Issues with High pressure too low mk5 GTI

[momo.mk5GTI]

So you have not replaced the intake cam yet?

If you don't do that then you will just eat through cam followers....

Not yet, i will open to see in what condition is intake cam. Normaly intake cam has not damage, like disforming or used when i change folower i looked for that. Today i will try with another intank fuel pump from another golf 5 gti and write again.

[rich83]

Change the intake cam..... seriously!

[ROH ECHT]

For intake cam im not sure that i must to change because its not very bad what were see. But i will make photos when i open cap for chain. Thank you.

You need the intake cam. Not only will it wear a new follower and damage its new hpfp piston quicker, but the hpfp pressure regulator will need to be open more to make the target rail pressure.

The wear on its tri-lobe is obvious in your pic. It gives you a clear sign that the peaks of its lobes are not as tall as they were when new or undamaged;


New cam;

[pudding]

Hello a litle update too the topic. This morning when i start the car you know that hold 1200 1300rpm but sometimes like this morning after the start car not hold the rpm in high. Its just started normaly and then the rpm is down to normal.

I think this is normal. Mine does this when the outside temperature is particularly low (a few°C or less). Seem to remember being told the car decides which best start up mode (high idle or straight to normal) is best based on environmental conditions at the time orf starting.

Yep, normal.  Idle speed vs ambient temp is not consistent through the 4 seasons and can be ignored.  There are a complex set of parameters in the ECU that govern the idle speed vs ambient temp, which is largely related to EGR (Exhaust Gas Recurculation) and cat warm-up.  Older VWs used a combination of cam phasing and an air pump (SAI - Secondary Air Injection) to manage that, but the TFSI engines seem to just use a combination of more precise fuelling & idle speed instead.

The main thing to focus on is engine smoothness.  Doesn't matter what the idle speed is, so long as the engine is smooth and responds quickly to pedal requests.  TFSI engines throw their toys out of the pram if coils, injectors, plugs and oil pressure aren't up to snuff.  It lets you know immediately if there's a fault.

And yeah, that cam is f'cked.  I'd be temped to throw a new head on it from VW.  Comes with cams, VVT and chain gear etc.  A new head also restores compression providing the bottom end is still tight.  Improved off boost torque and engine braking.

[momo.mk5GTI]

Hello a litle update to the topic, ive changed the intank fuel pump with used one, just for try and definetly car pulls beter than my pump, but after a litle test at the highway, when i was out and put the gas, first i dont have the problem car just flyed like before  and i dont know i was make like 160 180km/h and no cut out. After test when i take the highway out, its cut a new at 110 120km/h.    (when i push the gas the rpm just stays at the same). I dont know what happens i was changed fuel filter but not with the original VW, i think the fuel filter bars are much low than be must.  and i see thah thu hpfp pump is with letter L at the end mine was with F. (And the seelers must be send me with letter J) we also looked that J is compatible with my car and yes it was compatible, but with L and dont know. Is that can be play something. And after the test when i puted back my pump, its pulls like other fuel pump. And now im with my fuel pump, car goes beter but have this cut out... i cant understand this.

[momo.mk5GTI]

For intake cam im not sure that i must to change because its not very bad what were see. But i will make photos when i open cap for chain. Thank you.

You need the intake cam. Not only will it wear a new follower and damage its new hpfp piston quicker, but the hpfp pressure regulator will need to be open more to make the target rail pressure.

The wear on its tri-lobe is obvious in your pic. It gives you a clear sign that the peaks of its lobes are not as tall as they were when new or undamaged;


New cam;

I understand, what is the price of this cam? Must be the original one or aftermarket will done the same job. And what is the ref. number? And what you mean i didn understand that ' but the hpfp pressure regulator will need to be open more to make the target rail pressure.'

[muff1991]

Hi @momo.mk5GTI
What @ROH ECHT means is:If the cam lobe is worn then the High Pressure Fuel Pump is not mechanically operating how it should as the pump isnt being "pumped" in far enough by the lobe. Because of this the Fuel Regulator will need to allow more fuel going through (staying open) to reach the engine/Fuel Rails requested pressure.

The only thing i'm a little unsure on: if the pump has been changed and no real difference was made then it rules the pump out. You say the car pulls fine one minute and not so good the next minute. if the lobe was worn out and causing the above - would it not cause a problem all the time not just sometimes?

[momo.mk5GTI]

Hi @momo.mk5GTI
What @ROH ECHT means is:If the cam lobe is worn then the High Pressure Fuel Pump is not mechanically operating how it should as the pump isnt being "pumped" in far enough by the lobe. Because of this the Fuel Regulator will need to allow more fuel going through (staying open) to reach the engine/Fuel Rails requested pressure.

The only thing i'm a little unsure on: if the pump has been changed and no real difference was made then it rules the pump out. You say the car pulls fine one minute and not so good the next minute. if the lobe was worn out and causing the above - would it not cause a problem all the time not just sometimes?

