Originally Posted by Rohitpanoramic-3d.ru
Yes, the pigtail/plug and the sensor were replaced. My mechanic tried to match the colors on the pig tail to the wire harness but this resulted in two new MAF codes.
He later matched the wires based on wire position and using the old plug/pigtail as reference. This led to the IAT sensor code. The plug/pigtail is made by Nisformance. I used the torque app to read the temperature stuck at -40 deg C. I think the wire mismatch we had earlier caused this.
I will redo the compression test but I am sure I won't see over 150 psi. This motor came from an AWD G35 sedan that had 100k miles on it. My car is a RWD 6MT. The ECU was re-flashed right after because of this fuel delivery issue.
I checked the parts store and they have one fuel pressure regulator and 2 dampers (driver and passenger side). Based on what I have seen so far this has to be a fuel delivery problem.
I was considering swapping the injectors (left to right) to see if lean / rich gets reversed.
What's the o-ring for?
So, you don't get the IAT code anymore than right? If the temperature reads correct now then you can probably ignore that code and the wiring issue was the cause.
Was the sedan manual or AT? I think you'd get a code, but the MT model has two extra sensors that are for exhaust timing.
I'd try to get a fuel pressure reading if you can. I had to buy an adapter kit for like 60 bucks to tap into the system and that way you can at least see if you are within spec (51 PSI).
The o-ring goes over the damper, so if you disconnect it for testing or replacement it will leak if you don't have one. I bought a kit from Harbor Freight and matched them up.
I think the regulator is located in the pump housing itself and the dampers just reduce the noise. If you can get reading from the pump before it hits the rail (at pump itself), bank 1, and then bank 2 that would probably give the most info for a proper diagnosis. Try adding unlit propane into the vacuum line and see how it affects your short term fuel trim or pulling a vacuum line and see what the values are.
I think you're correct with the idea about fuel being a possible issue as well, but just not sure if it's bank specific or affects everything. I had a regulator fail in my Audi and it caused my fuel pressure to run at 100PSI and both banks to be rich.
If you still get low compression trying adding oil to see if it improves.