2JZGE Na-T TT Ecu Mod
02-20-15, 08:21 AM
#2433
02-20-15, 01:15 PM
#2434
gte & na-t
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Caon one of you guys post the pic of their setup? Maf location and intake pipe diameter in front of the Turbo will cause those issues.
I did a GS300 with VVTi gte and USDM Supra single conversion and it was a pain in the neck..
I did a GS300 with VVTi gte and USDM Supra single conversion and it was a pain in the neck..
02-20-15, 04:42 PM
#2435
I did read about people having issues with a shorter intake but it doesn't appear to be the root cause of the issue. As Ali pointed out earlier pretty much every obd2 single supra has to get rid of the maf in some way to avoid the issue. It's quite possible a smaller or longer intake could help but I don't think it would have a chance of solving the issue.
02-20-15, 06:12 PM
#2436
maybe if you use 4" to 3" reducer coupler off the turbo and a 3" pipe to the maf it might be better, there is no 4" piping after the maf on a gte car.
at least it will help with distributor clearance, that is what I used to run with the stock maf when I was n/a.
at least it will help with distributor clearance, that is what I used to run with the stock maf when I was n/a.
02-20-15, 07:13 PM
#2437
You would need a 60 degree reducer which I'm not sure is even a thing to clean the distributor. After my maf its just an air filter.
02-20-15, 08:34 PM
#2438
Lexus Test Driver
So here are a couple pics of my engine bay
My issue is that the car keeps misfiring on every cylinder and after checking the coilpacks, wires, plugs, everything ignition related, it still misses. It never shuts off or dies out or anything. I have the fuel trimmed back with an safc.
My issue is that the car keeps misfiring on every cylinder and after checking the coilpacks, wires, plugs, everything ignition related, it still misses. It never shuts off or dies out or anything. I have the fuel trimmed back with an safc.
02-21-15, 05:52 AM
#2439
Have you played around with your tps at all? When I was getting all cylinders/ what I have now it appears to be the tps because the misfire jumps around from cylinder to cylinder.
02-21-15, 07:30 PM
#2440
Lexus Test Driver
i had 3 different shops play around with the tps and the timing. Sound Performance, one of the best shops in the midwest when it comes to 2JZ's, swears its all set correct and they are just stumped why my car behaves as it does. They said the only way my car will ever run perfect is if i go stand-alone
02-22-15, 07:38 AM
#2441
just out of curiosity what does it sound like when its missing?
Edit* Got rid of the misfires and the idle is back down after fiddling(thanks ali). Here is how its running now, though its running a little bit weird. Still have the afr going up and down and what you see in the video when I rev and hold. Just seems like it is getting to much fuel again. Do you have to assume its the metered air causing the problem because the computer fuel trimming can't solve it?
Also right before I got rid of the misfires/idle I had a misfire on every cylinder, so I think you (mylex) can most likely do the same.
Video of how its running now
Edit* Got rid of the misfires and the idle is back down after fiddling(thanks ali). Here is how its running now, though its running a little bit weird. Still have the afr going up and down and what you see in the video when I rev and hold. Just seems like it is getting to much fuel again. Do you have to assume its the metered air causing the problem because the computer fuel trimming can't solve it?
Also right before I got rid of the misfires/idle I had a misfire on every cylinder, so I think you (mylex) can most likely do the same.
Video of how its running now
Last edited by 187; 02-22-15 at 12:19 PM.
02-23-15, 02:39 PM
#2442
187, so you have no misfires now and all its doing is that afr is a little off each time it settles right?
that pretty much sounds like how the maf is going to run on a single turbo, along with wanting to stall after boosting. I would continue to drive it and see how much more it learns. obd2 has a more complicated feedback system normally including long term and short term fuel trim's. what might happen is after a few drives the ecu will adjust the long term trims, and then might get you back into not fluctuating. sometimes in order for it to learn the trims, it has to fluctuate some that wont make sense. if it never stops though, that means no single value is doing it, and that the maf is not correlating close enough to what it expects, and the only thing that will help give it a maf signal it more expects is a vpc or a map ecu.
