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What all sensors on a 5.3 effect the way it runs? (Narrowed it down)

shady

shady

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I'm trying to compile a list of sensors to change on my boys 05 burb.
It has 185k so I figure a quick round of sensors isn't a bad idea.
It also has a problem we can't seem to identify. It randomly goes into reduced power mode for one. Already replaced the throttle body and pigtail leading to it. We also plan on replacing the pedal position sensor to help with that.

But it has another issue of randomly going into a real bad idle/barely running mode. I have a crappy code reader and plan on coding it again today.

What I'd like to do though is give him an early Christmas present and replace a bunch of small parts that affect running.

I know about the O2, map/maf, and we just changed the purge canister solenoid. .... But what other ones are there.?
 
They will do limp mode based off temp. Is it getting hot?
 
Not that we know of. It was hot a little while back because his water pump went out and he lost all his fluid. But it's been doing it since before that, and will do it at any point in the day... Including right after start up.
Sometimes he can go a few days without it happening. But then it may do it non stop to the point of being undrivable for a few days also.
I already planned on getting him plugs/wires if it has them. But decided to add operational sensors to the list lol.

I coded it once before it did the bad running thing. When it was just the reduced power mode. That code ended up leading us to the TPS, so we just changed the entire throttle body. It did run good for a while after that.
Then the reduced power came back. And after a while of that, it started running/ideling bad too.
 
Forgot to put in that last post that after it started running bad he coded it at o'rileys and it came up with an emisions system issue. Somehow through his own research it led him to the purge canister solenoid.

That was when I decided fuggit, we were replacing the sensors too lol. He's hauling my new granddaughter around and it's going into winter.
I just don't know how many or what all ones there are :dunno:
 
If they’ve got a crank or cam sensor replace those. IAT, coolant temp, oil temp, oil psi. Anything can affect how they run. Fuel pressure. Knock sensors.
 
See I didn't think like the oil pressure one would affect how it ran... I figured it was just an indication..:dunno:

I know when I started replacing the sensors on my 88 TBI there were a bunch more than I would have guessed. But some vehicles have some that others don't.
 
Technicaly all the sensors would affect it. I keep a cam and crank sensor in my trail kit.
 
I found the
Cam position
Knock
Crank position
Up and down stream O2
Oil pressure
Coolant temp

So far.
 
shady said:
I found the
Cam position
Knock
Crank position
Up and down stream O2
Oil pressure
Coolant temp

So far.
Click to expand...

IAT is in the MAF. Maf probably wont cause this issue. You can unplug the MAF and the engine will just run in open loop on speed density tune.

Assuming this is drive by wire? The throttle pedal actually has 3 circuits in it for safety redundancy and feeds the TAC module. That module then sends signal to the PCM. The failure of one sensor will store a trouble code in the ECM and the system will continue to operate normally. Failure of two sensors will result in reduced power, while an unlikely failure of all sensors, may command a complete engine shut down. I highly doubt you have a failure in the throttle system without knowing it. They are super robust. Also throttle pedals and Tac modules are paired. Only certain part numbers work with each other so don't just go replacing one or the other without being sure.


The intermittent nature of this leads me to wiring issue. somewhere there is probably a bad ground or wire that is damaged.

A $10 bluetooth OBD2 adapter and $5 app will give you all the positions and readouts of these sensors as well as pull codes if you wanted to check it before tossing money at sensors.
 
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? Yeah I'd do the adapter and app.... How/where do I find that?
 
I was just planning on replacing the sensors as a preventative maintenance measure.
 
shady said:
? Yeah I'd do the adapter and app.... How/where do I find that?
Click to expand...

Do you have an android or iphone? The app I use is called Torque Pro. You can use any bluetooth or wifi adapter for android, Iphone needs to be a wifi adapter. I have this one
 
Cam or crank sensors won't cause reduced power mode. That mode comes squarely down to the throttle control system. As Treefarm indicated there are multiple circuits for redundancy. If they don't agree on tps1 and tps2 or app1 or app2 (accelerator pedal position) it's going into reduced power mode and killing power to the throttle body motor. The codes will indicate if it's a tps issue or app issue or a wiring issue in-between. Issues in the TAC system won't cause the engine to stall, just go to an idle.

I've seen the issues go both ways at the shop. I will say a dirty throttle body can cause it too. If the motor command is to a certain position and does not get to it in the right amount of time it will assume there is an issue and throw it into reduced power. Typically in that case it would set TPS codes.

