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Good news: the new aristo VVTI ecu from Gerry showed up. I installed it last night, and the car started and ran beautifully. I'm not able to turn the car off and back on without resetting the ECU and it works wonderfully!
Bad news: CEL comes on almost immediately once you start driving. Gerry reminded me that you cannot diagnose the CEL codes on this motor/ecu as the Japanese ECU does not have any OBD function. I was able to get a couple of good pulls in (oof - this motor sounds so killer through a 3" exhaust and the turndown muffler, and pulls as hard if not harder than I was hoping for in such a heavy car). The one-two turbo transition is an awesome feeling! However, I did experience fuel cut and limp mode while hitting boost. As soon as I turned the car off the silver cap looking EFI relay was going crazy flipping back and forth, and you can hear the fuel pump turning on and off. It doesn't sound like it's doing this while its running, however, its hard to tell over the loud exhaust and motor sounds. I have a feeling that relay is doing odd things and causing the motor to lose fuel pressure under boost. I'm going to swing by my local Toyota dealer today and replace the EFI relay and give it another drive.
Since my diag connector was on my GE motor, I not longer have one built into the new harness.
I took the car out today with a new relay installed. Unfortunately, the relay still turns on and off (also turning the fuel pump on and off) after the key is pulled out of the ignition. The fuel pump seems to run steady while the key is on, but no clue what would be activating the relay like that with the key off.
Also, I was able to get a few good pulls in, however, as soon as you really get into boost the CEL turns on and the car goes into limp mode. I am able to turn it off, back on, and have the cel turn off while limp mode goes away as well.
Gerry and I went back and forth a lot and I checked everything from my coils to my 12v mod connection. Gerry thinks the maf May be on the way out... I did find it to be loose with a ****ty gasket, so I cleaned it (GTE maf痴 aren稚 harmed by cleaning), reinstalled with a new gasket, but the problem persists.
If anyone had a known working vvti Jdm maf sensor please let me know! I知 also concerned with that relay situation and have to admit I知 stumped at this point.
Car looks great. that is a bummer with all the issues. SC3rrt said he was able to use a scanner on his ge vvti setup running a gte vvti ecu and he somehow got codes in an advanced mode, didn't know that was possible.
Your car wont have the obd2 port wired up to try... but it is possible to wire one in though.
I have a vvti gte ecu and maf that I got from someone who went standalone, he said it was working before the switch but I can't say for sure as I didn't see it.
If you want to borrow those or come try it out let me know.
I feel like you might have 2 different issues going on though.
The first one could still be the new ecu messing with the EFI relay.
For the second issue are you sure you aren't just hitting boost cut? when you free up the exhaust on the twins they can hit boost cut pretty quick, especially on a cold colorado day.
You have a boost gauge in? If its happening around 16 psi or so at our elevation, then it might just be boost cut.
only say that cause you wrote "really get into boost the CEL turns on and the car goes into limp mode"; cause that sounds like boost cut to me but usually it just blinks the CEL and cuts acceleration for 2-3 seconds then it goes away without resetting... but that is on the non vvti ecu vvti ecu I have no idea if it resets right away or not. I am sure Gerry does though lol.
^^ There has to be some way to make it blink out diagnostic codes and by now there has to be a translation key guide for JDM GTE ECUs somewhere online. I've never thought about it but even though the OBD equivalent is different in Japan there must be some diagnosis system in place that the Check Engine Light uses for Japan.
If this wiring is not built into your current harness I'd be willing to bet that the pins exist on those ECUs for the Japanese equivalent of OBD diagnostics. Wires from them would have to be run through the harness to the right places on your SC's diagnostic port of course.
Or you'd have to find a Japanese diagnostic port on ebay or Yahoo Auctions Japan and use that to wire into.
Or you'd have to recreate the right labeling of the Japanese diagnostic port and transpose that onto a USDM diagnsotic port... or really ANY "diagnostic" connector you'd care to implement so long as you can access the right pins, know which pin is what and reference them with a translated guide for the Japanese diagnostic codes.
Still, if it's a CEL-blink style diagnostic system it can't be all that different from USDM (can it?).
It is rare to happen but EFI relays can go bad. It can't hurt to have a new one on standby if you need it.
However if you wired the fuel pump correctly it should be on its own brand new 10ga fuel power circuit with a 20A fuse and 30/40A relay capable of more than 12V(actual) maximum. If you re-used your SC FUel ECU as the trigger-controller for that aftermarket fuel pump relay then it will be outputting anywhere from 12-14V to your Denso TT fuel pump... which for that common setup is normal.
But the SC's standard EFI relay should only be controlling the injectors, TT igniter and TT coil packs and general ignition system. Maybe the SC's Fuel ECU is also on that original Lexus SC300 circuit that the EFI relay uses (since SC300's and SC400's only have only "EFI" circuit for everything... whereas Supra TT's, Aristo TT's and I think other 1JZGTE vehicles all had separate "EFI2" circuits from the factory for their high flow fuel pump setups).
Also Ali makes a good point since you're both in Colorado at higher elevation. Also relative atmospheric pressure density changes due to weather can also minutely affect things at different elevations so I understand.
I appreciate the input you two! I do not have the boost gauge hooked up yet, but I値l at least run a line to it tomorrow to see how much boost it痴 pushing. It must not be boost cut, because it doesn稚 simply flash the cel and go down on power for a few seconds. What it does is, the CEL will come on no matter what once I drive it a short distance. As soon as you get on the throttle, it will let you make a partial pull, turbos spool, and then it痴 like hitting a brick wall. CEL stays on and it goes into full limp mode - loses all power but will idle - hitting the gas pedal does absolutely nothing. I can however, turn it off, wait for a second, turn it back on, and the CEL disappears and it runs normally until you try to make a pull again.
