Ford Ranger Forum - Forums for Ford Ranger enthusiasts!

Go Back   Ford Ranger Forum - Forums for Ford Ranger enthusiasts! > > >
Forgot Password? Join Us!

Welcome to Ford Ranger Forum

Reply
 
Thread Tools Search this Thread

  #1  
Old 12-22-2011, 07:41 PM
illesg illesg is offline
Liking the Ford Ranger Forum
 
Join Date: Dec 2011
Posts: 18
Default Is 900rpm too high an idle?

My 1996 4x4 XLT 4.0L automatic idles at 900rpm. Seems high, higher anyway than it needs to be. No hissing or other misbehavior. Runs smooth and shifts okay. Might be a little off on power - - takes 3/4 throttle and 3000rpm to hold 55mph up a 6% grade. I'm beginning to wonder about intake leaks and a dirty MAF sensor.
Reply With Quote
  #2  
Old 12-23-2011, 06:33 AM
Badmotorfinger1 Badmotorfinger1 is offline
Better than Avg Mechanic
 
Join Date: Jan 2011
Posts: 183
Default Re: Is 900rpm too high an idle?

Does your idle drop when the a/c is turned on? If say at a stop light and you blip the throttle, does your idle drop below 900rpm and then climb back up or stay steady at 900?
__________________
2000 XLT 4WD 4.0L OHV, 5 spd, Alabama Cylinder heads, Delta Cams Valve Train and Pushrods, JBA Headers, KKM Cone Air Cleaner, BBK Throttle body, Dynomax Cat-Back exhaust, Summit Racing drilled front rotors w/ EBC pads, Cobra rear disk brake conversion w/ Hawk pads, 8.8" 4.10 Traction-Lok
Reply With Quote
  #3  
Old 12-23-2011, 06:37 AM
FireRanger FireRanger is offline
Blinded by the light
 
Join Date: Sep 2009
Posts: 7,674
Send a message via AIM to FireRanger
Default Re: Is 900rpm too high an idle?

That is definitely too high. It should be in the 650-750 ranger from I recall.
__________________
(Formerly)
FireRanger
2003 Edge 4.0 4wd

How to: Aux light wiring, relays, & fuses
Info: 300+ intake threads here on FRF
Info: HID Projectors
How To: NO HEAT Troubleshooting Guide
Reply With Quote
  #4  
Old 12-23-2011, 06:56 AM
STL STL is offline
...............

 
Join Date: May 2009
Posts: 23,399
Default Re: Is 900rpm too high an idle?

Ya it should be closer to 600 on the low side and no more then 800 on the high side.
__________________
2005 Edge

Reply With Quote
  #5  
Old 12-24-2011, 09:40 AM
illesg illesg is offline
Liking the Ford Ranger Forum
 
Join Date: Dec 2011
Posts: 18
Default Re: Is 900rpm too high an idle?

Quote:
Originally Posted by Badmotorfinger1 View Post
Does your idle drop when the a/c is turned on? If say at a stop light and you blip the throttle, does your idle drop below 900rpm and then climb back up or stay steady at 900?
Blipping the throttle doesn't help a bit. The A/C load has maybe a 50rpm effect if any. The throttle cable is not binding (and has full travel too). The cruise control cable also seems to be smooth and drag-free.

I'm going to hit the MAF cleaning and check out the throttle body and see if anything looks funny.
Reply With Quote
  #6  
Old 12-24-2011, 05:55 PM
Cdy291 Cdy291 is offline
Ford Tough
 
Join Date: Nov 2010
Posts: 281
Default Re: Is 900rpm too high an idle?

900 is a good idle for the 3.0, but like the others said the 4.0 should be lower.
__________________
2001 Ranger Edge
3.0 V6
Automatic
4.10 gears
97,780 mi
Reply With Quote
  #7  
Old 12-24-2011, 06:54 PM
Fordzilla80 Fordzilla80 is offline
Welcome to FRF!
 
Join Date: Oct 2010
Posts: 8,952
Default Re: Is 900rpm too high an idle?

Quote:
Originally Posted by Cdy291 View Post
900 is a good idle for the 3.0, but like the others said the 4.0 should be lower.
You're not kidding. My 3.0 runs like crap at 650.
Reply With Quote
  #8  
Old 12-24-2011, 06:55 PM
Rango88 Rango88 is offline
N/A
 
Join Date: Jan 2011
Posts: 9,031
Default Re: Is 900rpm too high an idle?

Quote:
Originally Posted by Fordzilla80 View Post
You're not kidding. My 3.0 runs like crap at all times.
living up to 3L reputation I see
Reply With Quote
  #9  
Old 12-24-2011, 10:26 PM
Rhodyguy Rhodyguy is offline
Ford Ranger 4X4 Owner
 
Join Date: Aug 2011
Posts: 787
Default Re: Is 900rpm too high an idle?

Yep, my 3.0 idles about 900 as well
__________________
2000 XLT 4 Door Super Cab
4X4 with off road pkg. Harvest Gold
3.0/auto /4.10/ 8.8L/S / Full power everything mostly stock
Reply With Quote
  #10  
Old 12-25-2011, 09:41 AM
illesg illesg is offline
Liking the Ford Ranger Forum
 
Join Date: Dec 2011
Posts: 18
Default Re: Is 900rpm too high an idle?

Well, I lied about the A/C -- it actually bumps the idle up over 1000 when the compressor is kicked in.

