LTFT Issues and Lugging

JohnnyTightlips said:
Yeah so next step is to make sure it is building full pressure with the KOEO with a hot motor. If not then it is opening early.
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I will do that now and report back. It was at 180 degrees on all three prior tests.

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Alright, I let it get to 181 degrees. KOEO and pressure started at 435 and is at 320 and falling now.

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JohnnyTightlips said:
Mine went bad at 135k and it seems more people are seeing this as they get up in mileage and people push them harder.
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Mine is at 65,000 miles now. It sounds as if it is clattering, as well. I checked it out for noise after watching a YT video. Again, I'm just really curious if this could cause bad fuel trims.

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Just got done with a 30 mile drive. Fuel pressure is rising as it should, now, however it has been stuck at 1033psi and extremely slowly now.ots falling. Maybe 3psi in the last minute. Coolant temp at 200~. Should I go through with the replacement? Already ordered.
 
Do you run corn? If so you might want to clean the spill valve. That valve still sounds like a place to start and if you don't need it won't go bad so you could resell it eventually use it.
 
JohnnyTightlips said:
Do you run corn? If so you might want to clean the spill valve. That valve still sounds like a place to start and if you don't need it won't go bad so you could resell it eventually use it.
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Nope. Just 91. If it's not the valve, then what? I'm running Autotech internals with maybe 30k on them.

From what I understand fuel pressure should ruse to 1600psi, correct? If it's not able to hit optimal pressure and starts backing down, this could still be the fpr valve?

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It cracks above 1900psi if working correctly.
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Just used a DIY smoke tester. It works well and is fairly cheap to build. I tested a used downpipe for leaks.

Here is the downpipe. I taped up the openings tight, threw a glove on the back to save time and watch pressure build.20181106_164710.jpg

Tester top.20181106_164757.jpg

Glass jar, I tore up a Terry towel into 1/8's and soaked it in baby oil.20181106_165722.jpg

Here is the top with some pneumatic fittings.20181106_164753.jpg

The whole setup in action.20181106_165903.jpg 20181106_164940.jpg

You only need 5psi or less from the air compressor. Anymore and it'll blow the heat out too quick and kill the smoke quicker.

The leaks are obvious, it's quite comical. I lit the towel on fire, let it blaze for about 30 seconds, then blew it out and immediately locked the lid on. The smoke is thick, and if you can only find the shea butter baby oil like I did, then the smoke will smell nice. That's an unexpected win, because you can smell the smoke too upon a leak.

I had a bunch of incense handy too in case the baby oil didn't smoke enough.

Just a tip since you are hunting a mystery leak.
 
I appreciate the post, and appreciate your sandals even more. 10/10. I also hope you only use that tester for legal purposes.

I will give this a go after I replace the relief valve. I believe it to be an obvious failure as I've done the KOEO test a few more times, and seen results as little as 450psi before the pressure is dropping. However not consistent, I do believe it is on it's way out.

Thanks again.
 
So the part is being special ordered, and then they send it out to me once they receive it.. whatever.

Can someone please analyze my log? I got a bad lug from 1st - 2nd during this log.
I cant find anything and im banging my head. I have a WOT log and also hit a 4.~ on knock... im about over this.

Datalog 95 is cruising with lug, 96 is WOT.

For clarity, Ive stayed out of boost all week. Been watching my HPFP like a hawk, and did this WOT for a datalog to see if I can find anything.
 

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First things first, that "WOT" log is not properly done. You're getting into throttle a bit up to 60 acel pedal position, but you're pussyfooting it and going in and out of it, so it's hard to follow the log. You are getting a lot of knock though and that's not good.

On your cruising log after skimming it, you're not overly rich or lean. You could use a mafcal, but you're not pegged in one direction or the other. Who is tuning you? What is done to the car? If you're just looking at peak STFT you're going to see +/- 25 if you're engine breaking or stomping on it real quick, so I wouldn't worry about that.

