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There's no corroded connector to the FCS or the purge valve. All the connectors I've checked are very clean no broken or split wires or anything.
theres no one way nothing to keep pressure in the line.
happened to me on another car. long crank after sitting over night and new fuel pump fixed it. that was the explanation I got.
they lied to you. or they have no clue. no set up will hold fuel pressure in the rail fully over night. you turn the key, the pump turns on and the injectors "prime" aka sprays some gas in the cylinders. thats what the engine first fires up on. once it fires up the injectors start spraying normally.
Lots of systems have anti drain back valves, they are often deleted in performance pump applications to help higher flow pumps flow better. I take them out of 03/04 cobra applications as well as f bodies and corvettes all the time. Not that they hold 60 psi over night, but they certainly help Maintain volume in the system.
What should the IAT read when the truck is cold? The CTS connector was missing the locking tab and when I pulled it out the connector was busted inside. It read max cold for a second on my scanner then went back to normal temps. I replaced both the connector and the sensor and had ran fuel system cleaner in it and drove it about 75 miles the next day and the CEL went away and no codes came up. It was perfect for a week or so and the other day it went right back to having this starting issue and I was getting low on fuel. So I don't know if it was because I was low on fuel or not. I just put some more fuel system cleaner in it and put gas in it yesterday and I haven't tried to start it today.
The ait is supposed to be what the temp is outside, so everything makes proper sense in your data provided for both key on and running. (Assuming it's 32 degrees out)
Not sure if it has been asked, but since you have a scanner, have you checked the fuel trims? I would be curious to see if the truck is pulling massive fuel once it is running.
Fuel trims are absolutely perfect. They were a little messy until I replaced the Coolant temp sensor but they've been where they are supposed to be since. I've pulled all the plugs out they look great and are dry, no fuel in the oil or anything. Pressure is solid. I just don't get it. I've never had something like this happen before. After we replaced the CTS and drove the truck all day 75 plus miles the engine light went off by itself and I scanned it and no codes and it started so good until the other day when it was acting up again.
Pretty sure at this point, if a gm tech were working on it, the diagnostic waterfall they were following would say to replace ecm. You are getting too much fuel from your key on injector pulse and or cranking injection pulses, then you are shutting the injectors off by holding the throttle open while cranking, then the truck is firing and clearing all the excess fuel from the pre start/cranking fuel.
Cylinders have no fuel in them. Injectors are not leaking. Plugs are clean and dry. Even tested the injectors with noid lights. After the truck has warmed up it'll fire back up with no issues whatsoever. That is until it sits again for a few hours or more. Also, when the truck is running and you disconnect the MAF, it doesn't die or change or anything. I've owned tons of cars and fixed tons of cars and every car I've had if I've disconnected the maf while running it will die immediately. No I don't have any codes for the maf though. Today it also threw the P0172 and P0175 codes on top of the P0178 and P0443. Both purge valves were replaced with OEM. Didn't change a thing. I was considering it being an ecm because it has some other weird electrical things that have made me think it could be the ecm. I know it is a common thing on GM trucks and cars of the 00's.
