14066255 throttle solenoid M1009

[Rrent]

I had an injection pump and lift pump installed. The throttle was sticking (at about 3/4 open) only when the engine was running. My mechanic found this 14066255 throttle solenoid was extending - but not retracting.
When unplugged the truck seems to run fine. What is it? What does it do? Where can I find one?

 

[dougco1]

Its called the Fast Idle Solenoid. No longer manufactured but still out there on eBay from time to time "$70.00+". It sets the idle up high when the engine is cold. Its activated by a temperature sensor in the top of the block by the firewall. Just keep it unplugged in till you find a new one. Won't hurt it at all

 

[dougco1]

I had an injection pump and lift pump installed. The throttle was sticking (at about 3/4 open) only when the engine was running. My mechanic found this 14066255 throttle solenoid was extending - but not retracting.
When unplugged the truck seems to run fine. What is it? What does it do? Where can I find one?View attachment 847424View attachment 847426

Purchase NOS AC DELCO 14066255 SOLENOID NEW NOS GM FUEL INJECTION IDLE SPEED CONTROL in Statham, Georgia, United States, for US $89.99

Purchase NOS AC DELCO 14066255 SOLENOID NEW NOS GM FUEL INJECTION IDLE SPEED CONTROL in Statham, Georgia, United States, for US $89.99

www.2040-parts.com

 

[Barrman]

If the fast idle solenoid is working. Then it doesn’t need replacement. The sensor on the outside rear of the passenger head is either faulty or the wire leads have been mashed together causing the solenoid to not turn off.

The sensor is supposed to put power to the solenoid any time the coolant is below 94°. However, when on the idle is supposed to be raised from 650 rpm to 800 rpm. The rod in the middle of the solenoid can be turned to adjust the “on” idle speed.

It reads like the person you are paying to work on this truck might not know much about the 6.2 and may not be worthy of anymore money.

 

[dougco1]

If the fast idle solenoid is working. Then it doesn’t need replacement. The sensor on the outside rear of the passenger head is either faulty or the wire leads have been mashed together causing the solenoid to not turn off.

The sensor is supposed to put power to the solenoid any time the coolant is below 94°. However, when on the idle is supposed to be raised from 650 rpm to 800 rpm. The rod in the middle of the solenoid can be turned to adjust the “on” idle speed.

It reads like the person you are paying to work on this truck might not know much about the 6.2 and may not be worthy of anymore money.

I had thought the same thing when mine had issues and logically replaced my temp sensor first. It turned out to be the fast idle solenoid that was bad and had a mind of its own. It would work fine one day but the next day it would race the engine to about 3/4 throttle. Just the same as the OP. I had a new fresh rebuild of the injection pump, new lift pump and same symptoms as the OP.