OBDII Codes came thru again
Thread Starter
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Post Fiend
Joined: Apr 2005
Posts: 5,720
Likes: 5
From: Washington state
OBDII Codes came thru again
found my poor fuel mileage problem that progressed into an intermittent miss on power acceleration and transmission bucking.
would not act up when i took it out to road test with laptop scanner connected.
finally got bad enough to trigger off the OBDII dynamic cylinder miss algorithm and set the CEL.
P301, cyl 1 misfire.
pulled #1 and 2 plugs. #1 slightly browner and slight amount of black compared to #2 but nothing out of ordinary. would not have even noticed if I were not looking for misfire. APP765s and wires only 10k miles 2 years.
replaced plug and wire. eureka, problem gone.
lots of power, no bucking on WOT and fuel mileage back 20 mpg on freeway at 65.
OBDII makes a cyl misfire even more pronounced by turning off TC lockup and/or shutting down the offending cyl/cyls injector fuel to prevent CAT damage and excessive emissions
if code would have not popped up, i would have waited until Spring thaw and then pulled all the plugs looking for a problem. got some 50d F weak sunshine today to work on it for an hour between rain showers.
I'm in Aero love again
would not act up when i took it out to road test with laptop scanner connected.
finally got bad enough to trigger off the OBDII dynamic cylinder miss algorithm and set the CEL.
P301, cyl 1 misfire.
pulled #1 and 2 plugs. #1 slightly browner and slight amount of black compared to #2 but nothing out of ordinary. would not have even noticed if I were not looking for misfire. APP765s and wires only 10k miles 2 years.
replaced plug and wire. eureka, problem gone.
lots of power, no bucking on WOT and fuel mileage back 20 mpg on freeway at 65.
OBDII makes a cyl misfire even more pronounced by turning off TC lockup and/or shutting down the offending cyl/cyls injector fuel to prevent CAT damage and excessive emissions
if code would have not popped up, i would have waited until Spring thaw and then pulled all the plugs looking for a problem. got some 50d F weak sunshine today to work on it for an hour between rain showers.
I'm in Aero love again
Elder User
Joined: Dec 2006
Posts: 830
Likes: 0
From: Kitchener,Ontario,Canada
Would not be without a scantool!
Really nice when a code pops up like that & it tells exactly where to look. I've found that the PO3XX misfire codes will set really quickly at idle (if present). However if the misfire is present at higher load/RPM settings it takes a lot longer to put the CEL on. I believe something to do with road related crankshaft deceleration (potholes etc). Misfire monitor has to be sure your not driving on a bumpy road, since this can create a similarity to the combustion related condition.
Same tactic cured my misfire also ( plug wires). However I think one of my plugs was also loosened, since I had just fitted new ones. Really important to make sure the threads & taper seats are clean. A torque wrench means nothing on a dirty thread.
Misfire at WOT sounds like a failed/contaminated plug though.
Same tactic cured my misfire also ( plug wires). However I think one of my plugs was also loosened, since I had just fitted new ones. Really important to make sure the threads & taper seats are clean. A torque wrench means nothing on a dirty thread.
Misfire at WOT sounds like a failed/contaminated plug though.
Thread Starter
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Post Fiend
Joined: Apr 2005
Posts: 5,720
Likes: 5
From: Washington state
think it was the 2 yr old Autolite ig. wire but not going to bother to try and test for intermittent. i've had my fill of that problem.
it's gone, good riddance.
the wire had worked its way out of its retainer on the valve cover allowing it to flop around and move which must have damaged the carbon coated fiber electrical conductor or the crimp connection to the metal plug cap connector.
the miss/stumble/shudder was not only at WOT but on hills and freeway on ramps. extra engine load made the problem appear and increased frequency. could drive for a week with no problem even when driven hard, then would show up
one intermittent problem like this and it brings home why service shops earn their hourly rate.
its a keeper though, ran perfectly for 11 years +. i'd forgotten what a screamer this 4L is off the line up to 80 mph.
Hondas watch out, the freeway ramp warrior is loose again
it's gone, good riddance.
the wire had worked its way out of its retainer on the valve cover allowing it to flop around and move which must have damaged the carbon coated fiber electrical conductor or the crimp connection to the metal plug cap connector.
the miss/stumble/shudder was not only at WOT but on hills and freeway on ramps. extra engine load made the problem appear and increased frequency. could drive for a week with no problem even when driven hard, then would show up
one intermittent problem like this and it brings home why service shops earn their hourly rate.
its a keeper though, ran perfectly for 11 years +. i'd forgotten what a screamer this 4L is off the line up to 80 mph.
