1996 Dodge Ram Dodge Blues

Tiny
SUNFLOWERJENK
  • MEMBER
  • 1996 DODGE RAM
  • V8
  • 4WD
  • AUTOMATIC
  • 161,000 MILES
I have a 1996 Dodge Ram and I recently got the Trottle positioning sensor replaced because the truck would stall when I would come to a stop. But always started again. Now that I have had it fixed the truck will only start when the weather is 60 degrees or warmer. It runs good when it starts. It's just when it's cold out it won't get a fire. Do you have any ideas? I'm puzzled
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Monday, April 27th, 2009 AT 2:25 PM

2 Replies

Tiny
CARADIODOC
  • MECHANIC
  • 33,699 POSTS
What have you tried? How much have you driven it since replacing the sensor? Did you get a diagnostic fault code that led you to the throttle position sensor?

By replacing the throttle position sensor, you may have inserted a new problem that didn't exist before. If the voltage on the TPS at idle is higher now than with the old sensor, the engine computer is never going to see "minimum throttle" that it has memorized. It will not try to control idle speed until it knows your foot is off the gas pedal, and it knows that by the TPS voltage.

Minimum throttle is also lost from memory if the battery is disconnected or run dead. The engine will not stay running at idle unless you hold the gas pedal down 1/4". To relearn minimum throttle, drive at highway speed, then coast for at least seven seconds without touching the brake or gas pedals. If this doesn't work, you may need to disconnect the battery for half a minute so it will lose its memory of the old TPS.

When you have trouble getting the engine started in cold weather, two possibilities come to mind. First, turn the ignition switch on for a few seconds without cranking the engine, then turn it off for at least five seconds. Do that two more times, then crank the engine. Every time you turn the ignition switch on, the fuel pump will run for two seconds, then turn off. This is to insure fuel pressure is up for starting. If it starts normally now, suspect a leaking injector bleeding fuel pressure down while the engine is off.

Another thing to check is the coolant temperature sensor. As long as the voltage on it is between half and four and a half volts, it won't set a fault code, however, it still could be reading an incorrect temperature. If the actual temperature is colder than the sensor is telling the engine computer, the computer won't command a large enough priming squirt from the injectors. Usually this just results in long crank time or the need to hold the gas pedal down just a little to get the engine started.

Caradiodoc
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Saturday, June 1st, 2019 AT 3:09 PM
Tiny
SUNFLOWERJENK
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Well, I Have taken the truck back to the mechanic that worked on it. He says no codes show up and he is baffled. I have drove the truck about 50 miles since I got it back due to the fact that I can only drive it when it's 60 degrees out or warmer. I am currently waiting for him to come get the truck again, it has been cold the last few days and has not started. I am not sure if they got a diagnostic fault code on the TPS he just told me it was bad. They also fixed Distributor Rotor, TP sensor, Fuel sender, Crank sensor, and Distributor cap. I tried the suggestion you gave me of turn it over and waiting 2 seconds then turn off for 5 seconds and then repeat 2 more times, and that didn't work either. Thank you for your quick response I really do appreciate all the suggestions and I will be sure to let the mechanic know has well. Thanks again
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Saturday, June 1st, 2019 AT 3:09 PM

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