High Idle Problem
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From: The Iron Range of Minneso
High Idle Problem
Could an out of range or missadjusted TPS cause a high idle (1500 and higher RPM) on an 88 5.0 F-150? The only code I get from the EEC is for this.
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Check the voltage it is puting out. It should be .5-1.0 volts with a closed throttle. As the throttle is opened the reading should increase smoothly to 4-5 volts at WOT. If it works good but the reading is high at Idle it can be adjusted down by loosening the screws and moving it.
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From: Connecticut
Howdy;
Question: The TPS is adjustable by loostening the 2 screws and rotating it? When it is removed, there seems to be a rotating "spring like action"!
When reinstalling it, how do I know that I have set it in it's proper position on a 2.3L EFI~4banger?
I also have the high idleing, but never over 1500rpm and it does decrease after about 10 seconds. While this is going my CEL is lit!
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Take a walk on the wild side + you'll find me there!!
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Last edited by wolfen; Oct 8, 2003 at 04:25 PM.
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From: Louisville,Ky.
The output voltage should be no more than 1.0 volts at idle position.
It is normal to idle up for a second when first started, then it will come down to around 750 when it settles.
If it is staying too long, I would look into the IAC for sticking or being sluggish. A good cleaning may help.
Jimmy
It is normal to idle up for a second when first started, then it will come down to around 750 when it settles.
If it is staying too long, I would look into the IAC for sticking or being sluggish. A good cleaning may help.
Jimmy
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From: Connecticut
Hi lxman1; Thank you for your response! Dissassembled, inspected + cleaned IAC valve< (Is this also known as an Air Bypass Valve?) Should the internal mechanism inside slide in + out tightly or have slack? My idle is high @ start up + any time but it does settle to roughly 8-900 rpm within 5-8sec.'s and stays there until I'm underway then when I approach a stop signal, I depress my clutch + the idle is @ 1500 then within 5 sec.'s drops to 8-900, never any lower. And also having disassembled the TPS to inspect, clean + reinstall it, I found there is a white plastic piece in it that rotates, under tension, and hooks up to the throttle plate thus regulating it's movement. How do I know it was reinstalled correctly by check the output voltage like you have stated?
COME - BACK!
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Take a walk on the wild side + you'll find me there!!
The Brain Is Always On The Move
_______________________________________________
My Beastie:
90 Ranger 2.3L EFI 2wd Mazda < with many new parts!
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From: Louisville,Ky.
You shouldn't move the plunger in the IAC at all, it probably has stripped gears on the motor. I would get a new one.
Jimmy
Jimmy
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From: Connecticut
Hi again lxman1; Thank you for your multiple responses! Will check into pricing of this sensor and definately not @ a dealership!!
FTE IS GREAT! FTE FOREVER!! 
_______________________________________________
Take a walk on the wild side + you'll find me there!!
The Brain Is Always On The Move
_______________________________________________
My Beastie:
90 Ranger 2.3L EFI 2wd Mazda < with many new parts!
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From: The Iron Range of Minneso
I checked the TPS voltage at idle. It was at 1.27 volts. However, I decided to check the timing. It was at 5 before TDC. I reset the timing to 10 BTD. Also did a deflection test on the timing chain it is tight. After reseting the timing the voltage on the TPS dropped to 1.0 volts and operates smoothly. I have yet to clear the old codes and see if the TPS code comes up again. I still suspect a marginal MAP sensor as I noticed the exguast pipe is black and sooty. So far the suggestions I have gotten in this forum have helped in trying to track the problem down. when I finaly hit on the problem I will share it with all. Thanks
The weird thing is, is that since it warmed up to 80 degrees out side my problem has not been as bad.
The weird thing is, is that since it warmed up to 80 degrees out side my problem has not been as bad.
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From: Connecticut
Hi brrossi; Unhook your battery for 20 min. to clear your codes! This process is one of the processes that are used! I have EFI! I assume you have a distributor?COME - BACK!
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Take a walk on the wild side + you'll find me there!!
The Brain Is Always On The Move
_______________________________________________
My Beastie:
90 Ranger 2.3L EFI 2wd Mazda < with many new parts!
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From: The Iron Range of Minneso
Just to keep you up to date on my quest to repair my high idle problem. After 4 days of running fine it finaly started the high idle routine again. This time I was armed with a digital volt meter and checked the output voltage on the TPS. It had jumped from 1.0 volts to 2.47! The throttle is still against the stop. I guess I may have a faulty TPS. (the weather changed also, from 70's to 50's) I guess I will have to replace it.
Anyone agree with this?
Anyone agree with this?
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From: The Iron Range of Minneso
Figured I would update you all on the idle problem. It has been solved with a new TBS. Thank you all for your input on my problem, the info on the TBS voltage output helped me track down the problem.
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