- Thread starter
- #81
Yes continuity has been checked. Leak down and compression test have been done and passed. Will a broken valve spring allow those tests to pass?
Ecu misfire?
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- Thread starter
- #82
This is completely ridiculous that I have this being looked at by toyota technicians here where I work and they can't figure it out. Beyond frustrated
Apparently this vehicle passed all the tests with a broken valve spring.
www.tundrasolutions.com
Misfire when cold mystery.
Misfire when cold mystery-- SOLVED Moved to a new thread ... I have a 2007 5.7 limited 62000 miles. The Toyota Tundra is throwing a P0302 code. Misfire on cylinder 2. It started this summer a few times. Now it does it every time the truck has been sitting for more then 6-8 hours...
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- #84
Mine only does it once it hits around 185 degrees while idling.Apparently this vehicle passed all the tests with a broken valve spring.
Misfire when cold mystery.
Misfire when cold mystery-- SOLVED Moved to a new thread ... I have a 2007 5.7 limited 62000 miles. The Toyota Tundra is throwing a P0302 code. Misfire on cylinder 2. It started this summer a few times. Now it does it every time the truck has been sitting for more then 6-8 hours...
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bloc
SILVER Star
I would have pulled the valve cover and given the springs a good look and probably some sort of tension test long ago.
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- #86
Seems very unlikely that a spring is broken in cylinder 4 and on the opposite side number 7 cylinder also.
bloc
SILVER Star
I agree, but it's not difficult to do and will rule that out as a cause.
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- #88
See part of the problem is I'm working with a technician at my dealership and not trying to tell him what to do. I'll suggest this tomorrow
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- #89
Compression and leak down tests pass.
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- #91
Just to see if the computer would pick up An actual misfire I unplugged the left side fuel injector harness. Started truck. Let run about 30 seconds or so and it didn't turn on the mil. It also didn't store pending codes other than the 304 and 307 that I've been struggling with. I turned the truck off and restarted it (it cranked for a decent amount of time), once running again still no mil no new pending codes. Hmmm?
I captured the bank 1 sensor 1 info for @TheGrrrr on my summer trip. Temps vary but it was holding at about 1450F normally in 5th gear when towing, and would spike to about 1560F if I was climbing in 3rd or 4th gear. I don’t recall what it would read if if shut the truck off and immediately turned it on… it might spike but overall it cools pretty quick j once exhaust gases stop flowing.
“Right corner is bank 1, sensor 1. I’m Towing in Wyoming. Seems to largely follow RPM. If I get down into 4th or 3rd it’ll move up to 1560F but seems to top out there, as the A/F mix drop and the ECU riches the mix the temp steadies out even at almost 5k RPMs”
“Right corner is bank 1, sensor 1. I’m Towing in Wyoming. Seems to largely follow RPM. If I get down into 4th or 3rd it’ll move up to 1560F but seems to top out there, as the A/F mix drop and the ECU riches the mix the temp steadies out even at almost 5k RPMs”
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- #98
Ok thanks that's some helpful info
Carbon build up and deposits alone shouldn't cause a misfire. Build up on a spark plug to the point of fowling could be a cause but you've already swapped plugs (I think). Trying to clean carbon buildup at this point might cause more issues but you might have nothing to lose by running something like seafoam in the crankcase and fuel system. I used seafoam on a BMW once with great result.
