4.63L p0305 problems **HELP**
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From: Land of a Thousand Trees
4.6L p0305 problems **HELP**
Hey Guys.
I'm lost. I'm not the best mechanic but I'm not sure what to do next. I'm trying to get my truck to pass smog and there is NO engine light on but when I took it in it blew a p0305 code so they won't pass it even though the emmissions are clean. So I replaced the COP and the Sparkplug with motorcraft parts but it still shows a misfire? I don't know what to do next? Could it be that my new COP was bad? thanks in advance
I'm lost. I'm not the best mechanic but I'm not sure what to do next. I'm trying to get my truck to pass smog and there is NO engine light on but when I took it in it blew a p0305 code so they won't pass it even though the emmissions are clean. So I replaced the COP and the Sparkplug with motorcraft parts but it still shows a misfire? I don't know what to do next? Could it be that my new COP was bad? thanks in advance
Last edited by FAT50RACER; Jan 25, 2011 at 07:03 PM.
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From: Beaverton Or.
Did you disconnect the battery while changing those? resets the pcm to clear the code. Then you will have to complete a drive cycle or your emissions test will not pass as it will say "unable to test, system not ready" or something like that.
Heres some info on a drive cycle for after you remove your battery to clear the pcm.
This is a quote from Bluegrass
"ANYTIME the PCM is cleared even if no codes were present, it causes a reset to test all Pids over again from scratch.
No battery removal, no program change. These will cause the same action.
You may not see a code or a CEL lamp if there are no actual fault codes either, in a system that had no faults.
The fuel system is a long involved two phase test sequence and is unpredicitable as to the amount of drive time and cycles it takes from truck to truck to reset and clear given age and condition of the tank systems and hardware.
You cannot clear anything by power down that cannot be seen by the inspection station.
The system was designed that way so the emissions test cannot be fooled.
Thank your fed gov for this.
Many states will ignor a fuel system test incomplete if it is just a PID not reset, but will not ignor an actual fault code, assuming there is a fault present that must be repaired.
If you have no faults, you just have to drive it long enough for the PID test to be satisfied.
All PIDS reset, clears the code P1000.
The drive cycles are so involved that you likely cannot "control drive" the truck to reliably address any of the Pids except maybe the simpler ones because you have no way to see what is happening and when.
Good luck.
"
And here is how it is accomplished...
http://www.obdii.com/drivecycleford.html
Hopefully your fresh plugs and cop got rid of the misfire and now it just needs to be cleared. Speaking of, what brand of cop did you install?
Heres some info on a drive cycle for after you remove your battery to clear the pcm.
This is a quote from Bluegrass
"ANYTIME the PCM is cleared even if no codes were present, it causes a reset to test all Pids over again from scratch.
No battery removal, no program change. These will cause the same action.
You may not see a code or a CEL lamp if there are no actual fault codes either, in a system that had no faults.
The fuel system is a long involved two phase test sequence and is unpredicitable as to the amount of drive time and cycles it takes from truck to truck to reset and clear given age and condition of the tank systems and hardware.
You cannot clear anything by power down that cannot be seen by the inspection station.
The system was designed that way so the emissions test cannot be fooled.
Thank your fed gov for this.
Many states will ignor a fuel system test incomplete if it is just a PID not reset, but will not ignor an actual fault code, assuming there is a fault present that must be repaired.
If you have no faults, you just have to drive it long enough for the PID test to be satisfied.
All PIDS reset, clears the code P1000.
The drive cycles are so involved that you likely cannot "control drive" the truck to reliably address any of the Pids except maybe the simpler ones because you have no way to see what is happening and when.
Good luck.
"
And here is how it is accomplished...
http://www.obdii.com/drivecycleford.html
Hopefully your fresh plugs and cop got rid of the misfire and now it just needs to be cleared. Speaking of, what brand of cop did you install?
Last edited by Toyz; Jan 23, 2011 at 02:41 AM.
Bueller
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From: Beaverton Or.
And a motorcraft cop? You can switch injectors and see if it follows..
You said there is no light on in your first post.... So it came back after the failed emissions? Or they picked it up
You said there is no light on in your first post.... So it came back after the failed emissions? Or they picked it up
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From: Land of a Thousand Trees
Sorry no. Motorcraft plug with BWD COP. no light but they picked it up and so does my scanner. Also now to top it off I keep blowing the p0401 and the p0305. I'm stumped. I just bought a bunch of throttle body cleaner and plan on cleaning the TB and the MAF. How hard is it to switch injectors? Any chance these may be related? The only thing I did before the smog inspection was put a new paper filter in it in stead of my K&N
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From: Easton, Pa.
A cylinder miss can be a plug, a coil or an injector.
Are you servicing the second cylinder from the front on the driver side. That one is cylinder 6.
How the cylinder miss is detected is by the crank sensor detecting a slow down in crank speed when that cylinder fires. This sets the code P0306.
The computer is that fast and does a compair of the time it takes the crank to rotate as compaired to all the rest of the cylinders it keeps track of on a continious basis. This is how the computer accounts for average engine wear over time by correcting the tables to reflect this.
