low idle when cold
Posting Guru
Joined: Feb 2002
Posts: 1,534
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From: Warren, MI
low idle when cold
Originally posted by rjschlif
86 Ranger auto, 2.3 liter 140-EFI
Does this engine have a idle up valve?
What controls the the idle speed?
86 Ranger auto, 2.3 liter 140-EFI
Does this engine have a idle up valve?
What controls the the idle speed?
Senior User
Joined: Oct 2002
Posts: 420
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From: Harrisburg USA
low idle when cold
Are you familiar with the TPS (Throttle Position Sensor)?? There is a little servo motor on the throttle linkage, with 4 wires coming out of it. It moves a stop in & out to control idle speed, and the rate at which the engines revs drop after the throttle is closed. The SENSOR, which is on the throttle body, often becomes dirty, & fails to send the correct signals to the computer. Sometimes, if you clean the sensor real good, and check & clean all the electrical connections to & from the sensor and the servo, the problem goes away.
Senior User
Joined: Oct 2002
Posts: 420
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From: Harrisburg USA
low idle when cold
Hey Ken, I don't have first hand experience with the IAC, but I do have some TPS experience. I know that the TPS has a sensor on the throttle body shaft (on my CARB, it is on the passenger side, the servo is on the driver side). I don't know if FI engines have the sensor in the same location, or even if it looks the same. If I understand correctly, the IAC (Idle Air Control???) allows some fresh air to "leak" (or trickle) into the fuel/air stream to raise idle speed without actually moving the linkage, whereas my TPS actually does move the linkage. Am I on the right track with that??? If yes, did they stop using TPS altogether when they instituted IAC??? Or do some engines have both??? I also don't know what year they started installing IAC.
rjschlif, if I completely confused you, so sorry. I should do a little homework on IAC (and TPS maybe also).
Ken, thanks for keeping me on my toes.
rjschlif, if I completely confused you, so sorry. I should do a little homework on IAC (and TPS maybe also).
Ken, thanks for keeping me on my toes.
Post Fiend
Joined: Dec 2001
Posts: 10,562
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From: South Jersey
low idle when cold
FI engines have a TPS that only tells the PCM what the position of the TP is, the IAC controls the idle speed. Didn't realise you had a carbed enigine, I guess the TPS is different on them, I'm not familar with that setup.
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low idle when cold
HI all thanks so much for your help. I found what I thought was the TPS (four wires attached to a plug, which is attached to the throttle body. I removed the screw holding it to the throttle body. Nothing mechanical must be a sensor. (The pins are slightly corroded hard to clean) It was attached to the back of the throttle body near the firewall.
Any idea of what I found?
Thanks, Rick
Any idea of what I found?
Thanks, Rick
Posting Guru
Joined: Feb 2002
Posts: 1,534
Likes: 2
From: Warren, MI
low idle when cold
Originally posted by rjschlif
HI all thanks so much for your help. I found what I thought was the TPS (four wires attached to a plug, which is attached to the throttle body. I removed the screw holding it to the throttle body. Nothing mechanical must be a sensor. (The pins are slightly corroded hard to clean) It was attached to the back of the throttle body near the firewall.
Any idea of what I found?
Thanks, Rick
HI all thanks so much for your help. I found what I thought was the TPS (four wires attached to a plug, which is attached to the throttle body. I removed the screw holding it to the throttle body. Nothing mechanical must be a sensor. (The pins are slightly corroded hard to clean) It was attached to the back of the throttle body near the firewall.
Any idea of what I found?
Thanks, Rick
Was there a shaft inside the hole with flats on it and the unit you remove spring loaded, it is the TPS.