Unique 1jz 3k rpm breakup

[Albert]

I put the same dm bypass hos. On my custmers 2jzgte. Just finished his single swap with the same to4r turbo. He doesn't have a 3k breakup.

It's odd Aarron. Steven ran the same hose on his stock 1jz no problem, but mine didn't.

I wonder if it has to do with being jzz30 or jza70?

His was a jza70 mine is a jzz30

 

[kamikazemkiii]

Does the tach go crazy when its breaking up?

 

[Albert]

No. Tho mine use to do a similar thing when my
CAS was grounding out...

 

[bigaaron]

The bypass hose itself works excellent on all the 2jz and 7m engines we have ever installed it on. The 1jz seems to be different for some reason, and only a small percentage of vehicles have had an issue. I know the 3k rpm breakup issue can be caused by wring and other piggyback issues that are unrelated to the fuel supply.

 

[OneJArpus]

Anyone have an idea to my symptoms?

 

[hamgatan]

i think i should pipe up and mention my issues as well..

i've got a GZ20 Soarer that i bolted a JZA70 halfcut into a few years ago now. I ran it for about 3 years in my old shell fine (albeit it was underpowered..), then I got defected and so I bought another shell to get around that.

So I moved the 1JZ + R154 over into the new shell and had a few issues, firstly the fuel wouldnt pump with the key to IGN, which i found to be a horribly rewired COR (as the previous owner was running a badass 2JZ with Surge Tank and 044's in the boot, he had rewired the pumps to work on a switch). So anyway i traced the wires off my spare loom and fixed that up. Fuel then pumped fine.

Now though, i'm stuck in a 3000rpm 'limp mode'. Engine idles ok but when you hit about 3krpm to 3.5k rpm it just starts spluttering and popping.

Compression on all 6 was about 170psi average.. (158 on cyl 1 being the lowest).

The only thing thats different from the old setup (besides the new car), is that I'm now running a R32 GT-R fuel pump intank. Otherwise it was a straight unbolt from one, bolt into the other job.

1JZ is stock except for Y Pipe dumps/FMIC/Exhaust I removed all silly computers like S-AFC/AVC-R. I've tested 3 different 1JZ-GT M/T ECU's.. all the same issue. FMIC piping is perfect and sealed (no leaks). No codes are coming up either.

Bit puzzled on this one, Can't really bolt up the big T04S i've got for it until i sort this problem out first..

 

[IBoughtASupra]

i think i should pipe up and mention my issues as well..

i've got a GZ20 Soarer that i bolted a JZA70 halfcut into a few years ago now. I ran it for about 3 years in my old shell fine (albeit it was underpowered..), then I got defected and so I bought another shell to get around that.

So I moved the 1JZ + R154 over into the new shell and had a few issues, firstly the fuel wouldnt pump with the key to IGN, which i found to be a horribly rewired COR (as the previous owner was running a badass 2JZ with Surge Tank and 044's in the boot, he had rewired the pumps to work on a switch). So anyway i traced the wires off my spare loom and fixed that up. Fuel then pumped fine.

Now though, i'm stuck in a 3000rpm 'limp mode'. Engine idles ok but when you hit about 3krpm to 3.5k rpm it just starts spluttering and popping.

Compression on all 6 was about 170psi average.. (158 on cyl 1 being the lowest).

The only thing thats different from the old setup (besides the new car), is that I'm now running a R32 GT-R fuel pump intank. Otherwise it was a straight unbolt from one, bolt into the other job.

1JZ is stock except for Y Pipe dumps/FMIC/Exhaust I removed all silly computers like S-AFC/AVC-R. I've tested 3 different 1JZ-GT M/T ECU's.. all the same issue. FMIC piping is perfect and sealed (no leaks). No codes are coming up either.

Bit puzzled on this one, Can't really bolt up the big T04S i've got for it until i sort this problem out first..

Are you running a fuel dampner?

 

[Albert]

Buddy just had the same problem recently turned out to be 3 of his coil plugs were broken and shorting out..

 

[zoppii]

Just to contribute another data point. I had the same 3K lean issue with 440cc / T61 single / Walbro / HKS264's in/out. Even with it tuned out as much as possible with my SAFC it was still stumbling. Although not dangerous at that low of an RPM, I was still sick of smashing my teeth against the steering wheel every time I punched it just before 3K so I decided to put back in the FPD. Now it's gone except for when the engine is cold and on high idle it goes just a little lean but not enough to feel it I can only tell because of the WB O2. Flattening out the fuel ratio all across the RPM band seems easier too.

 

[87supraguy]

yeah i had the issue with the coils fixed the connectors and boom reving way past 3 grand

 

[Sam Watson]

through id throw up my issue. as its simmilar to this.

car breaks down around the 3k mark at idle and in every gear. including reverse.

how most times if its 100 accel it only breaks down for a second then continues to rev past it how ever at a massive decresses in power.
if its under 100% accel then it hits 3k rpm breaks down and continues to break down untill u lower the rpm down. and the car ( jolts )

2jz has been put into a silvia s13. with a to4z turbo on the side. 255lp walbro fuel pump. fuel reg. standard injectors. and ecu.

changed plugs and coil packs didnt make any difference.

i still have the standard FPD on the motor and inuse. not sure if this would cause any restriction to fuel or not. running 13psi boost.

FPR is running 40psi at idle rising rate.

only things i can think of is either some loose earths that i cant identifie. or ecu or ingintion module. does any one have anyidea on what i can try to fix this ??

currently looking for a ecu to swap over to see if that fixes the problem and a ingnition module as well to borrow to see if either of them fixes this issues.