Air flow goes to defrost randomly - Ranger-Forums - The Ultimate Ford Ranger Resource


General Technical & Electrical General technical and electrical discussion for the Ford Ranger that does not fit in any other sub-forum.

Reply
 
LinkBack Thread Tools Search this Thread
  #1  
Old 08-11-2006
GubNi's Avatar
Member
Thread Starter
 
Join Date: Aug 2006
Location: Johnson City TN
Posts: 13
Air flow goes to defrost randomly

I have a 2000 Ranger 2wd 4cyl that is my daily driver. I have a problem with the air flow randomly going to defrost ducts. It happens most when I have A/C set to full fan and Max. It may be just that I notice it most then. Any ideals on what I should check? Has anyone else had this problem?
Reply With Quote
  #2  
Old 08-11-2006
jtslmn720's Avatar
RF Veteran
iTrader: (1)
 
Join Date: Oct 2004
Location: Kent State, Kent Ohio
Posts: 7,367
he i have the same problem... its that black box thats behind your glovebox that needs to be replace, ive heard its like 300ish becsaue they have to take the whole dash aprart to get to it...



heres my thread for some info if you wish...

https://www.ranger-forums.com/forum2...ad.php?t=25791
Reply With Quote
  #3  
Old 08-11-2006
GubNi's Avatar
Member
Thread Starter
 
Join Date: Aug 2006
Location: Johnson City TN
Posts: 13
Fortunately my problem isn't that complicated and it works most of the time. I did see by reading yours that it is vacuum controlled. I was hoping it was soleniod controlled.
Reply With Quote
  #4  
Old 08-11-2006
jtslmn720's Avatar
RF Veteran
iTrader: (1)
 
Join Date: Oct 2004
Location: Kent State, Kent Ohio
Posts: 7,367
yea its confusing, if you take it in, let me know what it was because it might give me some more options...
Reply With Quote
  #5  
Old 08-11-2006
HAZZARDJOHN's Avatar
Member
 
Join Date: Dec 2005
Location: Wyoming MN
Posts: 2,400
YEah that can be a problem. Also Does it happen mostly when you are under wide open throttle? The reason I ask is I had a buick in High school that when you floored it (Not that I would ever do that! ) would lose all the vacuum and thus change the direction the air came out from the floor to the vents. It would go away as soon as the engine slowed down a hair and built up a little more vacuum.

~HJ
Reply With Quote
  #6  
Old 08-11-2006
GubNi's Avatar
Member
Thread Starter
 
Join Date: Aug 2006
Location: Johnson City TN
Posts: 13
I do notice it most at highway speeds and around here it's very hilly, so could be. I wonder it an auxillary vacuum pump would fix it?
Reply With Quote
  #7  
Old 08-11-2006
V8 Level II's Avatar
RF Veteran
iTrader: (4)
 
Join Date: Nov 2004
Location: Michigan
Posts: 7,831
The defroster door is operated by a vacuum servo. The servo defaults to defrost when the vacuum drops. So, If you have this problem, it is most likely caused by a vacuum leak underhood at either the vacuum reservoir or the vacuum lines going to and from the reservoir. There is a check valve built into the reservoir to keep the vacuum from dropping off at WOT. If you can't find anything under the hood, it is also possible that there is a vac leak under the dash in the lines going to the servos.
Reply With Quote
  #8  
Old 08-11-2006
jtslmn720's Avatar
RF Veteran
iTrader: (1)
 
Join Date: Oct 2004
Location: Kent State, Kent Ohio
Posts: 7,367
you know of any way to detect where a leak could be bob?
Reply With Quote
  #9  
Old 08-11-2006
GubNi's Avatar
Member
Thread Starter
 
Join Date: Aug 2006
Location: Johnson City TN
Posts: 13
You can detect the leak by spraying carb cleaner while the engine is running and listen for a difference in idol speed. I wonder where the vacuum canister is though?
Reply With Quote
  #10  
Old 08-11-2006
V8 Level II's Avatar
RF Veteran
iTrader: (4)
 
Join Date: Nov 2004
Location: Michigan
Posts: 7,831
Quote:
Originally Posted by 4X2XLT
you know of any way to detect where a leak could be bob?
You can usually see the damage or hear it hissing. If there's nothing obvious, a hand vacuum pump could be used to check different sections of the vacuum supply to the A/C. That could narrow down the location of the problem so you can check it more carefully.

