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95 Intrepid 3.3 hard starting cold

Discussion in 'Repairs, Maintenance, Help' started by moparroy, Jan 13, 2018.

  1. moparroy

    moparroy Active Member

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    The old 95 Intrepid is acting up and a bit stumped by it - 3.3l with about 470k km on it - or about 300k miles. My son drives it more than me now. It is hard starting anytime it has sat long enough to get cold. With the really cold weather (we are in Ontario just outside Toronto - had some really cold nights in January) its almost impossible to start without either plugging in the block heater or using starter fluid. After changing several things on the ignition side with spares I had (wires, cam and crank sensor, coil pack, wires and checked plugs) I believe it is a fuel side problem. If you open the air intake and spray starter fluid (quick start) into the TB enough to pool a little it will fire right away - but then sputter and die if it is cold. Fuel pressure is good - around 52 psi and it holds. Tried changing fuel pump relay and run start relay. Topped up the coolant this morning (read that low coolant can cause false coolant sensor readings) - no help. It did throw a cam sensor code a month ago or so around the time this started (hence the sensor replacement) but it is not throwing any codes now. When / if it starts it usually sputters a bit runs rough for a minute then runs fine - takes multiple tries always to get it going cold. Replaced the battery as it froze one night - though other than that night cranking has been fine. Short stops it fires right up. I am suspicious of the coolant temp sensor - though Alex says the gauge reads normal. Then also suspicious of the MAP sensor. Don't have a spare of either of those (that I can find anyway :)). Debating to order a MAP sensor. Any other suggestions? ways to test the MAP?. I did reseat the connector on the MAP - seemed help a little - at least it fired at -12 C but still not right. At -12 it should not need the block heater. MAP sensor is original I believe - coolant temp sensor replaced some 5 years ago after it overheated - might have been a used one not sure. Any suggestions appreciated. Other thing on the MAP sensor now that I think about it, the car has for several years had the occasional back fire - when you released the key too early it seemed on starting - sure that did not help the MAP.
     
  2. ImperialCrown

    Level III Supporter

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    I see that the Champion Copper plugs are still OEM in 1995, not the Platinums.
    The VIN T engine takes Champion Copper Plus RN14MC5 gapped at .050" (1.3mm)
    The less common VIN U engine takes the RN12MC4 plugs gapped the same.
    The correct plugs are important, particularly when cold because of the high firing voltages required.
    Unplugging a sensor, like MAP or coolant temp, then turning on the ignition to start the car will make the PCM insert a default value. It may not run perfect, but should make a difference in starting if they are the problem.
     
  3. valiant67

    valiant67 Rich Corinthian Leather
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    Have you checked the coolant temp sensor? If one fails to tell the computer it is cold, this can cause a hard start.
     
  4. moparroy

    moparroy Active Member

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    I have RN14MC5 plugs in it - always stayed with those and checked that gap recently good at 1.3mm
    On the coolant temp sensor I have not tested it - reseated the connector on it that's all. What should the resistance be? I was thinking the temp sensor also drives the temp gauge through the PCM and Alex says it is reading normally - mind you that is at operating temp. Maybe I'll try unplugging it.
     
  5. ImperialCrown

    Level III Supporter

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  6. moparroy

    moparroy Active Member

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    Your money is good. Tried unplugging the coolant sensor this morning at around -20 C. The car started - stalled after a minute as the computer was searching for the right default but on second try it started and kept running find. Thanks much - will be ordering a new coolant temp sensor tonight.
     
    ImperialCrown likes this.

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