Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!

Mr Danner said in a honda video he hates evap ...... i agree

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4 years 11 months ago #28635 by Grayfox
2001 Dodge Durango SLT 4x4 4.7L Fed Emission

running -10 on LT/ 0ish on ST... can hear a vac leak by the battery where the purge and LDP are. so i pull the fitting off the Purge and seal the manifold hose with my thumb... hmmm, no more hissing, LT and ST zero out, idle settles down... "hmmm , maybe the LDP is leaking and what about this purge.......grab the solus and pull up the data.. the purge is being commanded at 100% duty cycle, the would perhaps let the LDP be the rascal leaking... and i have computer control.. it if let it stable out with 2 big vac leaks and then seal them back up fast but slow enuff the poor thing keeps running the pcm commands the purge down A LOT to a whopping 90% duty cycle...

thought i would put this post out and see if anyone else has ran into this while i hook up the Leak Tamer and see what i can see.... any and all ideas, thoughts comments and concerns are welcomed.

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4 years 11 months ago #28649 by Tyler
Any codes stored? Or are you concerned about the trims and noise?

While the PCM purge command is high, is the LDP switch PID showing open or closed?

I'm wondering if what you're seeing is the PCM trying to do its .090" (fuel cap left off) leak test. With the purge commanded wide open, there should be sufficient vacuum in the system to change the LDP switch state.

Alternately, if you use the EVAP System Test, does it pass with no codes stored?

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4 years 8 months ago #31956 by Grayfox
Tyler, I thought I already answered your comment. I apologize. We’re no codes. The LDP was cracked. Replaced it. Reset all adaptives. Drove it for a week and rechecked duty cycle on the purge was showing 100% down to 20% depending on conditions at time of checking... so maybe you was right about it trying to check for a leak and not able to complete it’s check

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