Lecatona HPFP (High-pressure Fuel Pump Upgrades)

Misfire issues/fault finding

GordieC

GordieC

Active Member
Sep 24, 2012
124
4
Glasgow/Islay
Hi guys,

Frequent lurker, infrequent poster here.

I have a 2007 Leon Cupra which is currently throwing up a code for misfire on cylinder 4. I have done some fault finding and would very much appreciate a few pointers as to what I should do next.

I have swapped coil packs and spark plugs with cylinder 1 and the fault remains on cylinder 4. Can someone let me know which way the cylinders are numbered (i.e cylinder 1 on nearside or offside of vehicle).

I understand that it may be down to carbon build up on the inlet valves or possibly an injector.

Is there any way to diagnose a fault on the injector without pulling it? I only have Carista to assist me with ecu faults (plus a cheap ebay scan tool).

If the injector is at fault, can I get away with changing just one or is it a full change out? Normally this would be ok, but it's going for a respray next week so I've dumped enough cash into it already, especially after getting a quote for £600 for a walnut media blast!!:blink:

I know that there is a tool for injector removal. Is this 100% required or can it be done without.

Does anyone know the details of what's involved when replacing the injector? (aside from disassembly of the manifold etc) Clamped in, push fit, push and turn etc.

I am planning to tackling this on my driveway (I'm a marine engineer, so these engines are a lot smaller and more fiddly than I'm used to, but plenty of research and prep and all should go well). I spotted a fantastic how-to from a user on here (Lee_M), so that will be my main guide.

I also plan on cleaning the inlet valves while the manifold is off. I will fabricate some thin copper scrapers and hooks to help me with this. Does anybody have any recommendations as to which carbon remover chemicals to use? We have some carbon remover for the turbochargers on my rig but I'm sure there will be better stuff available here.

Sorry for all the questions and the long story, hope someone can point me in the right direction.

Cheers,

Gordie
 
Sorry I got my mechanic to do the work so not got any hints or tips on the procedure. We did just replace the single faulty injector, although we removed them all to check how dirty they were and gave them a clean. Carb cleaner etc.

I would definitely recommend cleaning the valve ports and the intake manifold while its off.
 
No problem. I'll need to check and see which injector I should order for it. I want to make sure it's the same as the one it's replacing and that they don't have several that could have been fitted from the factory.
 
i spent today changing a injector and cleaning the inlet ports on my 09 cupra, after suffering from a misfire for the last few months. the same as you describes. i tried many thing to cure the misfire (swapping coil-packs around, swapped plugs around, redex, a good blast) but always misfire cylinder 3 on idle and a lack of power low down sometimes.

Removing the inlet manifold is quite straight forward, connectors come off easy, there are a few guides out there for removing this access is quite tight. The inlet manifold comes off in around hour and half but has it tricky bits, the most challenging bit being the throttle body. A wobble bar is a must for removing the rear left bolt!

You need a decent tool set with a good selecting of long short and allen type T30s, a couple of long narrow flat screwdrivers, triple square 10 socket, good pliers, long and short extensions and stubby ratchets are all very handy

when pulling the manifold out a plastic cable tray for the injectors is clipped to manifold and needs releasing..

my cars covered 65k and mapped for half of its life and there was about 2-3mm of oily crude on the intake inserts, and maybe 1mm on the intake ports and a bumpy huge build up on the valves :-o.

i used BG Injecting system cleaner, it dissolved the gunk easily. its strong stuff , scrapping the crap off first in the ports and intake flaps cuts down the soak time needed.

after a few hours of cleaning and a thunderstorm later i tackled the injector.

When i removed the inlet manifold 3 injectors stayed in the head and injector 3 came out with the manifold ::D happy days. The injector i need to change :D After cleaning the injectors port i push the new injector home with a 16mm socket, put the blue o rings on the injectors and did everything back up..


a few scrapped knuckles later i turned the key and after the fuel system built back up boom it fired up! After warm finished up and a beer later the revs dropped down and it idled lovely silky smooth.
:clap:
but
excitement was short lived :cry: on the road test there was no boost and would not rev past 3k without becoming stuttery. Out came vcds and camshaft sensor and intake pressure sensor were coming up as faults after a little fiddling and thinking the worst that i had to removed the manifold it turned out to be a multi plug not clicked in all the way :funk:

after another drive power is back strong and things feel alot smoother and definitely a lot quicker through the rev range

guide i used https://www.scribd.com/doc/156031056/2-0-TFSI-Inlet-Manifold-Injector-Valve-Clean-Guide
 
That's an awesome write up mate. Thank you very much for that. It'll help me a lot, especially seeing as you've done it so recently.

Can I ask where you got the injector from? Do you have a part number that I could reference?

Thanks again,

Gordie
 
The injector is part number 06f 906 036 F . Definatly contact dave hes a top parts bloke, i paid about £115 deliverd.
 
Thank you for that. I wasn't sure if it was the F or the A injector. F it is.

I'll also order up a new inlet manifold gasket. Any other gaskets I should be ordering?

