Crank but No Start - Low Fuel Pressure

[Yoyofatboy]

Hello all!

Been running through getting my pre-owned 2018 FiST back up to speed. Just this week got a P1450 code for the purge valve so I ordered the fuel feed line assembly that includes the valve (D2BZ-9C047-E).

Today after driving for groceries it stumbled and sputtered for a second when pulling up to my driveway. Now I'm getting a crank no-start condition and its throwing P0087 & P00C6 as well as the old P1450.

Fuel pressure from the sensor is showing around 10psi, and I believe the sensor is working as intended as when i unplug it, no reading is given. I removed the rear seat and cleaned up the pump top to prep for replacement, and I can clearly hear the pump prime in acc mode and send during cranking. The pump has clearly been replaced before as noted by the mangled metal hole.

I ordered a new Low Pressure Fuel Pump, but it wont come in until Friday. Any tips or suggestions on where to check and test while I wait?

Thanks in advance!

 

[XR650R]

That's a tough one. I'll just bump it and hope someone else has something useful to add.

 

[TyphoonFiST]

Which fuel sensor? The low pressure sensor on the fuel line near the firewall or the High pressure sensor on the fuel rail?

 

[Yoyofatboy]

Which fuel sensor? The low pressure sensor on the fuel line near the firewall or the High pressure sensor on the fuel rail?

I unplugged the one on the fuel rail to test, but I can try the one on the firewall if you think that would yield a different result or provide further insight. The readout was just an overall “Fuel pressure at rail” reading from my basic scanner

 

[ShakenCoffee]

This person on Reddit had the P006C code you have, and replacing the low pressure sensor seemed to fix it for him: https://www.reddit.com/r/FiestaST/comments/197kaa6 View: https://www.reddit.com/r/FiestaST/comments/197kaa6/beware_of_the_low_side_fuel_pressure_sensor/


I had a P008B code recently, and fixed it by replacing that sensor. Similar to you, my car would sputter and then die occasionally before I replaced it. However, my car would still start before I replaced the sensor, and just periodically die while driving.

TyphoonFiST has a good guide on replacing the sensor, as you may have seen already. Though I am not sure if that sensor would be the culprit in your case.

 

[Yoyofatboy]

This person on Reddit had the P006C code you have, and replacing the low pressure sensor seemed to fix it for him: https://www.reddit.com/r/FiestaST/comments/197kaa6 View: https://www.reddit.com/r/FiestaST/comments/197kaa6/beware_of_the_low_side_fuel_pressure_sensor/


I had a P008B code recently, and fixed it by replacing that sensor. Similar to you, my car would sputter and then die occasionally before I replaced it. However, my car would still start before I replaced the sensor, and just periodically die while driving.

TyphoonFiST has a good guide on replacing the sensor, as you may have seen already. Though I am not sure if that sensor would be the culprit in your case.

Thanks for that information, I saw a lot of videos about that sensor and the one on the rail. All the threads/videos I saw had their cars still running, just stumbling/dying. Mine doesn't start at all due to the pressure so I figured I could rule out a sensor fault. Though im about to hit 90k miles so it might be a great "while-youre-in-there" thing to get done as well.

 

[Yoyofatboy]

New fuel pump did not resolve the issue, still seeing the same fuel pressure levels. What else would cause it not to fire??? Are the sensors really that detrimental to starting the car? Lost now

 

[ShakenCoffee]

New fuel pump did not resolve the issue, still seeing the same fuel pressure levels. What else would cause it not to fire??? Are the sensors really that detrimental to starting the car? Lost now

You could give replacing the low side sensor a try. They seem to be a relatively common issue with the Fiesta STs. I'm not sure how many miles are on your car, but I am about ~85,000 miles I think, and had the issue with that sensor somewhat recently.

This is where I bought mine:
https://www.fordpartsgiant.com/part...bmodel=&extra1=&extra2=&filter=()&location=pd:,

It's very easy to replace, and not terribly expensive. Definitely take a look at TyphoonFiST's guide. One thing I noticed when replacing mine, is that the line where it screws into moves a fair amount while you are trying to loosen and tighten the sensor. It was helpful to have another person there to hold the line in place, just to potentially avoid anything further down/up the line from being stressed unnecessarily.

 

[Yoyofatboy]

You could give replacing the low side sensor a try. They seem to be a relatively common issue with the Fiesta STs. I'm not sure how many miles are on your car, but I am about ~85,000 miles I think, and had the issue with that sensor somewhat recently.

This is where I bought mine:
https://www.fordpartsgiant.com/part...bmodel=&extra1=&extra2=&filter=()&location=pd:,

It's very easy to replace, and not terribly expensive. Definitely take a look at TyphoonFiST's guide. One thing I noticed when replacing mine, is that the line where it screws into moves a fair amount while you are trying to loosen and tighten the sensor. It was helpful to have another person there to hold the line in place, just to potentially avoid anything further down/up the line from being stressed unnecessarily.

Just replaced the Low side sensor. picked up a Dorman OE Sensor from O-Reilly's. Still same pressure readings, though goes up to 11-12psi when cranking.

At this point its got a new Low Pressure Fuel Pump, and new Low Pressure Fuel sensor but still unable to reach good rail pressure. I have a Purge Valve assembly in the mail from two weeks ago when i was troubleshooting the failure to purge CEL, but otherwise I'm stumped.

While I enjoy dailying my 944 again, I'd really like to get this car back up and running.

Thoughts on a clogged line somewhere? Whats the likelihood there?

Could a bad fuel pump relay still allow it to run but not at full capacity?

 

[Yoyofatboy]

Swapped Relay47 (Fuel Pump) with Relay52 (Blower Motor), did not resolve