensor is telling it otherwise.

http://alflash.com.ua/vf1.htm

 

[7M4EVR]

Saweet....thanks for the replies.

Forgot to mention I am running a walbro 255 and have NOT done the 12V mod yet! I'll look more into that. I have messed around with my base fp alot, and it was really weird that really no matter what I adjusted it to it wouldn't affect VF or AFR's much at all. Without vac I believe it is around 38psi at the moment. I have seen AFR's that represent boost leaks, 14.1-16.1 at idle AND cruise, and pig rich during boost. Like so bad I've seen 9.1 on the gauge, but I have since repaired the boost leaks and need to get the WB back on it. It's a portable and a friend and I share it. I know, please dont flame me, I have one of my own coming. I know I'm risking alot by not having one on there ALL the time. It is my #1 priority to get my own...should have one arriving very soon.

I remember reading that the NA cams didnt really affect much except for a little gain in low RPM power. There was even a dyno chart and such, but it's been a long time.

The TPS issue is my main goal now... thank you. I need to understand how to read a multimeter better and calibrate it correctly. I WILL get this done next. I just adjusted it going off of the code 51 and moving it around until it stops method...Thank you for that informative link!

 

[Suprapowaz!(2)]

I would do the 12v mod, then adjust the fuel pressure to see around 3.5v Vf in cruise mode while still trying to maintain 14.7 afr's. Then when you go WOT see what your afr's look like then.
When you go 12v full time you won't get that boost in fuel pressure going from 9v to 12v, so hopefully that will lean out your top end some (I think).

 

[7M4EVR]

When you go 12v full time you won't get that boost in fuel pressure going from 9v to 12v, so hopefully that will lean out your top end some (I think).

That does match my symptoms...and I do notice the stock relay and resistor get very hot to the touch. Just to be clear (wiring scares me) I need to do this?:

1.) Disconnect battery and bypass stock resistor by soldering the two wires together
2.) Bypass stock relay- jumper FP and B+, then can remove relay
3.) Then I need to purchase a 12v relay (30amp), and ground it to chassis and power it from battery with an inline fuse
4.) Drop the tank and take positive from fuel pump to new12V relay (use at lease 10g), run negative of pump to ground (isnt the neg already to ground?)
5.) Run the wire that powers the fuel pump to the new relay- This is the part that doesnt make sense to me. Can someone please help clarify this part to me please?