What exactly are you having issues with now? I've read through the thread, but I'm not really sure where you're at with this now.
[doublepost=1541786143][/doublepost]In response to your first post after re-reading it there's a couple things you need to think about here:

  • It's getting colder, so inherently you're going to be getting more air, which means the car will be adjusting by adding a little more fuel to meet your fuel targets.
  • You had the battery unplugged when you were messing around with your intake/tip, so when you got the car all together again your ECU and fuel trims were all reset. You won't have any LTFT at all until you've driven around for a while. LTFT is just an average of STFTs at varying loads over time, so it will be at 0 for a while while the ECU is learning.
  • +/-12 isn't THAT bad. Usually you want to stay within +/-5 or so, but with the weather changing for us more recently, it's going to be hard to keep that dialed in perfectly.
  • I don't think you have a PRV issue and I think that that's one of the most frequently misdiagnosed parts in our cars.
Food for thought.
 
VashEXE said:
First things first, that "WOT" log is not properly done. You're getting into throttle a bit up to 60 acel pedal position, but you're pussyfooting it and going in and out of it, so it's hard to follow the log. You are getting a lot of knock though and that's not good.

On your cruising log after skimming it, you're not overly rich or lean. You could use a mafcal, but you're not pegged in one direction or the other. Who is tuning you? What is done to the car? If you're just looking at peak STFT you're going to see +/- 25 if you're engine breaking or stomping on it real quick, so I wouldn't worry about that.

What exactly are you having issues with now? I've read through the thread, but I'm not really sure where you're at with this now.
[doublepost=1541786143][/doublepost]In response to your first post after re-reading it there's a couple things you need to think about here:

  • It's getting colder, so inherently you're going to be getting more air, which means the car will be adjusting by adding a little more fuel to meet your fuel targets.
  • You had the battery unplugged when you were messing around with your intake/tip, so when you got the car all together again your ECU and fuel trims were all reset. You won't have any LTFT at all until you've driven around for a while. LTFT is just an average of STFTs at varying loads over time, so it will be at 0 for a while while the ECU is learning.
  • +/-12 isn't THAT bad. Usually you want to stay within +/-5 or so, but with the weather changing for us more recently, it's going to be hard to keep that dialed in perfectly.
  • I don't think you have a PRV issue and I think that that's one of the most frequently misdiagnosed parts in our cars.
Food for thought.
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Thank you very much for the reply. Anyways, to address a couple things. As far as battery goes, I've put 300 miles on my pu, just to have trims at +10 at this point. This is my LTFT, btw. I understand about the weather. When I first was taking my datalogs, when the issue was first prevalent, the temperature was around 80/90 at night, and I was sitting at a 2 LTFT. Now it's 60/70 degrees. Also, my initial tune was sent to me in the dead of summer so 115 degrees. This would make sense. I'm tuned by Stratified, Catless DP, Autotech HPFP, JBR RMM.

As far as my cruising log goes, that's where my headache lies. In that log I had a pretty bad lug from first to second gear, and I can't trace it at all. I don't see what could be going on. Essentially, it feels as if my car hits a wall. If I were to continue to accelerate through the lug, it stays "stuck" In the wall. It will try it's best to accelerate, but feels like I'm not building boost at all. But this is not represented on any log I've managed to capture. I'm also seeing 100 on my WGDC, even with a blip of throttle.

Lastly, for the relief valve, why do you say that? Sincerely curious. I have yet to crack even 1600 for my KOEO test. The highest was 1540, and the lowest it started dropping was at 430 psi. (This was after a 30 mile drive). If not the RV, what then? I was curious as to how I could be seeing mostly healthy HPFP during pulls. However, the KOEO is never consistent on results, but it will NEVER crack at desired PSI of 1850/1900. Always, less, and sometimes, severely. Thank you.

As for the WOT log, I will have to rerun that.

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