6.9 high idle not working

[Ronnie King]

any ideas how to fix this problem ?

 

[icanfixall]

Welcome to the forum. You realize you MUST press down on the throttle peddle to make it work. The solenoid is not strong enough to speed up the idle. Also the power it gets comes from the sender located deep behind the thermostat housing. If that plug is disconnected not only will you fast idle not work but you wont have the cold advance either in the injection pump during warmups. When the coolant temp reaches 120 degrees the sender opens and cuts power to the two items mentioned.

 

[IDIBRONCO]

Sometimes some dirt can get inside the plug and cause it to have a bad connection. You could try to unplug and then plug it back in several times. If you don't know where the above mentioned plug/sender is at, it's right below the spot where the upper radiator hose attaches to the engine. That piece your hose attaches to is your thermostat housing.

 

[rsaltaresjr]

Disconnect the two wires going into the switch behind your thermostat housing pipe. Jumper the two connectors, if the hi idle solenoid stays energized/on after you jumper, with key in on position, then the switch is your problem. If the thermo switch is the problem. You can remove and replace it for around 50 bucks from amazon. I took the advice of another member and ended up running a pair of wires from the factory harness connectors, at the thermo switch, to the interior and installed a lighted rocker switch under the dash. Now I just flip the switch, tap the throttle, and start it up after the glow cycle. I can leave the hi idle turned on as long as I need to. The lighted switch serves as a reminder, because I don’t always wait for a full warmup before I get rolling. Basically I just went from an automated temperature controlled switch to a manual switch in the cab. Also, in case anyone is wondering it’s completely separate from the temperature sender that operates your gauge. I’ve been using this setup for a few months now without any problems.

 

[rsaltaresjr]

If the thermo switch is the problem and you prefer to remove and replace it, I found this to be the best deal.

Oem Ford E8tz9e939a Engine Coolant Temp/Temperature Thermostatic Switch https://www.amazon.com/dp/B0042KYF50/ref=cm_sw_r_cp_api_ig6yAbNR06DSX

 

[icanfixall]

The switch above is the one you want if yours is bad. Its in a tricky area but a long extension and socket can reach it. If you need to replace it no need to drain coolant. Just let engine cool down and leave the radiator cap on and remove the sender. Very little if any coolant will run out. Same principle as thumb over a straw in soda. you can lift full straw out and nothing runs out till you let off the top of the straw.