Another 454 Vortec Build Thread - Documenting, Q&A, Help

[Supercharged111]

"Yeah, I'm going to have to go ahead and disagree with ya there..."

1998 c/k factory service manual:

If that's for me, you really need to take a closer look at what you and I have posted.

 

[Scottm]

Ok, I am trying to understand. You said this:

One is for the pump the other is for a fuel tank pressure sensor. It's a MAP sensor basically, part of the evap system. As far as I know 2500/3500 trucks never used that sensor.

I posted page from the 98 c/k service manual, showing the ftp circuit on the 7.4L engine, so it has to be a 2500/3500.

Edit - I see the top of the page that said 7.4l was cut off, sorry.

 

[Scottm]

Here is the full page. FPS started in 98. And I don't know if this is relevant to what you were saying.

 

[Caman96]

@Supercharged111 back in the Awesome column.

 

[Supercharged111]

Here is the full page. FPS started in 98. And I don't know if this is relevant to what you were saying.

I believe it started mid 97, basically once the plastic fuel bucket was introduced. But you kept calling it a fuel pressure sensor and it's not that at all. It monitors the atmospheric pressure inside the tank. My 1500 has it, but a 99 454 dually I scrapped did not have it. When I stole that fuel sender for my 1500 I had to drill a hole to use the MAP sensor from my old sender as I wanted to keep the evap system happy.

 

[Caman96]

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1998 CHEVROLET K2500 PICKUP 7.4L V8 Fuel Tank Pressure Sensor | RockAuto

RockAuto ships auto parts and body parts from over 300 manufacturers to customers' doors worldwide, all at warehouse prices. Easy to use parts catalog.

www.rockauto.com

 

[Scottm]

Ok I see, yes I was trying to say fuel tank pressure sensor, which is what I though OP was asking about.

 

[Carlaisle]

@Bachert24 it is entirely possible the fuel pump currently present is not the original.

@Scottm the stock rail/pump/FPR holds pressure very well. You might see it drop 1 psi/minute after you turn the key off. That's not a manufacturer spec - just what I have observed. It drops, and if you watch closely you can see it drop, but it is a slow drop.

 

[Spareparts]

Here is what i would do.
Hook up a fuel pressure gauge. Pinch off the return line under the driver's door inside the frame rail. Turn the key on and if the pressure jumps over 80PSI, your pump is probably ok.
If the fuel pump can build that pressure then you have a bad/wrong FPR. The bleeding off of pressure is probably leaky injectors.
It seems like a real PITA to get to the FPR but really it's not that bad. I had my upper intake off so many times i could do the job im under 45 minutes.
If i remember right this one is said to work. I just can't remember if thats the one i used or an adjustable one.

More Information for DELPHI FP10021

Also from what i remember, The California emission equipped trucks will have the fuel tank pressure sensor. Federal emission trucks will not have that.

 

[Bachert24]

Here is what i would do.
Hook up a fuel pressure gauge. Pinch off the return line under the driver's door inside the frame rail. Turn the key on and if the pressure jumps over 80PSI, your pump is probably ok.
If the fuel pump can build that pressure then you have a bad/wrong FPR. The bleeding off of pressure is probably leaky injectors.
It seems like a real PITA to get to the FPR but really it's not that bad. I had my upper intake off so many times i could do the job im under 45 minutes.
If i remember right this one is said to work. I just can't remember if thats the one i used or an adjustable one.

More Information for DELPHI FP10021

Also from what i remember, The California emission equipped trucks will have the fuel tank pressure sensor. Federal emission trucks will not have that.

Strangely it doesn’t have the AIR setup on the manifolds. Based off this pic I’m feeling like I need to just replace the fuel pump, FPR, Injectors, and manifold gaskets. I know it’s crazy to just throw money at it, BUT, I’m the type who likes to replace EVERYTHING. Simply because I’m looking for longevity. I won’t replace low failure rate items but remember I’m doing heads and cam next year. Oil pressure gauge isn’t working so thinking oil pressure sensor should be replaced.