HOWEVER - - I found a tiny little rotten vacuum hose just underneath the TB, hidden by all the shrouding and linkage. Also found that the air temp sensor had been yanked out of the air duct and was hanging free. Got those bugs taken care of and the idle is just a hair down to 800 now. The truck SEEMS to have a bit better power and throttle response as well.

While I was troubleshooting, I noticed a LOT of black coating inside the TB, so today that gets cleaned up, along with the MAF.

Fingers crossed.
Reply With Quote
  #11  
Old 12-25-2011, 07:19 PM
illesg illesg is offline
Liking the Ford Ranger Forum
 
Join Date: Dec 2011
Posts: 18
Default Re: Is 900rpm too high an idle?

Hmmmm - - better but still fast.
Got the MAF cleaned, the TB cleaned, the IAC cleaned. All vac lines checked. Air cleaner checked/cleaned. All looks copacetic. Idle still at 800-900. Truck truly does run better, but idle still high. Now what?
__________________
==================
Nearly stock 1996 STX 4.0 automatic
6" lift & 31" tires, 4.11's, snorkel,
locker rear end, aluminum wheels
Lots of light-weight changes (towed behind RV)
Reply With Quote
  #12  
Old 12-25-2011, 07:24 PM
FireRanger FireRanger is offline
Blinded by the light
 
Join Date: Sep 2009
Posts: 7,674
Send a message via AIM to FireRanger
Default Re: Is 900rpm too high an idle?

The stop screw on the throttle plate isn't by chance adjusted wrong and keeping the plate open a little?
__________________
(Formerly)
FireRanger
2003 Edge 4.0 4wd

How to: Aux light wiring, relays, & fuses
Info: 300+ intake threads here on FRF
Info: HID Projectors
How To: NO HEAT Troubleshooting Guide
Reply With Quote
  #13  
Old 12-25-2011, 07:50 PM
illesg illesg is offline
Liking the Ford Ranger Forum
 
Join Date: Dec 2011
Posts: 18
Default Re: Is 900rpm too high an idle?

Quote:
Originally Posted by FireRanger View Post
The stop screw on the throttle plate isn't by chance adjusted wrong and keeping the plate open a little?
Nope, checked that too when I cleaned the throttle body. I adjusted that screw carefully until the butterfly just BARELY didn't <stick> when starting to open. Figure that's the best position.

One thing I didn't do yet is un-plug the IAC to see if the idle drops. Gotta check that tomorrow.
__________________
==================
Nearly stock 1996 STX 4.0 automatic
6" lift & 31" tires, 4.11's, snorkel,
locker rear end, aluminum wheels
Lots of light-weight changes (towed behind RV)
Reply With Quote
  #14  
Old 12-25-2011, 07:52 PM
FireRanger FireRanger is offline
Blinded by the light
 
Join Date: Sep 2009
Posts: 7,674
Send a message via AIM to FireRanger
Default Re: Is 900rpm too high an idle?

The computer controls the IAC to regulate the idle air flow when the throttle plate is closed. So either the IAC is stuck/fucked or air is leaking somewhere else. I'd bet on the IAC being befuddled.
__________________
(Formerly)
FireRanger
2003 Edge 4.0 4wd

How to: Aux light wiring, relays, & fuses
Info: 300+ intake threads here on FRF
Info: HID Projectors
How To: NO HEAT Troubleshooting Guide
Reply With Quote
  #15  
Old 12-27-2011, 10:20 AM
illesg illesg is offline
Liking the Ford Ranger Forum
 
Join Date: Dec 2011
Posts: 18
Default Re: Is 900rpm too high an idle?

Progress, progress, but the pot of gold is still elusive.....

Replaced IAC after non-successful cleaning attempt. Replaced PCV and noticed significant difference between old and new valves flow characteristics (blowing through the valve).

Progress: Idle is down to about 800rpm now, and startup idle has dropped from 1500 to 1200. The sit-in-Drive idle level still feels just a tad high, but I'm getting to the point of diminishing returns.

There's 91,000 miles on this puppy, and while it hasn't been outright neglected, I don't have any service records. I'm pretty sure the plugs were replaced in the mid-80,000 range, maybe wires too. But everything else is suspect. I'm wondering about the EGR system. There are no codes/cel going on, but maybe I've got some leakage?

Another thing I've always noticed is that the truck never gets much above the lowest operating temperature level, just into the <white arc> range on the gage. I don't know how to measure it, so I don't know what it's actually running at. The thermostat is a 190 or 195, I forget.

This is now getting to be a pretty subtle problem(?) and I know from experience that I just might have to wait for something to get significantly worse before I can diagnose it. I've ordered a bluetooth OBD2 reader, so I can get more data on my Droid when I get that running.

Any help with how-to test/diagnose would be much appreciated. Meanwhile, the truck is running better than ever - - - maybe it just wanted some attention? LOL
__________________
==================
Nearly stock 1996 STX 4.0 automatic
6" lift & 31" tires, 4.11's, snorkel,
locker rear end, aluminum wheels
Lots of light-weight changes (towed behind RV)
Reply With Quote
Reply

Tags
idle, maf

Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Idle high scheider1980 4-Cylinder Tech 2 11-02-2011 02:30 PM
high idle nealretief 4-Cylinder Tech 2 09-06-2011 10:01 AM
High Idle on 87 2.3. Kmartcivic 4-Cylinder Tech 0 02-13-2011 10:01 AM
High Idle Blackhole2001 4-Cylinder Tech 0 12-20-2010 11:09 PM
89 2.9l high hydrocarbons and rough high idle dherndon99 2.9 Liter Tech 7 11-17-2010 06:50 AM