Vortec 454 Rough Running
October 22nd, 2018, 5:28 PM
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Vortec 454 Rough Running
Hey all. Sorry. I am new to the forum and this may be in the wrong place. I apologize and let me know where I should post the question if it is incorrect.
I have a Vortec 454 that I put in a 1979 Jeep Wrangler. It ran great but has been sitting for 2 years because I just had no time to use it. Now when I try to run it, it will idle but when I hit the gas it spits/sputters and will stall. I barely moved it 25 ft. So it acts like its starving for fuel. I've installed a new fuel pump, changed rotor, cap, plugs, wires (it needed it anyway). I put a scanner on it and it shows P0154 and P0103. I cleaned the MAF with no change. It does seem to run a bit better if I am spraying carb cleaner into plenum.
I put a fuel gauge on it and it reads like this:
0 psi with ignition off
45 psi when ignition on
58-60 psi when idling and stays same at WOT
Once shut down, it will leak back down to about 15 psi
Thinking now possible leak in fuel rail/injector or bad regulator maybe? Any ideas would be greatly appreciated. Much thanks.
I have a Vortec 454 that I put in a 1979 Jeep Wrangler. It ran great but has been sitting for 2 years because I just had no time to use it. Now when I try to run it, it will idle but when I hit the gas it spits/sputters and will stall. I barely moved it 25 ft. So it acts like its starving for fuel. I've installed a new fuel pump, changed rotor, cap, plugs, wires (it needed it anyway). I put a scanner on it and it shows P0154 and P0103. I cleaned the MAF with no change. It does seem to run a bit better if I am spraying carb cleaner into plenum.
I put a fuel gauge on it and it reads like this:
0 psi with ignition off
45 psi when ignition on
58-60 psi when idling and stays same at WOT
Once shut down, it will leak back down to about 15 psi
Thinking now possible leak in fuel rail/injector or bad regulator maybe? Any ideas would be greatly appreciated. Much thanks.
October 22nd, 2018, 6:57 PM
#2
CF Senior Member
MAF could be suspect,so could bank 2,1 o2 sensor,try unplugging the MAF,see if there is improvement, other would be check 02 sensor connection,green fungus in there ?
October 22nd, 2018, 8:23 PM
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I am suspect of the MAF as well. I just didn't want to spend $130 quite yet unless I was more certain. I did try to unplug it and no change.
So one thing to know about this setup is that the emissions have all been turned off. No EGR, no o2 sensors, etc... The only vacuum lines go to brake booster, tranny, manifold and valve cover. This thing ran like a scalded ape prior to it sitting so I am certain that the emission issues aren't the culprit.
So one thing to know about this setup is that the emissions have all been turned off. No EGR, no o2 sensors, etc... The only vacuum lines go to brake booster, tranny, manifold and valve cover. This thing ran like a scalded ape prior to it sitting so I am certain that the emission issues aren't the culprit.
October 22nd, 2018, 8:32 PM
#5
CF Senior Member
No change,not the culprit,you must be talking about post cat 02's,precat still in play,so swap them(front 02's) side to side,see if code swaps with it
October 23rd, 2018, 9:26 AM
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Is the fuel aspect acting correctly? I feel it shouldn’t be bleeding down after power is no longer applied. If it should hold, what would you say causes that to happen?
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October 23rd, 2018, 9:33 AM
#8
CF Senior Member
I have seen them behave both ways,and not be a problem, except for 0 psi, right after key off,my guess is you are gummed up in regulator,not closing completely,but holding proper pressure,if you had bleed down in spider,you would be rich on start up,or fuel odor, right now you are lean?
