fuel pressure reading through OBDII scanner

[Al_C]

Talking with my nephew the other day, I learned that you can get a reading on fuel pressure on an OBDII scanner. He didn't specifically say that works on a coyote, only that he had seen it elsewhere. And yes, I do have a fuel pressure gauge on the Aeromotive fuel pressure regulator. I'm just lazy and don't want to have to go through the gyrations of seeing what that gauge says, as it is conveniently pointed at the cylinder head. (Poor planning on my part...)

Anyway - I plugged my trusty scanner into the OBDII port and clicked on "live data". On the first screen, it shows two lines regarding fuel system, but neither of them appeared to be fuel pressure. OK, enough background. On to the questions:

1. Can one actually get the fuel pressure from the PCM on a GenII coyote?
2. Assuming the answer to #1 is yes, can you do that from any scanner, or do I need something more sophisticated than my Ancel AD310?

Google seemed to be at a loss on this one. But you guys are generally better than Google. Thanks in advance!

[i.e.427]

#1- Yes you can but it depends on the scanner and what available outputs it measures/monitors. We recently did a first start on a Gen 3 Coyote and set static pressure using the scanner.
#2- We use a BlueDriver bluetooth dongle scanner that works with your tablet or phone. It monitors every output the ECU has available.

[Al_C]

BlueDriver! That's the scanner my nephew recommended! Thanks for the confirmation. (My current scanner is not that one. I'll be getting one shortly!)

[cschwer]

Just took a look at bluedriver, wow, not cheap. FYI I don't have a coyote but I'm using a donor 2003 mustang and am running a cheap elm327 Bluetooth adapter and using torque pro app on my phone, cost me a total of $25 if I remember correctly. Definitely shows fuel pressure and any other obdii pid available.

I'd be happy to bring mine by if you want to try it out.

[Nigel Allen]

Hi Al,

I have a gen1 Coyote crate engine from 2012. As far as I can tell, there is no fuel pressure sensor. Looking at the fuel rails, there is the 8 injectors, but no other devices connected to the rails. Not sure if the later versions, or non crate engines had a sensor. In my case I used a Speedhut fuel pressure gauge with it's sensor installed on the pressure regulator output port.

Hope that makes sense.

[edwardb]

I looked at the data logs from my Lund Racing tuning sessions. Collected through the ODB2 port and I've found aligns with the data that can be viewed with the proper scanner. For my Gen 2 Coyote in the 20th Anniversary Roadster, there are two fuel pressure fields. But no data. So my guess is the Gen 2 doesn't have a pressure sensor. Or at least doesn't report it in the data stream.

The Gen 3 data logs from my Coupe have four fuel pressure fields and two are populated with data. So some kind of sensor in the Gen 3. Didn't dig any deeper to know exactly what they are. Clearly some changes with the Gen 3. No surprise I guess since they added the direct injection.

Don't know if this helps much but what I could find FYI. Both builds have Aeromotive regulators with a gauge. Pressures set per the Ford instructions at the regulator.

[Al_C]

Just took a look at bluedriver, wow, not cheap. FYI I don't have a coyote but I'm using a donor 2003 mustang and am running a cheap elm327 Bluetooth adapter and using torque pro app on my phone, cost me a total of $25 if I remember correctly. Definitely shows fuel pressure and any other obdii pid available.

I'd be happy to bring mine by if you want to try it out.

Given Paul's input, this might make more sense than me running off and getting a bluedriver... Please let me know what's convenient!

[Al_C]

I looked at the data logs from my Lund Racing tuning sessions. Collected through the ODB2 port and I've found aligns with the data that can be viewed with the proper scanner. For my Gen 2 Coyote in the 20th Anniversary Roadster, there are two fuel pressure fields. But no data. So my guess is the Gen 2 doesn't have a pressure sensor. Or at least doesn't report it in the data stream.

The Gen 3 data logs from my Coupe have four fuel pressure fields and two are populated with data. So some kind of sensor in the Gen 3. Didn't dig any deeper to know exactly what they are. Clearly some changes with the Gen 3. No surprise I guess since they added the direct injection.

