1jz-gte problem

[golddig]

Hi Guys...newbe here whit turbos

I posted a question and no answers so im trying again...her goes

I have a 1987 supra whit a 1jz the engine is stock and purrrrsss like a kitten exept when i open her up from 1st to 5th gear at around 6500 rpm it wont go anymore it kind of chokes and feels like misfire, coils are new,plugs also new. ive checked for vaccum leaks ...couldnt find any.its running whit the twins ct12a ive inspected the ceramic turbines and no damage ..its real clean in there. theres a 3 inch exhaust system all the way to the back, huge intercooler no leaks there eighter.

The motor starts and accelerate perfectly lots of power exept the aprox. 6500 rpm mark, its like the turbos wont open up, im pretty shure its not a firring issue, compression on all cylinders is 158 to 160...

The original motor was a 3 ltrs..im wondering if the fuel pump should have been replaced, there dosent seem to be any tampering in the fuel pump compartment in the hatchback...could this be an issue

can anyone help me please on to what i should be looking for

thanks

 

[suprahero]

how much boost are you running? I think I read where the 1jz hit fuel cut at 14 psi.

 

[golddig]

Thanks for the reply..

I have no idear, the car came with no boost gauge but ive ordered one its on the way, but that would explain why it just wont go passed a certain point it realy buckles up .

As mentionned the motor is stock and in great shape lots of pick up the tail is everywhere wen you punch it...so if that is the issue can i play a little with that while staying stock or thats the most i can get whitout major mods.I would rather reduce boost a little than have the car buckle up like that at the top end, on the other hand i would not mind putting a couple of hundreds if i can get a bit more out of it whitout damaging the turbos

I got the car 2 months ago this is my dream car i will be looking at replacing the twins with a single but im not there yet and the car is going to bed for winter soon.I would even say im satisfyed whit the power for now .I guess its the wastegate thats the limiter ..but i will comfirm boost pressure soon. That would make a lot of sens,like mentionned its realy stock.I hope i get the gauge before i have to put her in storage.

Is there another way to figure out the boost whitout the gauge..im fully equiped for mecanic work i have everything but the kitchen sink here unfortunately i dont know crap about turbos its all new to me, im a muscle car guy ive raced for 15 years and its my first turbo boosted engine and the last thing i whant to do is damage the engine or turbos as i know there are certain issue with the ceramic turbines on the ct12a. there in good shape but i dont whant to push my luck with them or can they take more then 14 psi.

thanks again..

 

[sfgsdfg999]

boost cut will happen just shy of 14.7psi, you will need a boost gauge and you will need an AFR gauge as well. Anything above stock boost and you will need to know your air-fuel - that will tell you when you start running too lean at boost.

 

[golddig]

Thanks..

Ok so i can play with fuel ajustment even with a stock ecu,Are there charts available to compare and see if im lean or what, ill get the gauge but ill need refrences to see where im at and of course the... how to play with fuel ajustments,and of course go around fuel cut sensor.

Would an electronic boost controller help me here as i could see all readings and ajust at the same time instead of having 10 gauges on the dashboard,like i said i dont mind spending a couple of hundreds..

Would there be ecus available that are tweekable and could get me around all that whitout going full stand alone, i could even send mine to have it modified or do it myself and learn at the same time, the car wont be going out to much we got another snow fall last night.

AS mentionned im not ready to go full mod yet and i kinda like the car the way it is for now but i just cant stand having it buckle like that so any input will be apreciated to get around that if possible of course...im open for sugestions

thanks..

 

[hvyman]

Can lower the boost.

Get a wideband if you want to monitor afrs.

The better piggy backs out there for the 1jz are stupid expensive to the point where you should just get a standalone. the ms3pro and ecumaster emu are not super expensive. With a good tuner the car should run better than on the stock ecu as well.

 

[golddig]

Thanks so much..

I now have what i need to make a decision, i will probably go stand alone. If i may ask one more favor...can you or someone tell me exactly what i will need for stand alone like part numbers or description and where to find it.

I know i can get parts here but im new to this and i have no idea on what i need and especialy cost wise ( best prices for reasonable quality).

I was just reading a post...what could a fuel cut defender do for me, would it give me a little play instead of going stand alone..im realy a newbe whit turbos ..sorry for the ton of questions.

Thanks again

 

[hvyman]

Fcd removes fuel cut which saves the engine. id pass on that.

for megasquirt see diyautotune.com

for emu zach has a section in the vendor part of the forum.

 

[golddig]

Thanks again..

I just emailled DIY and i will be contacting Zach soon.