Stumped
Thread Starter
|
New User
Joined: May 2011
Posts: 3
Likes: 0
Stumped
Hey Y'all! I've got a problem with a 1999 f150 w/4.6 V8 91,000 miles. First off let me thank all of the people who gave help with a p0401 code. I got the code and with the help of this forum found the throttle body ports plugged along with leaking boots on the pcv valve line. All fixed now! Anyway, a few months ago i got p0133 code O2 sensor CKT slow response. It also had a miss especially at highway speeds while accelerating. I replaced bank one O2 sensor and removed the code. No more code problems. The truck still has the miss and shows no codes. I checked the coils with a piece of hose between the coil and plug wire and a grounded screwdriver. I had a strong spark on all 8 cylinders with and didn't see one miss a spark at idle. I also raised the hood while it was dark to see if I could see a plug wire arcing but saw nothing. Any ideas?
Lead Driver
Joined: Sep 2006
Posts: 7,907
Likes: 143
Well you tested for spark the old way for single coil systems that is no longer valid with computer control.
A missing spark in general will set a code.
What you likely have is a low output condition you cannot detect with the method you used.
At cruise in light load and light throttle, the EGR opens.
At this point the air/fuel ratio goes very lean and needs full coil output to fire the lean ratios at higher than idle rpm.
You cannot detect this by a visual at idle when the coils are not asked to fire a lean mixture.
A condition such as this is not a hard fault because it is only present under certain conditions so any code history 'in the immediate' is canelled as soon as the condition is exited so no code will be set when the fault is not present.
Now it may be something different for you but this is one fault little understood and causes a hassle until caught up with.
Good luck.
A missing spark in general will set a code.
What you likely have is a low output condition you cannot detect with the method you used.
At cruise in light load and light throttle, the EGR opens.
At this point the air/fuel ratio goes very lean and needs full coil output to fire the lean ratios at higher than idle rpm.
You cannot detect this by a visual at idle when the coils are not asked to fire a lean mixture.
A condition such as this is not a hard fault because it is only present under certain conditions so any code history 'in the immediate' is canelled as soon as the condition is exited so no code will be set when the fault is not present.
Now it may be something different for you but this is one fault little understood and causes a hassle until caught up with.
Good luck.
Thread Starter
|
New User
Joined: May 2011
Posts: 3
Likes: 0
Thank you for the info. So you think my best bet would be to drive it until the coil pack gets bad enough to throw a code? Do you think that the P0133 code had anything to do with it? This truck belongs to my mother in law so I don't drive it therefor i dont know how long it's been like this. Yes I do drive a Ford lol! A 2004 extended cab lariat 4x4! Love it!
Lead Driver
Joined: Sep 2006
Posts: 7,907
Likes: 143
Only way is to have a dealer do a stress test to pick out any low output coil.
A 133 code is a slow responding Oxygen sensor bank 1 front (passenger side).
Not directly related to ignition.
The slowness is contamination on the tip where it senses oxygen through migration of the exhaust gas sample that changes the 'voltage' response signal the PCM used to control fuel injection amounts, on a real time basis.
Contamination can be from several sources such as additives in the gas, additive cleaners, excess oil consumption, leaded gas etc that deposits a coating on the sensor tip..
Good luck.
A 133 code is a slow responding Oxygen sensor bank 1 front (passenger side).
Not directly related to ignition.
The slowness is contamination on the tip where it senses oxygen through migration of the exhaust gas sample that changes the 'voltage' response signal the PCM used to control fuel injection amounts, on a real time basis.
Contamination can be from several sources such as additives in the gas, additive cleaners, excess oil consumption, leaded gas etc that deposits a coating on the sensor tip..
Good luck.
Thread
Thread Starter
Forum
Replies
Last Post
mike L
1987 - 1996 F150 & Larger F-Series Trucks
9
Jan 9, 2013 09:49 PM
