Recent Posts

91

Mk5 General Area / Re: Mk5 GTi stage 1 fuel pressure problems

« Last post by Lassebongo on August 29, 2025, 09:18:53 pm »

Yea as I feared I ordered a new pump and controller. The new pump will have a newer revision, 1t0 DB i think it was, same with the controller. It's weird though because its a low milage for its age. 130k
Yea I did log the duty cycle att some point, lost the file, it did max out at 95% if I remember correctly.
Thanks for the insight, I'll post the results after the swap!

92

Mk5 General Area / Re: Mk5 GTi stage 1 fuel pressure problems

« Last post by ZoliWorks on August 29, 2025, 03:46:20 pm »

Holy, yeah look at your low-pressure side, that's basically dead. I'd say in-tank pump, controller or maybe the filter but unlikely. Your low pressure side is basically starving your engine completely. It should never really drop under 4.5 bar on full WOT.



Try logging the in-tank pump duty cycle as well. I forgot the exact VCDS param for it. Auxiliary fuel pump or electric fuel pump? something like that.

If you're going to replace it, there are a few threads here with people and the pumps they used.

93

Mk5 General Area / Re: Back in a MK5 GTi, anything to urgently do?

« Last post by mjmallia on August 29, 2025, 02:27:58 pm »

It checks how much the cam phaser is adjusting to keep the engine in time.  As the cam chain stretches over time the phaser takes up more slack to a point where it can't and you start to get hard starts and/or chain rattle noises at start up etc.  You can see how many degrees off 0 it is making an adjustment.  Up to 3 is usually fine, but then 4 to 6 you will be getting a lot of noises (consider sorting it very soon) , then above 6 you are a ticking time bomb (change ASAP if you want to keep the car)...........when checked on a warmed up engine.

The chain starts to show its age from about 80k to 100k depending on how well the engine has been maintained and driven.  The phaser also wears out and struggles to keep oil pressure to maintain the adjustment.  I changed my chain and tensioner 8 years ago but not the phaser and the chain had to be changed again recently due to the worn phaser prematurely wearing the chain (it was on -3.0 degrees from 0 after 20k miles and 8 years)..........replaced it all now

94

Mk5 General Area / Re: Back in a MK5 GTi, anything to urgently do?

« Last post by darren4 on August 29, 2025, 02:04:44 pm »

Might as well check the cam Phase position - VCDS, Engine > Block 93, should be near or close to 0KW

Whats this checking for, sorry if thats a silly question

95

Mk5 General Area / Re: Headliner Repair Trim Piece

« Last post by Bassman1974 on August 29, 2025, 01:25:48 pm »

If you think the rear is brutal, you should see the price of the front. Pretty sure I paid about £120 for mine.

It fairly cured the sagging though.

96

Mk5 General Area / Headliner Repair Trim Piece

« Last post by Jons1001 on August 29, 2025, 12:06:09 pm »

My headliner is sagging around the rear interior light. I found these online but nowhere seems to have stock anymore. Also messaged the manufacturer but no response.



Does anyone know where i might be able to get hold of one? The price of £70 is a joke though for a bit of plastic, would be great if we could get hold of the specs so we could 3d print them!

Thanks

97

Mk5 General Area / Re: Mk5 GTi stage 1 fuel pressure problems

« Last post by Lassebongo on August 29, 2025, 10:03:43 am »

Ty for the reply
I did the filter swap myself last year and did check the pressure requirements beforehand so the filter is the correct one.
Here are the logs:
https://log.tunezilla.com/s/bbQzxooI

I'm doing tests on the n80 today and checking if the charcoal canister is clogged because there is a hiss when opening the fuel cap.

How do I test the controller on the fuel tank lid?

98

Mk5 General Area / Re: Mk5 GTi stage 1 fuel pressure problems

« Last post by ZoliWorks on August 29, 2025, 01:23:41 am »

Check the part number of your old pump and buy based off of that. IIRC you need a 6 bar pump and a 6.6 bar filter.

Log the low pressure side with vcds next time you go for a drive so you can check what the pump is doing. Could be the pump, could be the controller or could be a worn out HPFP lobe. Even just a slight bit ow wear on th elobe can mess with the regulator open/close times and in turn mess up your fuel pressure.

99

Mk5 General Area / Mk5 GTi stage 1 fuel pressure problems

« Last post by Lassebongo on August 28, 2025, 12:15:19 pm »

Hi!
Im new here so if the thread is posted in the wrong section let me know.

Ive got a 2008 Gti mk5 stage 1 with fuel pressure problems.
On hard pulls it jerks and in the VCDS logs the pressure drops from 110 bar to 7(with the new HPFP, the old one went up to 129 bar and dropped)
A local company loaned me a HPFP which is swapped but didnt solve the problem.
Fuel filter swapped last year.
The cam follower is also new, doublechecked and its in pristine condition.
There are no leaks from what i can see, atleast around the visible fuel rails and HPFP.

So whats left is the in tank pump and im pulling it out today but i dont know what to look for 

Could there be anything else causing this problem or can i just swap out the in tank pump and the problem should be solved ?
Can the in tank be repaired ?
Is a 4 bar pump enough?

100

Mk5 General Area / Re: Temp gauge dropping when heaters on

« Last post by Mk5gti on August 28, 2025, 08:12:16 am »

So my issue is the needle drops when I turn heaters on
Both thermostats have been done and temp sensors using genuine parts, while driving the needle doesn’t drop, the needle will only drop at idle with heaters on