It has to do with also how these look up the fueling. on a stock maf ecu, there is an extra airflow look up table that is programmed for those little twin turbo's specifically in the stock ecu.
so basically what the vpc is doing is fudging the maf numbers/airflow some to look more like a single turbo airflow look up table and that gives you the right fueling for a single turbo when it goes to that extra table.
map sensor ecu's directly look up the fueling from the load (pressure from map sensor) and "VE" (volumetric efficiency) of the motor and will be less affected by turbo changes versus a maf ecu that had to take the airflow, then use a twin turbo specific look up table to calculate the load, and then look up the fueling on the "VE" map according to the load.
hope that makes sense its the extra step of airflow lookup that makes it difficult to switch from twins to single turbo without a vpc or map ecu that can alter the airflow values into the ecu for what you need for a single turbo (not the values the maf would give it alone).
we are lucky that the airflows of a single turbo do sort of match up to sections of the airflow in the twin turbo's so you can find the right values to give it for proper fueling, problem is this does not happen as automatically as it seems to on stock map sensor ecu's.
Also take in to mind that I keep on saying it looks up fueling like that, but I should mention that the timing is looked up the same way, so when you have the wrong fueling you also prob have the wrong timing but its harder to tell. timing also affects afr's ou can lean it out by dialing in more timing and richen it up by taking out timing, so the ecu is seriously confused when it uses the wrong airflow value.
the better question now is how is it even running at all above idle with the wrong inputs vs outputs, not why are the afr's not perfect.
that gurgling sound you hear right after revving and letting off (right when you let off) is a pop from an incorrect combination of both fuel and timing, which ones its hard to say but my guess would be too much fuel and too much timing (too little timing when ecu starts pulling it should give you more awesome backfires).
that concludes my technical explanation of why your car's wont run right on the tt maf.
if any one of you guys can show me 3 pictures of a mk4 non-vvti 2jzgte with a single turbo and the stock maf I will drop the whole vpc thing and say I don't know why it doesn't run right, cause thats all I got right now is I think that people don't do single turbo and the maf cause it doesn't work right. I tried and didn't find much. I think every one of them has a vpc or standalone pretty much.
here is one picture I found on google images, and even in the article he says without the map ecu it won't run right. the stock maf was there for the map ecu "learning mode" wihch helps setup a basemap sooner, so even though he has a maf there he says it does not run right with it after installing the single turbo.
http://www.webpages.uidaho.edu/dcord...upra_mods1.htm
that pretty much sounds like how the maf is going to run on a single turbo, along with wanting to stall after boosting. I would continue to drive it and see how much more it learns. obd2 has a more complicated feedback system normally including long term and short term fuel trim's. what might happen is after a few drives the ecu will adjust the long term trims, and then might get you back into not fluctuating. sometimes in order for it to learn the trims, it has to fluctuate some that wont make sense. if it never stops though, that means no single value is doing it, and that the maf is not correlating close enough to what it expects, and the only thing that will help give it a maf signal it more expects is a vpc or a map ecu.
It has to do with also how these look up the fueling. on a stock maf ecu, there is an extra airflow look up table that is programmed for those little twin turbo's specifically in the stock ecu.
so basically what the vpc is doing is fudging the maf numbers/airflow some to look more like a single turbo airflow look up table and that gives you the right fueling for a single turbo when it goes to that extra table.
map sensor ecu's directly look up the fueling from the load (pressure from map sensor) and "VE" (volumetric efficiency) of the motor and will be less affected by turbo changes versus a maf ecu that had to take the airflow, then use a twin turbo specific look up table to calculate the load, and then look up the fueling on the "VE" map according to the load.
hope that makes sense its the extra step of airflow lookup that makes it difficult to switch from twins to single turbo without a vpc or map ecu that can alter the airflow values into the ecu for what you need for a single turbo (not the values the maf would give it alone).
we are lucky that the airflows of a single turbo do sort of match up to sections of the airflow in the twin turbo's so you can find the right values to give it for proper fueling, problem is this does not happen as automatically as it seems to on stock map sensor ecu's.