As for the relay, I did replace it with a brand new Toyota part today and it still turns on and off quickly for a few seconds after you turn the car off. The old relay would sit and do it for a while, but regardless, the issue persists.
I found that the MAF was a little loose, so I cleaned it, installed a new gasket, and it did run better (it would let me stay in boost longer, but still throw a CEL immediately while cruising and go into limp mode under boost). That makes me thing Gerry might be right and a maf May fix it.
Damn Ali, just sent Gerry some money for one haha. If you don稚 mind, PM me your number and I may give you a buzz and see how close you are. I壇 love to swap out the maf and see if that fixes it before Gerry ships his.
I値l continue to tinker tomorrow, thanks guys!
HUGE shout out to Gerry, he痴 been helping me diagnose things, sent me a good ecu, and is now sending me a good MAF. It痴 much appreciated sir, you sure know your way around these bad boys.
And a picture of the relay (old) before it replaces it today. I don稚 know why the ecu would send a signal to it spastically, but I suppose it痴 possible.
If you don't have the FCD (Fuel Cut Defender) or BCC (Boost Cut Controller) and you are simply on the stock ECU , then you more likely , as Ali said , are going into limp mode because you are hitting the max boost allowed with the stock ecu.
I値l hook up my boost gauge today and see what痴 going on. Is there anyway to bypass either of those functions without buying a fuel cut defender or boost cut defender for testing purposes?
However, despite being at a higher altitude, I壇 be surprised if a stock ecu with no boost controller hooked up would let that happen. Did every guy with an aristo in Japan get boost cut as soon as he went up for a mountain drive? Lol
no .. boost/fuel cut are ecu programmed . When you connect the FCC or BCC you are actually just fooling the ECU that you are not reaching the max. It clips and lower the signal voltage.
Yeah , get a boost gauge in there and see where you at . Boost/Fuel cut as Ali said is around 14psi . So if you reach that it will definitely go into a limp mode.
If they upgraded the downpipe/midpipe then pretty much
Whoa. I learned something myself just now. That's very good to know. So given that, Ali, would I also need to be concerned about hitting boost cut in full stock tune if I have OEM TT front and rear cats installed on my engine when I take my car up to 5,000ft-7,000ft+ elevation? Or would this still only apply to engines with downpipes and midpipes on stock ECUs?
I have an old Greddy Boost Cut Controller in my spare parts but never thought it would be needed if I were to stay in a stock tune.
Ali - interesting... I would never have thought! I ended up getting busy this weekend with family stuff. I値l have a new MAF from Gerry to try this week, and I値l also hook up a boost gauge ASAP to see if that could be part of the problem. However, CEL comes on before I ever get into boost, so I知 hoping the cut isn稚 happening (but we shall see). Thanks for the info!
Craig - weird, right? Who knows I might be hitting you up about that Greddy one here soon lol.
I値l post an update after I try the new MAF. Fingers crossed, I値l be sure to check everything I can.
I hope that new MAF cures your current issue Rudy! Hopefully!
The time we have for these projects is always challenged, no worries And the elevation changes causing boost cut to be hit faster seem weird at first but it's actually overall just interesting. It makes me laugh actually since one of my several reasons for doing my swap was to get away from an NA 2JZ-GE's anemic lack of horsepower and torque at very high elevations. Even so, I think it's just a tuning adjustment that will be needed to compensate. Even with the stock JDM ECU it should be possible with some mild usual suspects piggyback options from Greddy, HKS or Apexi (although this would all be fine tuning with 20+ year old piggyback electronics technology and I'm not sure how those options are viewed these days).
I'm keeping that old Greddy BCC unit I'm afraid It may come in handy for me down the road. The opportunity to use it just hasn't come up for me yet.
I just checked on Driftmotion's site. They actually still stock the HKS Fuel Cut Defencer. It's the same thing as a Greddy BCC from a functional perspective. Either company's offering will do to remove the stock boost cut restriction.
By the way, Greddy actually lists their Supra MKIV compatible BCC as one for the MR2 SW20 Turbo but it's common knowledge that it's the correct Greddy BCC model for Supra MKIV TT's to use. Again though, either the one from Greddy or the one from HKS will achieve the same goal.
But... once you use one of these things you do have to make sure the right amount of fuel is getting to the cylinders at the right time via an A/F or wideband gauge and probably some additional piggyback that allows some control over the fuel system. Exactly how to use those piggyback devices and properly is something Ali and Gerrb could answer WAY better than I can.
02-28-20, 06:33 AM
Whoa. I learned something myself just now. That's very good to know. So given that, Ali, would I also need to be concerned about hitting boost cut in full stock tune if I have OEM TT front and rear cats installed on my engine when I take my car up to 5,000ft-7,000ft+ elevation? Or would this still only apply to engines with downpipes and midpipes on stock ECUs?
And the elevation changes causing boost cut to be hit faster seem weird at first but it's actually overall just interesting. It makes me laugh actually since one of my several reasons for doing my swap was to get away from an NA 2JZ-GE's anemic lack of horsepower and torque at very high elevations. Even so, I think it's just a tuning adjustment that will be needed to compensate. Even with the stock JDM ECU it should be possible with some mild usual suspects piggyback options from Greddy, HKS or Apexi (although this would all be fine tuning with 20+ year old piggyback electronics technology and I'm not sure how those options are viewed these days).
It may come in handy for me down the road. The opportunity to use it just hasn't come up for me yet.