REGISTER NOW TO REMOVE ADS FOREVER

Fuel return line?

Richo

New Member
This may be a dumb question, ive searched to no avail although it seems most of you have return lines on you 1UZ's, im unable to find a return line coming off the fuel rails.

My motor came out of a UZZ30 91 model, i have owned 2 31's both having fuel return lines, do the 30's have one as well? (i imagine they wouldnt be any different)
 

Thermactor

Member
On my car (second generation LS400) the inlet and return both lead to to the left hand side of the motor. There's a hard line that runs from the regulator on the right hand side to the left hand side, and the return line attaches there with a rubber hose and clamp. Extremely easy to add an adjustable regulator to :)
 

converted

New Member
If Im hearing correctly, 1UZ's have a fuel reg on the motor or is it a stand alone item....?
I have a malapassi fuel reg on the return line back to the swirl pot is it not needed?
 

Beukes

New Member
Hi I have a lexus ls430 build into a Nissan navara but don't know what feulpump to use in tank. The engine dont have any return line. I have a feulpump in tank and engine starts good but after a minute the feulpump stops pumping and the engine dies. When starting again it starts and pump pumps again as if it never stopped. Can someone please help me with this
 

gloverman

Well-Known Member
I use a 265litre per hour nippon denso unit but with the vvti non return system it does require a pressure regulation system fitted to mimic the factory setup.
 
If you decide on a return line , It is easy to swap out the blanking plug on the end of the fuel rail for a screw in take off, and connect from there to a FPR




.IMG_20200316_114112.jpg
 

gloverman

Well-Known Member
If you decide on a return line , It is easy to swap out the blanking plug on the end of the fuel rail for a screw in take off, and connect from there to a FPR




.View attachment 13931
On stock ecu they run best leaving them as returnless with static fuel pressure. If fitting a aftermarket fpr as a solution on the vvti I prefer to fit before the engine. I prefer a regulated fuel filter by the fuel tank. I fix lots of these with running issues where guys are running stock ecu with a fuel system converted to variable pressure return type and fuel trims are all over the place, swap to how Toyota intended and they run much better.
 
  • Like
Reactions: JZH
Not something I was aware of. When I did the swap, I left the existing in-tank pump in place, had a return line already there, went from front of rail to a Malpassi set on 3.5, factory ECU, 20,000ks later, never had a hiccup. (only thing that has been done on the engine in that time is 4 oil changes.)
More room in my current clown car conversion, and it does not have a return line. will try your way . What's a good setting for the FPR?
 

gloverman

Well-Known Member
Do you have you reg set as static 3.5 or variable? Have you checked fuel trims to see where they are running?
 
Malpassi is rising rate, but do not have the vac line connected (not boosted, so is there any point in hooking it up?) 3.5 would be static. Fuel trims? sorry, don't even know what they areo_O
 

gloverman

Well-Known Member
Ok. So running static between 3.5 and 4 is fine. I always monitor fuel trims but thats another days lession.
 
I'm a basic old guy:eek:,(I have owned cars with crank handles) I keep everything running by maintenance, change fluids, use my ears to work out if anything sounds different, plug in my very basic code reader ($12) every now and then to see if it throws up a code. Only one I get regularly is rear oxygen sensors, probably because I don't have any.
 

L Delport

New Member
If you decide on a return line , It is easy to swap out the blanking plug on the end of the fuel rail for a screw in take off, and connect from there to a FPR.
Do anyone know the thread/pitch size of this blanking plug on the end of the VVTi fuel rails, please?
 
Last edited:
I can't help, I found my replacement in a box of brass fittings I'd accumulated over the years. Pull it out and take it to a bolt shop, they will tell you. ( probably wont help you but worth a mention,there is a bolt shop in Parramatta Sydney called "The Nut House")
 
Top