HHR LT w/2.4 Ecotec Starts but Doesn't Run

sirc01

Hello - looking for some help if anyone has come across a similar problem.
2010 HHR LT with 2.4L Ecotec and 140K miles.
Pulled out into traffic and it stalled. Tried to start it and it will crank and start up, then in a second or two just stop (stall).
Got it towed home and thought it might be the fuel pump. Checked for DTC's and NONE are present.
Checked fuel pressure:
Key on: 56 psi.
Run (for 1 to 2 seconds before stalling): 60 psi.
60 seconds after stall: 50 psi.
2 minutes after stall: 48 psi.
I removed the air box & MAF sensor and cleaned the throttle body & blade and gave it a spray of starting fluid. It started and ran for maybe five seconds until the starting fluid was used up by the engine, then stalled again. Fuel pressure didn't change, 60 psi right after stalling. Set code P0102 MAF circuit low, since I had disconnected it.
All fuses and relays are good, battery is fully charged, Took the cover off the steering column to check the ignition switch connectors and they're seated.
Is it possible it's still the fuel pump? Will a bad crankshaft position sensor produce these symptoms?
Any clue from anyone? I don't want to start throwing parts at it without an idea of what it might be. Thank you!

thecardoc3

The first task in diagnosing a problem like this is to first figure out what you are losing, and then why. The engine stalling suggests you are losing spark, fuel, or both. A crankshaft position sensor signal is important for the module to create those outputs, but there is more to it. The fact that you can get this to run on starting fluid put's emphasis on the idea that you are losing fuel, not spark. The crankshaft sensor signal is responsible for both spark and fuel so if you have either one of them then the module has to be seeing that signal. In the shop I can feed propane in a way that I can make the engine keep running as long as I need it to. That allows me to test for what is missing, with the engine running.

Some people like to rely on a "Noid Light" to check for injector command. When you don't have anything else it does help, but it takes very little power to flash that small lamp compared to what it takes to turn on a fuel injector so be aware, it can trick you. That being said, if you connect a Noid Light to an injector connector and it does not flash when you get the engine to run then you would have a direction to continue your testing. The things a Noid Light cannot tell you if it flashes are again, if the circuit can carry enough power to turn an injector on, nor low long the injector was on for. Starting a cold engine takes a lot more fuel than once it starts running, the fact that this fires for you when cranking means at least while it is being cranked you must have some injector command pulse, but what happens after it starts? Does it become too short of a pulse to fuel the engine? This is one of the things you need better tooling for. Depending on what you have as far as a digital volt/ohmmeter that can read pulse width in thousandths of a second or a stethoscope to listen to the injectors as you manage to keep this running you would have some idea if the injectors are still being fired or not. If they are then you need to get a fuel sample to see if it is contaminated.

There is more to this, but this basic outline get's you possibly to the answer, but at least out of the starting gate in the right direction. Let me know what you have in tooling and what you discover when starting to test. BTW a MAF sensor signal could do this. There could be a MAF sensor issue, or maybe tears in the tube between the engine and the MAF sensor. That is something you could at least check for visually.