.
The P0401 code is telling you the EGR test of exhaust flow is to low.
This can be due to carbon blockage behind the EGR valve into the intake manifold not permitting flow when tested.
A faulty DPFE sensor that is used to test and detect system faults could set the code.
The metal tube from the exhaust manifold to the EGRvalve has a calibrated orface that could be blocked.
To test these for operation, apply enough vacuum to the EGR valve with the engine at idle. If the engine gets rough, the EGR is opening ok, the port behind should be open enough and the orface is open.
This leaves the DPFE sensor you cannot really test for function. If you replace the DPFE, use a Ford part due to the very tight test limits the system has to use for the test.
Additionally, it is possible for the vacuum regulator to be sticky and not allow enough vacuum to pass to the EGR to control it's opening enough.
.
On the cylinder miss, be sure the boot is in good condition and that you used the proper grease inside the boot tip so it will 'find' the plug and slide on instead of jamming off to the side and cause the issue.
A single cylinder miss should not be that hard to solve. Be sure the connector plug is seated on the coil.
If you clear the codes after service, the PCM will do a complete system test but the 306 code should not return if the issue is solved.
The 401 code will take two drive cycles to see if it returns.
The rest of the testing will take place within the two drive cycles except the EVAP system. That may take a good while to complete due to it's complexity.
Most emissions testing will excuse the EVAP test if it is not complete at test time but then some may not.
Good luck.
Are you servicing the second cylinder from the front on the driver side. That one is cylinder 6.
How the cylinder miss is detected is by the crank sensor detecting a slow down in crank speed when that cylinder fires. This sets the code P0306.
The computer is that fast and does a compair of the time it takes the crank to rotate as compaired to all the rest of the cylinders it keeps track of on a continious basis. This is how the computer accounts for average engine wear over time by correcting the tables to reflect this.
.
The P0401 code is telling you the EGR test of exhaust flow is to low.
This can be due to carbon blockage behind the EGR valve into the intake manifold not permitting flow when tested.
A faulty DPFE sensor that is used to test and detect system faults could set the code.
The metal tube from the exhaust manifold to the EGRvalve has a calibrated orface that could be blocked.
To test these for operation, apply enough vacuum to the EGR valve with the engine at idle. If the engine gets rough, the EGR is opening ok, the port behind should be open enough and the orface is open.
This leaves the DPFE sensor you cannot really test for function. If you replace the DPFE, use a Ford part due to the very tight test limits the system has to use for the test.
Additionally, it is possible for the vacuum regulator to be sticky and not allow enough vacuum to pass to the EGR to control it's opening enough.
.
On the cylinder miss, be sure the boot is in good condition and that you used the proper grease inside the boot tip so it will 'find' the plug and slide on instead of jamming off to the side and cause the issue.
A single cylinder miss should not be that hard to solve. Be sure the connector plug is seated on the coil.
If you clear the codes after service, the PCM will do a complete system test but the 306 code should not return if the issue is solved.
The 401 code will take two drive cycles to see if it returns.
The rest of the testing will take place within the two drive cycles except the EVAP system. That may take a good while to complete due to it's complexity.
Most emissions testing will excuse the EVAP test if it is not complete at test time but then some may not.
Good luck.
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From: Land of a Thousand Trees
Toyz and Bluegrass thanks for the info.
I am going to go out on a limb and say I may have it figured out. I since i had already replaced the sparkplug(Motorcraft) and coil on cylinder 5(BWD COP)with dielectric grease for the p0305 misfire and it didn't solve the problem I went ahead and serviced the TB assembly and serviced the MAF also. I followed the info on this thread https://www.f150online.com/forums/articles-how-tos/312263-cleaning-throttle-body-6.html[/URL] and even added some pics of my TB glogged ports. I put it all back together and have driven about 45 miles so far. I have no CEL codes and all my monitors have cycled through and cleared minus the EVAP system.
Bluegrass I think your right about them letting that one slide but I'll find out for sure after work today when I take it back for the inspection. Thanks again for the replies.
I'm still not sure why I kept getting the misfire code as well and the EGR inssufficient code but after looking at the condition of the TB I'm suprised the truck even ran with all that junk in there.
I am going to go out on a limb and say I may have it figured out. I since i had already replaced the sparkplug(Motorcraft) and coil on cylinder 5(BWD COP)with dielectric grease for the p0305 misfire and it didn't solve the problem I went ahead and serviced the TB assembly and serviced the MAF also. I followed the info on this thread https://www.f150online.com/forums/articles-how-tos/312263-cleaning-throttle-body-6.html[/URL] and even added some pics of my TB glogged ports. I put it all back together and have driven about 45 miles so far. I have no CEL codes and all my monitors have cycled through and cleared minus the EVAP system.
Bluegrass I think your right about them letting that one slide but I'll find out for sure after work today when I take it back for the inspection. Thanks again for the replies.
I'm still not sure why I kept getting the misfire code as well and the EGR inssufficient code but after looking at the condition of the TB I'm suprised the truck even ran with all that junk in there.
Last edited by FAT50RACER; Jan 25, 2011 at 07:05 PM.