Misfire like fuel cut under throttle - Stumped!

[Chris@Rvengeperformance]

I tried to disable closed loop by disabling bit 4 in peripheries, now it just cranks and doesn't start. Anyone know the input code to reenable it?

Can you have ecuflash do a compare against what's in the ecu to confirm the flash was succesful?

[KeithMac]

Are you checking fuel pressure while driving or just at idle?.

Sounds similar to mine when I split a hose in the fuel tank (wrong grade pipe submerged in fuel delaminated it..).

Still got good fuel pressure now it won't start at all?.

[TwIzTeD_3kGt]

Are TT and NA coils the same?

Today I disconnected the battery to clear the fuel trims, and left closed loop disabled. Got it started up after excessive cranking, still idled rich but less so than before (13 instead of 11 AFR).

Took it for a drive while logging and it ran better than with closed loop. Actually let me get halfway through a gear, but still hit that fuel cut-like wall. And again, the more I drove the worse it got, to where I could only give it a crack of throttle or it would choke.

Swapped out the AFPR for the stock one since fuel was getting where it shouldn't and lowered the boost. Same problem.

On the log it shows timing under low load in the 30 range at 2k rpm when I'm beginning to accelerate, then it hits that wall. Knock shows 9 counts and timing stays below 5*. After that point, knock shows a continuous 7-9 counts even at idle. Even if I shut it off and turn it back on, knock shows 7-9 counts constantly. The AF is extremely lean at that point as well.
But during the first startup, idle, and drive there is no knock at all.

I'll check the hose in the tank since I suspected it before. Haven't checked the fuel pressure while driving, don't really have a way to. I'll try a coil pack and PTU as well, but I'm thinking that won't be it. Don't think it's a crank sensor since I could always read RPM, even when it wouldn't fire. Maybe cam sensor, but I would think it would be consistent, rather than get worse with driving.

It's just so strange. It can idle all day, and even drive perfect until the first time you really boost it. After that, it barely runs, knocks, and runs lean. Then goes back to normal after sitting a while. Pulling on all my experience working on cars for a living and tooling around with this thing, I'm struggling to pinpoint anything.

[Chris@Rvengeperformance]

the knock sensor wiring must be messed up.

[TwIzTeD_3kGt]

the knock sensor wiring must be messed up.

I noticed on the last log, right when the 9 counts of knock pop up, the narrowband O2's start reading voltage. I'm thinking it must be wiring or an electrical component failing somewhere.

[Chris@Rvengeperformance]

check the wiring near the left of the plenum.

[futurevr4man]

Knock sensors show continuous counts when they have gone bad as well, FWIW. It's between 7 - 9 as you describe. I've seen it first hand.

[CoopKill]

^^ x2

[KeithMac]

Run it at idle and give the wiring loom a good tug all the way around the engine bay (start at connector on plenum and work back).

If it starts faulting 7-8-9 it sounds like you have a break in the wiring loom, possibly when you accelerate for the first time the engine moves and moves the loom enough to cause the fault?.

Not surprised it runs like ass with only 5 degrees timing commanded by the ecu!.

[futurevr4man]

Disabling closed loop should not have an effect on the car actually starting. You have something else going on right now. If you know you have fuel and air, then its something electronic. Check cam/crank angle sensors, PTU, wires, coils, and plugs. I'll bet something has been getting loose and every time it stumbles, it reconnects briefly until the next jarring motion... like your PTU for instance...

Run it at idle and give the wiring loom a good tug all the way around the engine bay (start at connector on plenum and work back).

If it starts faulting 7-8-9 it sounds like you have a break in the wiring loom, possibly when you accelerate for the first time the engine moves and moves the loom enough to cause the fault?.

Not surprised it runs like ass with only 5 degrees timing commanded by the ecu!.

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