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So the other day, my car was running as it normally does (crappy idle, over boosting, backfires, etc.) but then i parked it, came out 10mins later and it would start, try to keep itself alive, but soon sputter/cough/auto-rev and die.

First thought, some major vacuum hose popped off since it smelled like gas and it was getting spark cause it was on while "coughing" then proceeded to die. Tightened down all my hoses, checked for any unplugged vacuum lines, then tried cranking it and it won't start! It'll crank though. (feels like if you try to start it with the tmic off...)

But today, i said what the hell, and gave it a shot to turn it on. It turned on! And i let it idle till it got warm (normal operating temp), idled fine. Took it for a drive, and it would take a sec for the boost to kick in even though it was reading 11psi and it would make some weird tapping/humming/burring noises from the intake and turbo area.

Got home and i was revving it on, off, on, off throttle motions to hear/feel air near the intake and turbo. Only thing was my atmospheric pressure sensor (the thing by the stock bcs) was clicking, which hasn't been hooked up for a very long time, but now starts to click... But once my fans turned on, the car did the same thing the other day, it fought to stay on but it finally died.

I'm trying to figure out what's wrong with it so i can get it running asap. The only things i can think of that it could be would maybe the turbo is clogging from too much oil blow-by, which makes sense cause the oil drains after a day, right? Or maybe is a coolant sensor, crank/cam sensor, or IACV be bad?

I'm just really confused cause it will turn on, idle fine, but after i start driving it, it'll take about 2 mins for the thing to shut down. AND THE ONLY CEL IS 35 CANISTER PURGE SOLENOID, which has been there on and off for a month now. But i'll try to check them again, just dont want to get stranded. Any ideas would help, I'm stumped on this and troubleshooting isn't my forte. Thanks and sorry for the long post, trying to be descriptive!

UPDATE: Swapped known working coil pack, cam and crank position sensors and still nothing. It just cranks and cranks but no turnover.

Chris,

Try unplugging the MAF sensor electrical connector and see if the car starts. Also, temperature related issues can be related to the coolant temp sensor. How old is your coolant temp sensor?

Its probably the factory coolant temp sensor which would be 195k miles. I've got a spare that I can swap though. I read the maf could do the same, but my car wants to start but wont stay on. Also, I searched around the forums, and people were having similar issues and it turned out to be their fuel pump or the connectors associated with it. So i gave it a look and the connectors looked fried, dark brown with melted plastic goop everywhere. Looked as if someone tried to do the ground bypass thing to but didn't do a bang up job of it. So i grabbed a good looking on from the junkyard, swapped them, and my car is still not starting. I checked the voltages of the car side pins (not the pins to the pump) to see if i was getting power. Are all 5 of the pins supposed to supply power when the key is in the ON position? Because of the bottom three pins, the two side ones dont have voltage (thick all black wire and thin all black wire). If that's all good to go, I might order a walbro gss341 with the wrx install kit, my pump is the factory one and I'm approaching 195k. Thanks Josh for the quick reply

Alright, I just tried starting it with the MAF unplugged and it did the same, it tries to start but won't stay on. It'll like get one crank in cause it goes to like 300rpm but immediatly dies. And it also seems like the longer i leave the key in the ON position, the more it wants to start...

Only one of the larger thickness wires at the fuel pump will have 12v to it. Keep in mind that the ECU only keeps power to the fuel pump for a few seconds once the key is in the ON position. Once the ECU detects a cranking signal it will then send power to the fuel pump. You can connect the green diagnostic connectors which will cycle all the relays, and allow you to test for power at the fuel pump. The voltage should be 12v and then 0v as the ECU cycles the power.

If the MAF didn't work and you end up testing that the fuel pump is getting power, I'd try the coolant temp sensor. If you have a small space heater you could try heating up the coolant temp sensor to see if that allows the car to start.

I think upgrading the fuel pump is probably a good idea.

Ok, well I ordered a walbro, should be here in the next couple days. But I'll try the coolant temp sensor thing when it gets warmer out, -10° isn't exactly what I'd call "working on car temperature"...

Installed the walbro 255 FP yesterday and she started right up! Got better throttle response and boost increases a lot more steadily instead of being choppy like in the past. Drove it around for a good 2-3hrs last night and no issue, multiple turn on/off's throughout and it started right up every time! Thanks again for the help Josh.

Good deal, glad that fixed the problem.