# 16825 cel



## esoxlucios (Sep 17, 2009)

*17536 cel*

Wondering if ChickenMan35, Max, DougLobue, Groggory, 20vMaster, or other experienced members have any ideas here:

I'm getting the *17536* error code (too lean, multi), which comes on a drive cycle or two after resetting. I have reviewed the 1.8t fuel lines & fueling FAQ and other threads on 17536 before posting here. I don't have a VAG-COM (thus, can't measure block 032, but asked my mechanic to, but don't think he did). Instead, I'm running the LiquidTT, and can do some limited monitoring on that.

This and a few other codes seem to have begun appearing after recently upgrading from the GT2860RS to the GTX2860R on an APR Stage 3+ system. (I do not know if there are any new APR files since installation about two years ago).

Additional facts:
► Every now and again, I'll switch to the AFR lambda view on the LiquidTT, and it seems to indicate that it is within proper values during idle and hard acceleration, except when decelerating (which I assume is normal)
► Was running 2.0FSI coils with PFR7B supplied by APR with about 10K miles gapped to .032". Just changed to the red R8 coils, BKR7EIX gapped to .037". I've tried the F5DPOR with no noticeable difference.
► Running ECS adjustable FPR set to 4-bar (I've substituted in fixed 4-bar with no difference)
► Running the OEM fuel pump that comes with the Quattro
► fuel filter last changed about seven years ago
► supplying boost-graduated water/meth through a 175 nozzle mounted post throttle body with solenoid
► running stock N75 valve
► have used Lemmi to turn down secondary fueling, and increase primary fueling — to no effect
► color on plugs is light tan — seems to be textbook coloration (see photo below)
► compression is stock 9.5:1 on AWP motor, but running the Autotech sport 195° intake cam that APR's Chris Teague recommended to me, and Ferrea valves & springs (not oversized). Also, pistons are only .5mm oversized Mahle (so, basically stock displacement).
► running ABD intake mani, 170mm throttle body, and APR front mount intercooler
► O2 sensors were both replaced about one year ago
► running whatever injectors are supplied with the APR Stage 3+ kit, and using the OEM fuel rail
► Use only 93-octane fuel from BP (the only 93 supplier in MN) on the APR 93-program
► recently smoke tested: no vacuum leaks, and no boost leaks
► have two MAF sensors believed to be good (one bought only a year ago from EuropaParts), and behavior is the same with either MAF

Watching the LiquidTT, it appears that the boost usually lags behind command, and also often doesn't reach the command level. This wasn't an issue before, and suggests to me that the GTX2860R is not as responsive as the GT2860RS. Therefore, it seems unlikely that this turbo is supplying too much air that the APR fuel maps are not able to keep up with. On the other hand, I guess that this turbo can supply more air at a given PSI than the former turbo could (meaning that maybe it doesn't need to reach the command peak boost?).

I also had the downpipe changed out from 2.5" to 3"at the same time the turbo was upgraded.

The next idea I had is whether I should experiment with turning up the FPR to 5-bar. Or whether the OEM Quattro fuel pump is unable to supply the required fueling?

Would appreciate any insights!










Edit: after writing this, I checked AFR. During heavy acceleration, lambda drops to .9 to .75. During deceleration with clutch out (engine braking), lamda always goes off the chart (max. possible reading of 1.99). I have secondary fueling in Lemmi set to 85%, to reduce possible backfires. I believe secondary fuel setting affects fueling during deceleration. Photo below shows idle, but displays max and min measurements.


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## esoxlucios (Sep 17, 2009)

Bump


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## 20v master (May 7, 2009)

16825 is EVAP emissions control incorrect flow. You're troubleshooting the wrong thing. 

http://wiki.ross-tech.com/wiki/index.php/16825/P0441/001089

Also, the lambda readings from block 031 are useless on narrowband cars. And you have a lot of misconceptions about how the ECU's work in relation to requested boost and airflow. Secondary fueling is adjusting the response/lag on the injectors, has nothing to do with backfires. Primary fueling adjustments will be cancelled out by adaptation unless they are truly needed, doubting yours are as you are running the MAF/injectors that the software calls for. There's no reason to go to 5 bar of fuel pressure without knowing injector duty cycle. Get a true dedicated wideband AFR onboard if you want to know if you're lean/rich.