As far as the rest of the sensors go I'm not sure other than O2 sensors, there isn't much to wear out. Cam and crank sensors are magnetic pickup units, no moving parts. Keep this in mind, you can loose the cam sensor and it would still run. It takes longer to crank so it can find #1 to start the fuel and spark, but it will start. Loose a Crank sensor and it won't start at all. The MAF sensor can and will get dirty over time, but it won't cause a reduced power issue. Coolant temp, intake air temp sensors won't cause any driveability issues other than potentially using more fuel if it assumes it's too cold and the engine isn't warming up.

After you pull codes if you need any of the GM diagnostic info hit me up and I can shoot them to you.
 
PCV valve can get dirty and goof with the idle. Mine would go from being unable to idle or power would just cut out. Found lots of carbon and oil in the pcv and after cleaning it, was like a new vehicle.
 
That's a good next step...:thinking:. when we replaced the throttle body the old one was real filthy. Sonic can imagine the pcv could be too.

I worked in the shop too long today and forgot to grab the code reader for him. :doah:
 
What about the intake manifold gaskets? May not be the whole problem, but a factor?

Just witnessed a Tahoe not start with the MAF unplugged, we had the intake out. Plugged one into it, but it wasn't in the air stream to the throttle body. Ran for a minute, then died out. Have an Escalade that had driveability problems until we swapped out the MAF out of curiosity. I don't remember what codes it was showing, I remember that it had a stumble on throttle application as one symptom.
I don't know if these two cases are normal.
I have no clue if this could be contributing to your son's problem.
 
I feel like an ass for it really. That's why I want to just replace a bunch of sh1t that aren't hard parts.

I know this motor is good for 250k+ and most of the rest of the truck hard parts wise is too.
That's why I bought it for him. I knew it was a good solid platform to last a while with a little maintenance. It was 4x4, Chevy tough, and big enough for his new family.
I bought it out of life insurance from my dad passing, and told him it was grandpa's last present......
And it has consistently ran like ass with different problems ever since :doah::notworthy:

Hence why I just want to replace a bunch off odd parts that help it run good. If I fix this problem with one of these sensors, then it does it again when the next sensor fails and they are 60 miles from home in the middle of January with the baby, I'd feel even more like an ass.
I figure a $500-600 pile of run good/reliability parts will make a nice Christmas gift.

Tomorrow afternoon if we can get it to the shop, I want to clean, retighten, and coat a couple different grounds.

Then start replacing parts with most important and then down the list of.
 
Rather than spending a couple hundred bucks on a whole new set of sensors for the engine, I'd personally get onto Amazon and buy one of these cheap vxdiag GM dongles. They come with a copy of GDS for newer vehicles installed on a windows 7 virtual machine that resets itself each time you shut it down to reset the timer on the software. They also come with a cracked tech2win installer which gives you a nearly fully functional virtual Tech 2 (no SPS) which you can use to see why the engine is going into reduced engine power mode. You can use their dongle to reprogram modules using SPS on TIS2WEB with a paid subscription which is actually fairly reasonably priced as well.

Tech2win and tis2web both require a 32 bit windows operating system. If your laptop is 64 bit you can always make a 32 bit virtual machine to install tech2win onto. I personally have a 7" 32 bit windows 10 tablet and one of these vxdiag dongles that I leave in the center console of my truck with tech2win and the gds virtual machine on it so I can scan any one of my vehicles with it whenever I need it. I also have a windows 10 32 bit netbook with the virtual machine on it that I use in my garage for a bigger screen as well. I rarely pull out my handheld tech 2 anymore.

The freeze frame data from tech2win's tech 2 emulator will show you exactly what reading was out of range or what wasn't communicating when the event occurred. Then you can fix the problem after you've positively identified it instead of shotgunning parts at it and hoping you happen to fix the problem (which likey will not be a sensor issue at all).

https://www.amazon.com/VXDIAG-Tech2...uPWNsaWNrUmVkaXJlY3QmZG9Ob3RMb2dDbGljaz10cnVl

The other tool you might want to consider buying is a USB based oscilloscope with a recording function. You can use it to verify that various sensors are producing a clean signal for the ECM to read such as square waves from the crank, cam and MAF sensors or clean variable 0-5V sensor signals from the MAP, APP or HO2 sensors.

https://www.amazon.com/Automotive-D...ywords=oscilloscope+usb&qid=1603674442&sr=8-8

The final useful tool is a quality multimeter which can read the resistance of temperature sensors like your IAT and CT.

This stuff can all be had under $200 shipped prime which is far cheaper than just replacing all the sensors.
 
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