Idle speed
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Laughing Gas
Joined: Dec 2003
Posts: 752
Likes: 32
From: North Carolina
Could be....I searched my old posts but did not go back that far....you have too much time on your hands 
and yes, I am. Dealership is useless...plugs look lean, have searched every hose and fitting for a vacuum leak with no success. I still think the 500RPM or less I see in drive with AC on is too low. Oh, and as an added tip, have a CEL , have cleared it and waiting to see if it comes back or is just an anomaly. Forget the code, but was basically upstream O2 sensor on passenger side.
and yes, I am. Dealership is useless...plugs look lean, have searched every hose and fitting for a vacuum leak with no success. I still think the 500RPM or less I see in drive with AC on is too low. Oh, and as an added tip, have a CEL , have cleared it and waiting to see if it comes back or is just an anomaly. Forget the code, but was basically upstream O2 sensor on passenger side.
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Laughing Gas
Joined: Dec 2003
Posts: 752
Likes: 32
From: North Carolina
Well...the plot thickens. Since nobody jumped on the idle speed question I tried to search the interwebs using every phrase I could think of, without any luck. Why is this information so hard to find ?? Anyway, came home today, having ran the truck down to about 1/4 tank (from nearly full). As I get out of my truck, I stop to pet the dog and I hear several loud pops and bangs from under the truck....look underneath and my plastic fuel tank is seriously collapsed in the middle. I have read of this issue before on here (just search out bent fuel pump). So, I'm off to fill up...and buy a part , cannister vent valve solenoid I believe, and see what happens.
Posting Guru
Joined: Jul 2008
Posts: 1,250
Likes: 1
Looks like just 750 RPM range is ideal.
What RPM should my 4.6 idle at? - Ford Explorer and Ranger Forums "Serious Explorations"®
A few other searches show that 500-600 is fairly common, but general consensus is that 700-800 is where it needs to be.
https://www.google.com/webhp?sourcei...le%20rpm%204.6
What RPM should my 4.6 idle at? - Ford Explorer and Ranger Forums "Serious Explorations"®
A few other searches show that 500-600 is fairly common, but general consensus is that 700-800 is where it needs to be.
https://www.google.com/webhp?sourcei...le%20rpm%204.6
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Laughing Gas
Joined: Dec 2003
Posts: 752
Likes: 32
From: North Carolina
Well, the purge solenoid is non functional. Removed it, observed it's current state, with truck running and 13v present in plug, attached plug and the state of the solenoid did not change. Sadly, no Auto Zone or Advance in reasonable distance has stock. I left the solenoid out but plugged in and zip tied up out of the way. Removed vacuum line from Purge valve on intake manifold and blocked off the port for now. Cleared codes and took for a drive to fill up tank. At least so far, I appear to have dodged the bullet of the pump and sending unit being damaged. Worst case, will order from Rock Auto tomorrow and install when it arrives.I just can't believe that Ford does not have some fail safe mechanical valve or a "fail open" type solenoid much like most thermostats are now. I did however notice a difference in filling up. For some time now, even if just filling up to the first shut off, I would have some spillage out of the overflow up top. Today, after removing the solenoid, etc... I filled up until the shutoff happened 3 times...no spillage.
Super Moderator
Joined: Aug 2003
Posts: 25,479
Likes: 742
From: Isanti, MN
Very interesting, I don't think I've heard of this before. Has your idle changed? Makes sense to me that a vapor lock in the fuel tank could restrict fuel flow and cause a lean condition.
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Laughing Gas
Joined: Dec 2003
Posts: 752
Likes: 32
From: North Carolina
Tom, not really sure if the AC idle is better..not much idling today. Drove about 250 miles today, no new CEL's and appears to run just fine. Still kinda cool in mornings here in mtns (mid50's) so did not run AC this a.m. and when I did run this afternoon a little , it was at highway speed. I am going to try to force in some AC idle time tomorrow, looks like another 250 mile day ahead of me again, so hopefully, I will get some results. On a good note, my local Ford dealer ordered it for me for the same price as it would be from Rock Auto, which is still about $30 less than Auto Zone or Advance, who did not have stock anyway It's literally a 5 min install, probably less, and so far the bypass is working...no collapsed tank today !
It's literally a 5 min install, probably less, and so far the bypass is working...no collapsed tank today !
