Engine stalling and dies few minutes after start

[PawelS]

Hey guys, it’s a pleasure to join the community.
I was happy 2005 V6 convertible mustang owner until now…
I was driving back home with tie rod ends (what an irony) and suddenly car starter to stall and died on the highway.
I towed it to the dealership and they “diagnose” faulty alternator, battery, fuel pump and FPDM… I blindly believed the dealer and changed all of these parts excluding battery (just charged it and it works great so far), but nothing seemed to help.
It’s still starting and after few (3-6minutes) stalling and dies.
The only recurring fault I can read is P0191.
I thought it may be clogged filter so I changed it right now, but that also didn’t work. When motor runs I hear this weird intermittent humming noise from the exhaust, but nothing else seams to be bad.
Is anybody here who run through similar situation and found the reason?
Thanks for any advice.

 

[MrBhp]

Fuel rail pressure sensor is either not liking the data it's getting. Or it's going bad. If you've another round for the parts shotgun, get another sensor. If you are tired of spending money, try to test out the fuel system before you spend another dime. Hopefully you are not missing work or school because of it.

 

[PawelS]

Fuel rail pressure sensor is either not liking the data it's getting. Or it's going bad. If you've another round for the parts shotgun, get another sensor. If you are tired of spending money, try to test out the fuel system before you spend another dime. Hopefully you are not missing work or school because of it.

Thanks for your reply.
I ordered pressure gauge and it supposed to arrive today. Maybe I’ll be able to check the pressure, what should be my first step after bringing car from the dealer instead of changing parts like crazy…
Well, people learn on their mistakes.
Bank 1 means the one the driver side?
I skipped over 2 days of work because of that, but I did rent a car, so I’m good now.
I’m trying to understand what happened to my vehicle and why dealership diagnosed all these components to be faulty at the same time, I just don’t get it.
Is there any chance of testing this sensor? I do have OBD2 scanner and it shows most of parameters from PCM,
Just don’t really know how to interpret these.

 

[Dino Dino Bambino]

By convention, bank 1 on any Vee engine has the cylinder that's furthest towards the front of the engine and is numerically the no.1 cylinder. On the 4.0L V6, bank 1 is the passenger side.

I’m trying to understand what happened to my vehicle and why dealership diagnosed all these components to be faulty at the same time, I just don’t get it.

I do. The stealership was looking for an excuse to fire the parts cannon and lighten your wallet without bothering to troubleshoot the problem.

The obvious item to focus on is the P0191 code for the fuel rail pressure sensor. When this goes bad, a common symptom is random stalling. This article may help with troubleshooting it.

Redirect Notice

 

[PawelS]

Fuel rail pressure sensor is either not liking the data it's getting. Or it's going bad. If you've another round for the parts shotgun, get another sensor. If you are tired of spending money, try to test out the fuel system before you spend another dime. Hopefully you are not missing work or school because of it.

Thanks for your reply.
I ordered pressure gauge and it supposed to arrive today. Maybe I’ll be able to check the pressure, what should be my first step after bringing car from the dealer instead of changing parts like crazy…
Well, people learn on their mistakes.
Bank 1 means the one the driver side?
I skipped over 2 days of work because of that, but I did rent a car, so I’m good now.
I’m trying to understand what happened to my vehicle and why dealership diagnosed all these components to be faulty at the same time, I just don’t get it.
Is there any chance of testing this sensor? I do have OBD2 scanner and it shows most of parameters from PCM,
Just don’t really know how to interpret these

By convention, bank 1 on any Vee engine has the cylinder that's furthest towards the front of the engine and is numerically the no.1 cylinder. On the 4.0L V6, bank 1 is the passenger side.


I do. The stealership was looking for an excuse to fire the parts cannon and lighten your wallet without bothering to troubleshoot the problem.

The obvious item to focus on is the P0191 code for the fuel rail pressure sensor. When this goes bad, a common symptom is random stalling. This article may help with troubleshooting it.

Redirect Notice

thanks for the article. I will check the fuel pressure whenever the gauge arrives, like also try to upload video on YT and share link with you what can be helpful.
It runs until temperature reaches some point, I would say approximately 50deg Celsius, at least that’s what I’m reading from the scanner.
When I spoke with mobile mechanic he mentioned that it looks for him like the wiring issue, either pcm -> fpdm or fpdm -> fuel pump.
That’s something I didn’t check yet. That is on the list in the case of fuel distribution issue checked by gauge.
I’m not sure if that’s the right direction, but I fully agree with stealership name…
Crazy, how untrusted they can be, when they should be the best specialists for diagnostics.
I uploaded videos:
Stalling
Parameters

 

[PawelS]

I finally hooked up the fuel pressure gauge and I found something what can be a good explanation.
First picture is a pressure built, second is 40 minutes later to check possible gas leaks on the injectors and the rail and 3rd is a value read by the fuel rail pressure sensor.
These are definitely not matching.
In this case I’m going to swap the sensor and check if that was an issue.
It’s the most logical explanation for me at this point. too high read from this sensor causes PCM to drop the pump pressure down.
I’ll keep the forum posted in the case if somebody will have similar issue.

 

[Dino Dino Bambino]

View attachment 105125

Your fuel rail pressure sensor is reading the equivalent of 51.4psi. That's a huge discrepancy from the 34psi (normal) that your analog gauge is reading, and that would explain why you have the fault code plus the engine stalling. Hopefully a new sensor will fix it.

Bank 1 means the one the driver side?

As I said in my previous post, bank 1 is the passenger side.

 

[86GT351]

Most likely the rail sensor

 

[PawelS]

Sensor has been changed and no improvement. I would say it’s even worse. It doesn’t die after few minutes, but below 1 minute now.
Pressure read from the sensor is relatively lower comparing to the previous sensor, but now the pressure from the pump is coming to the gauge but engine dies quickly.
Any other idea what can that be?
I’m loosing my hope…

 

[Dino Dino Bambino]

This is a proper headscratcher!
What fuel pressure reading do you get from the OBD 2 scanner and how does that compare to the reading from the analog gauge?
Has the ECU triggered any new codes?
I'm wondering whether you might have solved one problem and unmasked another.

 

[PawelS]

@Dino Dino Bambino
When engine died gauge was at 35PSI and the read from sensor was approx 290kPa. The only thing I noticed, it’s showing the pressure relative to manifold and it’s not matching the gauge exactly.
It is a head scratcher and some kind of mystery.
Fault stayed the same P0191. I’ll try to get somebody to help me with cranking and I want to measure all voltages coming to the pump driver module, including control signals/feedback however it’s called.
I’m missing something for certain.
That is incredibly weird, because this car has only 65k miles on it. No leaks of oil, gas, coolant, fumes, engine is perfectly dry and clean.
Here’s the question, if there would be a problem with throttle body or either clogged exhaust, would the PCM throw the related faults, or not necessarily?

 

[Rotgutrusty]

I’m having this same problem, OBD is scanning 65psi and gauge shows 35psi. Changed the fuel rail sensor but the problem persists. Have you come up with anything yet? Before this discovery all my signs were pointing to bad PCM.

 

[PawelS]

@Rotgutrusty
Unfortunately not yet. That is my next suspect, the PCM.
It has a communication with obd, but might just faulting out internally. Maybe somebody can give a hint how to check PCM other way than swapping with a working one?
If you will fix the problem, let me know. I really want my car back. I have to drive fiesta… ugh… no remote door lock, no cruise, no fun at all. How to live?