Julian's '91 200 20vt

[DE80q]

Pulling the bulb isn't the end of the world. I would be lieing if I said that I haven't done it.

What spring are you running in the WG?

[loxxrider]

Oh I thought you meant the actual brake light (in the back of the car) was on. I was confused about that too. So the one in the dash is on? I'm not sure, but that light may be double duty. It will light up when the e-brake is pulled, but also when there is something wrong with the sensor for brake assist pressure or something... right? That is how BMW used to do it in some cars anyway.

Well, that stinks that we can't solve your wastegate problem that easily. I'm interested in what spring is in there too. You are probably the only person who can't get the turbo to boost to high heaven when using 100% duty. Something isn't right and I'd rather fix that than have a bandaid restrictor solution. Then again, maybe your N75 is different than the ones we usually use? Maybe it doesn't have the restrictor in it? However, I would think it would boost more with no restrictor lol.

[Aktapod]

A failing brake bomb can also cause a lingering "brake" warning light after startup. It could be unrelated, but it's something to consider.

Actually, I'm just remembering years ago, my brake light was intermittently lit up unless you smacked the handbrake a few times. It was like this for at least 3 years. Eventually, I took a look under the handbrake to see if I could fix it, and, having found the switch, I decided "I'll fix that one day." I never actually touched it, but the day after I looked at it, it just starting working correctly, and the issue hasn't returned to this day! So maybe try to establish your dominance over the handbrake, and it'll fix itself?

[88a5tq]

I switched my pressure source to the IM and took out the restrictor as well as vented the other port to atm. What did I get? 229 kPa! At 90.6% DC! WAAAAAT!? I just don't see how it's possible to run spring pressure and only get that.

Of course! I just need the switch to see me looking at it aggressively! Lol I'll try that next.

Restrictor is being reintroduced now...

[88a5tq]

Yesterday I blew my turbo cold side elbow clean off. While u was putting it back on I re-tightened every clamp in the area. I can't imagine where an intake leak could be tbh. I even have a freakin 2.2 bar WG spring in there!

[loxxrider]

What happens if you take the wastegate line off?

What do you mean by "spring pressure only?"

[88a5tq]

I will be heading back out in a little while to check on that.

I just was referring to the 17 psi WG spring from 034

EDIT I meant that I couldn't believe that a even with 90% DC from the n75, AND the 17 psi WG spring, that the system could only manage 18 or 19 PSI in its current form. Almost unfathomable to me.

[loxxrider]

OK that makes more sense. It is strange indeed. I want to know what it makes with and without the wastegate line attached lol (with n75 not in the line when it is attached).

[88a5tq]

As requested:

Hope the results speak to you lol. I hit boost cut pretty violently

[loxxrider]

Nice I'll take a look in the morning. Do you know how much boost that wg spring is supposed to supply? I'm guessing it's 17psi, but with the n75 calling for stock ish boost levels.

[88a5tq]

No problem at all! I have the gauges out to swa odometers currently. It's this one:http://store.034motorsport.com/audi-wastegate-spring-2-2bar.html
Which says 17.5 psi boost in the description. Mines not painted red though! there's just some red "over spray" lol

[loxxrider]

I will be heading back out in a little while to check on that.

I just was referring to the 17 psi WG spring from 034

EDIT I meant that I couldn't believe that a even with 90% DC from the n75, AND the 17 psi WG spring, that the system could only manage 18 or 19 PSI in its current form. Almost unfathomable to me.

I'm not sure what you're looking at, but I'm seeing 24 psi using 80% duty cycle when I look at your logs... This is with or without the restrictor? Maybe that's the difference in the numbers we are looking at.

That log with everything hooked up isn't really too helpful honestly because it isn't WOT, but the other two at least verify some baselines for how fast the turbo will spool with the wastegate effectively shut all the time and they verify that the wastegate is doing its job. So now it seems we can narrow the issue down to something having to do with your N75 whether that be the physical unit itself or how it has been tuned.

[88a5tq]

Interesting. Maybe I need to get an n75 "race" valve like from 034?

Oops I should've said that last one was with the restrictor but also with the IM pressure source. I think I included it not realizing how far off the tps was. Sorry. I just remember how hard the car pulled that time and it being about 90 F out. I was surprised I guess. It felt very controlled as well.

[loxxrider]

You shouldn't need anything other than what anyone else is using successfully which is the stock N75. But hey, if you found something that works for you, then I'd go with it unless it is lacking somewhere.

[PRY4SNO]

I know it's a minor thing to check, but nobody's suggested it yet so I figured I'd chime in. Are the brake and PS fluids full? You can get an idiot light for that. The guy I bought my current UrS4 off of was sure there was something wrong with the braking system, and low and behold it was low on fluid (the first thing I checked).

