Low fuel pressure, running rich, and shitty idle. Please help a member out. - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

l8nightjay · 01-19-2017, 03:30 PM

Ok guys and even ladies looking for some solid help here, I'm at a loss. So after new turbo install my idle is erratic and even driving it doesn't feel right. Just installed a nismo fpr type b and a inline fuel gauge to try to fix the problem. It seems worse. My aem wideband is all over the place, when my fuel pressure gauge say's I'm sitting at 43 psi, and my wideband say's I'm supper lean, hitting 17 then maxing out. But when my fuel pressure gauge say's I'm running 20 psi my wide band says I'm running 10.5 on my wideband, super rich. I Can't seem to dial it in a happy medium. I've checked for boost and vacuum leeks and haven't found any, I just put in a new fuel pump (second one), fpr seems to not to be leaking and if I unplug my vacuum line fuel pressure jumps up. I'm going to try a friends z32 maf tonight to see if mines faulty, but I'm running out of Idea's and I'm getting frustrated. I've tried two different method's to set my static pressure, which seems to work till I run it for about a minute or two. Please, any knowledgeable idea's would help. Here's some basic car stat's for reference.

redtop sr
gt3071r turbo w/ atmospheric blow off
z32 maf as a blow through setup
340lph fuel pump
300zx fuel filter
nismo type b fpr
side mount 740cc injectors
stock fuel rail
nistune ecu (rocking tune I got from them)

Any Idea's or help would be much appreciated. I've spent the last couple days trying to diagnose and nothing seems to work.

derass · 01-19-2017, 03:56 PM

Quote:

Originally Posted by l8nightjay

...when my fuel pressure gauge say's I'm running 20 psi my wide band says I'm running 10.5 on my wideband, super rich.

This is a bad sign. The fuel pressure shouldn't ever be dropping below the base pressure, only increasing when in boost. Could be a number of things: faulty pump, bad wiring, kink in a fuel line, clogged filter etc.

Quote:

Originally Posted by l8nightjay

nistune ecu (rocking tune I got from them)

What do you mean by the tune you got from them? Is it a basemap or a map for your application? A basemap is only enough to start the engine, it still needs to be tuned afterwards

l8nightjay · 01-19-2017, 04:58 PM

The fuel pump is about 6 months old. Premium gas only and I start it run it weekly, just don't drive it much since the problems. Filter is about a year old, but it's a cheap part to replace...so yeah that will happen real quick. I've checked for kinks, primed my pump and set a base fuel pressure, now I'm about to test my rail and injectors just for piece of mind.

I did get a tune from Nistune for somewhat similar build, I believe it was from Pete, sorry i'ts been a hot minute. The tune was for a gt2871r with a cam upgrade, while I have no cams and a gt3071r. I believe the rest of the build was the same. I'm not going to lie, kind of nervous trying to tune my ecu solo for a first time. I have know problem wrenching, but I have a feeling I'll hit a wrong button or go down a rabbit hole to far to come out.

The nearest tuner to me in Eugene quoted me 700+ to tune. Which could be worth it atm, but not if they have to diagnose and fix current problems to move foreword. Just a bigger bill and my pockets are starting to run dry lol.

l8nightjay · 01-19-2017, 05:17 PM

I haven't dabbled with the Nistune rom, so there's a chance it doesn't read my maf and injectors right. That might explain the Uego jumping around and inconsistent idle, but not the weird pressure readings on my fp gauge. Maybe the gauge is faulty? It is brand new, been on a week, but its also a cheap part ( Marshall company). My flow chart of problems seems to keep changing as with the symptoms...

01-19-2017, 03:30 PM	#1
l8nightjay Leaky Injector Join Date: Aug 2006 Location: Eugene, Oregon Age: 41 Posts: 98 Trader Rating: (0) Feedback Score: 0 reviews	Low fuel pressure, running rich, and shitty idle. Please help a member out. Ok guys and even ladies looking for some solid help here, I'm at a loss. So after new turbo install my idle is erratic and even driving it doesn't feel right. Just installed a nismo fpr type b and a inline fuel gauge to try to fix the problem. It seems worse. My aem wideband is all over the place, when my fuel pressure gauge say's I'm sitting at 43 psi, and my wideband say's I'm supper lean, hitting 17 then maxing out. But when my fuel pressure gauge say's I'm running 20 psi my wide band says I'm running 10.5 on my wideband, super rich. I Can't seem to dial it in a happy medium. I've checked for boost and vacuum leeks and haven't found any, I just put in a new fuel pump (second one), fpr seems to not to be leaking and if I unplug my vacuum line fuel pressure jumps up. I'm going to try a friends z32 maf tonight to see if mines faulty, but I'm running out of Idea's and I'm getting frustrated. I've tried two different method's to set my static pressure, which seems to work till I run it for about a minute or two. Please, any knowledgeable idea's would help. Here's some basic car stat's for reference. redtop sr gt3071r turbo w/ atmospheric blow off z32 maf as a blow through setup 340lph fuel pump 300zx fuel filter nismo type b fpr side mount 740cc injectors stock fuel rail nistune ecu (rocking tune I got from them) Any Idea's or help would be much appreciated. I've spent the last couple days trying to diagnose and nothing seems to work.

01-19-2017, 04:58 PM	#3
l8nightjay Leaky Injector Join Date: Aug 2006 Location: Eugene, Oregon Age: 41 Posts: 98 Trader Rating: (0) Feedback Score: 0 reviews	The fuel pump is about 6 months old. Premium gas only and I start it run it weekly, just don't drive it much since the problems. Filter is about a year old, but it's a cheap part to replace...so yeah that will happen real quick. I've checked for kinks, primed my pump and set a base fuel pressure, now I'm about to test my rail and injectors just for piece of mind. I did get a tune from Nistune for somewhat similar build, I believe it was from Pete, sorry i'ts been a hot minute. The tune was for a gt2871r with a cam upgrade, while I have no cams and a gt3071r. I believe the rest of the build was the same. I'm not going to lie, kind of nervous trying to tune my ecu solo for a first time. I have know problem wrenching, but I have a feeling I'll hit a wrong button or go down a rabbit hole to far to come out. The nearest tuner to me in Eugene quoted me 700+ to tune. Which could be worth it atm, but not if they have to diagnose and fix current problems to move foreword. Just a bigger bill and my pockets are starting to run dry lol.

01-19-2017, 05:17 PM	#4
l8nightjay Leaky Injector Join Date: Aug 2006 Location: Eugene, Oregon Age: 41 Posts: 98 Trader Rating: (0) Feedback Score: 0 reviews	I haven't dabbled with the Nistune rom, so there's a chance it doesn't read my maf and injectors right. That might explain the Uego jumping around and inconsistent idle, but not the weird pressure readings on my fp gauge. Maybe the gauge is faulty? It is brand new, been on a week, but its also a cheap part ( Marshall company). My flow chart of problems seems to keep changing as with the symptoms...