Ktrain2k18
Member
I've tried searching every forum over the past 1.5 years and I haven't been able to figure this out. Most guys don't seem to update their posts on if they fixed it so I'm going to try here. (If this is in the wrong section I apologize)
I have a 2012 NMS TDI Passat with Kessy. I have right at 198k miles on it and I started having issues starting, this started back in 2022. The first start of the day it'll crank for over 8 to 12 seconds and stumble when trying to start. After the first start of the day it'll start fine until it's been sitting for over 8 hours. It's very very rare but sometimes while driving I've had a stutter for a second and it goes away, always right after start up. Almost like the fuel or power just shut off.
I've monitored everything from the Fuel pressures on the low and high side. both while running and cranking and haven't seen anything jump out at me or look suspicions. To the range of requested at 5xxx psi at crank and idle vs actual of 49xx-5050psi. While driving the car staying in 5th gear im over 20-25k psi almost to 30k if I remember right. I Have no knocks and ZERO codes at all. I've scanned with VCDS(I do not own this it is a neighbors), OBD11, and 4 different scanners with no codes at all. I've changed out the battery(730CCA) as I've seen suggested by hundreds of people to no avail. One thing I noticed was sometimes by cluster says the key is not in range even when I hold it up to the steering column, I've changed the fob battery and I only have 1 so I can't test another key.
I have noticed that when I open the door the tank fuel pump doesn't prime but I can cycle the Push bottom 2 or 3 times and it'll start right up, this is why I think it's fuel related. I'm really starting to wonder if it's a fuel pump issue as it's not priming when it's supposed to be, but I don't know what triggers this pump to turn on expect for the start button. Yes something is leaking off to where the fuel pump is having to prime so much but I cant figure out where or if this is the issues. Since this issue started I've changed the following parts AFTER the issues started. This is not temperature related either, I'm in central IL where it'll go from -25 to 115 degrees F and it doesn't matter either way. I've even put a tender on to make sure the battery was completely full before trying to start with the same results.
-Oil cooler
-DSG flywheel
-clutches
-fuel lines that are on top of the fuel filter going to the HPFP and every line connected to it
-Battery
-Key fob battery 2x
-Reprogrammed key
-Timing belt and water pump
-Fuel filter 6 times
I have also watched the cam and crankshaft sensor readings and they seem perfect both during and after cranking. The last thing I want to do is start throwing parts at it, if I throw 1k worth of parts at it I might as well changed every thing.
I'm a diesel tech as a profession for 7 years and I'm at a loss. I have watched every reading I can. I'm very worried about the HPFP but I've inspected it multiple times with no metal at all in it. I'm getting so close to just getting the CP3 conversion from Cascade, but that's 3k I really don't want to spend right now. I plan on keeping this car for as long as possible, I'll put 2 engines in it if I have to, I'm the second owner and I've had it since 2019 when it had 71k on it. This is one of 4 vehicles of mine so it's not the end of the world but I haven't been able to drive it much over the last year because of this and I want her happy again!
I know it's a lot but if anyone can tell me if they had a similar issue and what fixed it, I would appreciate it. PS VW wont touch it because the emissions "fell off".
I have a 2012 NMS TDI Passat with Kessy. I have right at 198k miles on it and I started having issues starting, this started back in 2022. The first start of the day it'll crank for over 8 to 12 seconds and stumble when trying to start. After the first start of the day it'll start fine until it's been sitting for over 8 hours. It's very very rare but sometimes while driving I've had a stutter for a second and it goes away, always right after start up. Almost like the fuel or power just shut off.
I've monitored everything from the Fuel pressures on the low and high side. both while running and cranking and haven't seen anything jump out at me or look suspicions. To the range of requested at 5xxx psi at crank and idle vs actual of 49xx-5050psi. While driving the car staying in 5th gear im over 20-25k psi almost to 30k if I remember right. I Have no knocks and ZERO codes at all. I've scanned with VCDS(I do not own this it is a neighbors), OBD11, and 4 different scanners with no codes at all. I've changed out the battery(730CCA) as I've seen suggested by hundreds of people to no avail. One thing I noticed was sometimes by cluster says the key is not in range even when I hold it up to the steering column, I've changed the fob battery and I only have 1 so I can't test another key.
I have noticed that when I open the door the tank fuel pump doesn't prime but I can cycle the Push bottom 2 or 3 times and it'll start right up, this is why I think it's fuel related. I'm really starting to wonder if it's a fuel pump issue as it's not priming when it's supposed to be, but I don't know what triggers this pump to turn on expect for the start button. Yes something is leaking off to where the fuel pump is having to prime so much but I cant figure out where or if this is the issues. Since this issue started I've changed the following parts AFTER the issues started. This is not temperature related either, I'm in central IL where it'll go from -25 to 115 degrees F and it doesn't matter either way. I've even put a tender on to make sure the battery was completely full before trying to start with the same results.
-Oil cooler
-DSG flywheel
-clutches
-fuel lines that are on top of the fuel filter going to the HPFP and every line connected to it
-Battery
-Key fob battery 2x
-Reprogrammed key
-Timing belt and water pump
-Fuel filter 6 times
I have also watched the cam and crankshaft sensor readings and they seem perfect both during and after cranking. The last thing I want to do is start throwing parts at it, if I throw 1k worth of parts at it I might as well changed every thing.
I'm a diesel tech as a profession for 7 years and I'm at a loss. I have watched every reading I can. I'm very worried about the HPFP but I've inspected it multiple times with no metal at all in it. I'm getting so close to just getting the CP3 conversion from Cascade, but that's 3k I really don't want to spend right now. I plan on keeping this car for as long as possible, I'll put 2 engines in it if I have to, I'm the second owner and I've had it since 2019 when it had 71k on it. This is one of 4 vehicles of mine so it's not the end of the world but I haven't been able to drive it much over the last year because of this and I want her happy again!
I know it's a lot but if anyone can tell me if they had a similar issue and what fixed it, I would appreciate it. PS VW wont touch it because the emissions "fell off".
