Check the injectors, it's possible that they are not working ideally as it was calling for a rich condition before and now it's calling for the opposite. And putting in a new upstream O2 sensor might help as well. In theory if you remove the fuel pump relay, I believe it disables the hpfp electronic part, I'll test it out when I get home on mine as if it's the relay it should tick in time with the hpfp. The car should start and then die if the fuel pump electronics are disabled, if it doesn't it's either the injectors or the hpfp, you can test the hpfp if it's leaking by removing the hpfp, if there is fuel sitting in there, it's most likely the hpfp. Technically removing the electrical connector from the hpfp should do the same thing. The design of the engine, the fuel in your oil, if it doesn't have compression or leakdown issues, would be more an issue with the injectors. Also when the car runs, the hpfp should tick about once a second as it pulses and adds fuel pressure to the fuel rail. And I plan on getting the timing chain replaced, I have had a compression test done on it and the car doesn't have any major blowby or compression issues despite being at 150,000 km on the original motor and it hasn't been rebuilt. The turbo has been rebuilt at least once though. The car can still squeal its tires without issue. Basically I've done extensive testing to make sure the engine is healthy at it's core. A cold wet compression test it gets 150 psi across the board, and a hot compression test it gets proper compression. I lucked out on mine and the car was broken in almost perfectly. Also have all the maintenance records for the car. It is possible you burned out your injectors.
​The fuel in my oil is caused by it calling for a rich mixture consistently at idle. As far as I can tell, the exhaust valves are opening just a touch early and allowing for improper combustion and increased O2 in the exhaust. I am very interested mechanically inclined and have torn down my car quite a bit in my first year of ownership. The engine looks almost new inside despite it being the original engine.

I do agree with the earlier post that if it was having a leak from the hpfp, the oil should be overflowing level wise and most likely you would be pushing smoke out the exhaust as well. On these engines, there are very few parts that are purely mechanical in nature, a lot is altered by electronics. The timing chain tensioner is mechanical, and the pistons and crankshaft are mechanical and I think a few other things, but the rest involve electronics. So when trouble shooting, it helps to make sure the essential sensors like the upstream 02 sensor, MAF and MAP are functioning properly as the ecu is more likely to assume it's getting proper data than a faulty sensor. In my case, the upstream 02 sensor was no longer accurate but wasn't malfunctioning enough to throw a code either.

 

it's still calling for a rich condition p2178. My car stft seems fine besides its running a tad bit rich.. my long term is -20 or more because my car is trying to take fuel away and it cannot. I am not very mechanically inclined in a automotive painter but I am trying to learn all of this. Hpfp is already at my house now I just have to install it if it looks like it needs replaced.

 

Fuel trims don't indicate a "call" for fuel; they indicate that the computer is compensating for a bad A/F ratio. Yes the #1 O2 sensor is responsible for sensing the A/F ratio and is faulty. Since the heater is not working the computer never goes into closed loop mode.

Fuel trims are misleading; if the fault is for "fuel trim rich" it means that the fuel ratio is lean. Most people just don't see the "trim" part of the definition.

Replacing or fixing the #1 O2 sensor might be all that is needed. It needs to be fixed at the least.

 

Alright, well I can't confirm if a relay controls aspects of the hpfp, but I know from working on mine that pulling the fuel pump fuse and relay should result in the car starting and then dying. If it doesn't, you are losing fuel pressure somewhere between the inside of the hpfp and the ports of the fuel injectors.

Just trying to help out as I learn about my own car. Also I may have to replace my upstream O2 sensor after getting the timing chain done. I'll know more after I connect my scan tool once it's replaced as the only system it hasn't checked was the EVAP, now it's the HEAT and EVAP but I did pull the battery recently when I was checking the timing chain so it's possible it hasn't had a chance.

Anyways though, a sensor refresh should help you hone in on your issue as you can guarantee more accurate data from the computer. Since these cars only have one upstream O2 sensor, unlike a V6 or V8 which is likely to have two, the computer is programmed to accept a wider range of data, even if it's faulty. In the aforementioned engines it's able to compare the two and find fault more often.
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And I don't mean to take over the thread, just seems like you might be experiencing a similar issue as I have, but slightly different sequence of failures. Honestly my timing chain was quiet until recently, started out as a tapping sound, like a valve was having issues, but now it sounds like a ratchet and is getting worse. However, if you plan on doing the hpfp, might as well zip the valve cover off and check your timing chain while you are at it.

 

where is #1 o2 sensor. is that upstream downstream? Before or after cat?

 

Upstream, before the cat. Probably worth replacing both. Don't use anything with silicone in it to install them, some brands come with copper anti-seize, GM uses a special glass stuff.

The problem may be just the wire laying on the exhaust and melting.

 

Does anyone have a hrr ss that hasn't been driven in a little while that can tell me how much pressure is suppose to be in my fuel rail while not running and been off? From my understanding it's suppose to be under consistent pressure even after been sitting. So if I'm losing pressure that means fuel injector right?

 

I went ahead and replaced fuel pump as I had it already bought. There was oil behind the fuel pump but it smelt a lot like gas and the oil was super thin behind it. Still same code p2178. I have watched my fuel pressure consistently drop over the last hour and a half wondering if its okay. Down to 830 psi and dropping. If its suppose to be holding then I think that would be injectors right? I have not ruled out o2 sensors yet but if my injectors are bad I will have to replace them anyways right?

 

Or check valve

 

how do I diagnose that?