neggles

Hey guys!

I've been on a bit of a long journey with this car but I'm hoping that someone can help me out in one way or another.

It's an MY2002 (revD) 3gen AUDM Liberty B4 5MT.

The ECU in the car has been modified by ECULabs and is running their software, this is because I want flex-fuel support.

I have ID1000 injectors (as the plan is to run E85) and supporting fuel system mods (pump/lines), Pierburg 3port BCS, a GM 3 bar MAP and GM IAT (installed in the throttle-side TMIC end tank) sensors, and a nice straight through exhaust. I've done some other things but they're not relevant to this particular problem. The MAF is new, the plugs are new, the packs all work, all the sensors work, I never get a CEL.

When I first got the car it was stock, but had a blown motor. I swapped a new one in (finding a motor from a revD was hard but I got there) and though the tune wasn't the greatest (stock tune never was on these) it did behave as you would expect, sequencing into twin mode from 3500 to 4000 or thereabouts and making ~1bar of boost on the primary and ~0.5bar in twin turbo mode. I'm lead to believe these are accurate numbers (less boost in twin mode due to more flow) but if any of you have experience with a revD/E and can let me know what I ought to be seeing boost-wise stock, that would be great. One of the problems i'm trying to rule out here is a failed secondary turbo.

I handed the car over to a fairly well respected tuning shop which has turned out to be a forking disaster. They do not have any forking clue what they're doing with ECULabs and I hope the next time someone asks them to tune an ECULabs ECU they turn them away. I won't name names but they're north of the city and they're probably the dudes to talk to if you're running a single-turbo Haltech setup on a Supra or Skyline but definitely not for 3gen TTs running ECULabs.

They installed the MAP/IAT/injectors (with plenty of fork-ups along the way... I'm not smart) but couldn't get it to behave on the dyno. I found a software glitch in my specific ECULabs firmware and had that fixed, and then decided to take it to someone who knows a little bit more about what the fork they're doing.

When I got the car back I could not for the life of me get it to sequence into twin mode below 6500rpm, but when it did sequence, oh BOY did it take off like a rocket for that last 1000rpm (redline 7500). I concluded there had to be something wrong tune-wise preventing it from sequencing, or something wrong with the BBOD.

So I took it to Got It Rex in Sunshine West, as recommended by ECULabs and the people I should have gone to in the first place. They've got her running like a dream on the single turbo but couldn't get it to sequence into twin turbo mode, so they handed it back over.

I took out the BBOD and cleaned every single line and solenoid, made sure the restrictor pill is in the right place, everything is working fine there. All the vacuum lines go to the correct points and the vacuum resorvoir is hooked up and holding vacuum. Then I notice they had the secondary duty cycle set to 100%, and in the case of the revD it appears that higher duty cycle bleeds more pressure out of the EGV +ve port and thus causes the valve to open LESS, so they were effectively commanding the car into single turbo mode at all times, which explained the weird results I was getting on a datalog. This also resulted in the car never building more than like 3psi of boost, which was pretty strange.

I tried the factory secondary duty map and got the same result, sequencing at 6k rpm even though the DPS is reporting zero differential pressure from 4k rpm upwards, but again there was no real boost pressure happening. It's been suggested that maybe my secondary turbo has kicked the bucket, and if this is the case I do conveniently have another one (off the old engine), and I suspect tomorrow I'm going to drop the y-pipe and check it anyway but would that make sense with these symptoms? and if so, why the hell did it work at 6500rpm with a mostly-stock-but-modified-for-injectors tune?

So I tried the opposite, setting the secondary duty to 0% and reasoning that this would cause it to have the mother of all VODs but at least prove twin turbo mode was working. Nope. It spends 2000rpm-6000rpm attempting to change over, the differential pressure sensor reports 3psi more boost coming from the primary than the secondary from ~4500 up, and then at 6000 it suddenly slams the intake air valve open as if it's decided that it's waited long enough. It's consistent. Every time, 6000rpm.

Here's a dropbox link to a log file: https://www.dropbox....150950.csv?dl=0 since I can't attach it to the post for some reason. I had the secondary duty set to cut out entirely at 4k and be circa 20% below 4k for this particular example but the behavior is consistent enough that it shouldn't really matter.

I know the smart thing to do is swap the ECU out for aftermarket management like a Haltech Elite or swap to single-turbo, so right away I'm going to reject those ideas. I don't want single turbo (the stepped power delivery of the sequential twin system is really fun, and I already have a daily driver single-turbo car) and I really don't want to spend $2500 on an Elite 2500 when I already dropped a grand on ECULabs and a wideband.

So beyond the bolded bits above, some questions;

• Has anyone here had any experience with a RevD/E using ECULabs?


• Has anyone had an experience similar to this (I could find none except one referencing a broken +ve solenoid, which is definitely not my issue here, i've tested and cleaned it myself and it clicks when the ECU is in test mode so the drivers are all OK) and if so how did you resolve it?


• Does anyone know (or know anyone who might have a better idea of) how the revD decides when to stage into twin mode? The maps I have available seem incomplete.


• Am I just being an idiot and ignoring an obviously blown secondary turbo?

This godforsaken machine is doing my head in, but I am determined to make it work. I would be incredibly grateful for any help anyone is able to give as subyclub seems to have almost all of the knowledge of how these work (insofar as I can't find anyone who knows their ass from their face when it comes to B4s other than here and SL-I) and it's incredibly frustrating to get this close to completing a project and then get cockblocked by software for six months.

E: See post #32 here for more info