Roller_Toaster

iTrader: (1)

I wish there was away to override the "auto downshift" when you were in sport shift mode, or whatever it is called.

Congrats, it sounds FIERCE!

Are you using the base turbo, or did you get an upgraded one?


I wouldn't mind seeing a printout of your boost levels vs rpm :D

Roller_Toaster

iTrader: (1)

I wonder if there is a way to "lock" it into whatever gear you select in the sport shift mode...

ScionFred

iTrader: (1)

Thanks. Our "sport shift" mode is a joke! My 88 Mazda 626 had a true "manual mode" that allowed the driver to manually select any gear and hold it. It's so easy and cheap to do. While I appreciate being able to downshift and hold that gear, being able to prevent unwanted downshifts would be even better.

I'm looking for options but coming up empty thus far...

ScionFred

iTrader: (1)

Yes indeed, the ECU has a hand in everything. I spoke with Level Ten and IPT about a manual shift controller or changing the downshift strategy and they offer nothing. I spoke wth Mr. Flash and was told the same thing. I did find some manual shift controllers that might work but they don't interface with the ECU in any way so the ECU would set DTCs and possibly go into limp mode. I did find one guy with a 1000whp Supra who is running a PCS controller with a black box ECU interface but I'm still searching to find out if it's even possible for us and what it might cost. The PCS controller alone is $750 and the black box is probably custom and very expensive.

http://www.powertraincontrolsolution...mildetails.php



AFAIK 08-12 share the same shift console.

ScionFred

iTrader: (1)

Sorry to hear about your issues but hopefully they can be corrected pretty easily. Although the P0420 can be "tuned" around, it can't be tuned out. It's easier to fix the problem than hacking the tune to correct for it. Besides which you won't pass an emission test with a CEL present or pending.

Contrary to popular misconceptions, the ECU does use the 2nd O2 sensor as a check against the primary AFR sensor and uses this info to make small corrections. Since the ECU expects to see exhaust gasses that have been burned again in the primary cat, the easy solution is to reduce the volume of gas sampled by the sensor when the cat is no longer present (header or turbo).

What kind of anti-fouler/spacer did Descendant install on the 2nd O2 sensor? I'm a big fan of the 90* angled CEL eliminators. They reduce the volume of exhaust gas measured by the O2 sensor and can further be tweaked by rotating their orientation to fine tune the CEL out. WR, Strup and Big Daddy's Garage all offer good ones in 304SS so they won't rust away quickly like the cheap plug anti-foulers do.

IMO the first step is to eliminate the P0420 CEL and see how it runs. There are likely some tune issues as well but I'm sure Chruches can sort those out. Another thing that comes to mind is that the engine always idles faster after a battery disconnect and doesn't settle down for a while. If there were a idle problem with the tune, it could be masked every time you disconnect the battery and then appear when the ECU eventually lowers the idle speed again.

Good luck and feel free to PM if you have any more questions.

ScionFred

iTrader: (1)

I've never seen a P015A before. I wouldn't worry about it unless it keeps coming back since it may be related to the recurring P0420. It is my understanding that the ECU may adjust the AFR a little based on the 2nd O2 sensor. For example if the 2nd O2 is reading too rich the ECU may lean the AFR a little and compare readings between the primary AFR and secondary O2 again. The 2nd O2 reading rich won't cause major issues but it could contribute to your lean-AFR stalling issue. I suggest installing a proper anti-fouler ASAP as it can only help.

The back firing is just a tune issue that Churches can sort out. Although
back firing during a shift is normal. The ECU pulls a ton of timing during a shift and I often get a "pop" from 1-2 and 2-3. They can probably tune out the stalling too even with the P0420 but IMO you still want to get rid of that code. 8psi and 270 whp/wtq is a good place to be with an auto. I was talking to Justin from P-Tuning at the car show sunday and he told me the same thing Toan did about "built" U241E trans... "Don't do it!". He said they've seen nothing but problems from them.

I wouldn't reset the ECU before the tune. Let the tuner see the codes and other issues firsthand. Let him decide if he wants to reset before tuning. Good luck!


