2000 Silverado 5.3 fuel pressure issues

LBcustoms

Original poster
Member
Jul 23, 2019
2
Louisville, KY
As the title states, I’m having some minor fuel pressure issues. My idle pressure is 40-45 psi, if I bump the throttle it will jump to around 50 psi. If I remove the vacuum elbow from the fuel pressure regulator the pressure will go up to 55 psi and stay with minimal fluctuation from throttle activity. I have a new fuel filter on the way and was wondering if anyone has some helpful input with this issue and if I could need a new fuel pump and/or regulator. Also, a little more info on the problem, it has a slight miss at idle and at light throttle. The cel comes on occasionally giving a lean reading. Current cel’s are
P0171
P0174
P0449
P0327

I attached before and after pictures of my truck from stock to 2 inch lowering shackles and wheels since this is my first post

Thank you in advance!
 

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mrrsm

Lifetime VIP Donor
Supporting Donor
Member
Oct 22, 2015
7,640
Tampa Bay Area
Welcome to GMT Nation… It’s Nice to see Another Owner of a “Y2K” Vintage Chevrolet Silverado 1500 Full Size Truck… Like Mine:

Best Thing To Do ...Right Off The Bat:

Visit THIS Link and select the “Full Size Truck” choice to Download a Complete GM OEM Digital Shop Service Manual for your Truck that is Very Hard To Find anywhere else and which will become Indispensable for Professional Grade Diagnostics and Repairs down the road:

https://gmtnation.com/forums/threads/full-size-service-manuals.19079/

You should be able to locate and compare your Fuel Pressure Findings under the “Engine Section” sub-categories and look for a “Diagnostic Tree” that can provide you with what the Nominal Fuel Pressure Conditions should be under varying RPM.

For the P0171 and P0174 Codes… Visit THIS Link:

https://www.silveradosierra.com/vortec-5-3l-v8/engine-code-p0171-p0174-t18097.html

For the P0327… Check out Ron Williams’ Video for the On Topic (albeit… Filmed “sideways”) but still containing what you need to know about what happens when the “Two Knock Sensors” Go Sideways...and Drown:


Another one on the Dreaded P0327 “Knock Sensor” Issue by Brian from "Briansmobile1" YouTube Channel that is just as Good for the “How To Do...” Information:


And from the “Fear No Fix” Boys… Here is How to Easily Solve the P0446 EVAP Trouble Code:

 
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LBcustoms

Original poster
Member
Jul 23, 2019
2
Louisville, KY
Thank you so much for the reply MRRSM! As soon as I get back to the house I’ll get on the computer and download the manual. I have a btr stage 4 camshaft to install soon, so I will get to the knock sensors then, but I have also heard that I will need to delete the knock sensors in a tune with the camshaft. Hopefully I can get everything straightened out soon.
 

mrrsm

Lifetime VIP Donor
Supporting Donor
Member
Oct 22, 2015
7,640
Tampa Bay Area
This is (...I Hope...) MORE Good News in that I TOTALLY FORGOT to mention another possible component that can go sideways on the Y2K 5.3L Engine and that is: The Fuel Pressure Regulator. Check out this First Video for What it is... Where it is... and How to Repair it by performing a Very Simple R&R:


And... WOW… That choice of BTR Stage 4 Cam is a Pretty BIG Bump Stick that will not only require a “Custom HP Tuners Tune” ...but also require a much Higher Stall Torque Converter just to make the Truck even vaguely Driveable on Surface Streets. Unless you have already purchased such an aggressive Camshaft Kit… You might want to reconsider after dropping in on my current (and much more modest) TSP Stage 2 212/218 112 LSA .550”/.550” Cam Kit, S/S Headers and S/S CAT-back Exhaust Project.

https://gmtnation.com/forums/threads/hoping-for-loping.18519/

The second link involves my becoming heavily invested in all of the requisite HP-Tuners SW & HW and an Expensive HPT Training Package from “The Tuning School” down here in Florida to be able to eventually perform my own tunes as well.

https://gmtnation.com/forums/thread...s-y2k-silverado-lm7-tsp-peformance-cam.19999/

Whenever I'm working on Complex Mechanical Projects… I tend to be as comprehensive as possible in covering all the details… so these can’t be considered “Light Reading”. Of course, I could be completely missing the possibility that you yourself are already an Accomplished “Tuner” and if that turns out to be the case… Please contribute your comments and images of your work when things get going either on my Threads… or by all means… Start some New Ones!

If not...and you are just now getting into the "Tuning" side of The Build... I would urge that your "Knock Sensor Delete" be only a very temporary thing...lest you accidentally run Way Too Lean ...say 17:1 at Much Higher RPM and do some serious damage to your engine. For the first few tests ... KS Deletion should only be done for the initial problems related to Starting and Idle problems...then perhaps after the initial tune is added... a little local driving at very low speeds to figure things out. You DEFINITELY need an AEM Wide Band Oxygen Sensor and Gauge Kit installed.... to WARN you before you get Way Too Lean!

Some Videos covering the Topic of Installing Higher Stall Torque Converters:



Here are some related articles that may prove interesting to your present “Tuning” situation:

http://www.silveradoss.com/forums/topic/89787-btr-truck-cam-stage-4/

http://www.masterenginetuner.com/ls-big-cam-idle.html

https://www.onallcylinders.com/2018...ormance-bore-stroke-cylinder-heads-cam-specs/
 
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