[Aphrodite2ss]

Hey everyone, I’m looking for some help diagnosing an issue with my 2023 Camaro SS / LT1.

I did a cam and fuel system build on the car and it was running great after tuning, but I’ve had a serious HPFP/fuel issue and I’m trying to figure out what the root cause is before I keep throwing parts at it.

Current setup/mods:

* 2023 Camaro SS / LT1
* Cold Air Inductions CAI
* J&L oil catch can
* MBRP axle-back exhaust
* Speed Engineering 2” long-tube headers
* Speed Engineering X-pipe/mid-pipe
* Lethal Garage Flex Fuel Kit
* LT4 high-pressure fuel pump
* LT4 injectors
* BTR Stage 2 Supercharged Gen V camshaft
* BTR cam has the 38% fuel pump lobe
* BTR .660” springs with titanium retainers
* BTR 7.850” .080 wall chromoly pushrods
* LS7 lifters
* BTR lifter trays/bolts
* BTR rocker arms with upgraded trunnions
* BTR Gen V Plus 0 Degree Phaser Limiter / Lockout Block
* HP Tuners MPVI3
* T93 TCM / tuned

The car was running great after the build and tune. Then while I was driving to a car show, the car suddenly went into limp mode. I had it towed home and found roughly 2 gallons of E85 mixed into the oil. There was also oil/E85 contamination up into the intake manifold and catch can area. From what I could tell, the HPFP seal failed and dumped fuel into the crankcase.

After that happened, I:

* Pulled all spark plugs
* Drained the oil/fuel mixture
* Replaced the oil filter
* Cleaned out the intake/catch can area
* Verified the engine would rotate by hand with the plugs out to make sure it was not hydrolocked or mechanically locked up
* Installed a brand-new GM LT4 HPFP
* Got the car back together and running
* Changed the oil and filter again after running it
* Cleaned the catch can again

After that, the car seemed perfectly fine for a while.

Now, months later, I started getting a flashing check engine light at low speed. I scanned the car and currently have the following codes:

* P163A — Control Module Fuel Pressure Regulator 1 Control Circuit
* P0174 — System Too Lean Bank 2

I tested the wiring harness going to the HPFP and also checked wiring going to the Bank 2 injectors, and everything I tested appears to be in working condition.

One thing I just found out about is the GM 12596509 .060” HPFP lash cap. I did not originally realize this was commonly used with +30% to 38% fuel pump lobes. Since my BTR cam has the 38% fuel lobe, I’m wondering if I should have had the .060 lash cap installed with the LT4 HPFP.

My main questions:

1. What would be the best diagnostic order to track down the current Bank 2 lean condition and P163A HPFP/fuel pressure regulator circuit code?

2. For the P0174 Bank 2 lean code, what should I check next besides the injector wiring? I’m wondering about injectors, plugs, O2 sensors, exhaust leak, intake/vacuum leak, fuel pressure, or tune-related causes.

3. For the P163A code, what should I check beyond the wiring harness? Could this be the LT4 HPFP itself, the HPFP/fuel pressure regulator connector, ECM control issue, fuel pressure sensor issue, commanded vs actual rail pressure issue, tune setting, or something else in the high-side fuel system?

4. Since my BTR cam has the 38% fuel pump lobe and I’m running an LT4 HPFP, do I need to be running the GM 12596509 .060” lash cap?

5. What is the correct way to check HPFP preload/installed height on these Gen V LT engines and make sure the pump is not bottoming out at max fuel lobe lift?

6. Could incorrect HPFP preload, no lash cap, or the wrong installed height have contributed to the original HPFP seal failure that dumped E85 into my oil?

7. Is it possible the original E85-in-oil failure damaged something that is now showing up later, such as injectors, plugs, O2 sensors, the HPFP connector/harness, fuel pressure sensor, or the new HPFP?

8. What live data should I log in HP Tuners to help narrow this down? I’m assuming commanded/actual rail pressure, low-side fuel pressure, injector pulse width, fuel trims, O2 readings, misfire data, and HPFP-related parameters, but I’d like to know exactly what to look at.

I’m not assuming the lash cap is the only issue. I’m trying to figure out the correct way to diagnose the whole problem before I keep replacing parts or risk damaging another HPFP.

At this point I’m trying to figure out whether I’m dealing with one issue or multiple issues, such as:

* HPFP preload / lash cap / installed height problem
* Bad or damaged new LT4 HPFP
* HPFP connector, circuit, or sensor issue
* Fuel pressure problem on the high side or low side
* Bank 2 injector issue
* Spark plug or misfire issue
* Vacuum leak or intake manifold sealing issue
* Exhaust leak causing false lean reading
* O2 sensor issue
* Tune/fuel pressure modeling issue
* Damage from the original E85-in-oil failure

Any help from people who have dealt with BTR 38% fuel lobes, LT4 HPFP installs, lash caps, Bank 2 lean conditions, P0174/P163A codes, or Gen V LT high-side fuel system issues would be appreciated. I want to diagnose this the right way before I start the car again or replace more parts.