Single turbo project

The 1UZFE EGR Delete Kit is available for sale here.


New Member
I was hoping I could get some help with a turbo build I purchased. It is a 92 Ls400, I read your build and purchased the book maximum boost. However I think my questions are specific to the car. The guy I purchased the car from installed the mass air flow on the intake side of the turbo. from what i found most people have it on the intake side under boost. What is the proper position of the MAF? The fella said it wouldn’t run on the side that is under boost.
Vacuum line for the Idle Air control valve, where should they be routed? I was thinking that I should route them to air cleaner on the turbo? Currently it is connected straight to the intake side that is unboost by the manifold so it is under boost when driving. I found it runs better with it completely unplugged.
The car starts and runs great cold, when it warms up it wants to cut out, and when I drive it does pretty good but as soon as I get to about 4psi it wants to cough and cut out. The car is running 8psi of boost, no BOV and all stock. They did install a fuel pressure regulator and it's constantly at 45psi seems to be running rich at idle. To me and my limited experience it seems to lean out after 2200 rpm. I have no idea why it doesn't want to idle well. My guess is the IACV needs to be plumbed to the air cleaner or close to it, maybe a bov? I bought the car for 500. I figured in today's market you can't find a running car for less then 1500 so i bought it. I built a turbo 2.7L tacoma from scratch like 10 years ago but everything on that went together sooo well i never had an issue and starting on a car i know nothing about and taking over some else's shit show has proven to be quite the challenge so any help would be great.

Thanks, I hope this is clear.


Super Moderator
Staff member
Sydney, Australia
From memory 38psi is stock 1UZ fuel pressure, so it is overfuelling a little.

The IAC I would plumb pre turbo.

The AFM/MAF I would have in front of the turbo.

I would also look hard at the FPR and ensure it's supplying the required fuel pressure as revs increase, I'm not a fan of rising rate FPRs but a quality FPR should sort it out if it's sensing boost pressure and not atmo.