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## Marcus_Aurelius (Mar 1, 2012)

Adam is correct, it's an Evap system output or incorrect flow code. You have either developed a leak, or one of components of the evap system failed (can be anything, down to the gas cap). You need to find a Vagcom and run output tests, without it you're forced to check everything in the evap system until you find the problem. Faulty valves or solenoid can be easier to spot, but leaks are much harder because normal pressure tests won't work (vagcom tests should point you in the right direction).


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## esoxlucios (Sep 17, 2009)

Sorry, my fault, wrong error. The 16825 was a spurious, random error that came once and went away, possibly due to cold weather (-24ºF in Minnesota) affecting the N80 valve. I corrected the title and the original post.

The actual error in question, which recurs constantly (every couple of days of driving, after being reset) is the *17536*.

Sean


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## esoxlucios (Sep 17, 2009)

20v master said:


> 16825 is EVAP emissions control incorrect flow. You're troubleshooting the wrong thing.
> 
> http://wiki.ross-tech.com/wiki/index.php/16825/P0441/001089
> 
> Also, the lambda readings from block 031 are useless on narrowband cars. And you have a lot of misconceptions about how the ECU's work in relation to requested boost and airflow. Secondary fueling is adjusting the response/lag on the injectors, has nothing to do with backfires. Primary fueling adjustments will be cancelled out by adaptation unless they are truly needed, doubting yours are as you are running the MAF/injectors that the software calls for. There's no reason to go to 5 bar of fuel pressure without knowing injector duty cycle. Get a true dedicated wideband AFR onboard if you want to know if you're lean/rich.



(1) My car is a wideband, AFIK. It's a 2001 AWP motor. I replaced the O2 sensors last year, and I seem to recall that one of them was the 5-wire wideband type.
(2) My "misconceptions" about how ECUs work and secondary fueling (specifically the setting by that name in LemmiWinks) is based on hours reading through various threads here, Audizine, AudiGeeks, TTforums, etc. on what that mysterious setting does. Users have claimed that turning it up by a factor of 10 or 15 or 20 has made their cars run smoother, but caused backfires between shifts. Therefore, it is reasonable to assume that the reason for backfires between shifts is because that setting is dumping fuel during deceleration, when the ECU normally cuts fuel. Is this is a misconception, or a reasonable inference? If the "secondary fueling" setting in Lemmi has "nothing do to with backfires," then why did all those owners who increased that setting experience backfires?


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## 20v master (May 7, 2009)

esoxlucios said:


> (1) My car is a wideband, AFIK. It's a 2001 AWP motor. I replaced the O2 sensors last year, and I seem to recall that one of them was the 5-wire wideband type.
> (2) My "misconceptions" about how ECUs work and secondary fueling (specifically the setting by that name in LemmiWinks) is based on hours reading through various threads here, Audizine, AudiGeeks, TTforums, etc. on what that mysterious setting does. Users have claimed that turning it up by a factor of 10 or 15 or 20 has made their cars run smoother, but caused backfires between shifts. Therefore, it is reasonable to assume that the reason for backfires between shifts is because that setting is dumping fuel during deceleration, when the ECU normally cuts fuel. Is this is a misconception, or a reasonable inference? If the "secondary fueling" setting in Lemmi has "nothing do to with backfires," then why did all those owners who increased that setting experience backfires?


As I said, that channel affects injector lag/response. Going too far in one direction would make the injectors more "lazy" and not respond to a throttle closing as quickly, hence unburned fuel in the exhaust. 

The lean code is usually caused by vac leaks or the MAF sensor reading incorrectly. I just replaced a low reading MAF on my AMU and it cured this code since I had already pressure tested and was certain there are no leaks. You'd need a MAF log/reading to know if it was bad, so go see what the peak value is on a WOT run with the liquid.


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## esoxlucios (Sep 17, 2009)

20v master said:


> As I said, that channel affects injector lag/response. Going too far in one direction would make the injectors more "lazy" and not respond to a throttle closing as quickly, hence unburned fuel in the exhaust.
> 
> The lean code is usually caused by vac leaks or the MAF sensor reading incorrectly. I just replaced a low reading MAF on my AMU and it cured this code since I had already pressure tested and was certain there are no leaks. You'd need a MAF log/reading to know if it was bad, so go see what the peak value is on a WOT run with the liquid.



Thanks for the advice. Will do.

As noted in the OP, I have two different MAFs, both of which are believed to be good. I don't use a K&N filter. But, the LiquidTT does have a MAF monitoring screen, so I can read it there. However, I have the larger MAF housing supplied by APR with the Stage 3+ kit, so I'm not sure what the correct readings ought to be.


