That was it. Replaced the FPR, no more pressure fluctuation or chatter in the rails, and fixed the hard start issue as well. Should've seen it, had a bunch of fuel come out of the vacuum line when I pulled it off. Sucker must have been bad for a while. Is there anything I need to do since there was fuel in that vacuum line?
New PCV fixed the rattling, old one was kinda gunky. IAC is making an odd noise when going from key on to key off, kind of like a ball bearing being shook around in a small metal cylinder. Noticed it when I was up front checking fuel pressure. Guess that's next on the list. Fuel pressure got up to about 54psi, then fell to about 50psi within 2 minutes, and then 48 psi after 5 minutes passed. Weird thing I noticed was I had a lot of chatter coming from the fuel rails, and the needle for the pressure gauge would shake a lot when the chatter occurred, like it would go back and forth past 60psi too quickly to follow with my eyes. Once the pump shuts off, pressure immediately goes to 54psi and the chatter quits. Noticed my hard start occurs when it does this, and I don't have an issue starting it when I don't hear any chatter from the lines. I didn't get chatter when I started it cold this time, but I kept getting it afterwards. Relieving the pressure in the lines via the fuel pressure gauge and cycling the pump again so pressure rose from 0 still gave me chatter, though it was delayed very slightly. Does this thing have a fuel pressure regulator, or is there something else that regulates fuel pressure or relieves it after it gets to a certain psi? I'm betting that's where my problem lies. I replaced the fuel filter prior to testing pressure and the chatter did occur before I replaced the filter. It went on the same way the old one came off.
Haven't dropped the pan to check if there was material in there. Wasn't sure if that would be a great idea at 108k miles with the 2-3 slippage, not sure how much material I might lose. Haven't tried WOT, but after reading a sticky about 4L60E issues where the TPS could be the cause of the delayed or odd shifting, I started messing around trying to see if throttle position changed the delayed shifting I'm getting. More throttle definitely makes it go away for the 2-3 shift, though I am still getting noticeable slippage in that shift. The 1-2 shift seems to do better when giving it more throttle in first gear. Don't think I ever went over maybe 30-40% throttle while messing with it. I still get the delayed shift most of the time, but not as much. And it still can be avoided if you let off the throttle right before it shifts. I'm ordering a new TPS since they're fairly cheap and I have order brakes for it anyways. Out of curiosity, I put it in tow/haul mode to see how that affected things. The delayed 1-2 shift went away, but my shifts became noticeably harder. I don't recall it slipping going from 2-3, but it slipped when I got out of tow/haul mode - had to get off the throttle to let it upshift.
I've got a 2000 Sierra Z71 with the 5.3, 108k miles. Noticed I'm getting some decent vibration hitting 50+, with it most noticeable at about 55. It's significant when on the throttle, coasting reduces vibration significantly. Can feel it mostly through the seat and steering wheel. Thinking it's either U-Joints or motor mounts. I remember there being some slight play in the U-Joints when I checked them for the same issue when I borrowed it about a year ago. However, I also get some noticeable delay in power being applied in my 1-2 and 2-3 shifts - you can feel where it shifts, and then about 3/4-1 second later the power sort of silently thunks into place. The way it feels makes me think there's play in the mounts - shift, pause, and then power kicks in. It doesn't happen with the 3-4 shift, and I can usually prevent it from feeling like it's doing this in the 1-2, 2-3 shifts if I let off the throttle right around when I know it's going to shift for just as long as it takes it to shift - usually no more than a second or so. Truck was a ranch truck before I got it and usually only went short distances, so not sure if the delay is actually motor mounts moving significantly at lower speeds when there's greater torque being applied, or if it's clutches slipping because it's seen so many short 1-2, 2-3 trips. I know 2-3 clutches had some slipping issues when I got it, though it seems to have lessened with more driving - but maybe that's just cause the clutch material in the fluid is being circulated around more often now. Still need to get the wheels and tires rotated and balanced to be safe, but considering it's most significant when applying throttle I don't think the significant vibration is related to wheels being unbalanced. Is there anything else I'm not considering? Thinking I should pop the jack under it and check wheel bearings too. Bushings don't seem bad, don't see much cracking if any.
Where's the hookup for the fuel pressure gauge on this truck? On my Vette it was right before the FPR on the passenger side, right behind the motor. Thinking I need to do fuel filter too since I seem to sometimes get some chatter when the pump primes - is it inline on the NBS, or is it in tank?
I've got a 2000 Sierra 1500 with a 5.3, noticed there's a rattling noise coming from a hose that looks like it hooks up to about the middle of the intake manifold on the drivers side. The other end of that hose looks like it goes into the top of the head at the far cab-end of the head on the drivers side]. I know that whatever is rattling is either in or connected to that hose as I can feel it vibrating at the same speed as the rattle and none of the other hoses vibrate. Would this be the hose going to the PCV? Oil was kind of sludgy when I did a change today (hadn't been changed in a few years I'd say), so if that sludge gummed up the PCV then I suppose that might cause it to rattle like I'm hearing, yea? It's occasionally been hard to start (takes a few seconds of cranking to start or you have to crank it over twice), so I figure that would go with having a bad PCV.
Got it. Does HP Tuners have some sort of walkthrough/guide for their program that comes with the hardware? Or is there a better thread/tutorial for figuring out what does what and why? Some people have mentioned the DVD's from Greg Banish are great for this, but they're almost as much as the MPVI2 and the license for the truck.
Would the MPVI2 from HP tuners work? And would the device be something I would need to leave attached for the limiter to be active, or will it allow me to reprogram the ECU and remove the device with the changes still being active when the device is removed? Also, where’s the powerband on the 2000 5.3? He has a habit of bringing things to redline (he’s blown motors in two different vehicles doing this) so I’d really prefer to limit him from ever getting to that point. I’m looking at a tq/hp curve for an ‘03 5.3 and it looks like tq peaks at around 4000rpms, and hp delivery is fairly linear, hitting about 250hp in the same area. That seems like it should be more than enough for him. I hit a lot less than that in my 92 w/ a 5.7 and it’s always been more than enough for what it needs - never had to go over 4000-4200 for anything.
I've got a somewhat new-to-me '00 4x4 1500 that I'm considering loaning to my younger brother. To ensure it lasts longer than his other vehicles, I'm wanting to see about setting a lower value on the engine speed and vehicle speed limiter if one already exists. My understanding is that the ECU is already programmed to limit these to like 98-99mph and whatever their red line is (like 4800-5200 or something?). I'd like to see about limiting vehicle speed to 80mph and, if possible, limiting maximum engine speed to 2700-3000 RPM's. This isn't something that should ever be used by him to tow anything and shouldn't go over 80 while it's on loan to him, so I figure these are good limits. My questions are this: Will this be something I can get the ECU reprogrammed for, or is it something I need a physical device for? If it's ECU programming, is this something that should be relatively simple for me to do myself with the right equipment? I figure ECU reprogramming for this would run anywhere from $200-$400, so if it's something I can do then I'll buy the OBDII to USB cable and the right software for it so I can alter it later if necessary. I've got a LQ swap planned in the future for my 92 K1500, so I figure the tools will be useful for messing with the tune I get for that (not setting the initial tune myself) and for diagnosing whatever is bound to go wrong. Is there anything I need to take into consideration in doing this? My initial thoughts are how will the trans react to limiting the motor speed (I'm assuming it would be a 4L60E, yea?) if he tries to downshift to go faster instead of just limiting the maximum vehicle speed. Thanks! ~Ken
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