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Moderator
Joined: Jul 2011
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From: Sioux Falls Area
i know it's a different animal, but my 2010 5.4 3v idles at 530 RPM in gear with the AC on and 630 RPM in park with the AC on. (According to the digital tach in the "engineering test mode") did not check idle speed without the AC.
i remember reading something about the 2009 and 2010 model years and the idle being set lower to help conserve gas, but couldn't find it now if i had to prove it.
i'd be less concerned about the actual idle speed than i would be concerned that it may have changed from what it used to be.
i remember reading something about the 2009 and 2010 model years and the idle being set lower to help conserve gas, but couldn't find it now if i had to prove it.
i'd be less concerned about the actual idle speed than i would be concerned that it may have changed from what it used to be.
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Laughing Gas
Joined: Dec 2003
Posts: 752
Likes: 32
From: North Carolina
Well..another long day behind the windshield and no CEL, and running quite well. It does seem to be smoother now with AC on and I ran it down to less than 1/4 tank and the fuel tank did not implode. Got my new solenoid few minutes ago, gonna plug it in and keep on trucking to see how it goes. I will update after some miles accumulate and may even pull a plug or two to see how the mixture is looking, but that probably won't happen until Saturday. Thanks to all who have helped out and stay tuned to see what happens from here
Senior User
Joined: Dec 2007
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the CPU controls the idle speed
when the idle speed is off much of the time it's the MAF sensor causing the issue then it's the idle air speed sensor then the injectors then the pump. (generally speaking) - of course you should always check for a dirty air filter first.
the trouble code will point in the right direction
when the idle speed is off much of the time it's the MAF sensor causing the issue then it's the idle air speed sensor then the injectors then the pump. (generally speaking) - of course you should always check for a dirty air filter first.
the trouble code will point in the right direction
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Laughing Gas
Joined: Dec 2003
Posts: 752
Likes: 32
From: North Carolina
The only code I ever got was for the upstream O2 sensor on passenger side. It may well end up being that...but not yet. Sometimes the codes can somewhat mislead...but time will tell in this case. The MAF was replaced sometime back with no change, not a single injector because all the plugs looked lean at last replacement and no offense meant at all(see ..smiling ), but I'm (modestly speaking) a slightly better than average shade tree wrench turner...the air filter has been replaced several times since this began. When it first began I took it to the dealer under warranty...no codes, they cant feel the problem...therefore no problem in their eyes. Bought the truck new and have put ever one of the 140,000+ miles on it...I know every creak , groan , rattle and squeak in this truck. I figured the final solution would eventually raise it's head if given enough time, so hopefully this is it and I got lucky to avoid tank and pump damage.
), but I'm (modestly speaking) a slightly better than average shade tree wrench turner...the air filter has been replaced several times since this began. When it first began I took it to the dealer under warranty...no codes, they cant feel the problem...therefore no problem in their eyes. Bought the truck new and have put ever one of the 140,000+ miles on it...I know every creak , groan , rattle and squeak in this truck. I figured the final solution would eventually raise it's head if given enough time, so hopefully this is it and I got lucky to avoid tank and pump damage.
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Laughing Gas
Joined: Dec 2003
Posts: 752
Likes: 32
From: North Carolina
meborder, I think you nailed it by asking if there has been a change. To be brutally honest, I never looked at idle speed until this issue began. It may well be at the correct idle speed, but if the condition is lean, under the AC load, it could well be rough and ...well, not normal. Like I said..time will tell. Curious if the mods could link this thread to the bent fuel pump threads...maybe someone could avoid pump and tank damage by noticing some of these symptoms ahead of time.
Moderator
Joined: Jul 2011
Posts: 6,513
Likes: 669
From: Sioux Falls Area
if there is any interest in doing so, i'll be happy to add it to the Technical Tips sticky.
probably good info to have at hand knowing about the purge solenoid as it relates to the fuel pump and possible rough idle conditions.
what do you say, guys?
it's your forum, tell me what you want to see!
probably good info to have at hand knowing about the purge solenoid as it relates to the fuel pump and possible rough idle conditions.
what do you say, guys?
it's your forum, tell me what you want to see!
Thread Starter
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Laughing Gas
Joined: Dec 2003
Posts: 752
Likes: 32
From: North Carolina
May not be bad idea. As I said before though, I think a little time will tell the true tale. I drive a LOT of miles, usually at least 150 mi round trip, each day. It won't take me long to be confident that the CEL does not come back, idle stays smooth and check a couple of plugs to see if mixture is better, and I fill up about every other day...so if there are any issues with tank for pump or sending unit, I should know soon. Thanks to all who chimed in..maybe we can all benefit from this if it all pans out for the better !