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## esoxlucios (Sep 17, 2009)

esoxlucios said:


> . . . This and a few other codes seem to have begun appearing after recently upgrading from the GT2860RS to the GTX2860R on an APR Stage 3+ system. (I do not know if there are any new APR files since installation about two years ago) . . . Watching the LiquidTT, it appears that the boost usually lags behind command, and also often doesn't reach the command level. This wasn't an issue before, and suggests to me that the GTX2860R is not as responsive as the GT2860RS. . . .


Another related question. Is it likely that the GTX isn't as responsive, or might something be amiss? According to the LiquidTT, maximum boost reached is 17psi. Does this sound right? I have a separate VDO gauge that I could confirm that with.

When the shop installed the upgraded compressor, they had to weld some bosses on the GTX compressor housing to accommodate the wastegate actuator (_i.e.,_ to simulate the positioning on the GT2860RS compressor housing supplied by APR with the Stage 3+ kit). Is it possible that it's out of adjustment and that I need to dial in or dial out the actuator adjustment nut by a few threads? Any suggestions on how much to get started?


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## groggory (Apr 21, 2003)

You do need to calibrate the wastegate to apr's spec if you want to use n75 control. I forget what their spec is. Call and ask. Even so... I don't know if it'll work due to the different characteristics of your new turbo.

You may have to get a mbc, ebc, or different software to regain good boost control.

As to your other issues, I need to do some more thinking


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## Chickenman35 (Jul 28, 2006)

Just a few observations.

1: Plug color does look spot on, so I don't think you have any major fueling issues.

2: 7 years on fuel filter? Probably time to change it.

3: Original random 16825 code could be connected to the current 17536 code. Have you physically checked the N80 valve. Pulled it off and tried blowing through it? Could be stuck open ( usually Carbon particle from Charcoal Canister. The result of " Topping off " fuel tank too much ). N80 connects via vacuum hose directly to Intake manifold, so you can end up with a hidden vacuum leak that will not show up on normal pressure/vacuum leak tests. A simple check is to plug off the vacuum line that connects the N80 valve to the Intake manifold with a bolt. If code does not return after clearing, then you've found your culprit.

4: Adding a 2-3 of turns to the waste-gate shouldn't hurt anything, and may point you in the right direction.

5: You're going to have to get a VAG-COM/VCDS eventually. Even VCDS Lite Paid version would help. It's only $99. That and a $35 E-Bay cable and you're in business. Or buy a Full version with Ross-Tech cable. IDC logging would be most beneficial in sorting things out.


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## esoxlucios (Sep 17, 2009)

Wow! I grabbed a spare Rev. F N75 valve I had sitting on shelf and swapped that in just for good measure: Now, I'm getting 22.6 psi out of my GTX2860R !!! Boost still slightly lags behind command, but it meet or exceeds the command peak. Power is great! So, this is what the Stage 3+ is supposed to feel like!

Also, I had a spare new-in-box N80 valve on the shelf, and swapped that in, too, and will monitor for return of the 16825.

One other issue: after car is warmed up, it occasionally misses and the idle is rougher. This happened after installing the red R8 coils and swapping out the PFR7B with .032 gap to the BKR7EIX with .037. I would have assumed that a bigger gap would smooth out the idle, especially with these more powerful coils. Perplexing.


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## 20v master (May 7, 2009)

Why are you increasing plug gap? If anything, that would cause more misfires at idle. No one had any trouble making power on stock coils, yet 2.0T FSI, now R8 coils are all the rage. :screwy: And you said you were only getting 17 psi before, yet you didn't realize this was low by looking at your boost gauge?


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## esoxlucios (Sep 17, 2009)

20v master said:


> Why are you increasing plug gap? If anything, that would cause more misfires at idle. No one had any trouble making power on stock coils, yet 2.0T FSI, now R8 coils are all the rage. :screwy: And you said you were only getting 17 psi before, yet you didn't realize this was low by looking at your boost gauge?


Increasing gap because, based on all the reading I've been doing here, the biggest possible gap, if the coils can support it, produces better power up top. These are the anecdotes that other members have been posting. They can't *all* be wrong (can they?). Also, the anecdotes claim that the idle smoothes out with the bigger gap. Is .037 outrageous on the 2.0TFSI coils? The BKR7EIX-11 comes as .044 out of the box. But, I'm happy to close it back down, if you think that's the best course, for our BT motors.

