Will not stay running?

Hi,

The first thing I would check for is an engine vacuum leak. Also, make sure there are no restrictions in the catalytic converter.

Here is a link the explains how to locate vacuum leaks:

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Also, if you remove the upstream oxygen sensor, that will allow an extra location for the exhaust to exit. If the converter is plugged, this should be enough to make a difference.

Take a look through this link and let me know if anything mirrors what you experience:

https://www.2carpros.com/articles/bad-catalytic-converter-symptoms

One last thought. If possible, record what it is doing and upload it for me to hear. Hopefully, that will helps. And if you haven't checked for diagnostic trouble codes, do that as well.

Take care and let me know what you find.

Joe

Hello, I'm Danny.

Here is the information relating to your code P0453 Fuel Tank Pressure Sensor Malfunction. Here is a tutorial on how to test electrical wiring:

https://www.2carpros.com/articles/how-to-check-wiring

I've attached a picture step diagnostic flow chart below for your Mazda truck. Let us know what you find and we'll go from there. Hope this helps and thanks for using 2CarPros.

Hello again.

Yes, your truck has both a fuel pressure regulator and fuel tank pressure sensor. The fuel pressure regulator is incorporated into the in-tank fuel pump assembly. The fuel tank pressure sensor is mounted in the top of the fuel tank. I've attached pictures below on the location of the fuel pressure regulator circled in red and steps on how to replace the fuel tank pressure sensor. You will have to remove the fuel tank to gain access. If you like I can attach instructions on how to remove and replace the fuel tank. Hope this helps and thanks again for using 2CarPros.

Danny-

Hello again.

Yes, if you choose to remove the bed and do it that way the sensor as I stated is on the top of the tank. Yes, that is the correct sensor. Keep us updated and let us know if you have any further questions on this issue. Hope this helps and thanks again for using 2CarPros.

Danny-

Hello again.

Sounds good. Thanks again for using 2CarPros.

Danny-

Hi,

If the vehicle is still doing the same thing, have you gone through the FTP sensor diagnostics that Danny provided above? The problem may not be the sensor, but rather a wiring issue or even the PCM.

Is it possible for you to record what it does in the engine area and upload it for us to hear?

Let us know.

Joe

Hi,

Thanks... Believe it or not, that helps. When I listen to it stalling, the idle drops until it finally just stalls. I have a feeling we either have low fuel pressure or a big vacuum issue.

Have you confirmed fuel pressure? Also, have you checked the EGR to see if it holds a vacuum? Have you removed the EGR to see if it responds to vacuum?

If you remove the fuel cap from the filler tube, does that chance anything?

One thing I noticed, and correct me if I'm wrong, it takes two tries for it to run for any length of time. That is what is leading me to think low fuel pressure or fuel pressure drop off.

Let me know if you have done these things. Keep in mind, a stuck EGR or one that doesn't hold a vacuum can be causing this as well. However, by pressing the throttle, you should be able to keep it running. That takes me back to the fuel pressure possibility. Here is a link that shows in general how to test pressure:

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

If you look below at the attachment, it provides the pressure/drop-off diagnostics specific to this vehicle. The directions indicate the use of a scan tool.

Let me know.

Joe

Hi,

I attached the manufacturer's specs for fuel pressure below. When testing, make sure to check drop-off. When the key is turned off, the system shouldn't lose more than 5 PSI in the first minute.

Let me know what you find.

Joe

Hi,

It won't identify fuel pressure. However, it does provide fuel trims. I saw them for a second but you moved and I couldn't see them again. I think it was around 18%. That indicates the computer is trying to add fuel to the mixture. Can you tell me what the short-term fuel trims are?

Joe