high idle problem on a 4.0

[Rollin]

Have you tried setting the idle like this,
Originally Posted by ransil
Idle reset procedure.

1. Unplug the SPOUT connector, start the engine and let it reach operating temperature, then check and, if necessary, adjust base timing.
2. Shut the engine down, then stick a .050-inch feeler gauge between the throttle stop screw and lever.
3. Disconnect the IAC solenoid connector, shift the transmission into Park, start the engine and allow it to stabilize for approximately two minutes.
4. Adjust the throttle stop screw as necessary to obtain an idle speed of 675 rpm 25 rpm.
5. Shut the engine down once again, then disconnect the battery for a minimum of five minutes to allow the PCM's keep-alive memory to time out.
6. Remove the feeler gauge, reconnect the SPOUT and IAC solenoid connectors, then start the engine and allow it to stabilize for two minutes.
7. Goose the throttle several times, let the engine return to idle, then make sure the base idle speed remains in spec.
8.Drive it for 15 minutes making frequent stops.

Is this the same procedure for all ford mass air EFI engines??
Thanks

 

[mailboxman]

yep--replaced the IAC also--no fuel in the vacuum line coming from the pressure regulator--and I dont think you can adjust idle on this motor??? No distributor.

I have a friend bringing his fuel pressure gauge home tonight--i sure hope this is it

 

[NoControl]

Sounds like the tps wires. If the voltage is correct in and out of the tps that doesnt mean the computer is getting the right voltage due to bad tps ground wire or signal wire. There is probably something wrong with one of those wires to the computer. Broken inside the loom,too much resistance or something like that. It happens a lot in 1st gen explorers.

 

[mailboxman]

hey guys--i may have been gone--but not forgotten--my fuel pressure is right on the money and the pressure regulator is working to spec----I made a gasket for the IAC valve and drilled two small hole through the gasket---my cold idle is low (around 500 rpm) so I try and let it idle for a minute or so with my foot on the gas pedal when cold and keep it around 1000 rpm. As soon as i start driving the idle slowly climbs to around 750 rpm when warm--this is acceptable but I still want to find the problem--i am not giving up yet--bit its too freakin cold outside to work on so this will have to be acceptble for now--when i do figure it out , i will post---but i am convinced as NoControl states that it is electrical and not fuel or vacuum related.

PEACE

 

[mike517]

I cant wait to hear what the solution is, I have a 91 ranger with similar issues.
been going on for 10 months and have not got it figured out yet.

Mike

 

[xentris02]

honestly i think you should take you entire intake and every thing touching it off and clean it. like upper intake and lower the hoses the whole 9 yards cause dirt could of got in the motor from a bad filter once and it all got cought together restricting air flow. you sitting here working on the out side of the motor your gonna have to move inward eventualy.

 

[mdgue]

Had the same problem with my 93. Changed and checked many things that I thought would cause the high idle. I dealt with this about a year. After ready many forums, found out ford puts some kind of coating on the throttle body and if you use to harsh of a cleaner it will remove this coating and cause issues. I cleaned the throttle body when I first got the truck. I think with carb cleaner. I decided to get an old gunked up throttle body off EBay and install. Idle returned to normal and is still normal after a couple of years. Sounds odd but worked for me. I think I paid $17 for the tb.

 

[fourtycal]

On my 93 4.0 standard 4x4
I had a similar experience. After scanning, replacing every sensor & valve, testing every vacuum line, I had removed inspected and cleaned the throttle body and spent many hours working on any possibility. One night I stared at the hole in the brass butterfly in the throttle body. I took a small square of duct tape and plugged the hole. It dropped my idle to around 500-600. I removed the butterfly, soldered the hole in solid and ran a 3/32 drill through the solder. It now idles at 800 RPM and runs great. All I can gather is the throttle housing and or the butterfly had worn enough to bypass too much air. Maybe a new throttle body would be best but for now I'm running it