Sorry if I sound like a stuck record but than you all very much for the assistance here. I'm used to Honda and Mitsubishi so this is still fairly new to me (Ask me about the Honda B series and I'll bore you to tears! :happy:). It's very much appreciated.

I'll take the next 2-3 weeks to get parts ordered and pick the brains of you lot.

Once I get started, I'll take pictures and post them up if anybody is interested although I suspect this has been done a few times before.

Cheers,

Gordie
 
A small jubily clamp, maybe a cam bucket follower as the hpfp has to come off and some brass brushes for cleaning.

I took some pictures when i got the manifold off before cleaning but they dont show how much was caked on the valves but took none before i put it back together at all.
 
Last edited:
Well, started the job today and what an absolute pig of a job it is to do. I used the guide I found on here and it was invaluable, couldn't have got so far without it.

Anyway, updates:

My valves and runners are absolutely caked in carbon/oil build up.

Intake runners had 2-3mm of build up on both sides of each one:

DSC_0008_zpsliawjcd4.jpg


Valves are minging too:

DSC_0018_zpsm5osjjca.jpg


I've got the valves on cylinder 1 and 4 soaking overnight in carb cleaner. Hoping it will soak in, evaporate off and make it easier to remove the crud. If not, I'll order some of the BG injector clean fluid.

Cylinder 4 after a quick soak and scraping:

DSC_0021_zpsfzp96v8p.jpg


Not perfect but certainly on the way to looking a lot better.
 
Got the job finished today. Cleaned up the inlet chambers and inserts, replaced #4 injector and replaced the fuel pump cam follower. It was in surprisingly good condition but worth changing anyway.

All reassembled, no bolts or nuts left over, primed the fuel system about 5 times before attempting a start. A good 5 seconds of turning before it started to kick. Tried a second time but it wouldn't idle at all. A quick check and I had forgotten to connect a breather pipe. Connected up and the engine fired up perfectly first time. A bit of smoke and crap from the exhaust but it soon cleared and was idling well.

Test drive went well too. Pulling as hard as ever and the throttle response is now better and smoother.

Ran a ECU scan and following the initial reset following reassembly, the only codes I now have are for a radio antenna earth fault and a blown nearside fog lamp. That'll do for me. :D
 
boggle said:
i spent today changing a injector and cleaning the inlet ports on my 09 cupra, after suffering from a misfire for the last few months. the same as you describes. i tried many thing to cure the misfire (swapping coil-packs around, swapped plugs around, redex, a good blast) but always misfire cylinder 3 on idle and a lack of power low down sometimes.

Removing the inlet manifold is quite straight forward, connectors come off easy, there are a few guides out there for removing this access is quite tight. The inlet manifold comes off in around hour and half but has it tricky bits, the most challenging bit being the throttle body. A wobble bar is a must for removing the rear left bolt!

You need a decent tool set with a good selecting of long short and allen type T30s, a couple of long narrow flat screwdrivers, triple square 10 socket, good pliers, long and short extensions and stubby ratchets are all very handy

when pulling the manifold out a plastic cable tray for the injectors is clipped to manifold and needs releasing..

my cars covered 65k and mapped for half of its life and there was about 2-3mm of oily crude on the intake inserts, and maybe 1mm on the intake ports and a bumpy huge build up on the valves :-o.

i used BG Injecting system cleaner, it dissolved the gunk easily. its strong stuff , scrapping the crap off first in the ports and intake flaps cuts down the soak time needed.

after a few hours of cleaning and a thunderstorm later i tackled the injector.

When i removed the inlet manifold 3 injectors stayed in the head and injector 3 came out with the manifold ::D happy days. The injector i need to change :D After cleaning the injectors port i push the new injector home with a 16mm socket, put the blue o rings on the injectors and did everything back up..


a few scrapped knuckles later i turned the key and after the fuel system built back up boom it fired up! After warm finished up and a beer later the revs dropped down and it idled lovely silky smooth.
:clap:
but
excitement was short lived :cry: on the road test there was no boost and would not rev past 3k without becoming stuttery. Out came vcds and camshaft sensor and intake pressure sensor were coming up as faults after a little fiddling and thinking the worst that i had to removed the manifold it turned out to be a multi plug not clicked in all the way :funk:

after another drive power is back strong and things feel alot smoother and definitely a lot quicker through the rev range

guide i used https://www.scribd.com/doc/156031056/2-0-TFSI-Inlet-Manifold-Injector-Valve-Clean-Guide
Click to expand...

I had a intake manifold runner fault code
Car would rev up to 5k rpm then hesitate.

Tried loads of things and nothing seemed to fix it until I came a cross this gem. Try it before changing any parts please all future sufferers

2.0l TFSI (AXX/BGB/BPJ/BPY/BWA) - Ross-Tech Wiki

wiki.ross-tech.com

You will need the VCDS software does not have to be original big bucks version as I done it with one I got off ebay or amazon.

After doing this it reset, took it for a drive and Holy **** does it shift now, zero hesitation at full rev range. The car has come alive and driving like it should have always been
 
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