Silverado, low fuel pressure?
Moderator: Team
Re: Silverado, low fuel pressure?
If it has theintake "spider" then the fuel pressure is to low. The vortec uses much higher pressure. Don't overlook the filter either.
Re: Silverado, low fuel pressure?
No spider, it's an LS V8 Vortec, I believe normal running fuel pressure is 50 psi... Recent Wix filter and new fuel lines...I personally pulled the injectors and tried a set from my other truck that has no issues...But it didn't make any difference...
i have been told a "crank sensor relearn' might be the answer...
Motorcycle land speed racing... wearing animal hides and clinging to vibrating oily machines propelled by fire
Re: Silverado, low fuel pressure?
I have ran into the same issues with the misfire and fuel pressure. My money would be on it needs a fuel pump even though it is 45psi (seems like enough) is not enough.
Mitch
Mitch
-
- Pro
- Posts: 482
- Joined: Tue May 06, 2008 9:59 pm
- Location: kansas city mo
Re: Silverado, low fuel pressure?
I would look at the long-term fuel trim table. There are all kinds of things that will set that code. Vacuum leaks dripping injectors ignition problems Etc.Truckedup wrote: ↑Thu May 03, 2018 9:08 amSo what you are saying is PO300 is related to ignition issues or a mechanical problem more than actual fuel issues? I know how modern engine management works..but I'm from the thinking that if the engine pulls well under load and idles smooth, the ignition is doing it's job and the mechanical stuff must be ok.......gnicholson wrote: ↑Thu May 03, 2018 8:53 am The guy above is correct that it will set lean codes long before it will misfire from being to lean.
Re: Silverado, low fuel pressure?
Gm vehicles almost always set a generic p0300. Use a scan tool to determine which cylinder or cylinders are causing the code. I am a GM tech. I work on these daily.
Re: Silverado, low fuel pressure?
P0300 is a generic misfire code. You need a scan tool with a misfire counter or graph to see what cylinder is causing your issue. Then go from there with basic checks like spark, fuel and compression. Ive seen injectors, plugs, valve springs, cams, lifters, intake gasket leaks and piston/ring issues all cause misfires on these engines.Truckedup wrote: ↑Thu May 03, 2018 9:08 amSo what you are saying is PO300 is related to ignition issues or a mechanical problem more than actual fuel issues? I know how modern engine management works..but I'm from the thinking that if the engine pulls well under load and idles smooth, the ignition is doing it's job and the mechanical stuff must be ok.......gnicholson wrote: ↑Thu May 03, 2018 8:53 am The guy above is correct that it will set lean codes long before it will misfire from being to lean.
Re: Silverado, low fuel pressure?
IF the motor doesn't have a noticable misfire then it probably has a buildup on the crank sensor wheel and is giving you a false misfire code, see this all the time as they get older, and whoever told you that it needs a crankshaft relearn is probably right. I work for a company with a fleet of 130 ls powered trucks in it, and i see it all the time. I would start there, especially if it shows in the misfire data random misfires on random cylinders with no rhyme or reason. If it was lean enough to actually misfire it would have lean codes in it also as already stated.
70 mustang coupe restored with the help of my Dad and LOTS of friends. 306 490hp/398ft lbs t56 magnum 5.00 gear
1986 F150 standard cab short bed build in progress!
1986 F150 standard cab short bed build in progress!
- midnightbluS10
- Expert
- Posts: 933
- Joined: Sun Oct 20, 2013 8:41 am
- Location: Shreveport, LA
Re: Silverado, low fuel pressure?
As long as you have a smartphone, you can read live data for about $25. The app is free and the OBD2 adapter is around $25.S10LS2 wrote: ↑Wed May 02, 2018 10:52 pmWow total bullshit, except for putting plugs and wires, its all a guessing game as the guy posts limited information. you can buy a scan tool for less then 100 bucks that will read live data.. Dont throw parts at it fix it. LOL 9 psipeejay wrote: ↑Wed May 02, 2018 10:45 pm How old are the spark plugs?
Low fuel pressure will set lean codes LONG before it misfires. I've seen trucks running and driving at 9psi fuel pressure. (Okay, not running WELL, mind you...) If there are no lean codes present, and you don't have a scan tool to be able to watch live data while the problem happens, I'd first look at the spark plugs. 100k isn't a guideline, it's a "you mean you didn't have to replace them 40k ago? Wow, get those suckers out of there!" maximum.
JC -
bigjoe1 wrote:By the way, I had a long talk with Harold(Brookshire) last year at the PRI show. We met at the airport and he told me everything he knew about everything.It was a nice visit. JOE SHERMAN RACING
Re: Silverado, low fuel pressure?