Also take in to mind that I keep on saying it looks up fueling like that, but I should mention that the timing is looked up the same way, so when you have the wrong fueling you also prob have the wrong timing but its harder to tell. timing also affects afr's ou can lean it out by dialing in more timing and richen it up by taking out timing, so the ecu is seriously confused when it uses the wrong airflow value.
the better question now is how is it even running at all above idle with the wrong inputs vs outputs, not why are the afr's not perfect.
that gurgling sound you hear right after revving and letting off (right when you let off) is a pop from an incorrect combination of both fuel and timing, which ones its hard to say but my guess would be too much fuel and too much timing (too little timing when ecu starts pulling it should give you more awesome backfires).
that concludes my technical explanation of why your car's wont run right on the tt maf.
if any one of you guys can show me 3 pictures of a mk4 non-vvti 2jzgte with a single turbo and the stock maf I will drop the whole vpc thing and say I don't know why it doesn't run right, cause thats all I got right now is I think that people don't do single turbo and the maf cause it doesn't work right. I tried and didn't find much. I think every one of them has a vpc or standalone pretty much.
here is one picture I found on google images, and even in the article he says without the map ecu it won't run right. the stock maf was there for the map ecu "learning mode" wihch helps setup a basemap sooner, so even though he has a maf there he says it does not run right with it after installing the single turbo.
http://www.webpages.uidaho.edu/dcord...upra_mods1.htm
Last edited by Ali SC3; 02-23-15 at 02:55 PM.
02-23-15, 03:31 PM
#2443
That was a very helpful explanation. I'll see what happens but, I have driven when the car was like this and it never figured it out. Also I have tried more advance timing at idle but it yielded the same results.
It's quite an interesting scenario the ecu seems to be in. I'll have to post over on SF this week and see if anyone has a vpc hanging around.
It's quite an interesting scenario the ecu seems to be in. I'll have to post over on SF this week and see if anyone has a vpc hanging around.
02-24-15, 09:38 AM
#2444
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I currently have a 1995 2JZGE that I am putting in my Datsun 280z, I was in the midst of using all 7MGTE electronics until I came across this thread. The jdm ecu route is a LOT simpler and it appears to be the way to go for the most power (400-500hp) until I go with an AEM v2 setup. I'm still debating as to whether I should go with vvt-i coils or ls coils (I have a couple sets of ls coils and a 7mgte coil pack in the garage)...I haven't read through all of this long thread yet but just wanted to say that this thread is a Godsend, thanks Ali and to everyone who contributed!
Last edited by Milwaukee; 02-24-15 at 09:51 AM.
02-24-15, 10:53 AM
#2445
Welcome to Cl and glad you enjoyed the write-up.
The 7mgte electronics will get the job done (sort-a), but the multiplex ignitor on those is a total pain not to mention the karman maf is still in play. when I was working on the tt ecu mod my motivation was to have something like that only better with the mk4 ecu.
Yeah on a 95 use the JDM ecu and you will have no problems, it will run well.
7mgte coilpacks are not all that dissimilar to vvti coils, but they are on that bulky bracket and have plug wires for every plug If you use them on the GE be sure to ground the bracket. you can use those but I would still go with vvti coils for cleanliness and ease of dropping them in. The LS coils you will need a front facing intake manifold for, and also an IGF simulator. I would say wait on the LS setup until you are standalone as not many of us actually use the IGF simulator, but if that sounds like something you want to toy around with then go for it but thats definitely adding some trouble into the mix at first if you have to troubleshoot.
I know a guy who tried to do all of that setup the first round with gte ecu and igf simulator and ls coils and he thought he could do the wiring, but the car never ran, and at that point its hard to troubleshoot cause everything was done at once.
Not saying that would happen to everyone but be sure to do it slowly and tripple check if thats the case.
now if he had done the ecu first maybe with the stock coil and ds62 ignitor, got it running, then installed the IGF simulator while disconnecting the stock igf wire and getting that working, then swap over to LS coil setup and then see if thats working.
sure he would have spent an extra $30 on a ds62 ignitor, but then he would have narrowed down where the problem was to fix it at each step.
