Misfire!
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Misfire!
Misfire!
Help! I have a 97 E super duty motorhome with the triton v10.
At first i had a bunch of codes saying lean bank1 and lean bank 2, as well the misfire codes on 3,6 and 8.
P171
P174
P303
P306
P308
Changed the COP (coil on plug), same codes.
Changed plugs, same codes.
Changed PCV, same codes.
Changed fuel filter, both O2 sensors, same codes.
Changed DPFS, same codes.
Changed injectors, same codes.
Changed MAS, P171 and P174 went away, started running consideribly better. Still missfiring on 3,6 now 7 and 8.
Passed smog tho..
Hooked up vacuume gague to see if possible worn or broken valve springs.
Vacuume shows about 21" at idle, shoots to 0" then 25" and back to 21" when quickly rev'd. Needle vibrates about 1", (21" to 21.5/22").
Ive read this indicates vacuume leak..
I've sprayed starter fluid like crazy on all hoses i can see, no engine speed change..
Any thoughts are appreciated!
Help! I have a 97 E super duty motorhome with the triton v10.
At first i had a bunch of codes saying lean bank1 and lean bank 2, as well the misfire codes on 3,6 and 8.
P171
P174
P303
P306
P308
Changed the COP (coil on plug), same codes.
Changed plugs, same codes.
Changed PCV, same codes.
Changed fuel filter, both O2 sensors, same codes.
Changed DPFS, same codes.
Changed injectors, same codes.
Changed MAS, P171 and P174 went away, started running consideribly better. Still missfiring on 3,6 now 7 and 8.
Passed smog tho..
Hooked up vacuume gague to see if possible worn or broken valve springs.
Vacuume shows about 21" at idle, shoots to 0" then 25" and back to 21" when quickly rev'd. Needle vibrates about 1", (21" to 21.5/22").
Ive read this indicates vacuume leak..
I've sprayed starter fluid like crazy on all hoses i can see, no engine speed change..
Any thoughts are appreciated!
Fleet Mechanic
Joined: Feb 2011
Posts: 1,812
Likes: 88
From: Thousand Oaks, CA
Did this start happening all at one time or gradual?
Might be a typo - did you change all the COPs or just one?
Maybe a sensor is intermittent - throttle position or crankshaft position.
Might be a typo - did you change all the COPs or just one?
Maybe a sensor is intermittent - throttle position or crankshaft position.
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Changed all suspect COP, (3,6,8, from codes that popped) this was all at once as i bought it in vegas and drove back to CA. It had sat for quite a while. A number of vacuume hoses were completley dry rotted..
Fleet Mechanic
Joined: Feb 2011
Posts: 1,812
Likes: 88
From: Thousand Oaks, CA
Usually the lean codes are a vacuum leak
I'm still fighting a P0171 on our 2003 5.4l Exped which may be a cracked intake.
The misfire codes are usually electrical - bad/wet spark plug boot/spring, cracked coil housing, poor connections.
Have you checked grounds - battery, PCM, engine to frame?
How do the COP connectors look?
Reseat the PCM connectors.
What is the system voltage?
What is the voltage getting to the COPs?
How is the fuel pressure?
I'm still fighting a P0171 on our 2003 5.4l Exped which may be a cracked intake.
The misfire codes are usually electrical - bad/wet spark plug boot/spring, cracked coil housing, poor connections.
Have you checked grounds - battery, PCM, engine to frame?
How do the COP connectors look?
Reseat the PCM connectors.
What is the system voltage?
What is the voltage getting to the COPs?
How is the fuel pressure?
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Cleaned the MAF sensor last night, reset codes... Came on tonight on my way home from work, the p0171 went away. Only showing p0174 now.
any ideas ? I'll check the torque app tomorrow. Too tired from long work day
any ideas ? I'll check the torque app tomorrow. Too tired from long work day
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Fleet Mechanic
Joined: Feb 2011
Posts: 1,812
Likes: 88
From: Thousand Oaks, CA
The P0171 may come back.
They don't necessarily get set at the same time.
I finally found the cause of my P0171 "only" code.
I had replaced the exhaust Y-pipe awhile ago because the CATs were bad.
The passenger side pipe to manifold flange bolts had worked loose or the connection seated better after use.
I thought an exhaust leak I had was a broken stud on the driver's side.
When I fixed the stud the exhaust leak didn't go away.
I checked all the exhaust bolts and found the loose flange bolts on the passenger side.
Tightened the bolts - exhaust leak fixed and no more P0171 code.
They don't necessarily get set at the same time.
I finally found the cause of my P0171 "only" code.
I had replaced the exhaust Y-pipe awhile ago because the CATs were bad.
The passenger side pipe to manifold flange bolts had worked loose or the connection seated better after use.
I thought an exhaust leak I had was a broken stud on the driver's side.
When I fixed the stud the exhaust leak didn't go away.
I checked all the exhaust bolts and found the loose flange bolts on the passenger side.
Tightened the bolts - exhaust leak fixed and no more P0171 code.
Junior User
Joined: Apr 2016
Posts: 62
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Do the motorhomes have the PCV hose under the throttle body that always gets a hole worn in it? It's pretty much the number one cause of lean codes on V10s
Might want to check that out if it is relavent to this situation.
Might want to check that out if it is relavent to this situation.
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