Krill
Full Access Member
So, I’ve stumped two shops with this issue…now waiting on an appointment at the dealership.
I recently did an in-depth overhaul of this new to me 200,000 mile L405 5.0SC
replaced everything I could get my hands on
Motor mounts, injectors, plugs, coils, water pump, metal cross over pipes for from and rear, alternator, every pulley and tensioner, intake gaskets, supercharger gasket, harmonic balancer, vacuum pump, valve cover gaskets, PCV valves, both high pressure fuel pumps, the low pressure fuel pump in the tank, fuel filter, both fuel pressure sensors and right now a shop is replacing the fuel lines…
The issue is essentially limp mode beyond 4000RPM. Car will run like a bat out of hell up until 4000rpm then it will cut out, feel like it goes into neutral till rpm’s fall back to 4000 then it will just maintain 4000 no matter how hard your standing on the gas. Transmission shifts smooth through all 8 and car will do 130mph+ AS LONG AS YOU DONT EXCEED 4000rpm to get there.
Only code the keeps coming up is P0089-92 fuel pressure regulator performance.
First shop said it’s “ definitely transmission problems” and recommended an 11,000 dollar transmission
Second shop said its crank shaft position sensors so replace them, said it was fixed, I test drove it and it was the exact same. Now they’re saying it’s fuel lines and the “ regulator inside the stainless lines between the fuel rail and HPFP” which as far as I know doesn’t exist..
Anyone have suggestions? Did not have the issues before I started the overhaul.
I recently did an in-depth overhaul of this new to me 200,000 mile L405 5.0SC
replaced everything I could get my hands on
Motor mounts, injectors, plugs, coils, water pump, metal cross over pipes for from and rear, alternator, every pulley and tensioner, intake gaskets, supercharger gasket, harmonic balancer, vacuum pump, valve cover gaskets, PCV valves, both high pressure fuel pumps, the low pressure fuel pump in the tank, fuel filter, both fuel pressure sensors and right now a shop is replacing the fuel lines…
The issue is essentially limp mode beyond 4000RPM. Car will run like a bat out of hell up until 4000rpm then it will cut out, feel like it goes into neutral till rpm’s fall back to 4000 then it will just maintain 4000 no matter how hard your standing on the gas. Transmission shifts smooth through all 8 and car will do 130mph+ AS LONG AS YOU DONT EXCEED 4000rpm to get there.
Only code the keeps coming up is P0089-92 fuel pressure regulator performance.
First shop said it’s “ definitely transmission problems” and recommended an 11,000 dollar transmission
Second shop said its crank shaft position sensors so replace them, said it was fixed, I test drove it and it was the exact same. Now they’re saying it’s fuel lines and the “ regulator inside the stainless lines between the fuel rail and HPFP” which as far as I know doesn’t exist..
Anyone have suggestions? Did not have the issues before I started the overhaul.