Reply With Quote
  #11  
Old 08-11-2006
V8 Level II's Avatar
RF Veteran
iTrader: (4)
 
Join Date: Nov 2004
Location: Michigan
Posts: 7,831
Quote:
Originally Posted by GubNi
You can detect the leak by spraying carb cleaner while the engine is running and listen for a difference in idol speed. I wonder where the vacuum canister is though?
The vac reservoir is under the engine air cleaner housing. It's a black plastic sphere about the size of a softball.
Reply With Quote
  #12  
Old 08-11-2006
jtslmn720's Avatar
RF Veteran
iTrader: (1)
 
Join Date: Oct 2004
Location: Kent State, Kent Ohio
Posts: 7,367
ok another thing bob... my vacuum gauge sits at 19-20 at idle... normal? or is it low meaning a leak? or would it not even matter waht that says because unless im on the leaking line, i wont detect it?
Reply With Quote
  #13  
Old 08-11-2006
GubNi's Avatar
Member
Thread Starter
 
Join Date: Aug 2006
Location: Johnson City TN
Posts: 13
Yeah, I found it and everything appears to be ok. I just checked with starter fluid. I also have a problem with insufficient EGR flow. I bet they are related. I replaced the EGR valve and that fixed it for a month or so, then the sensor at the back and that fixed it for a month or so. The light came back on and I've been ignoring it.
Reply With Quote
  #14  
Old 08-11-2006
V8 Level II's Avatar
RF Veteran
iTrader: (4)
 
Join Date: Nov 2004
Location: Michigan
Posts: 7,831
Quote:
Originally Posted by 4X2XLT
ok another thing bob... my vacuum gauge sits at 19-20 at idle... normal? or is it low meaning a leak? or would it not even matter waht that says because unless im on the leaking line, i wont detect it?
That would be about right at your altitude in neutral or park.
Reply With Quote
  #15  
Old 08-11-2006
jtslmn720's Avatar
RF Veteran
iTrader: (1)
 
Join Date: Oct 2004
Location: Kent State, Kent Ohio
Posts: 7,367
im 99% sure the insufficant flow is the dpfe sensor, i had the same code and it fixed it but the vents still dont work....

Quote:
Originally Posted by rwenzing
That would be about right at your altitude in neutral or park.
but would that rule out a leak then?
Reply With Quote
  #16  
Old 08-11-2006
V8 Level II's Avatar
RF Veteran
iTrader: (4)
 
Join Date: Nov 2004
Location: Michigan
Posts: 7,831
Quote:
Originally Posted by GubNi
Yeah, I found it and everything appears to be ok. I just checked with starter fluid. I also have a problem with insufficient EGR flow. I bet they are related. I replaced the EGR valve and that fixed it for a month or so, then the sensor at the back and that fixed it for a month or so. The light came back on and I've been ignoring it.
The insufficient EGR flow code is usually due to a faulty DPFE sensor. EGR flow cannot affect the vacuum to the A/C.
Reply With Quote
  #17  
Old 08-11-2006
GubNi's Avatar
Member
Thread Starter
 
Join Date: Aug 2006
Location: Johnson City TN
Posts: 13
I replaced item 3 first, then item 2 twice and most recently item 1. I think you are referring to item 1 as DPFE? I know item 3 is EGR valve and item 2 is idol control valve.

Reply With Quote
  #18  
Old 08-11-2006
V8 Level II's Avatar
RF Veteran
iTrader: (4)
 
Join Date: Nov 2004
Location: Michigan
Posts: 7,831
Quote:
Originally Posted by 4X2XLT
but would that rule out a leak then?
Not necessarily. There is a restrictor orifice in one of the ports to the reservoir. A vacuum leak could drop the vacuum level in the A/C lines without causing a big drop in engine vacuum. Besides, many vacuum gauges are only accurate within a inch or two anyway.
Reply With Quote
  #19  
Old 08-11-2006
GubNi's Avatar
Member
Thread Starter
 
