IAC purpose?
Thread Starter
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Mountain Pass
Joined: Jun 2003
Posts: 208
Likes: 3
From: Norfolk VA
IAC purpose?
What is the purpose of this little thing? I am having cold idle problems and I think it is the problem. I took it off and cleaned it without any success like I normally see. This time I played a little more and I plugged 12VDC into it to see if it worked. Yes I saw the plunger move back and forth. But what looks a plug that would go in between the two sides doesn't look like it is closing. I can blow into each hole and air comes out of the other. I also got the same results with it energized. Should I be able to blow air between the two? BTW yes I also get some air flow out the little vent in the side.
Couple of patially useless facts.
1. I measured accross the two terminals and it measured 10 Ohms
2. When the engine is cold I measured the red wire as getting 14VDC.
Couple of patially useless facts.
1. I measured accross the two terminals and it measured 10 Ohms
2. When the engine is cold I measured the red wire as getting 14VDC.
Post Fiend
Joined: Apr 2005
Posts: 5,720
Likes: 5
From: Washington state
I.dle A.ir C.ontrol
http://fordfuelinjection.com/?p=39
Ford says type with small black plastic filter cap not cleanable, replace only
they do become permanently plugged or jammed by crankcase products and dirt...
some on the forum have success...try soaking air end in TB cleaner
acuator voltage is correct for yours
change your PCV valve if plugged, leaking or older than 50k, major cause of IAC failure
http://fordfuelinjection.com/?p=39
Ford says type with small black plastic filter cap not cleanable, replace only
they do become permanently plugged or jammed by crankcase products and dirt...
some on the forum have success...try soaking air end in TB cleaner
acuator voltage is correct for yours
change your PCV valve if plugged, leaking or older than 50k, major cause of IAC failure
Post Fiend
Joined: Apr 2005
Posts: 5,720
Likes: 5
From: Washington state
reread your original post
cold idle only problems are usually a failed ECT sensor engine coolant temp sensor the 2 wire one not the one wire gauge sensor
check wire and connector, they often are damaged or get pulled off
replace only, not serviceable
cold idle only problems are usually a failed ECT sensor engine coolant temp sensor the 2 wire one not the one wire gauge sensor
check wire and connector, they often are damaged or get pulled off
replace only, not serviceable
Thread Starter
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Mountain Pass
Joined: Jun 2003
Posts: 208
Likes: 3
From: Norfolk VA
That makes sense. I just had my water pump die and the engine overheated. Plus the bolts were frozen and I had to get them machined out $$$$$. The single wire has to be good because i do see the guage move. Where is the ECT sensor located?
thanks
Doug
thanks
Doug
Thread Starter
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Mountain Pass
Joined: Jun 2003
Posts: 208
Likes: 3
From: Norfolk VA
I can find on the Ford Cd that it says this about the ECT.
The Engine Coolant Temperature (ECT) Sensor (Figure 7) detects the temperature of engine coolant and supplies the information to the Powertrain Control Module (PCM).
The ECT sensor is threaded into the heater outlet fitting or cooling passage on the engine. For engine control applications, the ECT signal is used to modify ignition timing, EGR flow and air to fuel ratio as a function of engine coolant temperature. On electronic instrument cluster applications, an additional ECT is used as a coolant temperature indicator.
It sure doesn't help find the darn thing.
The Engine Coolant Temperature (ECT) Sensor (Figure 7) detects the temperature of engine coolant and supplies the information to the Powertrain Control Module (PCM).
The ECT sensor is threaded into the heater outlet fitting or cooling passage on the engine. For engine control applications, the ECT signal is used to modify ignition timing, EGR flow and air to fuel ratio as a function of engine coolant temperature. On electronic instrument cluster applications, an additional ECT is used as a coolant temperature indicator.
It sure doesn't help find the darn thing.
Senior User
Joined: Aug 2005
Posts: 169
Likes: 0
Well, it's at the front, "top" of the engine, almost dead center...move your hoses aside and look for the thermostat housing; it should be near there. Follow the wires that are headed that way. Above the water pump. Hope that makes sense.
