METHOD FOR TESTING THE PURGE SOLENOID DTC 31

  • Tiny
  • dmel340
  • 1994 Dodge Dakota

Is there an easier method for testing the purge solenoid on a 1994 Dakota. My scan tool indicates DTC 31-purge valve solenoid. I have tested it for voltage to the dark blue power line. I bench tested the relay and it does activate. I can clear the code and it does not reappear until the engine gets warm. I have continuity from connector 52 on the computer plug and 0 ohm reading the pink wire but with black tracer at the relay. Why does the code keep reappearing? I need help with a test.

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Monday, July 30th, 2012 AT 5:02 PM

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  • Tiny
  • saturntech9
  • Expert
  • 29,879 posts

When it gets hot and is setting code see if it works when you add power and ground to it with it unplugged?If its a intermintant problem you have to test it when its acting up.

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Monday, July 30th, 2012 AT 5:14 PM
  • Tiny
  • dmel340
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Do you want me to run the engine hot and when the code appears, to clear the code, keep the relay unplugged and use jumper wires to the relay to activate the relay and rerun it to see if the code reappears. Am I interpreting your answer correctly? The engine is cold now with no code and I want to do your recommendation correctly.

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Monday, July 30th, 2012 AT 5:42 PM
  • Tiny
  • saturntech9
  • Expert
  • 29,879 posts

Were talking about the canister purge solenoid correct?If so I was saying to bench test it on the vechile same way you did it before but when its hot and the code is active or setting. If you have a intermintant code you have to test the system when the problem is happening. As far as testing I was say unplug the canister purge solenoid if you think thats bad and run power and ground to it and see if the solenoid works. Also what code is it setting?

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Monday, July 30th, 2012 AT 5:47 PM
  • Tiny
  • dmel340
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Still working on the 1994 dakota mpi fuel injection. No codes are present at this time. Installed a new coil and the truck is still popping in the exhaust, down on power, dropping at least one cylinder. When the engine is cold it appears to be idling fine. I did not test drive it cold. I plugged off he vacuum lines for the egr valve, disconnected the power line to the egr with no difference. I didn't mention previously, this is a rebuilt engine with 100000 miles and I did a compression test and all cylinders are 150 psi. I even checked the flex plate to ensure there were no cracks that would throw of the crank position sensor. Any suggestions what to look for next?

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Wednesday, August 1st, 2012 AT 9:10 PM
  • Tiny
  • dmel340
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Still working on the 1994 dakota mpi fuel injection. No codes are present at this time. Installed a new coil and the truck is still popping in the exhaust, down on power, dropping at least one cylinder. When the engine is cold it appears to be idling fine. I did not test drive it cold. I did test drive hot. I plugged off he vacuum lines for the egr valve, disconnected the power line to the egr with no difference. I didn't mention previously, this is a rebuilt engine with 10,000 miles ago and I did a compression test and all cylinders are 150 psi. I even checked the flex plate to ensure there were no cracks that would throw of the crank position sensor. Any suggestions what to look for next?

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Wednesday, August 1st, 2012 AT 9:21 PM

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