Sudden loss in power accelerating from 0-100km/h

[GolfLeFleur]

Greetings,

I bought a 2007 MK5 GTI in November of 2017, had a busted dv so i replaced that with the newest revision shortly after, end of July this year HPFP and cam follower both went belly up and those were replaced. When I first bought the car, it would accelerate no problem under heavy load from 0-100km/h and passed that no problem rolling 60 to however fast i was going, no problem. Then my HPFP gave me troubles and thats when I was introduced to the world of VW things that die. These were promptly dealt with, thought it seems like the intake cam lobe has been scratched and slightly grooved. I was not able to clear codes like I should have (rookie mistake) I know that the computer will reset itself in given time. Symptoms before were, low engine performance, poor acceleration, intense bucking under load, and soft limp thought the engine never truly limped and shuttered.

What I've done since November:
Replaced DV with newest revision
New OEM hitachi HPFP + cam follower
New NGK Iridium spark plugs

Since these items have been replaced and fixed, I still get a soft limp, there is no dash light that flickers on or stays on. Ive been thinking about replacing my ignition coils as I have an outdated revision (couldn't read part # because spark plugs were just before leaving for vacation and didn't have the time). I nearly shit myself almost getting into a head on collision with a car after trying to pass a semi on the highway and i accelerated and the car starts to quickly build boost and let off as i am trying to pass and will not let me go any faster. Gradual acceleration at high speeds are fine but hard acceleration (like in the situation of passing on dotted yellow) was impossible. I went for a couple test drives after clearing codes and it was smoother but this soft limp won't go away, 0-100km/h foot to the floor, no acceleration. Any advice and or knowledge helps, I have tried to find someone with similar symptoms but haven't found anything. Ive heard everything from spark plugs to ignition coils to injector cleaner to pcv valves etc etc.

Thanks

 

[vwengineer]

You need to replace the intake cam if the lobe has been damaged or the fuel pump will not build enough pressure due to a smaller displacement

 

[GTI's]

Run a scan with Vcds and then log fuel pressures. You can remove vacuum pump to take a look at the Hpfp cam lobe and compare with a new undamaged one. There are examples on the web. Seems like this car was sold with known issues or you were the unfortunate person that had the original follower fail on their watch. The CF is a maintenance item even if VW did not list it.


Vacuum pump removal showing intake cam revision B.

https://www.golfmkv.com/forums/showpost.php?p=801521&postcount=1



Worn intake cam Hpfp lobe

New left worn right

 

[GolfLeFleur]

Run a scan with Vcds and then log fuel pressures. You can remove vacuum pump to take a look at the Hpfp cam lobe and compare with a new undamaged one. There are examples on the web. Seems like this car was sold with known issues or you were the unfortunate person that had the original follower fail on there watch. The CF is a maintenance item even if VW did not list it.


Vacuum pump removal showing intake cam revision B.

https://www.golfmkv.com/forums/showpost.php?p=801521&postcount=1



Worn intake cam Hpfp lobe

New left worn right

Thank you, I have read that this it is not easy to replace the intake or any cam at that for a beginner. Is the revision B a harder version of the A revision? and thank you for the link but at the moment the images are not displaying.

 

[GolfLeFleur]

You need to replace the intake cam if the lobe has been damaged or the fuel pump will not build enough pressure due to a smaller displacement

And yes, I was unfortunate not knowing the condition of the cam follower and lobe after I had purchased the car, I also did not know that these are things that need to be checked at set intervals. I appreciate your input, thanks again

 

[ROH ECHT]

Run a scan...

THIS...↑↑↑...these are heavily loaded up with sensors, yet many want to solve an issue by relaying the symptoms and have everyone take stabs at it with replys related to their own experiences. Reality is that many issues, will have identical symptoms and, can have multiple possibilities causing them. But if you would rather replace everything we suggest...then we can do that. Given the description you give; sounds like you did find a worn cam follower(CF) and only replaced the CF. Yes, you should have had the intake cam's tri-lobe inspected as it is quite obvious when the hpfp-lobe is worn badly. This is going to cause the hpfp to be unable to make appropriate rail pressure. But begin with a look at its codes.

 

[vwengineer]

Replacing a camshaft is a bit tricky but not impossible as a diy, you need to buy a special tool to lock the cams (but you can find it on internet). However I think that in the US there an extended warranty for this issue, not sure in Canada.

 

[ROH ECHT]

Replacing a camshaft is a bit tricky but not impossible as a diy, you need to buy a special tool to lock the cams (but you can find it on internet). However I think that in the US there an extended warranty for this issue, not sure in Canada.

Cam lock can be achieved with zip-ties. My VW tech always uses them to lock down the cams on mine by running the ties over the tops of the cam and through access points in the head and cinches them tightly. Also, the warranty extension is long gone now. Only the early mk5's had the extension applied if they had the revision-A intake cam. This included just 2006 and part of 2007 build period. So the 10yr or 120k mile, whichever comes first, has passed.

 

[GolfLeFleur]

THIS...↑↑↑...these are heavily loaded up with sensors, yet many want to solve an issue by relaying the symptoms and have everyone take stabs at it with replys related to their own experiences. Reality is that many issues, will have identical symptoms and, can have multiple possibilities causing them. But if you would rather replace everything we suggest...then we can do that. Given the description you give; sounds like you did find a worn cam follower(CF) and only replaced the CF. Yes, you should have had the intake cam's tri-lobe inspected as it is quite obvious when the hpfp-lobe is worn badly. This is going to cause the hpfp to be unable to make appropriate rail pressure. But begin with a look at its codes.

I have scanned for codes, I have tested the car a little bit more and have driven it under heavy load while accelerating and it has not thrown a code right away as it did in the past. I did feel the lobe when everything was taken off and was checking things that were recommended to check such as cf etc etc. The cf and hpfp were both replaced as the valve or spring that rides the cf was damaged as well.

 

[GolfLeFleur]

Replacing a camshaft is a bit tricky but not impossible as a diy, you need to buy a special tool to lock the cams (but you can find it on internet). However I think that in the US there an extended warranty for this issue, not sure in Canada.

I know of some of the tools that would be needed, I had found a video on how to properly do it but it wasnt a full walk through and I am one of those visual people who need to see it done in order to complete what it is that I am doing, if you know of a thread here with pictures or a video that is decent and easy enough to follow, I would appreciate that very much as I really havent found much. I am fairly good with taking and putting things back together and being meticulous doing so, so as a DIY I would love to learn more on how to do it.

 

[vwengineer]

I don't have a DIY unfortunately but there is a video on YouTube with the same engine on a Passat where you can see the whole process. You can also go on ELSA (the official platform from VW) and get the guide there so you will have every torque, etc...

https://www.youtube.com/watch?v=DmXMqRr7tRQ

Also be sure to replace the cam chain & tensioner as they are known to fail around 120-150k miles.

Also it would be a great idea if you have VCDS to log your high pressure fuel rail to see if it's really the problem, but if the cam is damaged it's likely.

 

[njcatalano]

Hey

I have 2006 MKV GTI that had the same issue in the spring. Good news is the fuel filter was clogged. Inexpensive and easy to replace. There are good videos on you tube that will help locate and replace the part. If I remember the part cost $80. The car runs Great since I replaced. Good Luck.

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