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whats does this do

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Old Jan 27, 2009 | 03:52 PM
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whats does this do

95 F-150 302. im having problems with the truck starting in the mornings. i got the battery checked, its good. changed fuel, no help. it has problems starting in the morning after that it starts everytime. i found this(below pic) not connected, look at another truck and the line comes from a heater line through the TB, out from the bottom to a sensor near/on the thermostat. the line on the top pic thats kind of kinked goes to the top elbow..what does it do..



 
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Old Jan 27, 2009 | 04:15 PM
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The sensor in your bottom pic is your coolant temp sensor. The hole in the TB is where coolant runs through to warm up the air charge before it enters the engine. If your having problems w/ idle replace that sensor, i did and it smoothed my idle right out.
 
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Old Jan 27, 2009 | 04:23 PM
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the idles goes up and down every once in a while.. but will not having that hose connected mess with the truck not starting? i dont think so since it just warms it up..
 
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Old Jan 27, 2009 | 09:29 PM
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The coolant lines have nothing to do with the engine starting.

You'll have to be a little more descriptive than just saying the truck "has problems" starting. Does it crank or not crank? Does it just crank a long time? Will it start if you put the accelerator to the floor? How many miles? When was the last tune up?
 
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Old Jan 28, 2009 | 09:09 AM
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the truck cranks. no problem. putting the acc to the floor does nothing. it just cranks when it cold. after a few mins it starts. today's temp was high 40-low 50's and it started right away. last tune was about 8 months ago.. im going to change the fuel filter. but i dont think thats going to do it. .
 
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Old Jan 28, 2009 | 05:08 PM
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They've just got the throttle body coolant lines bypassed. That coolant running through the TB supposedly keeps it from icing up. I have mine disconnected as well. I removed the metal line that runs from the radiator and plugged it off at the radiator. That adapter where the coolant sensor is and where the other side of the TB line goes was bad and leaking on my truck. I ended up fabbing a new on w/o the TB line provision out of a brass nipple and fittings, couldn't find that fitting anywhere.

As always, I'd pull the IAC valve and check it out real good. Make sure the pintle moves freely. Make sure the ports are open as well. AIC valve may be sticking when it's cold.
 
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Old Jan 28, 2009 | 05:53 PM
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Mine's disconnected as well, although it doesn't get very cold here. I figure the EGR keeps it warm enough.
 
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Old Jan 28, 2009 | 06:07 PM
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Originally Posted by tgore3
They've just got the throttle body coolant lines bypassed. That coolant running through the TB supposedly keeps it from icing up. I have mine disconnected as well. I removed the metal line that runs from the radiator and plugged it off at the radiator. That adapter where the coolant sensor is and where the other side of the TB line goes was bad and leaking on my truck. I ended up fabbing a new on w/o the TB line provision out of a brass nipple and fittings, couldn't find that fitting anywhere.

As always, I'd pull the IAC valve and check it out real good. Make sure the pintle moves freely. Make sure the ports are open as well. AIC valve may be sticking when it's cold.

where is the IAC valve? is it in one of the pics?
 
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Old Jan 28, 2009 | 07:03 PM
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It's over on the other side of the TB
 
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Old Jan 29, 2009 | 05:31 AM
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well again temps in the high 40- low 50 and the truck started first try..
 
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Old Jan 29, 2009 | 12:09 PM
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Mine actually was hard to start last night after my last post, lol. Been pretty cold here and truck sat for a day or two. Normally it just fires right up.

If it does it again, try cracking open throttle while the engine is spinning over. If IAC is stuck that will give it air to start up.
 
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Old Jan 30, 2009 | 04:04 PM
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this morn at 4am truck started good, drove 1.5hrs away, for work.. at 11am got done and went to start it,, no go.. i was fustrated cause i was not going to be stranded that far away. i held in the accel and cranked, truck stumbuld 2 times and then went to idleing good. got home removed the IAC, it was full of carbon buildup. cleaned it out. also the connector to the IAC as 2 wires. i didnt have my MM, but i stuck a test light. 1 red wire light came on, other nothing, is it ground to accuate the solonoid? if so where does it come from?
 
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Old Jan 30, 2009 | 10:15 PM
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Yes, virtually all of the engine control outputs are ground-side switched by the PCM.
 
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Old Jan 30, 2009 | 10:23 PM
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controlled bt voltage pulses from the PCM. Should be about 10.5 volts with key on engine off at the plug. With it unplugged the resistance of the IAC valve should be between 7-13 ohms.

So if you just checked it with a test light and key on, the test light would light up pretty good at 10.5v.
 
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Old Jan 30, 2009 | 11:16 PM
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if you ask me i would say you have stuck open fuel injectors, i see it often, i am a mechanic for ford, what ahppens is the fuel injectors bleed off the fuel pressure into the intake manifold, which makes a very rich condition, flooding the vehicle, after you crank the engine for a while the fuel clears the intake and the cylinders, and the truck will start, to help start the vehicle, hold the pedal to the floor, this shuts off the injectors, to diag this concern correctly, hook up a fuel pressure guage, cycle the key to pressure up the fuel system, shut it off, and watch the fuel guage, it should not drop more than 1 psi every 5 mins. good luck
 
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