I pretty much do all my adventurous testing in stages for that exact reason, and probably why my stuff usually runs well.
definately do the tt ecu mod over the 7m electronics. its night and day difference running of a map setup.
If it was a mk3 then for simplicity alot of guys do the 7m electronics on the 2jzge, but I always tell my friends who do that to just take a 2jz-ge harness and make a swap harness into a mk3, then do the tt ecu mod and add things as you go and the main thing its missing is coils so after that its like a skinny gte harness with a few plugs going to different places. also whats nice is that with a 2jzge harness you can also use on a standalone like an aem ems plug and play, just wire up map sensor and IAT.
And another worthy mention is the 7m ecu uses batch fuel injection like a 1jzgte, so 2jzgte ecu which is full sequential injection and ignition (not with vvti coils though) is much better jump in technology.
And it turns out you can make great power on waste spark coils like the vvti one that toyota moved to later on, you just cannot do it with a 7mgte mulitplex ignitor that gets confused all the time.
You might not even want to go standalone once you get this setup and running well.
what are the plans for the Z ? feel free to post up a few pictures I was a nissan guy before I was a toyota guy and we all love pictures around here =)
The 7mgte electronics will get the job done (sort-a), but the multiplex ignitor on those is a total pain not to mention the karman maf is still in play. when I was working on the tt ecu mod my motivation was to have something like that only better with the mk4 ecu.
Yeah on a 95 use the JDM ecu and you will have no problems, it will run well.
7mgte coilpacks are not all that dissimilar to vvti coils, but they are on that bulky bracket and have plug wires for every plug If you use them on the GE be sure to ground the bracket. you can use those but I would still go with vvti coils for cleanliness and ease of dropping them in. The LS coils you will need a front facing intake manifold for, and also an IGF simulator. I would say wait on the LS setup until you are standalone as not many of us actually use the IGF simulator, but if that sounds like something you want to toy around with then go for it but thats definitely adding some trouble into the mix at first if you have to troubleshoot.
I know a guy who tried to do all of that setup the first round with gte ecu and igf simulator and ls coils and he thought he could do the wiring, but the car never ran, and at that point its hard to troubleshoot cause everything was done at once.
Not saying that would happen to everyone but be sure to do it slowly and tripple check if thats the case.
now if he had done the ecu first maybe with the stock coil and ds62 ignitor, got it running, then installed the IGF simulator while disconnecting the stock igf wire and getting that working, then swap over to LS coil setup and then see if thats working.
sure he would have spent an extra $30 on a ds62 ignitor, but then he would have narrowed down where the problem was to fix it at each step.
I pretty much do all my adventurous testing in stages for that exact reason, and probably why my stuff usually runs well.
definately do the tt ecu mod over the 7m electronics. its night and day difference running of a map setup.
If it was a mk3 then for simplicity alot of guys do the 7m electronics on the 2jzge, but I always tell my friends who do that to just take a 2jz-ge harness and make a swap harness into a mk3, then do the tt ecu mod and add things as you go and the main thing its missing is coils so after that its like a skinny gte harness with a few plugs going to different places. also whats nice is that with a 2jzge harness you can also use on a standalone like an aem ems plug and play, just wire up map sensor and IAT.
And another worthy mention is the 7m ecu uses batch fuel injection like a 1jzgte, so 2jzgte ecu which is full sequential injection and ignition (not with vvti coils though) is much better jump in technology.
And it turns out you can make great power on waste spark coils like the vvti one that toyota moved to later on, you just cannot do it with a 7mgte mulitplex ignitor that gets confused all the time.
You might not even want to go standalone once you get this setup and running well.
what are the plans for the Z ? feel free to post up a few pictures I was a nissan guy before I was a toyota guy and we all love pictures around here =)
Last edited by Ali SC3; 02-24-15 at 11:03 AM.