Join Date: Aug 2006
Location: Johnson City TN
Posts: 13
Quote:
Originally Posted by rwenzing
The insufficient EGR flow code is usually due to a faulty DPFE sensor. EGR flow cannot affect the vacuum to the A/C.
Vacuum lines go to the EGR sensor (if I'm not mistaken), so if the entire system has low vacuum wouldn't that cause both problems?
Reply With Quote
  #20  
Old 08-11-2006
V8 Level II's Avatar
RF Veteran
iTrader: (4)
 
Join Date: Nov 2004
Location: Michigan
Posts: 7,831
Quote:
Originally Posted by GubNi
I think you are referring to item 1 as DPFE?
Yes, that looks like the DPFE.
Reply With Quote
  #21  
Old 08-11-2006
V8 Level II's Avatar
RF Veteran
iTrader: (4)
 
Join Date: Nov 2004
Location: Michigan
Posts: 7,831
Quote:
Originally Posted by GubNi
Vacuum lines go to the EGR sensor (if I'm not mistaken), so if the entire system has low vacuum wouldn't that cause both problems?
I am reasonably sure that the two vacuum sources come from separate ports on the intake manifold. For it to be that low at both ports, the manifold vacuum itself would have to be very low. If that were the case, I think that you would have major idle quality problems and/or stalling. What I'm talking about is very low vacuum in the small A/C control vacuum lines because of a local leak there.

Also, are you sure that your current CEL is related to the EGR system? Has the code been pulled again since the CEL returned?

At any rate, I am here and you are there with the truck. You stand a much better chance finding the problem than I do.
Reply With Quote
  #22  
Old 08-11-2006
GubNi's Avatar
Member
Thread Starter
 
Join Date: Aug 2006
Location: Johnson City TN
Posts: 13
I have checked the code and same problem. I'm going to swap the DPFE sensor again and see if or how long that will fix it.
Reply With Quote
  #23  
Old 08-11-2006
V8 Level II's Avatar
RF Veteran
iTrader: (4)
 
Join Date: Nov 2004
Location: Michigan
Posts: 7,831
Quote:
Originally Posted by GubNi
I have checked the code and same problem. I'm going to swap the DPFE sensor again and see if or how long that will fix it.
Since you have already replaced the DPFE, I would take a look at the two hoses that run from the DPFE to the EGR tube and then check the EGR tube itself for any obvious problems. Any leak would cause flow measurement problems for the DPFE.
Reply With Quote
  #24  
Old 08-11-2006
GubNi's Avatar
Member
Thread Starter
 
Join Date: Aug 2006
Location: Johnson City TN
Posts: 13
Quote:
Originally Posted by rwenzing
Since you have already replaced the DPFE, I would take a look at the two hoses that run from the DPFE to the EGR tube and then check the EGR tube itself for any obvious problems. Any leak would cause flow measurement problems for the DPFE.
I checked all that last time. The sensor is still under warranty, so I'll try that. I guess the next stop is to pull the tube off and inspect it again. It was a real pain to line up when I replaced the valve.
Reply With Quote
  #25  
Old 08-11-2006
TXranger4x4's Avatar
Member
iTrader: (1)
 
Join Date: Dec 2005
Location: McAllen, TEXAS
Posts: 287
i have having a problum too.....my A/c blows out the deforster also but when i put it in 4x4 and then turn it off it works....i do not know what to check and i would really like to find out cuz it gets up to 110 here and its hummide as hell......any1 have any ideas??????
Reply With Quote
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Air only blows through dash defrost on all settings floor,vent. Only blows wide open? cseay99 SOHC - 2.3L & 2.5L Lima Engines 4 12-08-2011 10:42 AM
Air coming out of defrost Jomaralberto SOHC - 2.3L & 2.5L Lima Engines 11 11-27-2011 09:48 PM
Air blowing of defrost Jomaralberto SOHC - 2.3L & 2.5L Lima Engines 5 11-02-2011 12:03 AM
Only Hot Air Blows Through Defrost All The Time *PLEASE HELP* mx49dad General Technical & Electrical 4 03-08-2011 07:14 PM
cold air intake/ mass air flow sensor question RangerRunner96 2.9L & 3.0L V6 Tech 5 08-29-2008 02:01 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -6. The time now is 10:24 AM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.