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Help Please! 47rh OD issue different than most

774 Views 6 Replies 3 Participants Last post by  Ctfxr3
I know I'm going to catch a lot of heat for this and yes i have spent the last 3 days reading posts and searching forums and still can't find a concrete solution. I picked up a 95 auto trans today and am having a similar OD issue but it has a few added elements I haven't seen anyone else post about. My symptoms are check engine light will blink then go out, tach bounces around then dies, and the OD won't work and the cruise control won't work. Previous owner says it only happens in hot weather and has never happened in the winter. From what I read, thinking it could be temp sensor, it seems most people experience the issue when it's cold not in the heat? He also said sometimes even if the truck was parked in direct sunlight on a hot day it would happen immediately? I'm thinking its got to be temp or heat related, he said a diesel mechanic told him to replace the ECM.

Went on a half hour test drive yesterday and it was fine, today it was about 10-15 degrees warmer60-65F) and it happened on the way home. He's already done the alternator and CPS. Also a manual switch in the cab But OD does not engage with the switch it just feels like its not revving as high with the switch on. Sorry I'm a cummins newbie (coming from a twin turbo audi, way different animal). I got a smoking deal on the truck and bought it because i need to rip my other car apart and rebuild turbos and heads, but im worried I just walked into another nightmare. Thanks for any help in advance.
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Check to see that the wire connectors are clean. One person used dielectric grease on the connections and that solved the problem. Also, use a brass feeler gauge to set the gap.

Make sure the gap is correct.

You could have a broken or corroded wire or connector. The ESS is the only thing that tells the PCM the engine is running. Without that input the cruise control and overdrive never think to come on for a non-running engine.
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It is possible that the ESS is heat sensitive. While a good electronic part does not normally object to temperature a failing one can react badly when it gets to a certain temperature. Sometimes electronics hate getting warm. Strange things can happen with electronic parts.
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