.

ScionFred

iTrader: (1)

Here's a good explanation of the P0420 DTC from Toyota:

http://www.ncttora.com/FSM/2003/Repa...fe/cip0420.pdf


This DTC is a 2 trip detection logic code meaning that the CEL will come on during the 2nd trip (ign on/off cycle) following a reset if the problem is present. During the first trip it should show as pending and then after you shut down and restart, the CEL will appear shortly afterward.

I don't know of any connection between idle speed, the CEL setting and subsequent stalling but that doesn't mean there isn't one. Fix the P0420 and at least you can scratch that off the list of possibilities.

ScionFred

iTrader: (1)

You are correct. The ECU does raise the idle speed with A/C on and also adds some AFR enrichment. I should mention that I too have a lean idle issue in warmer weather and turning on the A/C helps. Even my idle fuel trims are unusual. With 20% larger inj's I have idle LTFT of 0 where -20 is expected. My LTFT crusing at 60 mph is -19 as expected. My theory is that the actual IAT is colder than the sensor reads because the hot intake air at idle is cooled by the IC. Since the actual IAT is colder than the ECU thinks, it requires more fuel. IMO this is the main reason why many prefer a blow-thru MAS over a draw-thru. IAT is a very key element for the ECU to calculate air density and the fuel required. However while this IAT discrepency caused lean idle issue isn't ideal, it isn't a deal breaker. I can't remember the last time my car stalled because of this, if ever.



A is possible but IMO very unlikely. I agree with you that B is the more likely cause. One more thing to check is the BOV. Although it's recirculated, I've found that a partially open BOV can still cause idle problems, even when recirculated. What is your vacuum at idle? Mine is 20-22 in hg.



That's what I'm hoping for. If not there's still a few possibilities including the BOV setting, another vacuum leak or maybe even the inj dead time setting in the FIC map.




No, I can't but I very much doubt that your problems are caused by a ECU change. I bet Rob has a larger exhaust that reduces the gas sample presented to the 2nd O2 sensor. He also doesn't have torque converter load on the engine at idle. Hang in there, Bro! Boosting the auto XB ain't easy but it can be done. You'll get there and enjoy the hell out of it when it all gels.

sp2

Rob is running stock exhaust

The O2 modifier helped with the 420 code on mine, the reason Rob told me that code was showing is that the gases were causing the 02 sensor to get too hot with out adapter.

ScionFred

iTrader: (1)

I'm feelin' those TRD gauges... nice choice. I have AEM gauges and my boost gauge simply reads a little further in vacuum and boost (30 in hg/35 psi boost). What is your elevation above sea level? This affects both vacuum and boost readings due to air density variation.

If you're between 0-1000' ASL like me, your engine vacuum might be a little low. It's too close to be sure but you could have a small vacuum leak. Small vacuum leaks have their greatest impact at idle when intake air volume is at it's lowest. A small vacuum leak can cause a lean idle condition and stalling. You should mention this to Descendant. Since they installed the kit using cheap hose clamps, they should verify that you don't have any leaks with a leakage test.

FWIW, I hate cheap, un-lined worm-gear hose clamps. The only clamp possibly less reliable is the wire spring clamp. Even oem wide-band spring clamps are better. T-bolt clamps are worth every penny. If I bought a Descendant turbo kit, before even installing it I would substitute T-bolt clamps for all the hose clamps. Then I'd never have to worry about vacuum leaks.

Not to say that you can't acheive a leak-free setup with cheap hose clamps, because it is possible. It's just more difficult and less likely.

ScionFred

iTrader: (1)

Interesting... I thought Rob would be sporting one of their exhaust systems.

Either way, It's not heat that causes a P0420, it's not enough oxygen in the exhaust gasses. When the primary catalyst is removed the secondary O2 sensor reads a richer (low oxygen) AFR because unburnt fuel from the primary combustion process has not been re-burned by the catalyst. The O2 sensor compares oxygen levels outside the exhaust to levels within the exhaust gasses. The reason for spacing the o2 sensor further from the exhaust gasses and reducing the gas volume it is exposed to make it read a higher oxygen concentration in the exhaust gas by reducing the sample size only on the exhaust gas side.


