Unique 1jz 3k rpm breakup

[Albert]

Ok, well As I'll try to explain clearly, i am get a 3k breakup on my 1jz. I have tried everything and I'm lost. Happens during free rev and during driving, yet it pulls from 3500-7k just fine.

The 3k breakup during free rev is with stock ecu 550s (mkiv resistor pack) fuel pressure set to 18psi idle.
(yes I know 18psi)

The 3k breakup will go away if I turn up the fuel pressure to 40psi, but then I can't drive it in boost or it will foul out the plugs.

I've tried running it off the fic with -35% fuel trim across the board, so it will run close to stock as possible. fuel pressure at 40. Running 14.6 afr at idle. Immulating stock o2 via lc-1.

Mods are:

1jzgte. Jzz30 version
AEM FIC
LC-1 Wideband
drewgo manifold
drewgo 3" downpipe
hks race replica 50mm wastegate
Garrett T67 T4 turbo .68ar
An ss oil lines
3" intake charge piping
24x12x3 fmic
custom moddified throttle body (trc delete)
synapse bov
2jz throttle cable
2jz 550s
AFPR
6 puck competition clutch disc


I've tried replacing many sensors and nothing.
Tried know working coils out of my Buddys 2jzgte. Ignitor, crank sensor, cam sensors, etc. Still nothing.

Had my friend here locally that does 1jz/2jz harnesses go over mine and delete as much stuff as possible in the harness, and to make sure the wiring is good. It had the 3k breakup before I sent it to him, now it still has it.

I've tried 2 jzz30 ecus. Same thing? both these ecus were fried by water getting into my junction box, but the resistors that blew from it were replaced with similar but not identical resistors. So I can't be 100% that it's not my ecu. A buddy across town will be coming down to my shop this weekend with his jzz30 ecu to verify. That it's not my ecus.

Idk if I'm missing anything. But if you have any questions feel
free to ask, I know I'm missing a few things, just lmk!

Thanks guys!

 

[super.secret.supra.club]

Your problem is not unique. Many members including myself have had this problem. Mine came down to a couple things.

I replace the file filter. Made sure line wasn't kinked. Replaced map sensor also replace the fuel line sincey current sd from drift motio. Had a kink in it. After all that the motor was good to go.

Also some other have also replace their fp with a walbro and kinked a line without knowing and only found out after they dropped it again

 

[Albert]

Your problem is not unique. Many members including myself have had this problem. Mine came down to a couple things.

I replace the file filter. Made sure line wasn't kinked. Replaced map sensor also replace the fuel line sincey current sd from drift motio. Had a kink in it. After all that the motor was good to go.

Also some other have also replace their fp with a walbro and kinked a line without knowing and only found out after they dropped it again

I have a walbro and the DM fuel bypass line. I've tried 3 differnt map sensors.

Tho I don't think I replace the fuel filter. That will be on my list to
try!

 

[Albert]

Your problem is not unique. Many members including myself have had this problem. Mine came down to a couple things.

I replace the file filter. Made sure line wasn't kinked. Replaced map sensor also replace the fuel line sincey current sd from drift motio. Had a kink in it. After all that the motor was good to go.

Also some other have also replace their fp with a walbro and kinked a line without knowing and only found out after they dropped it again

Okay so after thinking about it, why would the fuel filter cause that problem? Not saying it hasnt fixed other peoples 3k breakup, but if my car is boosting from 4k-7k at 16psi no problem, then why would it breakup at 3k during free rev and not under load when more Fuel is needed?

My buddy has a talon that was knocking and running lean at wot and he took off his fuel filter and was caked in crap!!

 

[gurley0916]

Any updates?

 

[Albert]

Any updates?

No not yet, i gotta hook up power steering so I don't burn up my pump. This weekend when I get the othe ecu I'll be trying grounding staps, anothe map sensor just for shits and giggles, and setting my tps to the certain settings. Possibly het under the car and do the fuel filter if all the easy stuff doesn't work...

 

[perpetualthought]

did u fix this issue

 

[Albert]

No haven't had time to go into it.

Did throw codes 12, 21 , 78 tho.

I believe I have a bad cam sensor, but I doubt that will fix my problem

 

[Satan]

TRD87T had similar issues and eventually thought he had a clogged fuel line. Turned out to be an elbow or FPR at the fuel line. PM him and see he did, that works. He's the only one who I know found/fixed the issue by replacing something that seemed to be that unrelated. The sensors, ECU, etc, etc, etc were all good. I think the 7M stock lines are maybe designed differently, so you have to "go back" so far in the fuel system to remove the constraint.

Good luck!

 

[stevenr816]

you fix this pile?

 

[RockPaperSwoRD]

I had this exact problem and it turned out the DM fuel line bypass. This was on a bpu 1jz with stock injectors/twins.
i switchd it back for the stock dampner setup and it went away. This was I dont understand why it does this on some cars and not others. When i went single turbo I put the DM line back on and i was able to tune out the lean with mapecu2 and 680c injectors

 

[87supraguy]

Hey Albert did you fix this?... need me to bring you any other sensors to test when i head up there to get my harness from billy?

 

[bhg4life]

I have pretty much the same problem. Fuel pressure is definately related as the problem gets worse the lower my base fp is. My old Walbro maxes out around 60 psi so I try to keep the base set around 35-40 psi for a bit of headroom.

I also have the DM dampener bypass so I started working on swaping the stock setup back in to see if it changed anything. I got partway and I looked at how the dampener I had fit into the stock fuel line banjo. It seemed to fit extremely tight without any room for fuel to flow around. I think I might've kept my 7M dampener and tossed out the 1JZ one. Does anyone have a 1JZ dampener handy that they could take a picture of or measure/describe it. I'm more than happy to test this out but I want to make sure I have the right parts first.

 

[Albert]

I'll def look into that bypass hose soon. Whenever I get time. Been busy lately converting a 2jzgte to single. Hopefully I get this shit fix in time for silv.

 

[bhg4life]

Well, I put the FPD setup back in and it 100% completely fixed my problem. Thanks to RockPaperSwoRD for suggesting the idea. I'm starting to like my car again...

Anyone need a DM FPD Bypass hose?

 

[Albert]

We should really contact Aaron about this problem.....

Anyway I dug through my stuff and found this:

it's from a 2jzgte. The owner went to a dm bypass line (haven't started it yet) rofl.

I'll think I'll borrow it to test my cut.

 

[bhg4life]

That setup wouldn't have fit my 1jz. The fuel line goes from the point in the tranny tunnel direct to the fuel rail. I'm still not sure that the FPD I had is a 7M or a 1JZ, but I put it in anyway with a slight "drill press" mod. lol.

Boosted 21 psi this afternoon, no prob.

 

[Albert]

What are your mods??

 

[bhg4life]

Engine side: 69mm turbo, BC 264 cams, 440s, Aeromotive FPR, S-AFC, Walbro, 4" cold air intake, huge IC up front + hardpipes and all the other necessary mods.

 

[Albert]

Cool so closer to my setup...