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Discussion Starter #1
So my aristo ecu took a crap on me and I bought a JDM mk4 supra 6sp ecu. To my knowledge the JDM supra is map based with 440cc's so I technically should be able to run the ecu. The seller that I received the ecu from stated it's a G-Force ecu. From other G-Force ecu's that I have seen on the forum it doesn't look identical.

I checked the part number on the ecu and its for a jdm mk4 TT 6sp supra.



Note the spacer for the "G-Force" ecu








Any help is appreciatede
 

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My g-force ecu has the raised section (space) where they installed a new daughterboard as well as the OEM stickers. The stock ecus do not have the spacer. Sometimes they will list the mods on the ecu case like speed cut, fuel cut, rev limit and fuel tweaks, but the best indication it is modified is the raised section since they cant simply reflash the stock ecu.
 

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When I had a G-force moded ECU (a USDM one) the IC's with those white label stickers where the ones that had modified parameters as mentioned above; I also had an extra IC for timing changes though I never used it. While they may be faded, can you read anything on those labels?
 

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Remember that G-force wasn't the only game in town installing daughterboards to remap the stock 2JZ-GTE ECU. Techtom, Mine's, Blitz Access, SARD Analyze, Trial, and others remapped JZA80 ECU's in Japan.

G-force ECU's use the Techtom daughterboards and that's what you have pictured. Here's a couple pics of two different G-force ECU's, my old one at the top, and my current one at the bottom:



Note that the top one only has one daughterboard - that's the board needed to alter fuel maps and remove boost cut & speed cut. That is typical of most G-force ECU's or other JDM remapping and it was almost always less expensive.
The lower one has two daughterboards, and that second one is the board that changes the timing map. Obviously, this means the ECU you have pictured has altered fuel mapping as well as timing, and it's using the G-force/Technosquare hardware so that jives perfectly with the seller telling you it's a G-force ECU.

Now Mine's had their own style of daughterboards, but like the G-force also used the machined spacer method to make room for them:




Others used a 'blister' method by having a taller cover plate, such as this Blitz Access ECU:

ECU's with the blister plates installed the daughterboards to the other side of the main board, so EPROM's could be switched by only removing the cover itself, instead of having to unscrew the second board too as with the Gforce and Mine's setups.
Another thing is that one could tell if only fuel/boost cut had been altered, or if timing had been altered as well just by looking at the cover. Because that Blitz ECU has the elevated 'blister' area only on one side, we know that only the fuel mapping & boost/speed cut has been altered on that particular ECU.

I've been trying to find pictures of the internals of the Trial, Blitz, and SARD 2JZ-GTE ECU's, so if anyone has one of those ECU's and is willing to take a picture for me to keep as a reference, I'd appreciate it.

Others still, well, simply lied entirely about tuning the ECU at all:


Here we've got a JET sticker on a chip in the factory ECU that's completely unrelated to fuel or ignition mapping, and that chip has not been changed out or removed from the board. That is how JET supposedly 'tuned' this ECU, but the fact is that someone was charged upwards of $400 for JET to slap a sticker on it and put seal stickers on an otherwise 100% stock ECU.
I've personally seen this sham performed on 7M-GTE ECU's, 4A-GZE ECU's, and now JZA80 ECU's. I have heard of JET pulling the same sham on 3S-GTE and 2JZ-GE ECU's as well, but I haven't personally laid eyes & hands on an example of either.

In conclusion, we can say with near certainty that you've got a G-force ECU, and we can say that both fuel and ignition timing have been remapped on that particular example.
The downside is the same as with any tuned ECU - it's impossible to know what it was tuned for without running it on the car.
While the JDM 2JZ-GTE's were all originally mapped for 440cc injectors, an ECU can be tuned for larger injectors in the fuel mapping EPROM by the original tuner much like a standalone. I've seen tuned JDM ECU's that were mapped for injectors as big as 800cc's. But you won't know anything about it until you plug it in and drive it - just keep a sharp eye on your wideband and EGT's!
 

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Discussion Starter #5
Thanks for the insight. The seller stated that he bought it from a place in japan. He tested it on his own motor to ensure it would start up and rev fine. It has fuel cut removed, speed limiter removed, raised rev limiter, and fuel map altered.

I did install the ecu and start it up but the motor would shut down within a few secs of start up. I pulled the codes to see if I can find a prob and I got codes 31 (MAF Circuit) and 47 (Sub-TPS Sensor). I don't understand how I can have code 31 when the jdm supra/aristo motors are MAP based. I also pulled that code on my aristo ecu as well. Code 47 is due to me removing the sub throttle.
 

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Thanks for the insight. The seller stated that he bought it from a place in japan. He tested it on his own motor to ensure it would start up and rev fine. It has fuel cut removed, speed limiter removed, raised rev limiter, and fuel map altered.

