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2000 Silverado Z71 4x4 5.3L 460k+ miles w/ GM rebuilt motor and trans
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Discussion Starter · #1 ·
Well, guys, I'm back. This time I don't think it's a fuel pump, but I could be wrong. I've been wrong before. I just hope not, since this one is less than 6mo old...

2000 Silverado Z71 4WD w/ 5.3L and ~470k miles suddenly throwing near half of every O2 sensor code known to man and a fuel pump related code I've never had before.

P0134 O2 Sensor - No activity (Bank 1 Sensor 1)
P0135 O2 Sensor - Heater Circuit Malfunction (Bank 1 Sensor 1)
P0141 O2 Sensor - Heater Circuit Malfunction (Bank 1 Sensor 2)
P0160 O2 Sensor - No activity (Bank 2 Sensor 2)
P0230 Fuel Pump Primary Circuit Malfunction
P0300 Random/Multiple Cylinder Misfire
P0332 Knock Sensor 2
P1133 HO2S Insufficient Switching (Bank 1 Sensor 1)
P0160P O2 Sensor - No activity (Bank 2 Sensor 2) Pending(?)
P1133P HO2S Insufficient Switching (Bank 1 Sensor 1) Pending(?)

The only code I have known about is the P0332 Knock Sensor 2. I haven't gotten around to pulling the intake to replace them. Other things keep breaking and taking precedent on the Suburban. Everything else is new. Even with previous bad fuel pumps, I have not gotten the P0230, so I'm not sure what to do about that one.

I pulled these codes, cleared them, and drove the truck around for a few hours running errands. Ran great. Idled great. No CEL . Wonderful! Magic and it's fixed... Or not.

About a mile from the house on the way back, the truck started to stumble and stutter (noticeable deceleration during misses of varying duration). I pulled the codes triggered during my errands and these are the ones I got.

P0160 See above
P0134P See above, but pending
P0160P See above
P1133P See above

I do not know my current fuel pressure or injector leak status. I will be digging around for a gauge this weekend to test all that. Will probably finally buy my own if I can't find dad's old one floating around. The truck is still drivable, but now much less reliable crossing traffic. I will be parking it as much as possible until I get this all straightened out.

So, my questions are as follows:

1. Could a[nother] faulty fuel pump cause all of these failures?
2. Could something else related to fuel cause all the O2 sensors to go at one time?
3. Should I just start replacing the O2 sensors?
4. Do I need to accelerate my attacking the Knock Sensors?
5. Should I just throw my hands up and take it to my mechanic?

Thanks in advance for the input.
 

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your code P0230 is a fuel pump relay control circuit . now because your truck is over 300K miles you have to replace the fuel pump relay and check for the voltage at the relay and the pins on the relay. another issue is you have to inspect the PCM connector pins for corrosion or wiring chaffing .. the PCM is in front of the driver side of the engine so that will cause a load of water on it ...
you other issue is the KS sensor will have water damage .. you have to replace both KS sensors buy the kit repair.
GM did a lousy job on the seal on the front of the upper intake manifold then water blows in ... many years ago I put a sealer over that nasty seal so no water gets under the upper intake manifold and damages the KS sensors ..KS is in a pit hole then water locks up in the KS spot...................
 

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2000 Silverado Z71 4x4 5.3L 460k+ miles w/ GM rebuilt motor and trans
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Discussion Starter · #3 ·
your code P0230 is a fuel pump relay control circuit . now because your truck is over 300K miles you have to replace the fuel pump relay and check for the voltage at the relay and the pins on the relay.
Pump relay control circuit...so the circuit from the brains telling the relay to kick. OK. Time to dig out a wiring diagram and pull the fuse box again...
another issue is you have to inspect the PCM connector pins for corrosion or wiring chaffing .. the PCM is in front of the driver side of the engine so that will cause a load of water on it ...
This makes some sense. I had the PCM out when I did repairs in that area for battery acid corrosion from a failed battery. I wonder if some of that acid didn't get into the wiring or I messed something up when I was in there. I'll look at that closely. I still haven't gotten everything in there completely put back together.
you other issue is the KS sensor will have water damage .. you have to replace both KS sensors buy the kit repair.
Yeah... I'm not looking forward to this job.
GM did a lousy job on the seal on the front of the upper intake manifold then water blows in ... many years ago I put a sealer over that nasty seal so no water gets under the upper intake manifold and damages the KS sensors ..KS is in a pit hole then water locks up in the KS spot...................
Do you happen to have a picture showing the exact location you are describing? I can post a picture of the engine bay, if needed.
 

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so go to a youtube video on your truck .....to replace the upper intake manifold gaskets .. yes GM created a gasket that does not handle alcohol fuels then these factory 2000 5.3L engines have spider cracks ..youtube videos are a great instruction on the gaskets and the fix of the KS sensors.... gas lines / injector connectors a PITA .. tricky..
the TB studs removed make it easier to lift up the upper intake manifold ..be careful on removing the hoses on the plastic manifold ports ...
 

