High LTFT K04 BPY

[BurgerGuy]

Exhaust needs to be tested first. If it's good, then I'll be picking up O2 sensors. I only get misfires on cold starts because of the RFD.

Have been thinking about the RFD being a contributor to my issue. Since flaps aren't there to control the amount of air entering the chamber or create the "tumbling" effect I'm wondering if that could potentially be causing my trims to go lean.

 

[ROH ECHT]

Maybe it is...I haven't yet seen people with RFD posting this. But it could just mean they aren't making themselves aware. I wonder if the RF lever is sealed where it went into the manifold...but you've tested for inlet leaks, correct? Have you thought of a thread asking for LTFT values posted from folks with RFD? There are a great number of them with RFD in the UK...you could ask there as well; https://www.mk5golfgti.co.uk/forum/index.php?board=3.0

 

[BurgerGuy]

The RFD kits come with a plug to seal that off. When the car was smoke tested we didn't find any leaks in that area.

 

[BurgerGuy]

So the shop says I should look into O2 sensors or just drive the car if there aren't any codes.

 

[ROH ECHT]

It's probable it is the O2s. If nothing physical(air and fuel related) is found, it has to be sensor reports...O2 or MAF.

 

[BurgerGuy]

And the MAF is new this year. Guess I'll pick up some O2 sensors then.

 

[BurgerGuy]

New O2 sensors in along with a Fluidamper. Engine runs very smooth even with upgraded engine mounts. New sensors provided some performance improvement as well, but LTFT partial still sitting at +16.4 after resetting trims. My only guess is that there may be a vacuum leak elsewhere or the value is skewed for some other reason and I should forget all this and enjoy the car. It runs very well now.

 

[ROH ECHT]

I, myself, would still be planning on testing both the air inlet and exhaust pre-MAF for leaks. Very thoroughly that is.

What intake do you have? Is it on this list? This is on a MK6 Golf R forum. They asked people to post their trims and added the range here when ten or so posted trims.

 

[BurgerGuy]

Am using Unitronic's intake which they say is required hardware for their tune. The car definitely runs better with it compared to the BSH intake I had previously.

 

[BurgerGuy]

Well I got the car smoke tested again. Inlet and exhaust side. They found one leak in the DV dump tube which they fixed by tightening a clamp. Can feel the difference, but the numbers haven't changed. This tells me it's...

• The tune
• Something inside the engine (piston rings?) or...
• MAF scaling even though I'm using their intake

Either way, the car runs great. Fuel economy could maybe be better, but that probably has more to do with my foot than anything else and it's probably pushing ~300whp so I'm not going to worry about it anymore.

 

[ROH ECHT]

I would guess it is the intake at this point and hope to try other intakes....if I had close by friends who could help me with that. But, you know, it could be internal wear or temp sensors reporting a bit off. The only thing to do to check if it is the intake is restore the OE air-box, if it itself is tightly sealed, and run it a bit for comparison.

 

[Chumeta]

Hi, try removing the engine oil filler cap and make sure it doesn't smell like gasoline. For me it may be leakage from the high pump seals. You should also check if the oil level rises, although sometimes if it is a small leak it is hidden with the consumption of it. Try a different high pump (friend, scrap ...) to make sure before buying new. Do you have any modifications to the plunger or the pump itself? The seals usually give those symptoms, as well as rare lambda measurements

 

[BurgerGuy]

I switched the pump out a couple months ago for a brand new APR HPFP so I would be surprised if it's that. I bought it new and did not do the rebuild myself.

 

[ROH ECHT]

How's things coming along? I was just out looking at timing, fuel pressures, and fuel trims and saw the LTFT partial has gone up to 12%. Did another clear codes and watched STFT and it bounces between -5% to 4%. LTFT at idle is just 1.1%. My guess is it is simply getting old. I'll need to do another smoke test. If nothing is leaking, I may have to consider removing the new injectors for testing. I don't get it really. Got the new turbo and perhaps a new catted DP going on this year. I'll likely do new coils and plugs. Then a compression test. Had a code today for B1S2...but I didn't even note the code. Probably should've done so....but it may reappear. I just didn't give it much thought and assumed it was for the catless DP or the additional smoke from the F'n turbo. I did see it had just one fault frequency and thought hmmph. I only wish I had been looking into this data when all was fresh on the engine. You know, so I would know if it has always been this way. If it is just from the intake or something to not be concerned with. But with the mpg dropping over the last few years...I feel it is a developed condition.

 

[BurgerGuy]

I've not chased it down anymore since my last update. The valve cover was replaced at the end of last year before a road trip which provided additional improvements, but the data still looked the same. The highest LTFT partial goes is +19% or so. With the warmer weather coming, I've seen it drop to +15%. My only guess is maybe leaky valve train or piston ring(s) as I'm not sure what else to check from a smoke test perspective since the shop checked both sides (intake/exhaust) and both O2 sensors have been replaced. Will be interesting to see what happens when gas stations put the summer blend in their tanks and the weather gets warmer. I once saw it drop to +11% when it was unusually warm out during the winter.

You had mentioned the coolant sensor potentially being a culprit, but I've kinda gotten tired of throwing parts at the car. A leak down test would tell me if the valve train is leaking so depending what I see this summer I may decide to do that. It runs well enough for me...at least compared to what I was working with when I started this thread.

Will add, am teasing the idea of reinstalling my runner flaps next time I get the valves cleaned to see if that has an impact. Throttle response and exhaust notes are better with them out, but if I get a cleaner or more complete combustion with the flaps in, then the other stuff doesn't matter as much.