engine racing after TPS change
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Senior User
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engine racing after TPS change
My TPS went about 6 months ago, and I just drove it until yesterday when I decided to change it over to a new one, evrything went smooth, even the engine light went out, and things were good until I took it out this morning. about 45 minutes into the ride, the engine light came back on, and the idle is racing, so I brought it home and shut it off, -I'm waiting for it to cool down right now to see if the check engine lite goes back out ..anyone got an Idea whats going on? ...-something I forgot to do?
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Assuming you did not bump or break a vacume line or anything else while you were working on it, I would think you either have a bad electrical connection, or the new TPS is faulty. New sensors can be bad. You can test it with a multitester. I have gotten in the habit of cleaning and then applying dielectric grease to every electrical connection as I work on the truck.
You might want to look at your throttle body linkage to see if it is returning all the way, and shutting the butterflys completely. Possibly you moved something yesterday, and it is not returning properly.
Good luck Frank
You might want to look at your throttle body linkage to see if it is returning all the way, and shutting the butterflys completely. Possibly you moved something yesterday, and it is not returning properly.
Good luck Frank
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tps,idle race..GUNKED THE IAC?
Ok, this is what just happened, I let it cool down, and started it, the check engine light went out, and it raced for a minute or so to reach engine temp then it slowed down to a normal idle..things seemed just fine.. about 4 minutes into it running, it immediatly began to race at a constant and the engine light went on as well.
I reached over and unplugged the IAC and the idle dropped down to a normal pace..of course the engine light stayed on.. But, I failed to mention that in the process of changing the TPS, I removed the TB and cleaned it out with GUNK..I was reading the Haynes book before it started racing and came apon a "caution" under the IAC info stating that "it was a electrical component and must not be soaked in any cleaner as damage may result"..I did leave it on the TB when I was cleaning it out, and I know some Gunk must have got into the ports leading to the IAC.
--whattya think?, mabey I messed up the IAC with the GUNK?..-the Idle did chill out after it was unplugged...anyone?
I reached over and unplugged the IAC and the idle dropped down to a normal pace..of course the engine light stayed on.. But, I failed to mention that in the process of changing the TPS, I removed the TB and cleaned it out with GUNK..I was reading the Haynes book before it started racing and came apon a "caution" under the IAC info stating that "it was a electrical component and must not be soaked in any cleaner as damage may result"..I did leave it on the TB when I was cleaning it out, and I know some Gunk must have got into the ports leading to the IAC.
--whattya think?, mabey I messed up the IAC with the GUNK?..-the Idle did chill out after it was unplugged...anyone?
Lead Driver
Joined: Nov 2002
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From: Concord, NC
Check your closed throttle TPS voltage. If it is above 1V, it will not idle properly. You should be able to adjust the idle voltage by rotating the TPS slightly before tightening the screws. If you can't rotate it enough, you can elongate the holes slightly to achieve the desired closed throttle voltage.
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Have you figured out your problem. I have the same situation and think that the holes in the throttle plates may be the key. They may have had a clear coating and in the process of cleaning the throttle body the cleaner dissolved the coating. Have any thoughts of your own? In my case did not change TPS or any adjustments, cleaned and reinstalled, engine idled at 1500-2000rpms.
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Originally Posted by Icantsmile
Have you figured out your problem. I have the same situation and think that the holes in the throttle plates may be the key. They may have had a clear coating and in the process of cleaning the throttle body the cleaner dissolved the coating.
Both of you need to Change the IAC .... and no more spraying stuff in there . Spray it on a rag and buff next time .... aight ?
FYI ..... The TPS wont make a the engine rev when its bad . The MAP sensor is the boss at all times .
You can unbolt the TPS , crank it up , and turn the TPS all you want with a big ol screwdriver .... and the MAP will holler to the puter " the TPS is Crazy dont listen to it "
Tried it out one day when I was bored .
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racing idle..
Originally Posted by Musclestang
wow ..... talk about wayyyyy over thinking
Both of you need to Change the IAC .... and no more spraying stuff in there . Spray it on a rag and buff next time .... aight ?
FYI ..... The TPS wont make a the engine rev when its bad . The MAP sensor is the boss at all times .
You can unbolt the TPS , crank it up , and turn the TPS all you want with a big ol screwdriver .... and the MAP will holler to the puter " the TPS is Crazy dont listen to it "
Tried it out one day when I was bored .
Both of you need to Change the IAC .... and no more spraying stuff in there . Spray it on a rag and buff next time .... aight ?
FYI ..... The TPS wont make a the engine rev when its bad . The MAP sensor is the boss at all times .
You can unbolt the TPS , crank it up , and turn the TPS all you want with a big ol screwdriver .... and the MAP will holler to the puter " the TPS is Crazy dont listen to it "
Tried it out one day when I was bored .
-I start it up cold, it races till its warm-mabey minute and a half-mabey 2min
then it chills out and idles nice..about 40 minutes into driving it the "CHECK ENGINE" lite goes on, and it races at about 1800rpm seems like it has to get to a certain temp b4 it goes batty..I dont know..I even backed off on the dead stop screw for the linkage to bring the idle down, and it did, but its working its way back up to a racing idle again..not when its cold though.
I dont know what to do anymore at this point.
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TPS's can be tested at autozone (some of them), I'm pretty sure all of ours can.
If it's related to the heat of the engine I don't see it being anything on the engine or above it, because that would heat up in 5 minutes.
If it's related to the heat of the engine I don't see it being anything on the engine or above it, because that would heat up in 5 minutes.
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Originally Posted by Musclestang
FYI ..... The TPS wont make a the engine rev when its bad . The MAP sensor is the boss at all times .
You can unbolt the TPS , crank it up , and turn the TPS all you want with a big ol screwdriver .... and the MAP will holler to the puter " the TPS is Crazy dont listen to it "
Tried it out one day when I was bored .
You can unbolt the TPS , crank it up , and turn the TPS all you want with a big ol screwdriver .... and the MAP will holler to the puter " the TPS is Crazy dont listen to it "
Tried it out one day when I was bored .
Lead Driver
Joined: Nov 2002
Posts: 9,557
Likes: 44
From: Concord, NC
You can't really tell anything about the MAP sensor by checking voltage. The MAP sensor outputs a frequency, so regardless of what signal it is sending, you will always read 2.5V on the output. You can either use the frequency scale on a multimeter, or you can use a tachometer to test the MAP sensor output.