crazy issue not starting
Thread Starter
Instructor
Joined: Dec 2015
Posts: 210
Likes: 119
crazy issue not starting
So crazy story.. Was bringing the wife vehicle to the stealership to get worked on for 1,000,000 time (2021 yukon denali) and it was raining it azz off. Dropped of the denali and decided to go eat before going home, when we were done we went to leave and the vette acted like it wanted to start but crapped out like it was out of gas (had 40miles to go to empty). After fighting to no available I walked to gas station got a gas can and put 2 gal in it and put it in the car presto it starts. Go to the gas station to fill it up, try to start and same thing car cranks but wont start. Checked my fuse for my fuel pump and it looked shady so I changed it and it tried to start like come on u almost got it kinda a start but no luck. Swaped the fuel pump relay with the windshield washer fluid relay since they are the same and presto starts no problem. Drive home, shut the car off and start it again no issues. Go to the gym this morning it starts no problem but leaving the gym it didnt start one time but then started the second try...
On believing unrelated side note I just changed the steering wheel and triggered an airbag light, and this has happened in the past in the rain. Once the car starts it runs with no issues its just to get it to start when she gets all temperamental.
Any ideas
On believing unrelated side note I just changed the steering wheel and triggered an airbag light, and this has happened in the past in the rain. Once the car starts it runs with no issues its just to get it to start when she gets all temperamental.
Any ideas
Safety Car
Joined: Dec 2006
Posts: 4,590
Likes: 1,669
From: Pearland / Houston Tx
Sounds like you need to narrow it down to either a fuel delivery problem or ignition/spark problem.
Fuel pressure: When you do ignition on without starting car, do you hear fuel pump whirring.....does it spray fuel from the rail test port.
Ignition: does it feel like car attempting to fire/start or does it just crank?
Fuel pressure: When you do ignition on without starting car, do you hear fuel pump whirring.....does it spray fuel from the rail test port.
Ignition: does it feel like car attempting to fire/start or does it just crank?
Thread Starter
Instructor
Joined: Dec 2015
Posts: 210
Likes: 119
Sounds like you need to narrow it down to either a fuel delivery problem or ignition/spark problem.
Fuel pressure: When you do ignition on without starting car, do you hear fuel pump whirring.....does it spray fuel from the rail test port.
Ignition: does it feel like car attempting to fire/start or does it just crank?
Fuel pressure: When you do ignition on without starting car, do you hear fuel pump whirring.....does it spray fuel from the rail test port.
Ignition: does it feel like car attempting to fire/start or does it just crank?
Last edited by thebert; May 26, 2022 at 01:29 PM.
Thread Starter
Instructor
Joined: Dec 2015
Posts: 210
Likes: 119
update: ok so I went get a loaner fuel pressure gauge from O'Reilly and hooked it up this is my first time using one of these but I think I did it right. With the car off and hooked the gauge to the fuel rail I was reading 20psi, try starting the car and it is still 20 psi. I think I read somewhere it needs to be between 30-45psi.... So what ya'll think next swap the fuel filter and fuel pump?
Instructor
Joined: Aug 2012
Posts: 162
Likes: 40
From: Griffin GA
Yes, you need more than 20 psi.
The fuel pump should energize as you start the engine, and should develop around 50 psi.
Since you have doubts about using the fuel pressure guage...start there and make sure you are getting good information.
If you determine that the 20 psi reading is correct, then you will then want to ensure that you are getting 12 volts to the fuel pump.
There is not a replaceable filter on these cars; if you are getting full voltage to the pump and not developing adequate pressure, it looks like you need to drop the drivers side tank to check out the fuel pump module.
The fuel pump should energize as you start the engine, and should develop around 50 psi.
Since you have doubts about using the fuel pressure guage...start there and make sure you are getting good information.
If you determine that the 20 psi reading is correct, then you will then want to ensure that you are getting 12 volts to the fuel pump.
There is not a replaceable filter on these cars; if you are getting full voltage to the pump and not developing adequate pressure, it looks like you need to drop the drivers side tank to check out the fuel pump module.
