random rough idle, misfires on all cylinders randomly
#11
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want me to post up a scan of the ignition advance? or any other values that could help you determine a place I should start looking?
If you look at the oxygen sensor info, the bank1 seems to go crazy, which then the bank2 starts to follow it. Could my bank1 sensor be bad at a low flow rate going across it (at idle) and then bank 2 tries to follow it thus resulting in bad afr/misfiring
#12
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here you go, the voltage does drop quit a bit (down to 12v) but I don't really see a relation to the misfires
you can see in one part I hold the rev at about 3k and all the misfires go away
The "misfire history" on this truck is ridiculous... every cylinder has over 800 misfires lol
you can see in one part I hold the rev at about 3k and all the misfires go away
The "misfire history" on this truck is ridiculous... every cylinder has over 800 misfires lol
I'd say get some jumper cables and borrow power from another running vehicle and see what happens with your voltages and rough running concerns.
#13
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Voltage drop will cause all sorts of unexpected failures. Everything from the fuel pump to the ignition coils are affected by a voltage drop, considering they are designed to run at 13.5-14.5 volts. Also, if your alternator is failing to keep up, it will cause some unbelievable electrical noise which the interference canceler (if equipped) cannot suppress.
I'd say get some jumper cables and borrow power from another running vehicle and see what happens with your voltages and rough running concerns.
I'd say get some jumper cables and borrow power from another running vehicle and see what happens with your voltages and rough running concerns.
#14
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My fuel pressure is pretty high, 60-65 psi when not in boost. Idk why it is so high
want me to post up a scan of the ignition advance? or any other values that could help you determine a place I should start looking?
If you look at the oxygen sensor info, the bank1 seems to go crazy, which then the bank2 starts to follow it. Could my bank1 sensor be bad at a low flow rate going across it (at idle) and then bank 2 tries to follow it thus resulting in bad afr/misfiring
want me to post up a scan of the ignition advance? or any other values that could help you determine a place I should start looking?
If you look at the oxygen sensor info, the bank1 seems to go crazy, which then the bank2 starts to follow it. Could my bank1 sensor be bad at a low flow rate going across it (at idle) and then bank 2 tries to follow it thus resulting in bad afr/misfiring
We already know that your misfire isn't a voltage issue from the scan you posted.
I would fix the fuel pressure, and any other issues that you know about, first.
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yeah, when the rough idle starts it goes down to about 12 then shoots up to a little over 15 while it idles rough. Then as it straightens itself out it goes back to 14.6-14.8
Could my spark plugs be causing this? NGK TR6 set to .035, unless I set them wrong
edit: I guess it couldn't be my spark plugs if it wants to run lean under the rough idle condition/misfires.. if plugs weren't firing it would cause it to go rich, right? unless the computer sees that first 12afr (from plugs not firing) and immediately cuts off fuel creating the lean misfires
Could my spark plugs be causing this? NGK TR6 set to .035, unless I set them wrong
edit: I guess it couldn't be my spark plugs if it wants to run lean under the rough idle condition/misfires.. if plugs weren't firing it would cause it to go rich, right? unless the computer sees that first 12afr (from plugs not firing) and immediately cuts off fuel creating the lean misfires
Last edited by Wilde Racing; 03-04-2012 at 10:09 AM.
#17
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I'm going to mess with the o2 sensors, because it seems like bank 1 is sort of lazy when there isn't a good flow going past it (at idle). I'm not sure if the o2s on my truck have ever been replaced and I'm at 130,000 miles!
#18
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I've seen bad alternators "jackhammer" the electrical system by switching from none to high output at midrange frequency.
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The LT fuel trims need help, new 02s might be the fix but if it all started when the injector were installed I'd lean more toward the tune/injector offset....
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