Car won't rev past 3900 rpm (5.4L with FR ECU pack)

uae_lightning

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I am building this 2001 Lightning with a GT500 engine swap and a TR6060, Finished the mechanical work and it drives good, shifts good no issues there. Got done with Start up, idle and cruise tuning made sure stft's are on point and when I got up to 4k for the final cruise stft fine tuning i noticed the car would'nt rev past 4k rpm and the car cuts down or bogs down for a bit before going back to normal under 4k rpm.

so far I have swapped throttle bodies, cleaned out the MAF sensor, made sure there was no vacuum/exhaust or any type on leaks, spark plugs look good.

using FBMMOC2 on sct for strategy and I have tried other "stock" strategy codes with no difference at all.

mods are Full boltons (jlt cai,frpp 65mm TB, upper pulley, lower pulley,dual fans runing on a stand alone controller, 2" long tubes,dual in tank aeromotive stealth fuel pumps return style)
other than that everything else is stock including the injectors and I am running a FRPP ECU pack been able to datalog almost everything except for the Fuel pump duty cycle and the e.fans.

through out the log cruising, the fuel pressure is around 57~60 psi and once my foot goes slowly into the pedal the fuel pressure lowers to around 35~40 psi but if I try to floor it fuel pressure just drops to around 50~55 psi. now even if the wasn't enough fuel going into the engine I'd at least see it rev past 4k RPM. (so this might be another small issue i'll look into later)

I am using SCT Advantage III tuning it and I have tried out everything i know/remember and thought I might have missed something so feel free to point out what might cause this issue.

any ideas or questions are welcome.


thanks.
 

gt347mustang

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You say it feels like a limiter, whats the computer shutting off to keep it from reving? Spark or fuel?
 

uae_lightning

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You say it feels like a limiter, whats the computer shutting off to keep it from reving? Spark or fuel?

spark on the datalog looks completely fine and reaches the targeted Borderline spark ( 13*) but the limiter feels like spark is cutting out since the engine just cutsout and bogs down.
 

01yellercobra

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How's the MAF curve? It's linear right? Also, double check all your rev limiters. I know there's two for Cobras.
 

uae_lightning

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traction control?

just a thought if it's sensing a slip on driveline

Traction switch is off

How's the MAF curve? It's linear right? Also, double check all your rev limiters. I know there's two for Cobras.

MAF curve is smooth I only fine tuned the STFT's and added a bit of for the open loop.

REV LIMIT ON =6,600
REV LIMIT NEUTRAL ON = 6,600

any other limiter you think I may be missing ?

Post a log showing fuel source and spark source when you hit the wall.

Unfortunately I couldn't find Spark/Fuel source and I am using FBMM0C6 as a stratey.

You specificaly stated fuel pressure dropped to 30.

Definitely going in to fuel pressure fault.

You need to dial in the fuel pump voltage.

just about yesterday I tweaked the Fuel pump voltage all to "15" havent tried it yet and would need a couple of days to get back and try the tune, but the Fuel system is seperated off the ECU pack.

would that still play a role ?

Thank you,
 

uae_lightning

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stock gt500 has fuel pressure limiters that cut power if fuel pressure goes too high or too low

This might be the reason, I don't remember going through them, I found these two switches on advantage,

fuel rail pressure failure management select
&
fuel supply failure management select
 

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