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Discussion Starter #1
So my 95 F150 4.9 has been running like crap for the last month,so after it dying 3 times in 1 day-driving along ,ck engine light comes on/dies,finally would'nt restart-called GF,she came over,put a strap on it/towed home...Next am,started right up/idled like crap/ran 7min/died...Took off AIC whatever valve,took apart,cleaned-idled like new(for 7min).Tried OBD2 with Ford OBD1 adapter-no workee----Actually did something SMART--used jumper wire on plug-went in cab with phone camera on video-turned key-recorded through cycle-2 codes....Went on line-Throttle Position Sensor(replaced Durangos twice in 2 yrs,weird)----stopped and asked mechanic-I have to see truck to diagnose-really?-how about this and showed him video-he smiled-yep TPS and VSS...Going to pick up parts later....
 

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When you pull the throttle body off to replace the TPS, THOROUGHLY clean the throttle bores and butterflies. Even when fully closed, there is supposed to be some airflow through the throttle body. Over time, carbon deposits build up and restrict the airflow, eventually beyond the IAC valve's or the computer program's ability to compensate. This is even MORE necessary on modern throttle by wire systems.


Tom
 

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Discussion Starter #3
When you pull the throttle body off to replace the TPS, THOROUGHLY clean the throttle bores and butterflies. Even when fully closed, there is supposed to be some airflow through the throttle body. Over time, carbon deposits build up and restrict the airflow, eventually beyond the IAC valve's or the computer program's ability to compensate. This is even MORE necessary on modern throttle by wire systems.


Tom
I don't have to remove TB-it was just screwed to side and 3prong connector...Should I just clean entire area with electric spray cleaner???
 

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When you spray cleaner into it, you run the risk of having the cleaner run down the throttle shaft and into the TPS, or getting into the IAC valve and ruining them. Plus, you can't really clean it well still on the vehicle. I pull them off, hold the butterflies wide open, and clean from both sides. I start by wiping out whatever will come off using a rag or paper towel with your preferred cleaner sprayed onto it. Then I take a dull pick laid mostly on its side and scrape off the harder deposits all the way around from both sides. followed by the towel solvent wipe again. It only takes 10-15 minutes to clean it to like new condition once it's off the vehicle. And don't forget to clean the butterflies and their edges as well.


Tom
 

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Discussion Starter #5
Great,thx...southern truck so it's real clean under hood.
 

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My wife's GMC Terrain has a touchy throttle body, gives her grief about once a year. I take to my guy and he cleans it for $40 and I am good to go for another year. I've am to the point that the only thing I do to cars anymore is change out a battery and maybe a air cleaner.
 

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I was thinking your jet and needle were worn but throttle bodies don't have them.....I think....:D

Awto, I do a very similar procedure anytime I have the pistons out of the dashpots on SU's or Stromberg's. Fortunately there's only 3 screws that hold the dashpots on and the pistons and needles just lift out, giving you complete access to the venturi. The butterfly's are a bit more involved and only get done on a rebuild. They also very rarely give one problems.
 
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My wife's GMC Terrain has a touchy throttle body, gives her grief about once a year. I take to my guy and he cleans it for $40 and I am good to go for another year. I've am to the point that the only thing I do to cars anymore is change out a battery and maybe a air cleaner.

If he would take the throttle body off and clean it thoroughly instead of just wiping out whatever he can on the vehicle, you would be good for several years. It would cost a little more, but it would be right.

Tom
 

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Great,thx...southern truck so it's real clean under hood.
The throttle plate is not going to be clean. It's going to be a crusty mess.
As Automan mentioned, this is a big issue in FBW systems, particularly Toyotas. If your Camry won't idle after a dead battery, clean the throttle plate. Killing the power causes the ECM to close the throttle plate 100%. The ECM has a guestimate throttle plate idle value. It picks that and goes. Problem is, when the ECM closed the plate, the crud prevented it from closing all the way, then it opened it several %, and viola! No idle. Posted this because its ultra common and people chase their tails.
Not your issue exactly, as Automan again points out, your IAC is expecting a certain amount of air passing the plates, then it fine controls the rest of the air for idling. Obstruct the plate and the system cannot compensate.
 

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Discussion Starter #11
Appreciate the responses......I've had it with electronic crap----have a spare 5cyl MB diesel,looking for motor mounts now/adapter bellhousing with hi-po starter is 485$.I don't tow heavy.mainly use pu to get hay for livestock.
 

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So, if I understand that statement, and correct me if I am wrong, you're going to cause yourself immense amounts of grief and aggravation, probably amounting to more hours than you currently anticipate, eventually resulting in a half finished project that never gets done installing a different engine into your truck, because you are frustrated by a minor electronic issue that could be solved inexpensively by an old salt familiar with this vehicle? You should rethink that before it's too late.


Tom
 

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I don't have to remove TB-it was just screwed to side and 3prong connector...Should I just clean entire area with electric spray cleaner???
Every 4.9 Ford I've seen has the TPS mounted on the bottom with 2 screws. From memory the closed throttle TPS voltage should be around 800mV.

That generation Fords, using a scan tool is a waste of time. A digital voltmeter is the best tool
 

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Every 4.9 Ford I've seen has the TPS mounted on the bottom with 2 screws. From memory the closed throttle TPS voltage should be around 800mV.

That generation Fords, using a scan tool is a waste of time. A digital voltmeter is the best tool
The scan tool we used on them was called a Sun scope. Then we got 2 Bear scopes, they hung from the ceiling, they weighed as much as the car.
 
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