[doodlestj]

I had a cheap coil pack and it vibrated up the tube leading to an occasional misfire.. I also bought some bkr7s from ebay and one of them cylinder 1 failed, it would only miss like a lul if hot and ~5500rpm..

If its intermittent is it possibly wiring? Or maybe oil getting into the spark plug hole? From the centre cam gasket..

Could be wiring. Tracing that back is going to be a bitch.

I saw there was a bunch of oil on the spark plug so I replaced the valve cover gasket... haven't checked since I did that but I assumed that fixed it

Just replaced the downstream O2 sensor :/. If the code comes back I'll order some new PCV pipes and an intake manifold gasket and try replacing that. Unfortunately shipping takes a long time

 

[doodlestj]

Still getting the codes... going to take it apart a bit and order new PCV hoses today. Pretty hard to find online... if you have any recommendations on places to shop for them I'll take any advice.

Will probably replace the intake manifold gasket while I'm at it

 

[StuartDB]

I don't think the post cat sensor does anything, mine is coded out for sports / de cat.

Is everything properly plumbed in?

Underneath the inlet manifold there's the two 4mm connectors for FPR and N249 (or straight to DV if N249 deleted) on the left and in the centre there's a bigger (maybe 6mm) connector which connects to the PCV valve.

I think if you run blocks 1, 31 and 32? You can view long term and short term fuel trims. And then if you clear all errors (even if there are none)? That will reset the fuel trims. If there's an air leak it will be easy to tell.

Running blocks 1, 31, and 32 it seems my lambda stays pretty close to 1. Not sure how to view long or short term fuel trim

Group 32 I don't really understand... it says my bank 1 sensor 1 idle is about 2.6% and my bank 1 sensor 1 partial load is -7%... no idea what to make of these #s

Attached the log for those blocks

Sorry it is 32 and 33 not 31 and 32

Essentially, if you are leaking air you will get fuel trims out side the target range...

There are some other linked videos, essentially the goal is 0%, long term fuel trims are adaptions based on how much more or less fuel is required to correct for unmetered air (a leak) as idle is always at vacuum. But there are acceptable settings. Like maybe 4% for long term and -10 to +10 for short term. If you have -2.6 in LT and clear all errors (even if none) fuel trims are reset and then looking at ST FT your short term might be -10,+7,'-10,+7.... etc then after a while the LTFT might be -1 then your STFT should be -9,+8,-9,+8... etc. Short Term always go less, more,less,more but its ideal to get the gap between the numbers smaller..

There's also a Map table called FKVVS which stores a profile based on Audi Stock Injectors, but that sometimes needs adjusting... there's a tool you can get to tell you the best new values, it's based on the throttle position (maybe load?) and revs, and you drive around trying to cover as many rpm, TP combinations and it will show you the adjustments for your table..

 

[doodlestj]

I don't think the post cat sensor does anything, mine is coded out for sports / de cat.

Is everything properly plumbed in?

Underneath the inlet manifold there's the two 4mm connectors for FPR and N249 (or straight to DV if N249 deleted) on the left and in the centre there's a bigger (maybe 6mm) connector which connects to the PCV valve.

I think if you run blocks 1, 31 and 32? You can view long term and short term fuel trims. And then if you clear all errors (even if there are none)? That will reset the fuel trims. If there's an air leak it will be easy to tell.

Running blocks 1, 31, and 32 it seems my lambda stays pretty close to 1. Not sure how to view long or short term fuel trim

Group 32 I don't really understand... it says my bank 1 sensor 1 idle is about 2.6% and my bank 1 sensor 1 partial load is -7%... no idea what to make of these #s

Attached the log for those blocks

Sorry it is 32 and 33 not 31 and 32

Essentially, if you are leaking air you will get fuel trims out side the target range...

There are some other linked videos, essentially the goal is 0%, long term fuel trims are adaptions based on how much more or less fuel is required to correct for unmetered air (a leak) as idle is always at vacuum. But there are acceptable settings. Like maybe 4% for long term and -10 to +10 for short term. If you have -2.6 in LT and clear all errors (even if none) fuel trims are reset and then looking at ST FT your short term might be -10,+7,'-10,+7.... etc then after a while the LTFT might be -1 then your STFT should be -9,+8,-9,+8... etc. Short Term always go less, more,less,more but its ideal to get the gap between the numbers smaller..

There's also a Map table called FKVVS which stores a profile based on Audi Stock Injectors, but that sometimes needs adjusting... there's a tool you can get to tell you the best new values, it's based on the throttle position (maybe load?) and revs, and you drive around trying to cover as many rpm, TP combinations and it will show you the adjustments for your table..

Thank you! This helped a lot.

So I'll update as this progresses but my LT FT seems to be around +2%... not enough to throw a code. ST FT hovers around +/- 2%. So nothing crazy there

HOWEVER the good news is that I was spraying starter fluid around the engine bay and measuring ST FT while doing so. I found spraying it right on the PCV caused a spike to around -20% ST FT. So I ordered some parts to replace the PCV hoses. Supposed to ship here by Friday, surprising how fast that is

Also, the code for the pressure drop between turbo & throttle body registers almost immediately after a reset. The other 3 can take a while to materialize

Thanks again for the help Stuart, I'll update you as I go. Hopefully will replace all PCV stuff this weekend and the intake manifold gasket while I'm at it. Was thinking perhaps since the LT FT seems normal that maybe my fuel injectors are just not dumping enough fuel? Or the cat is bad? I'll wait until after replacing the PCV to assess

 

[rawlins]

Do you have access to an air compressor?

I have a 3D printed boost test adapter you are welcome to borrow to do a proper pressure test.

It'll probably work with a decent bike pump or foot pump too.

Drop me a DM.