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so go to a youtube video on your truck .....to replace the upper intake manifold gaskets .. yes GM created a gasket that does not handle alcohol fuels then these factory 2000 5.3L engines have spider cracks ..youtube videos are a great instruction on the gaskets and the fix of the KS sensors.... gas lines / injector connectors a PITA .. tricky..
the TB studs removed make it easier to lift up the upper intake manifold ..be careful on removing the hoses on the plastic manifold ports ...
vidoe for 2003 5.3L .. he is a great instructor ...
 

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‘01 Silverado 2500HD 8.1/Allison 5sp xcab long bed
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Jacob, I bought a brand new Bosch pump only without the sending unit. Put it in my ‘95 because the three year old Delhi was only delivering about 6psi. Stupid Bosch only lasted three days!

So frustrating. I ended up buying a Delco Vortec pump. Never looked back. She delivered a solid 13psi from that moment forward.
 

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Looks like you have a power distribution and control signal issues.
1. Missing fuel pump relay coil control voltage.
2. O2 sensor heater circuits
3. O2 sensor signal circuits

I'll work on the fp relay and fuel pressure first.
-Pull the fp relay.
-Put a fuel pressure gauge on the rail.
-Put a jumper on fp relay socket at terminals 30 and 87. Fuel pump shd run. If you have a DC clamp meter, better, for measuring current draw.
-Check fuel pressure. Don't run it too long. Report.

Then you can move to O2 sensor heater circuits next.
 

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2000 Silverado Z71 4x4 5.3L 460k+ miles w/ GM rebuilt motor and trans
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Discussion Starter · #8 ·
Thanks for all the info, folks. The wife's birthday was today and one of the kids is sick, so no diagnostic work on the truck, yet. I'll try to dig into it in the morning and see what I can come up with. I will return with details...eventually.
 

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Jacob, enjoy the day with the wife and hope your kid feels better.
 
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Discussion Starter · #10 ·
Jacob, I bought a brand new Bosch pump only without the sending unit. Put it in my ‘95 because the three year old Delhi was only delivering about 6psi. Stupid Bosch only lasted three days!

So frustrating. I ended up buying a Delco Vortec pump. Never looked back. She delivered a solid 13psi from that moment forward.
I'm on my 4th pump in 10 years. This new one is AC Delco, the whole assembly. I'm hoping jcat is right and it's just the control circuit...
 

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Discussion Starter · #11 ·
Looks like you have a power distribution and control signal issues.
1. Missing fuel pump relay coil control voltage.
2. O2 sensor heater circuits
3. O2 sensor signal circuits

I'll work on the fp relay and fuel pressure first.
-Pull the fp relay.
-Put a fuel pressure gauge on the rail.
-Put a jumper on fp relay socket at terminals 30 and 87. Fuel pump shd run. If you have a DC clamp meter, better, for measuring current draw.
-Check fuel pressure. Don't run it too long. Report.

Then you can move to O2 sensor heater circuits next.
I do not have a clamp meter. Guess that's my next "miscellaneous money" list item. Wonder if I can roll it into "automotive"... 🤔😁
 

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Discussion Starter · #13 ·
Update 2/7

Tested and checked the fuel pump relay. All voltages good (12.1 +/-) and functions as normal. Priming controls of the fuel pump working as normal (on 2s, cut off). Have not tested running. Will do next.

Pulled the PCM and checked all pins. Clean as a whistle.

Trying to get in touch with my courrier to bring me a fuel pressure test kit. The unit I have here is for oil and transmission fluid pressure. I don't have the fittings to make it work.
 

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Thought you're taking a break to celebrate the Mrs bday.
You don't want to piss her off or you'll never hear the end of it.
Haha.
 
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Discussion Starter · #15 ·
Thought you're taking a break to celebrate the Mrs bday.
You don't want to piss her off or you'll never hear the end of it.
Haha.
Oh, that was yesterday. I was updating posts while you old guys were sleeping. 🤣
 

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‘01 Silverado 2500HD 8.1/Allison 5sp xcab long bed
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I resemble that remark!
 
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engine on ,,, voltage at the fuel pump relay 12.1 volts .. should be 13.5 volts ..
check all the fuse voltages engine on should be over 12 volts .. clean up the battery/alternator connections and ground straps connections clean it up...
 

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Discussion Starter · #18 · (Edited)
should be 13.5 volts
Oh, boy...here goes nothing.

Edit: Forgot to mention this was with the engine OFF. Will advise of running voltage when battery reconnected.

Edit 2: 14.5V at relay pin for fuel pump circuit. Holding steady.
 

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Discussion Starter · #20 ·
Should the fuel pump relay get hot?
 
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