Fuel Pump Relay issue...maybe?

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east302

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After talking to them again, they said they smelled gas up where the intake is where it attaches to the center of the motor. I'm not exactly sure what that is supposed to be. They said they didn't particularly rule out the fuel pump, but the fact that they smelled gas there made them think it might be the fuel pressure regulator or the "lines". Not sure exactly which lines those are, not the fuel lines though and he said they are plastic. I know I'm way over my head here, so any help is greatly appreciated...

One additional thought...Back in August, there was a little run where it would make this loud pop sound when starting occasionally. That went away and then Monday afternoon it did it again. But just the once. Not sure if that leans toward the fuel pressure regulator or just weird coincidence.
Without pulling the upper intake, they wouldn’t be able to see if it is the regulator leaking externally or if one of the plastic injector lines is leaking. Of the two, I’d suspect the regulator (silver thing in photo below) before the lines. It can be replaced independent of the entire injector assembly. Maybe $30 for the part?

It’s really not a bad job should you want to do it. The only required “special” tool that comes to mind is a 1/4” inch-pound torque wrench. I’m sure there are YouTube videos that would give you an idea of the process.

Old (original) style is shown below. These are typically replaced with an updated style (MPFI).

EC02F6E7-0E5A-4392-A4AC-9F70C640766C.jpeg
 
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doncaruana

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They quoted me $740 to do this!! Aren't shops supposed to charge "standard" hours for repairs (at least here in Michigan)? I just looked up R&R for a fuel pressure regulator (w/AC) on my truck and I got 2.7 hours from Mitchell. A brand new, full price OEM from GM fuel pressure regulator would cost $144. Even a "latest" AC Delco "OEM" would only be $55. Over $600 in labor...? Labor rates here are still in the ~$100 range, give or take. What in the world am I missing??

I definitely will consider doing that regulator myself!! (How to Replace Fuel Pressure Regulator 88-98 GMC K1500)

I'd absolutely love to convert to the MPFI, but that is farther over my head than I can even see!
(How to Install Multiport Fuel Injection Conversion 96-99 GMC K1500)
 
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east302

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$740 for the regulator or for the complete injector assembly? Sounds like the whole assembly - retail original style runs around $200 on RockAuto, so figure they’d charge $300-$400 for the part at a shop. Throw in labor, taxes and miscellaneous shop fees and you’re there.

Since you’re pulling the injectors out to get to the regulator, it makes sense to just swap in a whole new injector assembly (which comes with the regulator already installed).

Whether you then reinstall the old injectors or put in a new assembly (be it the old style or MPFI) makes no difference in the installation procedure. The MPFI comes with instructions on which way to position the lines so it’s pretty straightforward.
 
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doncaruana

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$740 for the regulator or for the complete injector assembly? Sounds like the whole assembly - retail original style runs around $200 on RockAuto, so figure they’d charge $300-$400 for the part at a shop. Throw in labor, taxes and miscellaneous shop fees and you’re there.

Since you’re pulling the injectors out to get to the regulator, it makes sense to just swap in a whole new injector assembly (which comes with the regulator already installed).

Whether you then reinstall the old injectors or put in a new assembly (be it the old style or MPFI) makes no difference in the installation procedure. The MPFI comes with instructions on which way to position the lines so it’s pretty straightforward.
That was *just* the regulator, which is why I was a little shocked. Doing the whole thing like you mentioned wouldn't be so bad.
 
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doncaruana

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Funny side note - place that did the ECM said if another shop does the work and fixes the problem, bring the truck back and they will put my original ECM back in and refund my money. Were it my company, I would offer to do the additional work for free, especially since at this point they just think it's replacing the fuel pump. Then again, I wouldn't have tried bilk a customer out of money above and beyond a pass through to program the ECM in the first place.
 
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doncaruana

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$740 for the regulator or for the complete injector assembly? Sounds like the whole assembly - retail original style runs around $200 on RockAuto, so figure they’d charge $300-$400 for the part at a shop. Throw in labor, taxes and miscellaneous shop fees and you’re there.

Since you’re pulling the injectors out to get to the regulator, it makes sense to just swap in a whole new injector assembly (which comes with the regulator already installed).

Whether you then reinstall the old injectors or put in a new assembly (be it the old style or MPFI) makes no difference in the installation procedure. The MPFI comes with instructions on which way to position the lines so it’s pretty straightforward.

I got the breakdown from them today. $135/hr for labor. Four hours just because ("well you have to take the intake manifold off" - who cares what the published hours are) - and then $200 for a $50 part. *sigh*
 
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doncaruana

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Being as I'm such a know-nothing, before I tackle anything, I'm curious about the thought that it's the fuel pressure regulator. I've been looking around at symptoms of a leaking fuel pressure regulator and I really don't have any of those symptoms. Of course adding to my frustration in all this is very clear "Fuel System Diagnosis" troubleshooting section in the service manual that walks through how to sort all this stuff out - instead of just randomly replacing stuff. Interestingly it also has this, where (shocked face) it mentions right there the check valve.

1679616812148.png

I found this out in the wild in comments on a youtube video...is this valid?? Because it seems like a damned simple and easy way to rule in/out a bunch of things.
1679617973604.png
 
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east302

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Yes, that’s the way you test a fuel pressure drop. Technically, you’d install shutoff valves on the return and supply lines at the fuel filter. GM provided a union on the return line for this purpose. After 20-something years of having these trucks, I’ve never looked to see if there are rubber lines in the fuel piping. Maybe there are but I’m always hesitant to clamp something like that shut in case it has some type of hard lining inside that could be damaged by doing so.

Starting with the supply, you’d remove the fuel filter, install the valve, pressurize the system and close the valve. If pressure held at the test port on the intake, you’d know it was the check valve in the pump.

If it dropped, you’d know that it was either an injector leaking or the regulator leaking either externally or back into the return line to the tank.

To test, you’d then switch the valve over to the return line where the threaded union is. Pressurize, close the valve and see if it drops. If it holds, then it’s the regulator leaking back into the return line. If it drops, it’s an injector.
 

jc98ss

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For what its worth, i wanted to come back and post that my starting issues have been fixed.....i replaced both the fuel pump and upgraded spider injector...

fires up first crank every time now, idles super smooth....fuel mileage increased
 

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