New Member / Sensor Problem?
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New Member / Sensor Problem?
Hi everyone. I just joined this site. I am the owner of a 1992 f150 4wd 302 truck. I love my truck. Absolutely love it. It is acting funny though. When I start it, it will idle very very rough almost to the dying stage. It surges sometimes while driving lower speeds and my gas mileage has gone to crud. I have changed the map sensor and the tps. I just changed the throttle position sensor this morning and it was a rough start after that. I am starting to get a bit confused as to what the problem is. I just want my truck to stat and idle correct again, lol. Any help would be great. Thank you.
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Joined: Nov 2003
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From: Chilliwack
Hi BruceMoose welcome to the FTE. I had a rough idle on my truck that was helped when I cleaned all the carbon out of my IAC (Idle Air Control), it is bolted to the side of the throttle body with 2 bolts and has 1 electrical connection. I just cleaned mine out with some throttle body cleaner.
You may also want to check to see if you truck has any stored codes, there may be codes even if your check engine light hasn't come on. The procedure for checking codes is outlined here Fuel Injection Technical Library » How To Run a Self-Test
If it does have some codes stored go ahead and post them up here and the fine folks of the FTE will help you decipher them.
You may also want to check to see if you truck has any stored codes, there may be codes even if your check engine light hasn't come on. The procedure for checking codes is outlined here Fuel Injection Technical Library » How To Run a Self-Test
If it does have some codes stored go ahead and post them up here and the fine folks of the FTE will help you decipher them.
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Joined: Sep 2008
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Hi BruceMoose welcome to the FTE. I had a rough idle on my truck that was helped when I cleaned all the carbon out of my IAC (Idle Air Control), it is bolted to the side of the throttle body with 2 bolts and has 1 electrical connection. I just cleaned mine out with some throttle body cleaner.
You may also want to check to see if you truck has any stored codes, there may be codes even if your check engine light hasn't come on. The procedure for checking codes is outlined here Fuel Injection Technical Library » How To Run a Self-Test
If it does have some codes stored go ahead and post them up here and the fine folks of the FTE will help you decipher them.
You may also want to check to see if you truck has any stored codes, there may be codes even if your check engine light hasn't come on. The procedure for checking codes is outlined here Fuel Injection Technical Library » How To Run a Self-Test
If it does have some codes stored go ahead and post them up here and the fine folks of the FTE will help you decipher them.
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New User
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I just cleaned out the iac. It was a bit dirty, had some buildup. I am going to try the self test for codes thing that was posted. I just need to find a bit of wire long enough. After cleaning the iac it still started rough.
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The only time I have ever had to give it gas when starting is when it would die from the low idle. Other than that I have had no problems.
I ran the self test and it came up with this. I dont know what it means at all.
Test started : 3 blinks with a 1/2 second in between or so...2 second pause...3 blinks same as first...2 second pause... 1 blink. 4 second pause roughly then 3 quick blinks pause 3 quick blinks pause 4 quick blinks pause 3 quick blinks pause 3 quick blinks pause 4 quick blinks then I heard the test stop
I ran the self test and it came up with this. I dont know what it means at all.
Test started : 3 blinks with a 1/2 second in between or so...2 second pause...3 blinks same as first...2 second pause... 1 blink. 4 second pause roughly then 3 quick blinks pause 3 quick blinks pause 4 quick blinks pause 3 quick blinks pause 3 quick blinks pause 4 quick blinks then I heard the test stop
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You should reset your PCM because the closed throttle voltage may be off. I was replacing my TPS yesterday and datalogged the correct TPS voltage of 0.85v but I had to start the motor by pumping the gas pedal. After that I found the PCM considered closed throttle at 1.256 volts when the TPS was set at 0.85v. I was able to start the truck when the TPS was incorrect but it idled like crap until I reset the PCM.
Read in that article about clearing the codes. When codes are cleared, turn off key, disconnect battery, turn on headlights (to drain residual power). Do those steps in order and leave the battery disconnected for at least 2 min. That will ensure this isn't the issue and then you can get codes again knowing they are recent.
Read in that article about clearing the codes. When codes are cleared, turn off key, disconnect battery, turn on headlights (to drain residual power). Do those steps in order and leave the battery disconnected for at least 2 min. That will ensure this isn't the issue and then you can get codes again knowing they are recent.
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Posting Guru
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The only time I have ever had to give it gas when starting is when it would die from the low idle. Other than that I have had no problems.
I ran the self test and it came up with this. I dont know what it means at all.
Test started : 3 blinks with a 1/2 second in between or so...2 second pause...3 blinks same as first...2 second pause... 1 blink. 4 second pause roughly then 3 quick blinks pause 3 quick blinks pause 4 quick blinks pause 3 quick blinks pause 3 quick blinks pause 4 quick blinks then I heard the test stop
I ran the self test and it came up with this. I dont know what it means at all.
Test started : 3 blinks with a 1/2 second in between or so...2 second pause...3 blinks same as first...2 second pause... 1 blink. 4 second pause roughly then 3 quick blinks pause 3 quick blinks pause 4 quick blinks pause 3 quick blinks pause 3 quick blinks pause 4 quick blinks then I heard the test stop
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I reset the pcm per your instructions. I ran the test again and it gave me this :
3 pause 2 pause 7 pause 3 pause 2 pause 7 then it gave 5 very slow blinks with 3 or so seconds between the blinks themselves.
I tried starting the truck and it did the same...just to see.
I ran the test again after that and it gave me :
3 pause 3 long pause 1 3 3 4 3 3 4
3 pause 2 pause 7 pause 3 pause 2 pause 7 then it gave 5 very slow blinks with 3 or so seconds between the blinks themselves.
I tried starting the truck and it did the same...just to see.
I ran the test again after that and it gave me :
3 pause 3 long pause 1 3 3 4 3 3 4
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New User
Joined: Mar 2013
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/FACEPALM I just decided to try something for s**ts n giggles. I unplugged the vacuum line from the egr valve. I started the truck and it ran smooth, so very smooth. While the truck was running I plugged the vacuum back in and it started sputtering and rough idling. I do believe I have found the problem. Only thing is, I dont have the 85 bucks to get a new one right now. Next week I can fix the problem so that is good news.
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