Search:

It appears based on this diagram that when this fuel mass valve (4) opens high pressure is able to push the plunger up allowing high pressure to bleed off back to the vacuum side of the high pressure...

In a perfect world I agree. It would be nice if it always stored the last 30 seconds of full throttle so you could download them at any time. There is some memory left but it would not be enough to...

Working on the control valve front. Here is a photo of the setup and a video of the valve at 50%, 75%, and 100%.. I'm not 100% sure how it works yet. I do know in car during deceleration it's running...

lol!

The last problem was a second hand JB4 G4 board that someone missoldered. Any update with a new board yet?

Fair enough. As far as I know there are no tuners running the N54 beyond 7200rpm. So that is an unknown area. I personally don't believe fueling would be an issue but as I said I also personally...

When was the last time you posted a readable or useful chart of anything? You've been looking at these fuel pump logs for Vargas since the beginning yet nothing has been posted.

Their handheld unit basically is a laptop only with a very tiny view screen. The only parameters not in the JB4 that I'd like to add are cyl 2-6, but bank1&2 afr are in there. I personally need to...

It still drops but the only logs I have handy were E50. With E85 I have a feeling it will crash just as bad. Will need to search my email box to see if anyone has sent any in. The nice thing about...

With 3000psi fuel pressure behind the injector you don't need much time to push a lot of fuel through. Once the high fuel pressure system is sorted I have a feeling RPM won't be an issue. But again...

I tried playing around with the high pressure target, and put a meter on the valve, but so far have not found much. When it falls under target it goes to 50% PWM. that may just be as much as it can...

It's possible the DME is reducing PWM to the in tank pump as it sees the low pressure over target. But, since low pressure held a fairly steady 100psi, doesn't seem to be any issue there.

Super high fuel pressure = shorter injection duration required. I don't see how the RPM thing is an issue from a fueling perspective. Might be from a VE perspective, though.

Since low fuel pressure is not dropping then the stock in tank + cheap inline (post regulator) move enough flow to support the overall tuning. If at some point high fuel pressure is dropping below...

We run an inline pump in our E92, and a single Walbro (normally) in our 135i. For this testing the 135i has the factory in tank pump. The inline is generally inferior for lower pressure targets but...

Sounds like you're confusing these tests results with the in tank pre regulator fuel pump tests we did. As a result of those tests I came to the conclusion that a single Walbro in tank or a single...

Ah, OK. I only spoke to them once and they mentioned they had them. Maybe they meant under development. What are you doing with yours? Forged pistons / head job?

The code that comes up is 29DC Cyl. injection switch-off. Basically, it means fuel pressure is so low the DME goes to a limp mode as it's worried it won't atomize/inject properly. Now keep in mind...

The midrange drop is the killer. I may try a beefier pump that can hold ~120psi at the pump inlet. Will also have to spoof the factory low pressure signal to the DME thinks its running ~72psi.

This is map 7 stock turbos so its around 480wtq. I have not tested this fuel pump setup on the dyno but during steady single gear pulls it seems OK. I'm starting to suspect something else is going on...

What's happening at 5000rpm is the million dollar question. I have my theories of course, so I'll keep poking around at possible solutions. It would be nice of others experienced with fuel system...

Fuel pressure drives everything. When it drops then trims and AFR go wacky as the DME struggles to sort it out.

The second run was just another run at 100psi where it happened to not nose dive...

When it drops to around 6 in JB4 logs then you have serious problems. DME throws a fuel injection cutoff fault among other potential issues. In a perfect world it would hold close to its target with...

I think VAC has everything sorted already for this. Probably cheaper than trying to source/test your own. I'd contact them first.

At some point in the near future. But, I'm afraid it's not the answer to our < 5500rpm fuel pressure issues. Does wonders at higher RPM though.