Any advice would be appreciated:
Aston Martin DB9 2009 30,000 miles.

Problem: P0171/P0174 on secondary PCM with Check Engine Light (no other codes except P1000 on both primary and secondary).

Drivability: Car runs well. Slight idle irregularity. No issues at high RPM

Problem started after Spark Plug/Coil pack change.

History: Car ran well but with intermittent rough idling. OBD II showed misfires on several cylinders. I decided to replace the plugs and coil packs.

Replaced: Spark plugs (AM plugs) x 12
Coil Packs (AM plugs) x 12
PVC valves (Ford) x 2
Clean both Throttle Bodies
Replaced both MAF sensors
Cleaned both Air Filters (No oil)
Oil and Filter change (Mobile 1 0w-40; AM filter
New intake manifold gaskets (AM)
New Fuel injector O-rings (AM both on all 12 injectors)

As expected, the P0171/0174 appeared on both Primary and Secondary since the fuel rails were depressurized in the process. These were cleared, but the codes returned on the Secondary. The cleared code will repeatedly come back when the engine reaches normal operating temperature. After clearing the codes, it remains off when the engine is cold and it appears to trigger when the normal operating temperature is reached. The code then remains when the engine cools and is restarted. P0171 appears first followed by P0174.

Long Term Fuel Trim was ~14 on Primary and ~30 on Secondary at idle (both banks 1 and 2). At 5,000 RPM, the Primary went to ~7 and the Secondary to ~14 (both banks 1 and 2). Fuel rail pressure and Manifold to Fuel Rail Pressure were the same on both Primary and Secondary. The engine runs fine at thru 5,000 RPM.

After the code was cleared, the KOEO was cleared but the KOER test would not complete with my scanner (ThinkDiag). The engine RPM increased, followed by a Communication Error.

After dropping the car from the lift, the gas filler door would not keep shut. Just a slight bending of the metal hinge put it back in the correct position. Whether the action that caused this could also have cracked an EVAP hose or fitting there is unknown. I also don’t know if a cracked or pulled EVAP hose there would throw the P0171/0174 code on just one side or not.

I've tried the listen, look and propane tricks to detect a vacuum leak, but didn't discover any. It would seem unlikely that it was bad O2 sensors as two would have to go out at the same time and coincidentally when changing the coil packs. I had cleaned the MAF with MAF cleaner, but thought that it might have become damaged doing that, so I replaced both MAFs with new sensors. Nothing else with the intake system (from ground to throttle bodies was changed or altered). I double checked the manifold bolt torque and the fuel rails bolt torque.

I've put about 50-75 miles on the car since and have done the misfire protocol. Still gives me the code on secondary PCM.

So I'm stumped. Any geniuses out there with some insight or testing suggestions?

 

These code are saying too lean. Might want to check:

1) cat on the problem side, remove the top o2 sensors and check cats with bore scope.
2) fuel injector, either check fuel mist pattern or just change them.
3) Fuel pressure

is there vacuum building up in the gaz tank?

 

V12AM provided some very good insight. I also had some help interpreting the P0171 codes from BigDog50001's YouTube video
My take aways have been:
1) It's most logical that it had something to do with my re-installation rather than a new problem that just happened to crop up. Not that that couldn't happen, but highly unlikely.
2) When the STFT (short Term Fuel Trim) and LTFT (Long Term Fuel Trim) decrease as the engine RPM increases, it points to a vacuum leak rather than a fuel pressure problem. This was my case.
3) Vacuum leaks are often difficult to pinpoint and a small leak can effect the fuel trim.
4) Since the issue occurred only on the left side (secondary PCM), the vacuum leak should be limited to something there.
5) It could have been a displaced fuel injector O ring (thanks V12AM) and I was about to remove the fuel rails on the left side to check them.

My solution (so far) was to remove the brake actuator hose (which connects to the left side) with the engine running. I had removed and replaced before with the engine off with no change. When it disconnected, the engine ran very rough and created some misfires, but I placed the brake actuator back in (engine running) and let the intake manifold vacuum suck the hose to place. I cleared the codes and started the engine up again. My STFT returned to normal and matched the right side. My LTFT remains about twice that of the right side but no codes appear and in fact even the P1000 code went away. I still want the LTFT to come down, but everything seems to work properly now without throwing any codes.

 

I have an '09 DB9 with 63k miles. I think the problem is you're using too many genuine AM parts

Jokes aside, the vacuum lines that go to the fuel rails are super brittle at this age. Mine kept cracking when I tried to move them so I replaced them with a high quality silicon hose. The vacuum tubes 80s Mercedes used are also a good replacement. But you would then need to reuse the elbows. Mercedes part #0001581435

Good luck. Emissions stuff is always a pain.

 

Well, my codes returned. You're right that the vacuum lines to the fuel rails would appear to become brittle with age. I did disconnect each one with the engine running and felt a good vacuum on each one. There could be a crack in one, but my feeling is that even if there was a small leak there, it wouldn't be mu culprit. I like your suggestion of fuel injector o-rings not fully seated. But with my experience with the brake actuator hose and the problem temporarily correcting itself, I'm getting focused there. I think a smoke test is in order. If I don't find anything with the smoke test, then I'll look at the injectors.

Update: Problem finally solved. It was indeed the brake actuator vacuum line connection to the manifold. It was not completely seated. I had seated it until it stopped, but not until it snapped fully. When I had let the engine pull it in, I thought it had solved the problem as the STFT had returned to normal. But I was still concerned that the LTFT had not. As the engine cooled and then restarted, the hose had pulled out slightly and the lean condition returned. When I went looking to see about replacing the canister in the manifold, I seated the hose back in firmly until it snapped. Both SSTFT and LTFT returned to normal and matched those on the other side. This hose being fully seated is basic and I should have known better. But hopefully at some point, someone will have a P0171/0174 trouble code, read this thread and it will help them. I appreciate the insight provided to me. Now time to drive!