In fact, by removing the primary catalyst, exhaust gas temp at the secondary O2 sensor should be reduced.

ScionFred

iTrader: (1)

Maybe you can just suggest to descendant that you suspect a small vacuum leak and ask if they can test for one? A small leak could certainly explain the lean idle and stalling issues. Although as I said, I hate cheap worm-gear hose clamps I must admit that once you acheive a leak-free seal with them, they probably won't leak again if left alone. Well, except for coolant hoses that expand and contract a lot but that's another issue.

Good luck tommorrow and I sincerely hope everything gets sorted out 100%. You're very welcome, I'm glad I could be of some help.

ScionFred

iTrader: (1)

I'm happy to hear that things are getting better. Did you ever find out what your elevation is Above Sea Level (ASL)? Specifically where you were when you took those pics of your vacuum readings? At 500' ASL I'm pulling 22 in hg and your vacuum seemed a little low, suggesting a possibly leak. However if you're at 2500' ASL, your engine vacuum would be the same as mine.

To adjust the BOV, remove the recirculation hose and cap the opening on the intake pipe. With the hose removed you should be able to see the valve inside the BOV. At idle your BOV should stay closed. It shouldn't flutter or move at all. If it does tighten the spring preload until it stays firmly closed, no more, no less.

You might consider replacing the hose clamps between the turbo and TB with T-bolt clamps. Hose clamps are fine for the air filter to turbo inlet. If you order them online they're pretty cheap and work a lot better. Good luck and enjoy.

xseveredveganx

If it keeps fudging up, I'll drive out and trade you all my stereo equipment for the turbo kit!

xseveredveganx

I've been eyeing the Descendant kit for a while. Just need to get stuff paid off, just to put the kit on credit! Ha!

sp2

well unless Rob added exhaust last couple months,
when picked my car up in May after gauges and boost controller install, Rob took me for test drive in my car, he said was a beast compared to his with stock exhaust, haha

glad everything is working better for you now

ScionFred

iTrader: (1)

The most likely cause for lean idle, stumbling and stalling is a vacuum leak that allows un-metered air to enter the intake after the MAS. The MAS doesn't see it so the ECU doesn't add fuel for it. The result is a lean idle but the car runs great off-idle because the leak is too small to matter when the intake air volume increases. If it's not that, there could be a problem with your idle air control valve or several other possibilities. 700cc injs flow almost double what the stock injs do and they'll never idle as smoothly. It's even possible that the ECU will eventually learn to compensate since it controls the IACV.

As for the BOV, here is a good read:

http://www.frozenboost.com/stpg.php?page_id=bov

Technically you have a bypass valve since it's recirculated and shouldn't have the same vacuum leak effect when open at idle but I have the same setup and it idles much better with the BPV closed during idle.

Anyway, I'm glad you're enjoying the boost and hope the idle problem gets resolved soon.

sp2

i have 2.5" custom back to tanabe concept g

ScionFred

iTrader: (1)

The way to check BOV, CBV (or ByPassValve) adjustment is to look inside the BPV exhaust port with the engine idling. The piston or valve should remain closed while idling. If you rev the engine, the valve should open a little when you close the throttle and slowly close again. Kind of a moot point though since I realized that your BPV isn't adjustable. It's an oem style made for some oem turbo car. It's probably fine.

I'm not sure what else to suggest. Did Descendant install new spark plugs? Copper or iridium? Copper ND plugs didn't work very well for me but 1-step colder NGK Iridium IX pre-gapped to 0.032" work great.

Here is a DIY for a boost leak test in case you need it:

https://www.scionlife.com/forums/sho...oost+leak+test

Good luck and keep me updated on this. I'm very curious to know what the cause and solution are.

ScionFred

iTrader: (1)

Either or both can cause idle problems. I'm glad you found a solution so you can really enjoy the new turbo kit. Congrats!