Help with the gti

[PunkST]

I know its not a fiesta ST. But im running out of ideas and things to try to get my gf's car back running. So far its new plugs, going to put new coils on, and replaced the HPFP and follower.

It runs great for literally an hour. Thats it. After that it screams about misfires and goes into limp mode. Car hasnt jumped timing and hasnt had a turbo failure that i can diagnose.

And as far i can tell has good compression.

 

[powermatt]

vwvortex.com?

Main thing I know of is a lot of old German cars with direct injection that won't stop misfiring are suffering from carbon buildup issues.

 

[PunkST]

Its not a carbon issue. After replacing the HPFP and letting it run for an hour the thing had multiple misfires on all cylinders and literally just repeated the original issue that started the whole mess.

 

[PunkST]

Now ive replaces spark plugs, coils and the hpfp and fuel filter and its still running like garbage.




Like i stated. It will run perfectly fine for an hour. Then out of nowhere it starts acting up.

 

[powermatt]

Its not a carbon issue. After replacing the HPFP and letting it run for an hour the thing had multiple misfires on all cylinders and literally just repeated the original issue that started the whole mess.

Generally it does tend to manifest more on cold starts, but I wouldn't rule it out unless you've had a borescope in the intake runners and had a look for yourself. It a pretty common known issue with the EA888 motors, especially the gen 1 that older GTIs used (not enough data on gen 3 motors yet).

 

[PunkST]

Why would it suddenly happen after an hour of operating perfectly fine?

 

[powermatt]

Why would it suddenly happen after an hour of operating perfectly fine?

That I don't know, but a symptom that doesn't show up for a while almost always comes down to heat. Out of curiosity, what codes is it throwing when it happens? Have you had a laptop with VCDS connected to it yet?

 

[PunkST]

No because i dont have vagcom or any vw friends.
Car never overheats or gives temp warnings...

 

[powermatt]

No because i dont have vagcom or any vw friends.
Car never overheats or gives temp warnings...

So you've not read any codes at all? How do you know it's misfiring? That's information you need. VAG cars have sensors and codes for everything, and there's a million things it could be. I'd go over to vwvortex.com, find someone in your area that has VCDS, and set up a time to get a full scan of the car. You might also be able to find an independent shop that works on VWs and will do a scan for you for cheap.

Worst case, maybe look at picking up an OBDEleven bundle. It's not quite as powerful as VCDS, but it's a lot cheaper.

 

[PunkST]

I have a cheap obd2 reader. I just cant get much deeper into how the car is running past the basics.
We've gotten it to only repeat p0304 now. And swapping coils or spark plugs around changes nothing. Exhaust reeks of fuel and when i pulled the plug for #4 it was wet with fuel to the point it was clean, like brand new compared to the other 3 plugs which were sooty and black. Its almost as if nothing is happening with cyl. 4. Even though i get voltage at the pins for the coil.

 

[powermatt]

I have a cheap obd2 reader. I just cant get much deeper into how the car is running past the basics.
We've gotten it to only repeat p0304 now. And swapping coils or spark plugs around changes nothing. Exhaust reeks of fuel and when i pulled the plug for #4 it was wet with fuel to the point it was clean, like brand new compared to the other 3 plugs which were sooty and black. Its almost as if nothing is happening with cyl. 4. Even though i get voltage at the pins for the coil.

Takes me back to what I said about heat. Something in the harness for that coil when it warms up? Maybe right when it does it, pull that coil and check for spark? Also maybe compare it to another coil to see if the spark looks weak.

Electrical gremlins are some of the most annoying things to track down.

 

[Hypergram]

Wish I could provide something to help, but it's funny cause right now my friend and I are trying to fix an electrical issue on his Mk5 GTI. At least you're not the only one with issues.

 

[Ford ST]

Have you tried swapping the fuel injectors around?

Sent from my LG-LS997 using Tapatalk

 

[PunkST]

Have you tried swapping the fuel injectors around?

Sent from my LG-LS997 using Tapatalk

Have not since its a 2011 and we have to pull the manifold to even see them. Doing some more talking with a tech, we may have and injector that stuck open

 

[The_Ryan]

So you've not read any codes at all? How do you know it's misfiring? That's information you need. VAG cars have sensors and codes for everything, and there's a million things it could be. I'd go over to vwvortex.com, find someone in your area that has VCDS, and set up a time to get a full scan of the car. You might also be able to find an independent shop that works on VWs and will do a scan for you for cheap.

Worst case, maybe look at picking up an OBDEleven bundle. It's not quite as powerful as VCDS, but it's a lot cheaper.

This is the answer. You need to start with proper diagnosis, and that can't be done without OBDEleven or VCDS. With those tools you can run various tests to check what's exactly wrong.

 

[Ford ST]

Have not since its a 2011 and we have to pull the manifold to even see them. Doing some more talking with a tech, we may have and injector that stuck open

It really does sound like a stuck open fuel injector on that cylinder, but I didn't realize it was so difficult just to change one of those out.

Sent from my LG-LS997 using Tapatalk

 

[theblue]

as a former owner. you need to get new coils. GOOD ONES. oem or better. they are really sensitive

 

[CSM]

Hit up Humble mechanic on Instagram. He's the VW wiz and responds often to questions

 

[powermatt]

This is the answer. You need to start with proper diagnosis, and that can't be done without OBDEleven or VCDS. With those tools you can run various tests to check what's exactly wrong.

VCDS can also tell you exactly what the fuel injectors are doing, which a basic OBDII scanner can't.

 

[PunkST]

It really does sound like a stuck open fuel injector on that cylinder, but I didn't realize it was so difficult just to change one of those out.

Sent from my LG-LS997 using Tapatalk

Not difficult. Just time consuming. Vw though they were being clever putting them there. Which causes a lot of the carbon buildup problems on the engines as well. Apparently its common. And the injectors are cheap is at 55 a pop. Putting new coils on didnt change anything.