Pump interchange?

[Phantom240]

Long story short, a friend of mine with an NBS Silverado has a brand new fuel pump he doesn't need, and I was wondering if there would be a way to make it work on my OBS Denali... I see the pumps are different from one another, looking at Autozone's website, but I was thinking maybe butcher the two assemblies, and try ti swap out the sending unit from his onto my assembly, or something like that. Has anyone tried to do something like this before?

 

[_Dylan_]

why?

 

[Phantom240]

Because I'm fairly certain my sending unit is no good

 

[SunlitComet]

you have a 1999 unit the sending unit does not report directly to the fuel level gauge there is a middle man in play. and no it may not be used. how about changing the thread for a new problem diagnosis. i will start.

what is wrong with you fuel level indicating system that you suspect something is wrong with the sender unit?

 

[Phantom240]

Because my gauge always reads empty. I know the gauge may be bad, but you've seen what it does when I turn the key to the run position. The gauge moves, so I know it's not 100% dead, so provided the PCM is getting a signal, and that signal is making it's way to the gauge, it should at the very least hummingbird. If the PCM gets no signal, then the sending unit is bad. If the PCM gets a signal, but the signal doesn't make it's way to the gauge, it's either faulty wiring or a faulty PCM. If the signal gets to the gauge but it still reads empty, then it's the gauge. I'm hooking it up to a Snap-On scanner on Saturday at my friend's shop, to scan for some other unrelated problems, but should I be able to see what the actual readout is on the sender, using that tool? Also, isn't there some sort of onboard diagnostic for checking operation of the cluster?

Now, if I recall correctly, I should read 40ohms at empty (probing harness between sender and PCM), and 250 at full. If I read a direct short, it's got to be a short to chassis. If I'm reading open circuit, it's likely a bad sender, but I'll have to check the connector to make sure it isn't toast.

 

[SunlitComet]

something like that but look closer at your system. you sender does no go from gauge to sender to chassis ground voltage wise. here is some stuff to help you out. as far as dtc there are ones as it relates to evap pressure and stuff. but ohter the procedure below i am am not aware of any dtc codes related to a screwy level sender except as related to emissions concerns.


Fuel Gauge Inaccurate or Inoperative Fuel Gauge Inaccurate or Inoperative

Diagnostic Aids

• Verify that the fuel level is in the same range as the customer concern.
• Use the fuel level sensor resistance in order to verify the fuel level sensor operation. When the fuel tank is empty, the fuel level sensor resistance is approximately 40 ohms. When the fuel tank is full the fuel level sensor resistance is approximately 250 ohms.

Test Description

The number below refers to the step number on the diagnostic table.

22. DTCs will set in the PCM when you perform this diagnostic table.

 

[Phantom240]

Wait, what's this about a primary and secondary level sensor?

 

[SunlitComet]

i bet that made your heart skip a beat. dont worry about secondary. this procedure covers vehicles with single and dual fuel tanks from the same general gmt400 platform of the same year.