Ok going to extend my pressure line on gauge Tom to get readings at higher speeds but all and all does this seem like a pump issue or still hard to say without further info? I'll post psi at highway speeds Tom if I get a chance to!
It probably is the pump. Testing the pressure while under load eliminates it being probably and makes it a certainty. When the rotors arc out, it usually jumps to the mounting screws. If they changed the dist, I'd assume it came with a new cap and rotor, but you know what is said about assuming. Also if the combustion chambers are getting water in them is the leading cause of burning rotor buttons in my experience.
Cap and stem is def new on dizzy rotor I'm not positive of! I assume way to much usually, trying to be smart and use process of elimination through testing instead of throwing money at it and parts! I've kept a watch on coolant bc manifold issues on these engines and so far hasn't lost a drop from what I can tell. Great info I appreciate the knowledge!
Ok so did driving test today while watching pressure gauge anything under 2000rpm I'm sitting at 42psi and goes up to max of 55 psi when up hills and heavy throttle!
IMO you need to check fuel pump without regulator by blocking return line momentarily. If you achieve 60 psi or more then the regulator is not utilizing available pressure unless there is flow or volume issue. I learned to buy GM regulators
You can also test max pump pressure by removing the feed line and running it straight to a gauge. 42 is low. Timing is right or wrong on the vortec motors. If you don't have a cam crank correlation error code, it's right.
Maybe I am reading your description horribly wrong, its certainly possible.
But you describe a lack of power at low rpms, but not an apparent miss or skip, just a lack of power.
My gut tells me you are experiencing the "power" of differing rear end ratios. Ive driven a Burb with 3.73s and one with 3.08s....and my ass-o-meter dyno said there was a 150hp difference.
Yeah sorry I suck at describing mechanical issues lol there is a skip/jerk but it's not hard at all feels like a very small miss when heavy acceleration it isn't as noticeable at highway speeds! My 94 and 79 burbs are 3.73 so it's different for sure but I'm about 93% positive there's something else at hand hopefully it's just a r&r on the fuel pump and I can go back to being happy with my 1000$ 2500 burb! Lol So can I pull my filter and plug the gauge in there to get max pressure? Gonna research some more but I don't get any codes at all so timings good then.
The exhaust seems replaced recently but no guarantee to if the cat was? did find out the suburban use to be either a fire/police vehicle bc it has a siren up front still attached under the bumper plugs up top where lights use to be and a steel mount for computer under pass seat only reason I found this out bc I had a buddy look at it and he happens to be a Lt at fire dept!
Apparently spark plug gap on a 99 5.7 vortec is a very heated debate lol don't foresee it being my issue tho my gas gauge jumps when I turncoat the key on also sending unit going bad and pump at same time typical?
Gap to .060 and improved my sloppy idle and gave it a very little increase in acceleration! I'm thinking I should replace fuel pump unless there is other tests I can run to rule it out? My fuel pressure gauge doesn't have a purge so not sure how to check volume
Considering the other wiring issues at the rear of the truck, I'd look at the grounds for the sender and pump. Could be a bad ground causing a low flow/low voltage issue. Could also explain the gauge jumping. If you pull the tank to look, though, I'd go ahead and slap in a new pump while you're at it.
I'm gonna cut access in back of truck to replace pump the ground look clean under the rear if the two grounds I see are for pump and sending unit I'm gonna disconnect and retorque em to be safe starting the pump r&r Tom wind is 40mph today and I'm not interested in all that! Anyway to cover the tank to cut a hole or just have a fire extinguisher on hand? Using a big Dremel with their new $20 no shrink cutting wheels I feel like it would do best job bc of better control!? All the info I've gathered seems to point to the pump I will try a test with the return line blocked off after I cut the hole out just for peace of mind! I can't think of anything else to be causing the low pressure and I'm "assuming" it's factory pump in it...
I'd personally just use a cut off wheel on a disc grinder. Unless you cut through the lines or smell fuel, you'll be pretty OK, at least in my experience.
is there a way to tell if relay is bad for fuel pump without just buying a new one? testing electrical stuff is not my thing to be honest I'm always afraid of frying my shit bc I don't have a higher understanding of how it all works together...
Can I just unplug connector from fuel pump and use volt meter on gray hot wire? If I have 12v there relay and all wires up the pump should be good!? Is this correct? I don't even know what setting on my volt meter to use... that's bad I know don't judge me!