Hondas watch out, the freeway ramp warrior is loose again
Senior User
Joined: Nov 2004
Posts: 463
Likes: 0
Quote: "i'd forgotten what a screamer this 4L is off the line up to 80 mph.
Honda's watch out, the freeway ramp warrior is loose again"
So your 4.0 is running strong? and after the install of a plug that was fouling out? cool! You must be feeling the same euphoria that I feel every time I punch mine to the floor. Lets see-brings back a thought of mine some time ago. Oh yeah! Hear it is:
Mini van Jammin'
short*long the aerostar is always strong,
strong enough to pull, competitors drool,
just right for the carpenter with an 8 foot sheet,
roomy enough for a soccer moms feet.
Problems they happen, so what?
extended bench seats folds out for nappin'
take it to the park, just right for campin'.
At the light getting ready to turn,
4.0 under my feet, locked & loaded, ready to BURN!
Rice burner beside me looking up-thinking GREAT,
I'm looking down, son don't try it-I won't hesitate!
Light turns green, launch my mighty "BAUER" off!
Rearview mirror, civic just died with a cough.
160 horses might not be that big in cubic inch,
but when you really need them, their there in a pinch!
Honda's watch out, the freeway ramp warrior is loose again"
So your 4.0 is running strong? and after the install of a plug that was fouling out? cool! You must be feeling the same euphoria that I feel every time I punch mine to the floor. Lets see-brings back a thought of mine some time ago. Oh yeah! Hear it is:
Mini van Jammin'
short*long the aerostar is always strong,
strong enough to pull, competitors drool,
just right for the carpenter with an 8 foot sheet,
roomy enough for a soccer moms feet.
Problems they happen, so what?
extended bench seats folds out for nappin'
take it to the park, just right for campin'.
At the light getting ready to turn,
4.0 under my feet, locked & loaded, ready to BURN!
Rice burner beside me looking up-thinking GREAT,
I'm looking down, son don't try it-I won't hesitate!
Light turns green, launch my mighty "BAUER" off!
Rearview mirror, civic just died with a cough.
160 horses might not be that big in cubic inch,
but when you really need them, their there in a pinch!
Lead Driver
Joined: Sep 2003
Posts: 7,017
Likes: 209
From: SoCal
I wish I could feel the same when I punch mine to the floor. My feeling is it still could be the transmission. So, was there a big difference between the A4LDs for 4 liter engines in 1990 vs 1991? I still refer to my former 1991 van as having what felt like much better transmission performance than my 1990 van.
Lead Driver
Joined: May 2003
Posts: 9,303
Likes: 48
From: Lyndonville, Vermont
pour some sea foam in the gas tank. Took two cans to wake up one of my 96's. It runs like a raped ape...If you have that wheezy exhaust sound vacuum cleaner sound when you punch it and no intake roar you need a cleaning...My 4.0 now sounds like I took the air cleaner off on a four barrel carb...Never mind 80 mph its still pulling hard....Really fun to drive.
96, glad you found the problem. I'm guessing it was the wire.
Dick
96, glad you found the problem. I'm guessing it was the wire.
Dick
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Post Fiend
Joined: Apr 2005
Posts: 5,720
Likes: 5
From: Washington state
the Ford 4L OHV engine is notorious for carbon build up in the combustion chamber and in the ring grooves. both cause power loss and poor performance. the ring groove build up drastically increases ring pressure and thus piston-ring drag.
about 6>8 years ago, I got tired of the way mine was running poorly. had read about the solvent combustion chamber cleanings and water mist cleanings. only thing i had in the garage shelf was a can of brake cleaner. that stuff worked except the huge cloud of white smoke and fumes killed all the neighborhood mosquitoes along with a number of lawn scrubs, may have blinded some neighbor dogs. stunk and the fumes burned the eyes and made one cough badly. read the warning label then and online info.
BAD stuff.
followed up with the water misting. engine ran great. had to change the oil, looked like black molasses
keep a can or 2 of Berryman B12 on the shelf now just in case. rigs get a soak dose down the plug holes or thru the TB plate every 20k>30k miles now.
about 6>8 years ago, I got tired of the way mine was running poorly. had read about the solvent combustion chamber cleanings and water mist cleanings. only thing i had in the garage shelf was a can of brake cleaner. that stuff worked except the huge cloud of white smoke and fumes killed all the neighborhood mosquitoes along with a number of lawn scrubs, may have blinded some neighbor dogs. stunk and the fumes burned the eyes and made one cough badly. read the warning label then and online info.
BAD stuff.
followed up with the water misting. engine ran great. had to change the oil, looked like black molasses
keep a can or 2 of Berryman B12 on the shelf now just in case. rigs get a soak dose down the plug holes or thru the TB plate every 20k>30k miles now.
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