Air flow goes to defrost randomly
#1
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?
#2
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
heres my thread for some info if you wish...
https://www.ranger-forums.com/forum2...ad.php?t=25791
#3
#5
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
~HJ
#7
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.
#9
#10
Originally Posted by 4X2XLT
you know of any way to detect where a leak could be bob?
#11
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?
#12
#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.
#14
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?
#15
#16
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.
#17
#18
Originally Posted by 4X2XLT
but would that rule out a leak then?
#19
#21
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?
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.
#23
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.
#24
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.