running rough after new TP senson
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From: staunton
running rough after new TP senson
My 89 F-250 w/ a 351 started running rough losing power and backfiring through the exhaust, I gave it a tune up, Plugs,wires,cap,button,Ignition Control Module,and a Idle Air Control Valve. That did not help my problem.
I just put a Throttle Position Sensor on it and that seem to fix it at first but the longer I ran the truck and after it got warm it went back to running rough again BUT not as bad, and now it is Idling at 2500. Does the system need to be rest or something when a TP sensor is put on or could it be possible I put it on backwards?
I just put a Throttle Position Sensor on it and that seem to fix it at first but the longer I ran the truck and after it got warm it went back to running rough again BUT not as bad, and now it is Idling at 2500. Does the system need to be rest or something when a TP sensor is put on or could it be possible I put it on backwards?
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Fellow ford guy, two things disconnect the tps and run the motor,if no difference is observed youare not getting a return signal from the tps this thing is basicly a rheostat and sends a voltage signal to the cpu also determine if you have voltage on one terminal of the plug coming from the wiring harness, iwould try putting the old tps back if results are the same you probably have a open connection in the harness or a loss of ground the tps is somewhat adjustable by rotating ti on it,s mount but the range is small good luck
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Could be the air temp sensor. I have the same problem and that's what I'm trying next. The new TPS got rid of my stumble, but the engine won't start when it's hot and acts like a carbureted engine with the choke stuck on.
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From: staunton
I will have to check the volts on the TPS. my next part was going to be an air temp sensor, I just getting to the point that I keep throughing parts on it and it nickel and dimming me to death, The engine light is not on and I'm not sure how to read the codes from under the hood.
Post Fiend
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I would read the codes, can be a great help (or none at all). Look at the banner across the top of this forum page and click on "Tech Info" and then on OBD1. Follow the instructions and you can read any codes by counting the light blinking.
For instructions on setting up the new TPS go to fordfuelinjection.com it tell you there about the codes as well.
Whike you are at it check for a vacuum leak and for leaking EGR valve.
For instructions on setting up the new TPS go to fordfuelinjection.com it tell you there about the codes as well.
Whike you are at it check for a vacuum leak and for leaking EGR valve.
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The only part I've thrown at mine is the TPS, but mine's overdue for a tuneup anyway. Plugs, wires, distributor cap and rotor are coming up, so I figure an ATS in the bundle can't hurt and might help. Also, it being an '89, it's overdue for an o2 sensor.
I will have to check the volts on the TPS. my next part was going to be an air temp sensor, I just getting to the point that I keep throughing parts on it and it nickel and dimming me to death, The engine light is not on and I'm not sure how to read the codes from under the hood.
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From: staunton
Lazy K, I checked out the link and it seems that it will be very help full, One question though it reads (You need to back probe the harness while reading the voltage between the TPS and SIG RTN pins.) What and where is the SIG RTN pins??
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Post Fiend
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I think that is if you are using a volt meter. Just take the single wire connector and ground it. You can ground it by using the pin in the multi-pin plug or by running a wire from it to the neg. battery terminal and then count the blinks of the CEL, with the key "on". Hope this helps.
Fleet Mechanic
Joined: Mar 2005
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From: St Louis
As Nuts was trying to say, yes you need to reset the computer by removing the batter cable to clear the ECU memory. Then you need to drive it for awhile so that ECU can learn the "curve" of the new TPS. Another thing, if you do not have the vacuum sealed for the lines and throttle body, you have just introduced un expected air that the truck will compensate for in the engine. Keep the air moving only through the correct routes into the motor, i.e. PCV and the intake as the only inlets.
Lead Driver
Joined: Nov 2002
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From: Concord, NC
One question though it reads (You need to back probe the harness while reading the voltage between the TPS and SIG RTN pins.) What and where is the SIG RTN pins??
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From: staunton
Alright guys, I'm getting fed up. I put a air temp sensor on it and a new eec and still not any better. I took the new TPS off and put the old one back on and it would hardly drive at all, so the new TPS did somthing but didn't cure it,
Im thinking I might have gotten a bad TPS so I'm going to get a new one and try that. I friend said I might have an exhaust loob off the cam. Also I thought at first it was back firing out the exhaust but it is poping back through the intake and air box when it is reved up, or in a pull
I checked the gas pressure and it 32+ all the time.
Im thinking I might have gotten a bad TPS so I'm going to get a new one and try that. I friend said I might have an exhaust loob off the cam. Also I thought at first it was back firing out the exhaust but it is poping back through the intake and air box when it is reved up, or in a pull
I checked the gas pressure and it 32+ all the time.
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From: Altus,AR
I know tracing problems when you have so many sensors involved can be tedious and frustrating. The one thing i learned is that while pulling codes may be helpful it doesn't give all the answers. Get's you headed in the right direction,sometimes. Also even if you have a non- adjustable TPS you will want to take the time to test it while on the truck with a volt meter. Mine was off just alittle, loosened the screws, moved until at 0.9V and tightened while making sure nothing moved. After clearing codes and driving for several days, never had another problem. Is your truck still idling at 2500RPM?
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From: staunton
I put another new TPS on it yesterday and that one seem to have worked better but it is still popping back through the intake. I put a timing light on it yesterday and tuned that in a bit, When it is at idel the timing mark jumps around a bit, high about 1/4" and low of the mark 1/4" is this normal or should it stay right on the mark all the time?