I have an iphone and an ipad...So can you recommend the OBD2 wireless adapter and a particular App?....Do they display all the info such as fuel trims,timing, O2 sensors and various other information?midnightbluS10 wrote: ↑Mon May 07, 2018 8:28 pmAs long as you have a smartphone, you can read live data for about $25. The app is free and the OBD2 adapter is around $25.S10LS2 wrote: ↑Wed May 02, 2018 10:52 pmWow total bullshit, except for putting plugs and wires, its all a guessing game as the guy posts limited information. you can buy a scan tool for less then 100 bucks that will read live data.. Dont throw parts at it fix it. LOL 9 psipeejay wrote: ↑Wed May 02, 2018 10:45 pm How old are the spark plugs?
Low fuel pressure will set lean codes LONG before it misfires. I've seen trucks running and driving at 9psi fuel pressure. (Okay, not running WELL, mind you...) If there are no lean codes present, and you don't have a scan tool to be able to watch live data while the problem happens, I'd first look at the spark plugs. 100k isn't a guideline, it's a "you mean you didn't have to replace them 40k ago? Wow, get those suckers out of there!" maximum.
Motorcycle land speed racing... wearing animal hides and clinging to vibrating oily machines propelled by fire
Re: Silverado, low fuel pressure?
https://www.obdsoftware.net/software/obdfusionTruckedup wrote: ↑Tue May 08, 2018 7:00 amI have an iphone and an ipad...So can you recommend the OBD2 wireless adapter and a particular App?....Do they display all the info such as fuel trims,timing, O2 sensors and various other information?midnightbluS10 wrote: ↑Mon May 07, 2018 8:28 pmAs long as you have a smartphone, you can read live data for about $25. The app is free and the OBD2 adapter is around $25.
I use this mostly on Mopar platforms but it works with all makes. Originally got it on amazon several years ago and worked with the developer on some issues i was having with it regarding instant and average fuel economy results it was displaying.
Since then It's been flawless. Frequent updates and always improved features. Has a built in performance timer, HUD display capability, etc. I use a bluetooth adapter but the latest version also connects with a WiFi adapter. Installed it on my kindle fire HD6, website says it is compatible IOS 7 or later.
Not sure on cylinder misfire counts graphing but I would be surprised if it wasn't capable. May want to check with them before purchasing.
Re: Silverado, low fuel pressure?
Thanks, I sent an email to them..
Motorcycle land speed racing... wearing animal hides and clinging to vibrating oily machines propelled by fire
Re: Silverado, low fuel pressure?
I would do a crank re-learn. If you approach that way any scan tool that can do that also can give you a misfire graph. Tech 2 is still the best but many after market scan tools can also do this(Autell, Snap-on, Matco, etc... and also Efi live and HP Tuners shops have this capability.
Re: Silverado, low fuel pressure?
Least expensive tool that can do a relearn, from what I find, is the Autel MX808 , 360-400 bucks....There's rumors that the Foxwell NT510 can do it, about 200 bucks....V Remian wrote: ↑Thu May 10, 2018 8:27 pm I would do a crank re-learn. If you approach that way any scan tool that can do that also can give you a misfire graph. Tech 2 is still the best but many after market scan tools can also do this(Autell, Snap-on, Matco, etc... and also Efi live and HP Tuners shops have this capability.
People say you can just drive into a local shop or dealership and ask for a relearn, supposedly less than $100....
Motorcycle land speed racing... wearing animal hides and clinging to vibrating oily machines propelled by fire
-
- Guru
- Posts: 1045
- Joined: Mon Aug 07, 2006 10:31 am
- Location: usa
- Contact:
Re: Silverado, low fuel pressure?
X2 for cam/crank relearn...anytime I see random misfire codes with none other ( p0300 only),,,I do the procedure...BLstangin wrote: ↑Fri May 04, 2018 1:40 pm IF the motor doesn't have a noticable misfire then it probably has a buildup on the crank sensor wheel and is giving you a false misfire code, see this all the time as they get older, and whoever told you that it needs a crankshaft relearn is probably right. I work for a company with a fleet of 130 ls powered trucks in it, and i see it all the time. I would start there, especially if it shows in the misfire data random misfires on random cylinders with no rhyme or reason. If it was lean enough to actually misfire it would have lean codes in it also as already stated.
A loose timing chain will set that code as well,,,Especially during cruise conditions.....
Re: Silverado, low fuel pressure?
What do you techs prefer to use to clean the crank sensor with so it wont screw it up?