And x2 on what Chris said regarding the OEM N75, every Audi platform I've read about, people have had success with the OE one and as soon as they monkey around using some "race" version (aftermarket or OEM) all hell breaks loose. They can be temperamental sonsabitches though, maybe see if you can find a known good unit to test against yours.

[88a5tq]

Listen guys, I'm not embarrassed to admit that I've never checked any fluid under there. I know how to change a headgasket but I'm afraid this one is beyond me lol. Jk jk. I'll look after work. I did actually have a realization that I'd feel incredibly useless if it turned out to be that. Of course I started thinking that those particular brake warning only manifested in a light within the autocheck system IIRC. I will look nonetheless! Thank you for chiming in

[88a5tq]

Just realized I mightve sounded like a jerk there. I meant I don't know how the brake warnings work in the 200 since I don't have a manual. Maybe some code pulling would be in order?

[88a5tq]

All levels are good and all level sensors are plugged in as well

I came to the realization that I couldn't know it it was fixed until I have the gauges all back in and the airbag installed properly as well as the car actually running. I decided early on to just pull the brake bulb . Last night when I was pulling the cluster, I did have to turn the ignition on for a split second to move the wheel to centered. I had the airbag unplugged too! I hope it doesn't set yet another warning light I'll feel like removing later lol

[Aktapod]

Hahaha, I hate to break it to ya, but that airbag light will stay on forever until you hook up to the module and clear the code. Ask me how I know!

[88a5tq]

Dude how do you go about doing that?! Lol always some problem I created on my own

EDIT: IT CAME ON AND WENT OUT HAHAHHA! Although I didn't start the car hah

EDIT again: I tore the crotch of my shorts while installing the cluster

[88a5tq]

Are the brake and PS fluids full? You can get an idiot light for that.

Sorry I doubted you. I could've sworn you thought I was talking about the autocheck light. Even then, I was remembering wron I guess. Sjm says the light I'm talking about does what you're talking about lol. Maybe the sensor went bad? I'll knock them around a bit and see

Today I stalled at an uphill light taking off when it turned green. It always catches me off guard. What I do is I hold the brake and then let the clutch pedal out in first to right before it starts engaging. Then I let out enough to drop the rpm's ~100 and start applying gas etc. I'm not asking for clutch advice but figured I'd preface the stall. At this point, instead of the rpm's dropping 100, the car just straight died lol. WTF!?

I turned the car off and back on but I guess I didn't completely power off vems since it turned into a long crank and I needed to push the gas (while coasting backwards towards a driver that actually gave me the proper distance behind me. Kudos to him) so the light turned red when I finally started the car and ppl were bitching. Not ashamed of this but, next, I invoked the student driver sign. "Sorry I'm a beginner" lol. That usually shuts everyone up! END

Ya I really just wanted to say that to ask this (chris )... Is tuning IAC valve PID just like boost? The P term sets the aggressiveness of rebound while I determines how quickly the ECU works to bring the idle back up from a load (i.e. AC or engagement of the clutch for taking off) based on the error present. D, I guess would just be the damper term that keeps overshoot to a minimum after the ECU reacts.

Will it really be all that different from tuning boost in the end?

This semi-embarrassing moment reminded me that my idle was only sufficiently set to keep the car running with a 1k rpm idle instead of my more recent 850 idle. I never did set it based on knowledge Mere guessing.

Hey, maybe this will be the last time I ramble about PID!

[88a5tq]

I went for it and got idle correct in about 8 minutes

No lie, my exposure to the PID thread made it pie

[loxxrider]

Hmm you must have edited your post becuase I didn't see the long part before! I guess you got it figured out.

I was going to say either it's dipping a little too lean with that partial combination of loading or maybe you need to tune your isv. But yeah it's the same as tuning anything pid but it is more susceptible to overshoot than boost is.

[88a5tq]

Things have been going pretty well with the ISV tuning up until today when, during the rain and use of the windshield defroster on low fan, the car stalled during off throttle decel out of gear. Having a difficult time trusting the ISV to catch the car before death. Heres a log of one such stall:

Stall from out-of-gear decel.vemslog

(79.5 KiB) Downloaded 1048 times

I tried messing with the PID control further but backed the P off after getting constant high then low idle as the idle valve was presumably over-compensating for the initial dip. I dont understand how the valve can start compensating around 2500 rpm and bring it down slowly and softly to my target and other times it drops like in a free fall to around 400 and jump violently up to ~1400 and eventually gets to target. I would think the water/meth would keep the valve pretty clean, especially in combination with the catch can.

With ambient at 58 F today, Im unsure whether the AC compressor is always running and loading the engine or if the car only dies from the initial, and well-timed? shock of it switching on as the engine falls towards idle.

[88a5tq]

Today I used ALL the same settings I was given in my base map file. First start idled immediately at 1800 and then died in 2 seconds or less. Second start it stayed there but when open loop came on, the idle would fluctuate between something like 700 and 1700 rpm. It's cray!