Engine Code P04DB and the UPR dual-vacuum catch can

[Racket]

Back in June I was tweaking my Unleashed Tune with Torrie then late that month I added the second vacuum line to the UPR catch can. August/September I was testing the Velossa Tech Big Mouth which was netting some better MPGs... until after about 600+ miles after a gas fillup I got a 'check engine' light and the truck went into 'limp mode.'

I was convinced it was bad gas, so I cleared the tune and took it to Ford figuring any repair was going to be on the gas station (I had the receipts plus I was posting odometer readings with dates here).

Ford blamed a loose vacuum connection on the catch can, but when I pressed the tech, he said it was the one that had been connected for a year already. I've been dumping oil/vaporized solvent/water condensate out of it every several thousand miles.

I paid for two hours of shop time for the lesson and it's bugged me since. Then I found this:

https://www.mustang6g.com/forums/threads/p04db-return-code-upr-dual-catch-can.41781/

The Mustang guys experienced something similar with the dual-vac catch can, the fix has to be in the tune.

I just emailed Torrie. With the recent intake mods that have improved my gas mileage (!) on top of the addition of the second vacuum line maybe it's time to tweak things again!

Sponsored

 

[Racket]

In this forum post the OP complains the 'clean side' vacuum line doesn't catch anything - but I don't think that's the purpose of the clean vacuum.
https://www.mustangecoboost.net/threads/p04db-crankcase-ventilation-pressure.21251/

and ths note on 5 Star's page for UPR CC for other Fords:
'CEL Note: UPR designed this can so that it does not throw a P04DB trouble code for your F150’s VPS sensor. However, even with UPR’s updated can design, some F150s may still throw a code, and UPR cannot guarantee with any certainty that their can won’t trip a P04DB code. Only a custom tune can permanently disable the VPS sensor and eliminate the P04DB CEL.'
https://5startuning.com/product/201...-can-with-electronic-css-upr-5030-238-1-ecss/

 

[Racket]

I didn't mention above - but after consulting with Torrie and my notes from talking with the Ford tech that my truck also threw a generic P0300 and more specifically the P0068 code regarding the intake system.

He wasn't willing to have the PCM ignore the specific P04DB code like in the links above (something about breaking the law - and we're not in California) but changed my tune to accommodate the P0068 code. I also asked him to soften my shifts since I don't want my wife scared to drive the truck.

We'll see. It's fun doing all this fine tuning.

Sponsored