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Mountain Pass
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From: Norfolk VA
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Postmaster
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Originally Posted by DOUG5G
I spoke to soon. I found it!!! How do I test it?
Thanks
Doug
Thanks
Doug
To answer your question, take the ECT sensor out and let it stay at room temp (or lower). Connect an ohm meter across the two terminals. You can actually just pick it up at this point and hold it tightly in your hand. If it is working, you will see the resistance start going down. (There are charts to match resistance and temperatures to see if the ECT is within specs.)
Elder User
Joined: Dec 2006
Posts: 830
Likes: 0
From: Kitchener,Ontario,Canada
Originally Posted by DOUG5G
What is the purpose of this little thing? I am having cold idle problems and I think it is the problem. I took it off and cleaned it without any success like I normally see. This time I played a little more and I plugged 12VDC into it to see if it worked. Yes I saw the plunger move back and forth. But what looks a plug that would go in between the two sides doesn't look like it is closing. I can blow into each hole and air comes out of the other. I also got the same results with it energized. Should I be able to blow air between the two? BTW yes I also get some air flow out the little vent in the side.
Couple of patially useless facts.
1. I measured accross the two terminals and it measured 10 Ohms
2. When the engine is cold I measured the red wire as getting 14VDC.
Couple of patially useless facts.
1. I measured accross the two terminals and it measured 10 Ohms
2. When the engine is cold I measured the red wire as getting 14VDC.
What does the engine idle like when hot?
ATB Aeroman.
Thread Starter
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Mountain Pass
Joined: Jun 2003
Posts: 208
Likes: 3
From: Norfolk VA
I checked the resistance hot and it read 2.2K ohms and cold it read 9.5K Ohms . Normal????? I removed it while it was cold and started her up and she idled even worse then when connected. I didn't try it removed while hot but normally she idles pretty good while hot. When I say she idle poorle when cold she idles bad enough that I can see the Votage guage jump around. Hot it is steady.
Thanks
Doug
Thanks
Doug
Elder User
Joined: Dec 2006
Posts: 830
Likes: 0
From: Kitchener,Ontario,Canada
Originally Posted by DOUG5G
I checked the resistance hot and it read 2.2K ohms and cold it read 9.5K Ohms . Normal????? I removed it while it was cold and started her up and she idled even worse then when connected. I didn't try it removed while hot but normally she idles pretty good while hot. When I say she idle poorle when cold she idles bad enough that I can see the Votage guage jump around. Hot it is steady. Thanks
Doug
Doug
Can you buy a new sensor & compare readings on your multi-meter? if good take it back! You could do the same with the IAC, as long as you dont fit it to the engine they are usually returnable. If the resistance changed from 2.2 k up to 9.5k on the ECT it sounds like it's doing the job.
Post Fiend
Joined: Apr 2005
Posts: 5,720
Likes: 5
From: Washington state
ECT way too low at cold temps.
should be 25K ohms at 85d F.
at 9.5K ohms, it's telling the PCM that your engine is 140d F, almost warmed up closed loop condition for the hwy.
will cause a lean fuel condition on cold idle=rough idle
overheated engine often kills ECT and knock sensors
replace the radiator cap also, often toasted in engine overheat
check the hoses, they get stressed from overheat and can blow at anytime
should be 25K ohms at 85d F.
at 9.5K ohms, it's telling the PCM that your engine is 140d F, almost warmed up closed loop condition for the hwy.
will cause a lean fuel condition on cold idle=rough idle
overheated engine often kills ECT and knock sensors
replace the radiator cap also, often toasted in engine overheat
check the hoses, they get stressed from overheat and can blow at anytime
Last edited by 96_4wdr; Jul 26, 2007 at 01:20 PM.
Elder User
Joined: Dec 2006
Posts: 830
Likes: 0
From: Kitchener,Ontario,Canada
Originally Posted by DOUG5G
Should I put any type of sealant or antiseize around the new ECT?
Wrap the threads in PTFE tape or Teflon tape, that way if you ever have to replace it again , it will be removable. Antisieze is not really a thread sealer.
2-3 complete turns of tape should do it.
Aeroman.
Last edited by Aeroman59; Jul 26, 2007 at 06:05 PM.