 

[doodlestj]

Do you have access to an air compressor?

I have a 3D printed boost test adapter you are welcome to borrow to do a proper pressure test.

It'll probably work with a decent bike pump or foot pump too.

Drop me a DM.

Hey tried to direct message but it won't let me because I'm too new to the forum.

Anyway, I do have an air compressor and also a 3D printer. If you link me to an STL I can print it and hopefully figure it out from there

 

[doodlestj]

Well this weekend I took my intake manifold off. Replaced all PCV hoses (where I thought there might be an air leak) and the intake manifold gasket

Still have the same check engine lights:

-P1297 Pressure Drop between turbo valve and throttle body (Check DV!)
-P0300 intermittent misfires all cylinders
-P0303 misfire cylinder 3

EXCEPT this code: -P0420 Catalytic system efficiency below threshold (running lean)

Has changed to this code1136 Fuel Trim Bank 1 (add) system too lean

And now my LT FT is more like 6.4%... Damn it

Not sure what to do now. Going to do some more spraying around. Maybe replace the fuel injectors?

 

[doodlestj]

In other news my Rosstech vc scope seems to not work anymore. Not sure why. The graph function displays the value and individual gauges work but the vc scope won't plot them along the screen of the graph as time goes on

 

[StuartDB]

it sounds like it is sucking in unmetered air or not giving enough fuel, you obviously disturbed the injector rail, to remove the inlet to get to the PCV stuff. (did you break the dip stick tube when you did that?)
- Have you checked the FPR on the end of the fuel rail to see if it is blocked?

the fact you have worsened this whilst changing / disturbing stuff is probably a good sign as you are around the right area - have you check the S bend thing on the end of the inlet manifold (left side if looking at a 225)

 

[Charmadize]

As you've replaced a lot of the intake (air) system, then it points now at the fuelling, maybe?

Before we go down that route, the cross member that joins the intercoolers get very rusty abs on mine, I was worried that it was close to rusting through so I replaced it.

If that is ok, then the misfires could be from lack of fuel in the chamber. The cat issues could be because the firing is so lean, due to lack of fuel. So, I think next you need to check the fuelling and the injectors. Have you looked at these already?

 

[doodlestj]

Thanks for the replies gents. When I was replacing the PCV system I think one of the other hoses just came a little loose and that was the big leak. Fixed that but still getting all the codes

When I spray starter fluid around the engine bay I can get ST FT to drop to like -7%... nothing as crazy as it was before. I will look at the FPR to see if it's clogged

And is there any way for me to tell if my fuel injectors are bad before just buying new ones? I don't see any measurement blocks that show me a volume of fuel injected

 

[doodlestj]

Fuel pressure regulator looks clean so far as I can tell

One thing of note - while trying to diagnose all this I deleted the N249 system. As a result of that I had to route a hose off the secondary air injection to the intake manifold so I teed it off to the hose that goes from the manifold to the FPR... I read to do that online. I don't think that's my problem because I had the codes before and after doing that

Any other ideas on where to route the secondary air injection hose to? When I just capped it off I got a separate, unrelated code so that doesn't work.

 

[doodlestj]

Measured the resistance of all the fuel injectors.. all were 12.5 ohms, right on spec

Took hose off the FPR while engine was running, it's definitely got suction. No fuel dripping out of FPR

Could be a leaking o-ring at the fuel injector? I need to get a fuel pressure gauge and check that

 

[StuartDB]

You could replace the injector o-rings they are only a few quid. Just try to avoid any dirt falling into the manifold.

 

[doodlestj]

Got a fuel pressure tester, here are the results:

Turned the key to 'on' but no ignition. Fuel pressure held right at 40 PSI. I let it sit for 10 minutes and no drop.

With ignition on fuel pressure was about 35 PSI. Held that at any steady RPM. And if I blipped the throttle the fuel pressure would blip accordingly

To test if the fuel injector O-rings were leaking was 10 minutes enough time? Or should I let it sit longer?

 

[doodlestj]

One more thing - I noticed right after I clear the codes my short term fuel trim is around +25% and I get a lot of misfires on cylinder 3 and 4. After maybe 3 minutes the short term fuel trim winds down to +/- 1% and long term fuel trim is maybe around +3%. Is this normal?

 

[doodlestj]

I decided to check how it looked on a cold engine. So I cleared the codes then started the engine-

ST FT slowly climbed to +25%. Pretty much as soon as the engine was fully warmed up it dropped to around 0%. I am getting misfires much more frequently than I was a couple of weeks ago... now I'm sometimes getting P0304 as well for a misfire in cylinder 4.

No idea what's going on but it seems to have gotten worse. Once I get a chance I need to tear everything down again

 

[doodlestj]

Bought a fuel pressure tester to do a leak down test... nothing found. Fuel pressure was good both with car off and on. Additionally tested the fuel pressure regulator which was good and the resistance of the injectors, also good

I was trying to test the MAF by looking at my g/s when redlining... I only reached about 130g/s and I'm pretty sure it should be 180g/s for my 225hp TT. Going to try replacing the MAF

One more thing - It's been a while since I've cleared codes. My LT FT values are as follows: +5% @ idle and -7% under partial load. Still have the same codes I've always had

 

[doodlestj]

So after replacing the MAF I dropped two of the codes! Progress!

Now here's what's left:

-P1297 Pressure Drop between turbo valve and throttle body (Check DV!)
-P0420 Catalytic system efficiency below threshold (running lean)

Going to try the smoke test again. If that doesn't work I'd like to find a way to test/check the DV even though it's basically brand new. And if neither of those work then I suppose I'll replace the catalytic converter

 

[vladthetodge]

I read somewhere on t'internet that dv being wrong way round can cause p1297 code. Maybe worth a double check?
Hope you get this sorted soon man.