So I finally got this thing on a dyno for a tune. All went better than expected except for 7-8k higher boost after multiple runs it started to get lean intermittently.
The driver swore he saw a dip in fuel pressure on the last few runs. (Had a fuel pressure sitting in view outside windshield)
Good news.... at 8.5 psi she was kicking about 290-305 whp. At 11.5 we were around 330.

New motor, street port, REC coated seals new "sp" twins with PFC

Supra TT pump rewire (stock wires in tank though), 2200 secondaries. RP rail. Stock fpd (new)

Grounding cables everywhere.

Could it be possible that the wires in tank is holding me back? I will rewire asap. I will keep stock setup and just add another wire through bulkhead for pos and negatives, but is there anything else I should be looking at? I know we were running low on fuel, but I wouldn't think that would matter. I still drove it to fill up after without any issue. I can send a copy of the log from datalogit if anyone minds taking a look? Or any ideas welcome to what else could be the cause.
IAT stayed the same, we allowed cooling before every run.

Damn thing was running too cool with an ambient temp of low 70s outside for street tuning. I have to put the 83° thermostat back in. The mishimimoto is wayyy to cold. The dyno runs would hit around 95°c very shortly and quickly go back to 80-81. I actually removed a fan from rad and put it on the lil coolers only.

 

I've had my fair share of fueling problems myself and for what its worth, an electronic fuel pressure sensor was one of the best purchases I've made for my car. With it, you can be a lot more confident than "I think I saw the pressure drop...".

With that said, most of the issues I've had were all in-tank related. The tube where it connects to the output of the pump itself was leaking and would plummet my fuel pressure once the boost climbed past a certain point. I also had one of the in-tank connectors pop out due to being tugged on. So my recommendations would be to first, make darn sure your in-tank tubing is sealing properly, then possibly see about bypassing the in-tank connectors, but I generally just say that for safety's sake.

 

I really wanted to avoid another damn gauge. That's why we just put an external one in the windshield for tuning. Maybe I need to invest in a "failsafe" one for inside.
I will check everything interal. I kind of hope I find something.

 

Really should be logging fuel pressure.. with all the funds spent on these cars dont skimp on it.
Im sure you're being careful, having a intermediate pressure drop off is rollin the dice.
Check that bulkhead connector. They are know for being a problem when running a aftermarket pump.
I've been there and had to upgrade my bulkhead connector and wires feeding the pump.
Goodluck, glad she's ripping again 👍

 

So, what I meant to get at is that really the biggest benefit here isn't looking at a gauge, but logging the pressure while doing the pull.

I've got my sensor just wired into my ECU so I can log that as an extra channel, no gauge at all. Sure, it means you can't keep a direct eye on it but being able to look at the log and view when the drop happened, by how much, and if that behavior is consistent, is critical information.

 

That makes sense. I ordered this.


I will keep the factory set up and just add this.
is the fuel on the log on not enough? I am not sure what its logging. I would think it is some form of voltage?

 

Also I am thinking of the aem failsafe afr/boost in one gauge. I can swap my boost gauge sitting in front of my gauge cluster and pull my afr from my 3 gauge pod on dash. Add a fuel pressure gauge or something else I guess. Or I could do what Alexander said and just run an electronic in engine bay for logging.
I am thinking the ability to log with the aem boost and afr would be pretty nice and use the failsafe on the wastegate controller (the apexi). I really do not think it would react fast enough, but it could be better than nothing and if it is already there why not use it.
The "tuner " wanted a manual controller so I have to swap my pfc apexi controller back in.
Thoughts?

 

I like that bulkhead connector! I was also looking at the radium surge tank/fuel pump hanger that would also neatly fix several problems you're running into. Not sure I'm ready to drop 700 dollars on that however, expensive fix for just a wiring issue.

Is it possible to log fuel pressure with a PFC? Ideally you want to be able to correlate the AFR dip you're seeing with the fuel pressure drop on the same axis. This is where you either hack it in to the data logit using one of the inputs (although I don't know of a gauge that puts this out on 0-5v, and then have to track down the logarithmic scale for that specific input).
I was up to 6 gauges, AFR, Fuel Pressure, Boost, Water, Oil press and oil temp with the PFC, was not a fan of not being able to easily log the fuel pressure with the datalogit. This is where the PFC starts to show it's age.

EDIT:
Side note, a Supra TT Pump is good for 290lph@43PSI with 13.5V, a Walbro F90000285 is good for 470lph at the same PSI and Voltage. It costs about the same, is the same size and It also eliminates the janky o-ring fit that leaks (as mentioned earlier in this thread). You just cut the feed tube and use the PTFE hose in the tank.

 

I will see if I can loop the AEMs together on a log. If not I will just focus on the fuel pressure to make sure there is 0 dip anywhere, but yes it would definitely be ideal to log. All other parameters look excellent.
I just looked and it shows 0-5v capability for the aem so I may try that route.

 

Well, I believe it wasn't fuel pressure after all and just some lean cells around P17..... FC-Tweak caught it and fixed it with auto tune.... the car is not holding steady in the 10s and 11s on boost.
I will keep an eye on it of course incase it happens to be some over heating of connectors or something causing a surge, but I believe the problem fixed.

I may rewire the pump anyway, just for redundancy.

 

what do you mean it's not holding steady? How much boost does it make with boost controller turned off/unplugged ?

 

The boost is steady. The tuner said he thinks it is leaning out for fuel pressure and the driver said he is pretty sure he saw the fuel pressure drop on the last 2 runs at high rpm (7-8k).

The pressure was 45 or closer to 50. I never saw it drop. Voltage stayed solid.
I am not saying it never dropped. I just didn't see it. i want to add wire as a back up. Maybe the pump or connectors got hot and did drop. I just never saw it.