Low power and missing under load...

[AnotherPerson]

Does anybody have any ideas for me here? We did some on it and decided to send it to the VW mechanic. VW mechanic went thru everything and doesn't see any signs of anything having issue. No codes, clean intake, fresh fuel filter. Tried it on both Malone tunes I have and it does the same. Map is reading boosting but with the miss you can hear in the turbo its trying to spool down during misses.

My only next step is to get the pump replaced. Mechanic verified timing on the car, SOI is set within spec. Doesn't appear to have any starting issues or long cranks even after sitting overnight.

 

[indysoto]

"We did some on it " what did you do to it? Did it happen out of the blue one day? or ?

 

[AnotherPerson]

I guess I just worded it wrong. The fuel filter and thermo-t we did. Don't have any problems with fuel draining back to the tank and causing any long starts.


It started about a month ago without much power loss so I thought at first maybe it was a exhaust leak, its when I checked on that I realized it was a misfire and its progressively gotten worse, it does on occasion give some decent power maybe for a couple seconds. Ive even had it before when I'm just cruising along in 4th where you can feel the car gets a little boost of power with steady pedal. VCDS shows everything good. So I don't know what else to check. I will prob run another can of diesel purge and this time strap it down and drive it around and see if its better when bypassing the filter and all the feed from the tank.


Even checked the IP Temp sensor but didn't read it while driving around, heard on occasion a damaged wire can cause it go crazy on what the ECU reads but wouldn't this throw a code?


Thanks for the reply and hopefully you can at least throw me a couple ideas to check out.

 

[maxmoo]

If it was mine I would try swapping out the maf sensor for a known good one.....assuming everything else is set properly and vcds shows no other issues.

 

[AnotherPerson]

If it was mine I would try swapping out the maf sensor for a known good one.....assuming everything else is set properly and vcds shows no other issues.

I talked to DFIS on the phone a few minutes ago and they said the noise my pump is making is a bad sign. To pull the cover and look for metal flakes or residue. So I guess thats my next step.

 

[AnotherPerson]

Also on another question. If the pump is wearing out and has tiny metal dust in it. Can that get thru to the injectors and clog them up or how does that work?

 

[indysoto]

doubt it holes so tiny..does it puff black smoke when it 'misses' Sounds like ip, if making noise.

 

[AnotherPerson]

Under normal driving and minor missing barely any smoke. If you give it some more gas it try’s to go and starts to smoke a lot more. They said something about mechanical wear causing the pump timing to go off which I guess injecting at the wrong time can cause. Someone who better understands pump operation would be better at explaining this I guess. Don’t know if too early or too late would cause the missing.


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