Car Cranks, No Start

[NastyStang113]

So my buddies car is sitting in my driveway because it won't start. It's a 2007 Mustang GT. He drove it to my house and a couple hours later it won't start. It just cranks, cranks and nothing. It has no fuel pressure so obviously it's something electrical or with the fuel system?

We checked every single fuse, moved around a few relays for the fuel pump, etc. We found a broken COP connector and bought a new one. Even knowing that wasn't the issue. We cleaned the crankshaft position sensor connection worrying that maybe it was the issue. We switched the fuel rail sensor and that didn't make a difference. We've checked wiring visually. We tore the trunk apart to verify nothing was wrong with the fuel pump wiring.

What are the chances the crankshaft posistion sensor is bad? Could a bad TPS cause this? Anything else? The PCM is fine because we were able to reflash the PCM with no issues. Could bad FPDMs cause this issue? All accessories work fine. Next thing we're doing is taking a volt meter to anything and everything.

 

[tmcolegr]

Just asking...

did you try resetting the fuel pump inertia switch?

 

[NastyStang113]

Just asking...

did you try resetting the fuel pump inertia switch?

Forgot to mention that. Yes we did verify it was in the down position and we did push it to reset it. Could the inertia switch go bad?

 

[tmcolegr]

Forgot to mention that. Yes we did verify it was in the down position and we did push it to reset it. Could the inertia switch go bad?

I've never seen one fail but that doesn't mean it can't happen

 

[Aandf1978]

Did you hear the pump prime? Sounds like possible pump is bad, maybe?

 

[NastyStang113]

Just trying to come up with ALL possible scenarios right now. I'm really stumped on this. I know if the crank position sensor goes bad it won't have fuel pressure and obviously won't allow the car to start. Just don't know how likely it is...

Did you hear the pump prime? Sounds like possible pump is bad

It has GT500 fuel pumps so it would be hard to believe both pumps failed. With one pump the car would still start, just run out of pressure on top.

 

[Aandf1978]

Oh sorry man yeah seems kinda unlikely just thought I could suggest something uneducated

 

[NastyStang113]

I appreciate it because I need as many brains as possible. LOL

 

[Alfiedagr8]

Based on the info sounds like the FPDM. A crank sensor being bad it will still have fuel pressure on key on position but will not kick on the fuel pump while cranking. A bad tp sensor if the car goes to flood mode it will still have fuel pressure just not fire up. U can log tp voltage to verify.

 

[s8v4o]

Did you guys try to see if you could pull any codes? May or may not have been better to have done it before flashing, IDK.

 

[tmcolegr]

It has no fuel pressure

how did you determine this?

 

[5.SLOW]

i say wire came off the pumps inside the tank

 

[one eyed willy]

im guessing you checked the gt500 pump fuse up by the fuse box under the hood?

how much gas is in the car?

i would think if a crank sensor went out you would get a code.

tps or anything TB related you should get a code and the car usually starts but will be in limp mode and RPM's wont rise when pushing the pedal.

use the meter and confirm you are getting power on the red wire going to the FPDM's.

 

[Charlie Sheen]

Did you hear the pump prime? Sounds like possible pump is bad, maybe?

It has GT500 fuel pumps so it would be hard to believe both pumps failed. With one pump the car would still start, just run out of pressure on top.

But can you hear the pumps prime and then stop or do they continuously run?

 

[Aandf1978]

Gotta guess no priming sounds...

 

[NastyStang113]

I got it fixed. I ended up getting a volt meter and started checking the FPDMs. I was getting all sorts of crazy ass readings. I moved one of the grounds for the FPDM and voila! Bad ground... Car went 3+ years on this ground and than all of a sudden.

I'm going to go ahead and answer these questions for anyone in the future...

Did you guys try to see if you could pull any codes? May or may not have been better to have done it before flashing, IDK.

Yes, no codes prior to reflashing.

how did you determine this?

Fuel rail pressure sensor.

i say wire came off the pumps inside the tank

im guessing you checked the gt500 pump fuse up by the fuse box under the hood?

how much gas is in the car?

i would think if a crank sensor went out you would get a code.

tps or anything TB related you should get a code and the car usually starts but will be in limp mode and RPM's wont rise when pushing the pedal.

use the meter and confirm you are getting power on the red wire going to the FPDM's.

One of the first things I did. I actually put a new one in it just to make sure. It had at least 3/4 of gas in it.

But can you hear the pumps prime and then stop or do they continuously run?

Well I've never heard something like this it was super weird. The pumps would make the weirdest noise with the key on. Sometimes they would run and stop, than they would run until I turned it off, but it wasn't just a running sound. All I can say is that it was odd!

 

[s8v4o]

Glad you figured it out!

 

[Aandf1978]

Good to hear something simple!

 

[NastyStang113]

Now it can be off my driveway!

 

[one eyed willy]

I got it fixed. I ended up getting a volt meter and started checking the FPDMs. I was getting all sorts of crazy ass readings. I moved one of the grounds for the FPDM and voila! Bad ground... Car went 3+ years on this ground and than all of a sudden.

did it sound like the pumps cutting on and off over and over again? cause mine has been doing this same thing on occasion and i have not been able to figure it out