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Rolex

Rolex

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As some of you know, I had a problem with my car and changed the electro/mechanical module that's the Throttle Positioning Sensor. The battery was disconnected to blank out the computer memory (allegedly), and the car ran like it was brand new except for the check engine light being on. After 10 minutes of driving, that light went off, and the car reverted to the same problems it had before the module was replaced.
How do I reset the computer to permanently recognize the new component?

Ford Thunderbird LX, 5.0
 
You can unhook the negative on your battery for at least 5 minutes wich might clear it. What year is it?
 
Unhook the battery for at least 15 min to clear the code. The question is what was the check engine light on for? I'm sure you probably don't have a code reader,so if you can, take it to an Auto Zone, Pep Boys etc. and have them pull the code for you before you clear it. It may help solve all the problems.
 
The bird is a '93 LX, 5.0 HO. The check engine light would come on when that component was faulty, and it still comes on.
I've disconnected the battery 3 times already, the last time for 24 hours. The car runs beautifully for the first 10 minutes or so and reverts to the old problem when the light goes out.
 
Racer 1966 said:
What exactly is the problem when it goes out?
Click to expand...

High idle, drifting RPM, idle surging, hesitation or sudden stalling when accelerating from a stop,
poor fuel economy, bucking and jerking occasionally at highway speeds, driver cursing out loud.
 
Last edited:
Rolex said:
High idle, drifting RPM, idle surging, hesitation or sudden stalling when accelerating from a stop,
poor fuel economy, bucking and jerking occasionally at highway speeds, driver cursing out loud.
Click to expand...
that last problem seems to come about with any mechanical issues on any car, doesent it?:hehe:
 
Have you checked for a vacuum leak, Ralph? That could cause most of those symptoms except the last one. That one is usually caused by any automotive or stupid driver in the other car....
 
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The entire system was checked out and cleaned by a mechanic while doing a tune up and changing all the filters.
I'm the one that isolated it to the TPS. I brought it back to the shop, they put in a new one and it idled at 2 grand. I told him to take it out and put the old one back. He did, and I barely got the car home. I did some research on the internet, and disconnecting the battery brought it back to where it was. Obviously he never did that.
I don't remember the code # he got, and I have no way of reading it.
 
So the old sensor is what's in it now?

Can you drive the car? If you can get to an AutoZone,they will read it for free,at least they do here. It could help if you knew the code,I'm gonna have to do some checking for you on this one. Just curious,how old are the plug wires?
 
Sounds like a small exhaust leak or vacumn leak that only shows up when the engine bay is fully heat saturated..Good luck. Old cars with electronics can be a nightmare.
 
Racer 1966 said:
So the old sensor is what's in it now?
Click to expand...

No, I put the new one in after researching the problem further and disconnecting the battery. ALL the symptoms pointed to the TPS, and like I said, the first 10 minutes of driving are flawless after reconnecting the battery.
 
Update

After many months of driving with 2 feet so it wouldn't stall when leaving a light, it's done.
I've been shopping for a new car, and several people have already offered to buy the bird. In good conscience, I couldn't sell a car that had that problem, so after laying out over $700 in the last 6 months or so, I went to another shop nearby that I never knew existed, and asked about resetting the computer.
2 hours later, after a parts drop from Napa, the car is like brand new.
$101 total parts and labor.

There's a sensor that tells the computer what the engine temp is...not the sensor to the gauge, but to the computer to determine the fuel/air mixture.
It was constantly telling the computer that the engine was 5 degrees, so it caused the car to run excessively rich.
 
Man, wish I had seen this post back in July when you were having the problem. That's one thing I would have suggested you check for me was the resistance of the ECT (engine coolant temp) sensor when engine was cold and after warming up...

Have any further questions feel free to PM me, I've worked on/built dozens of 5.0s in my career, well, both careers!

Mark
 
Thanks stang. The car is running so good, I just might put off getting a new one for a while.

It's always good to learn something new, and I'm glad I found a shop that was totally honest with me. I'm their customer forever, and I told them that.
 
That's great news! I hate phantom issues.

May have to ask MustangMan about my current issue I've had with my 06 MGM... pretty much since I bought it. Know anything about the 4.6's and a weird hesitation issue around 1700-2000 rpm's? If so, PM me. I'm all ears!
 

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