Unfixable misfire
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Unfixable misfire
My 91 302 f150 died in the road with no warning months ago and was running rough but we'll enough to go places worry free
after getting it home it still refused to fire at all after replacing the wires which were probably the issue going into this it fired and ran very rough after replacing the cap and rotor it was able to just barely move under its own power after the module it was able to drive but would still be misfiring all over after the plugs nothing changed I have plenty of fuel pressure and even jumpered the fuel pump relay
the only codes this whole time have been a not enough fuel code ive had for 10 years almost through a new fuel pump, relay and filter and a vss code but the exact number on either I dont remember
after getting it home it still refused to fire at all after replacing the wires which were probably the issue going into this it fired and ran very rough after replacing the cap and rotor it was able to just barely move under its own power after the module it was able to drive but would still be misfiring all over after the plugs nothing changed I have plenty of fuel pressure and even jumpered the fuel pump relay
the only codes this whole time have been a not enough fuel code ive had for 10 years almost through a new fuel pump, relay and filter and a vss code but the exact number on either I dont remember
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It runs perfect until it decides to misfire a bunch and if it doesn't stall it runs perfect for another few minutes
fuel pressure was measured at normal a year ago or so I dont remember the actual readings but even with the code it ran fine and measured what it was supposed to
The vss code is new but only shows up during tests so it may have been there a long time
fuel pressure was measured at normal a year ago or so I dont remember the actual readings but even with the code it ran fine and measured what it was supposed to
The vss code is new but only shows up during tests so it may have been there a long time
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I thought I was being less than helpful so I ran another test
codes read as of now are 41 77 52 while running 87 95 96
now I'm left to wonder what happened to the vss code or if I just read the thing wrong
things to note is that during the running test a slight dip in rpms from a misfire would have the tach needle drop significantly
codes read as of now are 41 77 52 while running 87 95 96
now I'm left to wonder what happened to the vss code or if I just read the thing wrong
things to note is that during the running test a slight dip in rpms from a misfire would have the tach needle drop significantly
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So your saying you get 41, 77 and 52 from the KOEO test?
41: O2 sensor always lean (stored code)
77: operator error -failed dynamic responses (this is a KOER code)
52: power steering pressure switch open (could be active or running code)
Then you got 87, 95 & 96 from the KOER?
87: primary fuel pump circuit (active fault)
95: fuel pump secondary circuit fault (active or stored)
96: fuel pump secondary circuit/ high speed fuel pump relay open. (active or stored)
How are you retrieving codes : paper clip or code reader? So what did you get when? Which was an active fault and which was stored? Your speedometer was cable driven in ‘91 so the only thing the sensor in the rear differential does is provide information for the rear abs system.
Depending on how accurate your codes are it could be weak fuel pressure causing a lean condition. Do you have one tank or two?
41: O2 sensor always lean (stored code)
77: operator error -failed dynamic responses (this is a KOER code)
52: power steering pressure switch open (could be active or running code)
Then you got 87, 95 & 96 from the KOER?
87: primary fuel pump circuit (active fault)
95: fuel pump secondary circuit fault (active or stored)
96: fuel pump secondary circuit/ high speed fuel pump relay open. (active or stored)
How are you retrieving codes : paper clip or code reader? So what did you get when? Which was an active fault and which was stored? Your speedometer was cable driven in ‘91 so the only thing the sensor in the rear differential does is provide information for the rear abs system.
Depending on how accurate your codes are it could be weak fuel pressure causing a lean condition. Do you have one tank or two?
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