Is this a bad TPS?
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Joined: Sep 2002
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Is this a bad TPS?
I've been working on getting my 351W running smoothly after replacing it with a reman engine. It's a long story, but the current chapter is about ignition timing. I've got the base timing set at 10 before, per spec. When I reconnect the "spout" connector, the timing jumps up, as expected, to about 12 before or so (doing this from memory). I noticed that if I open the throttle, the timing jumps way up, but it does it all at once. Basically, if I nudge the throttle off the idle stop, all or most of the advance comes in at once, before the engine speed changes much.
Is this what we should expect? I'm surprised it comes in all at once. I've got some problems with the engine running badly coming off idle when cold, so I'm wondering if I'm looking at a bad TPS.
Any suggestions greatly appreciated.
91 F250 351W
Is this what we should expect? I'm surprised it comes in all at once. I've got some problems with the engine running badly coming off idle when cold, so I'm wondering if I'm looking at a bad TPS.
Any suggestions greatly appreciated.
91 F250 351W
Postmaster
Joined: Nov 2001
Posts: 3,351
Likes: 1
From: Escondido, CA
Is this a bad TPS?
Do you have an idiot light in the dash? If not check the bulb. You can take it to some auto part stores. Most of them have the code extractors to help you idintify your exact problem. Also you can buy a Fuel Injection manual (Hanyes) that shows you how to test all of the sensors in the system using a Multi-meter.
Not exactly the easiest answer but you know for sure rather then hearing everyone elses fix for what was wrong with there engine before. No I am not slamming or dismissing anyone ideas. So don't kick me in the jimmy over this.
Not exactly the easiest answer but you know for sure rather then hearing everyone elses fix for what was wrong with there engine before. No I am not slamming or dismissing anyone ideas. So don't kick me in the jimmy over this.
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Joined: Jan 2001
Posts: 56,984
Likes: 2,738
From: Virginia
Is this a bad TPS?
When the throttle is closed, make sure the tps sensor is sending about .73-1.22 volts. Take this reading between the darkgreen/lightgreen wire and the black/white wire. Most of them are adjustable with slots in the mounting. While you have the meter hooked up, you can slowly open the throttle while watching the meter, to see if the voltage rises slowly and smoothly.