Hello muff1991 thank you for the answer, yes exactly what amazes me too is that sometimes the car goes all the way and nothing but after pushing it about 10 15 minutes on the highway and doing high speeds, it just goes into service mode and stops the throttle , even if I didn't press the throttle, it just sits at its rpm and after a short while, it did, I had it done before changing the folower and the hpfp. Because it is already 138xxx km and I am doubtful that it will enter service mode because of the timing belt or the chain (since I had a fault with the chain and they told me about the cover payment I will order them and change them). And the other thing is that the filter is not original from vw but it is purflux and it reads 3 or 4 bars, which makes me think that the filter cannot deliver enough fuel to the engine. Once the check light comes on, even when the drive is normal. very slight tingling that is almost not felt on a rough road. I just don't know where the problem is. I was looking and asking about the problem of the cam but cars with the problem cam work in a completely different way and when i was open the hpfp the folower was wear good to the cam. I just don't know where to look for the problem.

[muff1991]

If the fuel filter hasn't been replaced for the updated 6bar filter, or never been replaced at all.. its a cheap enough part to replace and try 

[momo.mk5GTI]

Hello everyone, because of the lack of time i could not play with the car and write here. A week ago, I removed the high-pressure sensor and cleaned it with a WD40. After putting back the power on the first 3 4 hard riding it was as unique as before, but after a short while it went back to the mode it is now. Today I took a few laps with the laptop, I also posted a schedule and this was noticed. When car is cut of fuel this thing goes very down at mybe 60 or more down when he upper the values car is back to his force and continur to up the rpm's when is stationary he is at -5xx -6xx values. When i push i see at the graphic, this goes high, while im riding and he's go down car cut of power. 

[rich83]

Have you changed the intake cam yet?

[momo.mk5GTI]

Have you changed the intake cam yet?

No i dont change the intake cam, and im not gonna change because probleme is not there. I was out folower for inspect if it have a contact with lobe, and when i was out it the folower and lobe make a contact like my friend gti is same, If i have problem with intake cam, car wiĺ not be same as before sometimes. He will be poor in every gear. Unfortunetly i cant make anything because i have an accident and dont know what expert will say. I think i was said before that im not change timing belt and timing chain yet. And also i have a oil leak from valve cover and add1L oil every mybe 3000km. I have a litle bit work then if its not gone i will think for the intake cam as you said. But for now i dont think that the cam is problem. But thank you for your help i will keep in mind. 

[ROH ECHT]

Look, I believe you do need a new intake cam, but if you do not accept this...the rail pressure is failing you. This can be related to more than one issue.

The FPRV; 06D 133 400 A may be unable to hold rail pressure and may be releasing fuel back into the low side.

The high pressure outlet valve on the bottom of the hpfp may not be sealing to retain rail pressure.

One or more fuel injectors are sticking open.

The hpfp regulator isn't working, but you replaced the hpfp with a new one, right?

The "fuel pressure sensor-high" on the rail is failed, but you replaced it too, right?

The low pressure is insufficient; meaning the lift pump or fuel filter is failed or incorrect(not 6.6 bar regulated filter).

The lift pump PWM controller is failing when warm/hot.

Or, the intake cam tri-lobe is worn...and your picture proves that.

BTW...I cannot make out the pics of the vcds screen you post as they become fuzzy when I zoom on it. Cannot tell which MB you are on or tell what the data reads. Please try getting in closer for those shots in the future.

[momo.mk5GTI]

Look, I believe you do need a new intake cam, but if you do not accept this...the rail pressure is failing you. This can be related to more than one issue.

The FPRV; 06D 133 400 A may be unable to hold rail pressure and may be releasing fuel back into the low side.

The high pressure outlet valve on the bottom of the hpfp may not be sealing to retain rail pressure.

One or more fuel injectors are sticking open.

The hpfp regulator isn't working, but you replaced the hpfp with a new one, right?

The "fuel pressure sensor-high" on the rail is failed, but you replaced it too, right?

The low pressure is insufficient; meaning the lift pump or fuel filter is failed or incorrect(not 6.6 bar regulated filter).

The lift pump PWM controller is failing when warm/hot.

Or, the intake cam tri-lobe is worn...and your picture proves that.

BTW...I cannot make out the pics of the vcds screen you post as they become fuzzy when I zoom on it. Cannot tell which MB you are on or tell what the data reads. Please try getting in closer for those shots in the future.

I was changed hpfp with new this is true, i think i was post it somewhere that the hpfp the last letter is different then mine, i dont know if this play something.

The fuel filter was changed with NOT OEM but 4.0 bar filter i was market this too.

The fuel pressure regulator was cleaned with WD-40 and placed at the rail. (NOT CHANGED with new one) 

This FPRV as you said can not be hold the pressure at the rail this must be true because sometimes when i start the car he turn a litle bit longer then must turn until start.

Oke then i have a question, if the cam lobe is worn why sometimes power back at any gear? And why when i push slowly the gas pedal car runing well? As everyone said if my cam is worn car will not running good at any other gears? When llobe is worn car has no power right?

Sorry abaout picture quality when i upload the quality drop down i dont know why.

https://scontent.fbru2-1.fna.fbcdn.net/v/t1.15752-9/91711718_821418891704115_6447991692330008576_n.jpg?_nc_cat=110&_nc_sid=b96e70&_nc_ohc=4BkPP4EhzUsAX_6LRco&_nc_ht=scontent.fbru2-1.fna&oh=b815fc2f66fd1fde2461fbdc246ee4de&oe=5EAF896A

At the group 103 the second window with name 'Fuel Pressure Regulator' values drop down i dont remember whic was the values he drop very very down like 50 or 60 mybe i was alone and drive at the same time cant see everything, then car cut of power when he up the values car goes better.

[FJB]

Your cam lobe is bad, you can clearly see it in the picture.