I've done a lot of searching both here and other boards. If you guys have any ideas let me know...

Current issuejust started a week or two ago. Only drive it once or twice a week), runs perfect A/F at idle, while on highway or keeping throttle steady/ and perfect in boost! But out of boost during light to moderate accel I'm getting choppy/lean conditions. Bouncing from stoich to 16/17:1 and even dropping past 18 at times! (Really falling on its face)

Current setup: (disclaimer: before the flaming begins, yes I know this isn't the ideal setup, and yes I have more proper tuning solutions in the works. However, in the meantime I'd like to find the solution. I've been running this set up with no issues at all for over a year)

I'm running a revhard log Mani, precision t3/t04, tial WG, vortech BOV, Vortech FMU, Synapse missing link, walbro 255lph, mishoto radiator, down pipe with connected WG dump tube, AEM boost guage& controller, AEM uego wideband. Running @ 6psi max until I get my AEM EMS.

I replaced my missing link to ensure the valve wasn't sticking but no help. I've got no codes, no CEL.

Any Ideas?!

Thanks!

 

How does a rising rate fuel pressure regulator even give you any kind of consistent safe fueling for a turbo set up? And worse yet its a Vortech unit which has no calibration adjustment, unlike a Comptech. With a SC the boost is totally predictable and linear so you can set a rising rate and have it be consistent, your using a mechanical fuel map that was designed for a SC.

I will tell you right now you have taken it upon yourself to step outside reasonable perimeters with this tuning set up, and therefore will get no productive advice here, simply because none can be given. You will have to figure out whats changed and what your working with. But take in consideration with what I said above about the mechanical fuel mapping with such a device on your set up. If you were smart you would stop boosting now before you cause permanent damage to your motor.

The hardest part your tuning set up will have is trying to give the proper fuel from partial load to boost transition, and that's where it sounds like your having the problem. You need a standalone EMS, which is still a lot cheaper then a new engine.

This is about the best info and advice you will find here on your situation, I wish you luck.

 

Nope, nope, and nope.
The fuel management unit only effects fuel pressure in the rail under boost. And for that matter, can only raise fuel pressure.

I am getting LEAN conditions OFF BOOST. Perfect A/F in any amount if boost. Sounds like my terribly unsafe FMU is working absolutely fine.

The problem is elsewhere. The problem is during No-boost, No FMU-compensation, No missing link compensation, No-wastegate or BOV purging, etc. only factory components are running the show when this issue is occurring....

Any ideas what would cause me to run lean during moderate accel, but still allow perfect a/f under boost during much higher fuel demands, and perfect at idle under much lower fuel demands?

 

"How does a rising rate fuel pressure regulator even give you any kind of consistent safe fueling for a turbo set up?"

This is true. FMU is unreliable way controlling fuel.
I found this the hard way (using BELL FMU for a turbocharged hayabusa 7).
Most of my FMU problem is in the diaphragm & spring. Fmu diaphragm sometimes needs to be shimmed and sometimes becomes floppy and affects the metering.
Fueling system of the past. Buy standalone ECU.

 

What size injectors?

 

Comes in to ask for help.

Posts sarcastic ass response.

:roll:

Seems like you've got it all figured out already toughguy

 

You are asking the STOCK ECU to run part throttle in a closed loop environment with a different header, different exhaust and partial boost input. It has NO clue how to do that. Some people run lean in part throttle by just installing a test pipe, yet you have changed the whole exhaust side of things. Even at partial throttle, you are getting a very small increase in MAP pressure that the FMU has no way of correcting. Something changed in your system and we can't help fix this with your current setup. Get a tuneable ECU and fix it.

 

Few things, firstly how is your o2 sensor and does your system affect when you go into open loop?

I'm not convinced as said above about not being able to cope with mods and stock ecu there is of course an easy way to check look at your ltft and stft they have a min/max range of -/+ 30%

 

Thank u for the input Jaundice.

Also my response wasn't "sarcastic-ass"
I was only asking for thoughts of what may be causing my newfound issue. As I mentioned, I'm well aware that EMS is the way to go. That's not what's causing the problem though.

Update: after doing some research it looks like it could be my TPS. Looks like a common problem. I'm going to pull off my TB and check voltage

 

Thanks s2konroids, if my TPS potentiometer voltages read true ill check into that next