One Sick Truck 2001 GMC Sierra 5.3l 175k

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#1
Make
GMC
Model
Sierra
Year
01
Miles
17500
Engine
5.3
2001 Sierra 5.3l with 175k trouble free miles.

I have a truck that doesn't want to run and is throwing a bunch of codes at me. I heard the fuel pump howling, and I figured it was the filter. Nope. I have swapped that pump twice how. This will be pump 3 unless you think its something else. And yes, I only use OEM pumps.

As for the brake light, I swapped out the wheel sensor a few years ago when that was in the only code it was throwing. Now, it shows it isn't picking up either of them. So, something else is wrong besides the wheel sensors. Would appreciate your thoughts. This has been a great truck. Would love to know what happened to it.

Codes...

C0281, co226, co222, co265, po101, po131, po151, po171, po174, po300, po420, po430
 

billr

wrench
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#2
Did these codes all pop up at once, or have you been accumulating them for a while?

First suggestion: use a gauge to check FP, and use a meter to check pump power, don't just keep throwing pumps at it.
 
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#3
A Plan get it running address drivability misfires, o2 sensors, and cat first. the C codes next.

you are aware the FP (fuel pump) will only run @2 seconds if engine does not start?
We can jump FP relay* to check the voltage and GROUND circuits at the pump.... OR lets look at fuel pressure, with a gauge.

* a simple "fused" jumper wire at relay
 

Attachments

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#4
Have you inspected the pump pick-up screen for clues of tank contamination?

"Howling pump"...some other restriction like a fuel pressure regulator? Other have mentioned pressure test...

Always putting in $5 gas when you hit "E"? Pump is much happier when totally immersed for cooling.

Electric motors don't last long if they run without adequate power. Crusty wires due to cracked insulation could effect longevity.
 

nickb2

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#5
I would do a quick erase of ALL codes. See which ones come back first. I rarely see misfire codes alongside a P0420 cat code. So that one will probably go away once you find out why you are burning FP.s .

Low fuel pressure will cause half the codes you got. The 171 and 174 are lean codes for both banks. Focus on why they are lean. I would not focus on the cat yet.
 

nickb2

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#7
The ground on these pickups likes to disintegrate. I think that ground is close to the rear bumper behind license plate. Maybe you don't have a good contact there and blowing OEM fuel pumps. But normally, when that ground goes, you truck just won't start. I don't know, but here a scope would shine.
 

nickb2

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#8
Afterthought, if you can, get a technician or buy a good scanner that can do a injector balance check. Also, do a exhaust back pressure test also.

That is quite easy to do on this type of truck. You could also use vac gauge for that also.

Here is a cool video from eric the car guy. As he adeptly says, the vacuum gauge is a wonderful tool, been around for years. Might also help you to find a vac leak, which I strongly suspect also seeing that bunch of codes.
 
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#9
You are going to love this. I go to do my fuel rail test. What do I find? The whole K and N assembly had come off the throttle body. Lol. I'll bet running without the mass airflow could cause it to run a little funny. Should be good for another 175k. I am thinking about pulling the ABS computer and going through the solder joints. Found it on YouTube. Fixed the wiper blades about 10 years ago same way. Wonderful age we are living in. Dude online makes it look easy from underneath. Uhm. No. Going to tilt the bed. Will let you know. Thanks again. Love this site.