Don't know if this helps much but what I could find FYI. Both builds have Aeromotive regulators with a gauge. Pressures set per the Ford instructions at the regulator.

Good input. I also saw the two fuel components on my scanner screen, but no data. So you may have hit on it. We'll try CSCHWER's app and see if it shows anything. As I indicated originally, I have the gauge on the regulator, but you can't really monitor that in motion. This entire effort is a "nice to have" rather than a "must have".

[Alan_C]

I have had my BlueDriver since I built my MK4 10 years ago. For the $100 I paid online, worth every penny as I have used it on a half dozen cars for one reason or another.
I was excited about being able to see fuel pressure data from my Coyote, but then it looks like the Gen 2 Coyote does not have the sensors.
If you are mechanically inclined at all, having a BD scanner is a great investment for when the dash idiot light goes on in your car. Knowing what the code is that turned on the dash light is priceless when going into a dealer.

[Mastertech5]

I'm not a Ford guy but I was a GM tech for 35 years. As far as I know if your computer controls your fuel pressure by pulse width modulating your fuel pump (returnless system) then you should be able to read fuel pressure on a scan tool. These systems have a sensor so the ECM/PCM can modulate the fuel pump accordingly. If your have a fuel return then the pressure is regulated by the pressure regulator and there is no input to your computer for fuel pressure. If you have fuel data lines on your scan tool and no data for fuel pressure you are SOL. The earlier Coyotes may have the capability to show fuel pressure, I don't know, but without a sensor to measure it your scan tool won't show the data.

[Nigel Allen]

I'm not a Ford guy but I was a GM tech for 35 years. As far as I know if your computer controls your fuel pressure by pulse width modulating your fuel pump (returnless system) then you should be able to read fuel pressure on a scan tool. These systems have a sensor so the ECM/PCM can modulate the fuel pump accordingly. If your have a fuel return then the pressure is regulated by the pressure regulator and there is no input to your computer for fuel pressure. If you have fuel data lines on your scan tool and no data for fuel pressure you are SOL. The earlier Coyotes may have the capability to show fuel pressure, I don't know, but without a sensor to measure it your scan tool won't show the data.

On the Coyote crate engines, the ECM controls a relay for the fuel pump, there is no PWM. Based on the earlier posts on this thread, only the gen3 show fuel pressure. I added a Speedhut fuel pressure gauge to the dash. I had the calibration checked by a friend in the avionics field and it was spot on. It works really well. The sensor is screwed into the gauge port on the pressure regulator. Top left gauge in the video below:


https://youtu.be/BYSfEz3WX8g

For those that might be interested: The Mallory pressure regulator is mounted on the firewall and supply and return fuel lines are standard as supplied with the kit. As can be seen in the video below, about 5-7psi is lost at full noise. Pump is Walbro 255 mounted in tank. Fuel filter is standard as supplied with kit.

For normal driving gauge always sits on 60psi as set. However if the tank goes below 1/4, the pressure will drop to around 35-40 on hard corners, heavy braking. This is probably something worth considering to avoid starving your engine.

All the best,

Nigel

[edwardb]

I'm not a Ford guy but I was a GM tech for 35 years. As far as I know if your computer controls your fuel pressure by pulse width modulating your fuel pump (returnless system) then you should be able to read fuel pressure on a scan tool. These systems have a sensor so the ECM/PCM can modulate the fuel pump accordingly. If your have a fuel return then the pressure is regulated by the pressure regulator and there is no input to your computer for fuel pressure. If you have fuel data lines on your scan tool and no data for fuel pressure you are SOL. The earlier Coyotes may have the capability to show fuel pressure, I don't know, but without a sensor to measure it your scan tool won't show the data.

To expand on what Nigel said, a Coyote in a Mustang with the stock PCM calibration does have a returnless style fuel system with a variable pressure pump. For the crate motor control pack from Ford Performance, they changed to a regular return style setup and run the fuel pump at full pressure all the time. Thinking about it a little more, it's possible the Gen 2 does have a pressure sensor on the fuel system, but it's just switched off in the crate motor calibration and thus doesn't show in the data stream. But again, just a guess. Might see data if scanning a stock Mustang setup.