I did install the ecu and start it up but the motor would shut down within a few secs of start up. I pulled the codes to see if I can find a prob and I got codes 31 (MAF Circuit) and 47 (Sub-TPS Sensor). I don't understand how I can have code 31 when the jdm supra/aristo motors are MAP based. I also pulled that code on my aristo ecu as well. Code 47 is due to me removing the sub throttle.
I suspect the error codes for the USDM ECU that you're referencing aren't correct for the JDM ECU's you're testing. Sadly I do not know of a source to find a JDM ECU troubleshooting guide in English (or Japanese for that matter)

If your Aristo ECU 'took a crap on you' and you're having issues with another ECU, I'd suspect something wiring/power/ground related going into the ECU as a possible culprit instead of the ECU itself. An ECU getting damaged or dying is almost always caused by some sort of wiring or voltage issue and not the ECU itself just dying randomly.

What symptoms did you see when your Aristo ECU failed? Can you keep this modded ECU running with throttle input?

IIRC, Code 31 is a MAP sensor fault on the 1JZ-GTE ECU. It's possible that it'd be the same on the early JDM 2JZ-GTE ECU's.
 

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Discussion Starter #7
If your Aristo ECU 'took a crap on you' and you're having issues with another ECU, I'd suspect something wiring/power/ground related going into the ECU as a possible culprit instead of the ECU itself. An ECU getting damaged or dying is almost always caused by some sort of wiring or voltage issue and not the ECU itself just dying randomly.
You sir are correct. It's my charging system. I used to my daily to jump my car after leaving it on and it fired up and idled perferctly. Soon as I took the jumper cables off the motor just cut off. After replacing my serpintine belt tensioner I never checked my battery or alternator for voltage. I checked my cca for my battery (CCA 750, I have a Nissan 240sx with 2jz swap) and it's only putting out 450. After I charge my battery I am going to do a voltage test for my alternator to see if it's doing it's job.
 

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Bringing back! I have a G Force now (It came in the 98 I bought) But I'm sure it doesn't have any OBDII stuff as the engine there was from a 94. Reading above, I guess there is no way of knowing what the new mapping is. Car runs real rich and idles high. Plus there is some hesitation or slight mis-fire on acceleration.

Is there any places these days that still do flashes for these? (US Model)

Stu
 

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Here's the G-Force ECU I just installed, but bought 4 years ago. It's the 2-chip G-Force upgrade, according to Wreckless's pictures and description. What I know about it is:
  • Rev limit raised to 9000rpm. I'll never run it that high. I just wanted to be able to get to 7500 on the track so that I had more flexibility of shift points, for example, so I don't have to shift in the middle of a turn while accelerating and holding 1.3Gs of lateral force.
  • Speed limit removed. At some point I will hit 155mph on the track and I don't want to remove my Trac fuse since it's powering other stuff and I'm against removing telltale warning bulbs.
  • Boost cut removed. No more need for the GReddy BCC.
  • Set up for stock fuel injectors (550cc), with stock lean spot removed (I think).
  • Unknown timing changes (because of the 2nd daughterboard).
Is there any way to know what kind of timing changes were generally made on these?







 

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Nice score!

Generally speaking the timing changes were to moderately reduce timing advance in the midrange and advance it a little to suit higher RPM's on raised rev limits. I suggest keeping an eye on EGT's mostly with JDM tuned ECU's because sometimes the tuning was very aggressive and meant to suit a very specific set of hard parts, which are almost never known for sure.

That said, reducing timing advance through the midrange for safety can sometimes increase EGT's slightly, and reducing timing advance too much will definitely increase EGT's. Again, keeping an eye on things is generally a good idea since the exact tuning data is basically unknown in most cases. Japanese tuning houses tended toward large turbine housings on singles or big twins, so running an 'American' sized smaller hotside with an ECU specifically tuned for a much larger turbo like a T88H could result in pretty high EGT's from the increased backpressure.

Since you have a G-Force ECU, those were typically marked with specific tuning data and I'd run one of them much more confidently and without those worries. But keeping an eye on things is always a good idea if you have the means, but if your A/F's aren't doing anything crazy I'd bet on things being just fine so long as the gasoline you're running can keep up with the boost levels you're at.

Note that since the rev limit and boost cut are both on the fuel side of things, a 'fuel only' GForce will have basically maxed out any timing advance by the end of the stock mapping which I believe is around 7500rpm. But if you're not revving it that high in anger, no worries there.
 

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Thanks Wreckless! That's great info...exactly what I needed.
 

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Toyota Aristo -92 "JZS147" 2JZ-GTE
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I bought 2JZ Blitz Access ECU, for my JZS147 Aristo, and it has a blue wire hangin outside, like in the photo. Where I should wire it? I guess it has something to do with a traction control or 180km/h speed limiter... Any tips?
 

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I haven't seen one on a Blitz ECU or any 2JZ-GTE ECU for that matter, but I saw a Trial ECU tuned for a 1JZ-GTE with such a wire.

The wire was the VSS output to be wired directly to the speedometer input, if memory serves. The speed cut is a fuel board function but the VSS that has to be faked to eliminate it also runs the speedometer, so that was a way to get a VSS signal to the speedometer.

But I'm not sure if that's the same thing with the Blitz ECU or not, but I'd guess it's something like that.
 
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