Calling All Tech-2 Owners - Fuel Pump Data

[swathdiver]

For those of you that can see your Fuel Pump Module, what are your Fuel Pump trims?

Mine started off at about 1.25 three years ago and is now at 1.54. Is this a sign of the pump's health? And if so, how high means it is time to replace?

 

[mikeyss]

I will try and see mine today. However, I have an emergency dentist appt this morning and don't know what all they will be doing to me.

 

[swathdiver]

I will try and see mine today. However, I have an emergency dentist appt this morning and don't know what all they will be doing to me.

Probably yank out some teeth! No, nowadays, they give you anti-biotics and pain meds and have you come back to pull or fix the tooth. Good luck my friend!

 

[Fless]

What are fuel pump trims? What do they indicate?

 

[mikeyss]

Probably yank out some teeth! No, nowadays, they give you anti-biotics and pain meds and have you come back to pull or fix the tooth. Good luck my friend!

Thanks, I think I'll need it, haha. My furthest back molar chipped almost a year ago, but I didn't get it checked because it didn't hurt, and I couldn't afford to spend 1 to 2 grand. Now that I have savings, I was hoping to ride this out. But last week the nerve woke up or something and my jaw even hurts to open

 

[thompsoj22]

For those of you that can see your Fuel Pump Module, what are your Fuel Pump trims?

Mine started off at about 1.25 three years ago and is now at 1.54. Is this a sign of the pump's health? And if so, how high means it is time to replace?[/QUO

Good project for a tech2 newbie like me, ill check mine after work and post the results.

 

[swathdiver]

What are fuel pump trims? What do they indicate?

Not really sure Steve. I'm speculating that they operate like the motor, adding or taking away pump power to meet the desired output. If the computer commands 33% so it delivers X amount of pressure or volume and 40% is required then that makes sense to me as I write it out here.

Thanks, I think I'll need it, haha. My furthest back molar chipped almost a year ago, but I didn't get it checked because it didn't hurt, and I couldn't afford to spend 1 to 2 grand. Now that I have savings, I was hoping to ride this out. But last week the nerve woke up or something and my jaw even hurts to open

Have a friend yank it out = FREE
Let the doctor pull it out = $200-300
Root Canal = $2000

 

[gooffeyguy]

For those of you that can see your Fuel Pump Module, what are your Fuel Pump trims?

Mine started off at about 1.25 three years ago and is now at 1.54. Is this a sign of the pump's health? And if so, how high means it is time to replace?

Where would this be found in the Tech2?

I'm off today (holiday), and don't plan on going anywhere, but I can get a reading later with it idling in the garage.

I know years ago, at least on my 5.0 mustang, it used a fuel pressure regulator that operated via vacuum. Then on the 4.6 mustang like my wife's, it uses a FPDM modual to raise/lower fuel pump voltage to increase/decrease pressure as the motor needed it.

2001 Yukon SLT
2012 Yukon Denali XL
2011 Yukon Denali RIP 5/20/18

 

[swathdiver]

Where would this be found in the Tech2?

On mine it's in the Engine Control Module and in there it has its own heading, under the engine and above the Transfer Case and Transmission. My brain cannot remember the exact terms used right now.

 

[Doubeleive]

hmm, interesting, I will have to check mine I have had suspicion that some of my poor fuel mileage has to do with low fuel pressure, my fuel pressure runs at 45 with the engine running which seems to be the bare minimum required. I see some reporting 50-55 but mostly on the nbs's, the fuel pumps on the nbs's are rated for 100k the dealer told me the nnbs pumps go farther but i never got a official rating. mine has 125k on it as far as I know.
pre-start mine will be 65lbs
running it is only 45lbs

 

[gooffeyguy]

the original fuel pump on my 2001 went out about 2-3 years ago around 170k

 

[swathdiver]

hmm, interesting, I will have to check mine I have had suspicion that some of my poor fuel mileage has to do with low fuel pressure, my fuel pressure runs at 45 with the engine running which seems to be the bare minimum required.

Mine has always been commanded to 43.5 psi. At WOT it has dropped to 42 psi for a moment and then catches back up.

 

[Doubeleive]

Mine has always been commanded to 43.5 psi. At WOT it has dropped to 42 psi for a moment and then catches back up.

interesting I thought 45 was the minimum, have you checked what it say's in the service manual?

 

[swathdiver]

interesting I thought 45 was the minimum, have you checked what it say's in the service manual?

Yep, 43.5 psi.

 

[gooffeyguy]

@swathdiver
Here's mine, idling in the driveway with the AC on

2001 Yukon SLT
2012 Yukon Denali XL
2011 Yukon Denali RIP 5/20/18

 

[swathdiver]

Bump, last time I checked mine was 1.47

 

[2007 Denali XL]

About to swap my pump, 146k miles and pressure is whacky, slow pre start press build up to 63 and then after start flickering between 63 and 55.

anyone put an aux inline fuel pump on as a mod?

 

[swathdiver]

About to swap my pump, 146k miles and pressure is whacky, slow pre start press build up to 63 and then after start flickering between 63 and 55.

anyone put an aux inline fuel pump on as a mod?

Only the racing trucks, see Randy's build page. @randeez