Vacuum leak?
#1
09-20-2014, 07:57 AM
Vacuum leak?
1995 2 door 4.3 4x4
About three years ago I bought the truck with a blown motor and did a motor swap on it with another 'w' vortec. Just recently I pulled the whole upper and lower intake because it was completely caked with carbon, it always threw an egr code for 'insufficient flow' but the passage was clogged solid. After cleaning and putting back on the motor I did new plugs wires cap and rotor. I recently started driving it again and I got a code for low voltage to throttle position sensor, never came back on but took a voltmeter to it and it's doing exactly what it's supposed to. So here's my question, what else would cause these symptoms. Hardly any power between 2.5-3 grand, have to put foot to the floor to get it to move. Doesn't want to shift itself until 3, but will shift after 2500 if I let off. Idles a little rough at a stop, and a few times idling at 1500 rpm. Never stalled on me, but acted like it's wanted to at a stop. Can't find a disconnected or cracked hoses, or any vacuum leaks. Also, shifts harder into second than the others. Doesn't always want to go into gears every now and then too. Hoping no tranny issues. Any ideas?
About three years ago I bought the truck with a blown motor and did a motor swap on it with another 'w' vortec. Just recently I pulled the whole upper and lower intake because it was completely caked with carbon, it always threw an egr code for 'insufficient flow' but the passage was clogged solid. After cleaning and putting back on the motor I did new plugs wires cap and rotor. I recently started driving it again and I got a code for low voltage to throttle position sensor, never came back on but took a voltmeter to it and it's doing exactly what it's supposed to. So here's my question, what else would cause these symptoms. Hardly any power between 2.5-3 grand, have to put foot to the floor to get it to move. Doesn't want to shift itself until 3, but will shift after 2500 if I let off. Idles a little rough at a stop, and a few times idling at 1500 rpm. Never stalled on me, but acted like it's wanted to at a stop. Can't find a disconnected or cracked hoses, or any vacuum leaks. Also, shifts harder into second than the others. Doesn't always want to go into gears every now and then too. Hoping no tranny issues. Any ideas?
Last edited by samadams; 09-20-2014 at 08:03 AM.
#2
09-20-2014, 03:18 PM
1995 2 door 4.3 4x4
About three years ago I bought the truck with a blown motor and did a motor swap on it with another 'w' vortec. Just recently I pulled the whole upper and lower intake because it was completely caked with carbon, it always threw an egr code for 'insufficient flow' but the passage was clogged solid. After cleaning and putting back on the motor I did new plugs wires cap and rotor. I recently started driving it again and I got a code for low voltage to throttle position sensor, never came back on but took a voltmeter to it and it's doing exactly what it's supposed to. So here's my question, what else would cause these symptoms. Hardly any power between 2.5-3 grand, have to put foot to the floor to get it to move. Doesn't want to shift itself until 3, but will shift after 2500 if I let off. Idles a little rough at a stop, and a few times idling at 1500 rpm. Never stalled on me, but acted like it's wanted to at a stop. Can't find a disconnected or cracked hoses, or any vacuum leaks. Also, shifts harder into second than the others. Doesn't always want to go into gears every now and then too. Hoping no tranny issues. Any ideas?
About three years ago I bought the truck with a blown motor and did a motor swap on it with another 'w' vortec. Just recently I pulled the whole upper and lower intake because it was completely caked with carbon, it always threw an egr code for 'insufficient flow' but the passage was clogged solid. After cleaning and putting back on the motor I did new plugs wires cap and rotor. I recently started driving it again and I got a code for low voltage to throttle position sensor, never came back on but took a voltmeter to it and it's doing exactly what it's supposed to. So here's my question, what else would cause these symptoms. Hardly any power between 2.5-3 grand, have to put foot to the floor to get it to move. Doesn't want to shift itself until 3, but will shift after 2500 if I let off. Idles a little rough at a stop, and a few times idling at 1500 rpm. Never stalled on me, but acted like it's wanted to at a stop. Can't find a disconnected or cracked hoses, or any vacuum leaks. Also, shifts harder into second than the others. Doesn't always want to go into gears every now and then too. Hoping no tranny issues. Any ideas?
So I take it there aren't any 'current' codes that are pending ???? Did u actually test the sensor? Or just check to see if it had power? U need to do a snap throttle test , voltage if I remember right will range from .05 volts to 5 volts .... U may wanna try cleaning the MAF sensor, as I have seen them cause some shifting issues as well as idle in the past....also, given the terrible design of the poppets on these motors, I say a fuel pressure test is in order!!!!!
my guess is u have more than 1 issue going on!do a search for fuel system diagnosis, this will walk u through it!!!!
u are in the right place for HELP
#3
09-21-2014, 06:17 PM
just had two codes pop up today
P0122 Throttle/Pedal Position Sensor A Circuit Low Input
P0141 Oxygen Sensor Heater Circuit Bank 1 Sensor 2
But when I said tested it, i tested the voltage on my signal wire while closed and at open throttle and opened/closed it slowly too, and it was where it was supposed to be and did what it was supposed to. And my 5v ref was where it was supposed to be, and the ground was good also. So not sure if i tested wrong or what. Have not done a fuel pressure test on it though. Have never smelled any fuel. But can test to be sure.
P0122 Throttle/Pedal Position Sensor A Circuit Low Input
P0141 Oxygen Sensor Heater Circuit Bank 1 Sensor 2
But when I said tested it, i tested the voltage on my signal wire while closed and at open throttle and opened/closed it slowly too, and it was where it was supposed to be and did what it was supposed to. And my 5v ref was where it was supposed to be, and the ground was good also. So not sure if i tested wrong or what. Have not done a fuel pressure test on it though. Have never smelled any fuel. But can test to be sure.
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