Yes, I obviously did realize that the 17 psi I was getting before was low (hence my posts, above, asking "Is something amiss? Do I need to adjust my wastegate?"). To clear up any ambiguity, I have two boost gauges — the LiquidTT (which uses the OBD-II port and the OEM MAP sensor), and the pod-mounted VDO guage, and the both appeared to be in sync.

Also helping with power this morning was the fact that it was -11° F


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## groggory (Apr 21, 2003)

Just gap at .028 and see what happens.


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## 20v master (May 7, 2009)

^^^Beat me to it. 0.028" has worked for me from stock 180hp to 550chp on BKR7EIX/8EIX. There's no hidden HP in spark plug gap's, only gaps that are too large. If anything, the larger gap puts more strain on the coil, leading to it's failure sooner rather than later. Cold weather doesn't help this. In all your reading, you missed the posts addressing that 2.0T coils don't make more power, don't allow larger gaps, and aren't any more reliable than 1.8T coils. The fact that actual boost never hit requested boost would lead me to look at N75 duty cycle if you knew there were no leaks, other issues. If it was 0, then you'd know something wasn't right. You've sinced moved on after randomly replacing the N75.


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## lite1979 (Sep 9, 2005)

P1128 still screams vacuum leak to me. In my experience, it's not the type of leak that will cause a performance decrease, either, so you'll boost just fine. It's also worth noting that my car is the same year, and I just had a problem with the evap system that was quickly remedied by checking the connection to the test pump (located in the front passenger's wheel well behind the fender liner). There was some oxidation at the connector, so I cleaned it up and re-connected it, and that fixed it.


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## esoxlucios (Sep 17, 2009)

20v master said:


> ^^^Beat me to it. 0.028" has worked for me from stock 180hp to 550chp on BKR7EIX/8EIX. There's no hidden HP in spark plug gap's, only gaps that are too large. If anything, the larger gap puts more strain on the coil, leading to it's failure sooner rather than later. Cold weather doesn't help this. In all your reading, you missed the posts addressing that 2.0T coils don't make more power, don't allow larger gaps, and aren't any more reliable than 1.8T coils. The fact that actual boost never hit requested boost would lead me to look at N75 duty cycle if you knew there were no leaks, other issues. If it was 0, then you'd know something wasn't right. You've sinced moved on after randomly replacing the N75.


No argument from me! I'll regap tonight when I get home. You're right, I missed any posts stating that the 2.0T coils don't produce bigger spark or enable a bigger gap (if you've got the links handy, I'd be very interested to read those).

Also, wondering if you'd recommend I go a step colder on the plug in the summer (BKR8EIX). You might recall my thread discussing the thermal barrier coatings that were applied by my engine builder to the piston tops, combustion chamber, and valve faces, which seems to have led to timing pull problems, which in turn led me to install a water meth system to deal with.

Sean


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## esoxlucios (Sep 17, 2009)

lite1979 said:


> P1128 still screams vacuum leak to me. In my experience, it's not the type of leak that will cause a performance decrease, either, so you'll boost just fine. It's also worth noting that my car is the same year, and I just had a problem with the evap system that was quickly remedied by checking the connection to the test pump (located in the front passenger's wheel well behind the fender liner). There was some oxidation at the connector, so I cleaned it up and re-connected it, and that fixed it.


Thanks, I'll check that out, too. Didn't even know I had a "test pump" there. But, I'll have to wait for a spring or a really warm garage, because that whole area is caked with snow, salt, and ice right now.


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## Marcus_Aurelius (Mar 1, 2012)

esoxlucios said:


> No argument from me! I'll regap tonight when I get home. You're right, I missed any posts stating that the 2.0T coils don't produce bigger spark or enable a bigger gap (if you've got the links handy, I'd be very interested to read those).
> 
> Also, wondering if you'd recommend I go a step colder on the plug in the summer (BKR8EIX). You might recall my thread discussing the thermal barrier coatings that were applied by my engine builder to the piston tops, combustion chamber, and valve faces, which seems to have led to timing pull problems, which in turn led me to install a water meth system to deal with.
> 
> Sean


Sean, I have personally experienced/tested the 2.0T coil not contributing to any increase in spark strength. Others have also separated the placebo effects from the facts, for example Oeisten (Gulfstream) Dyno-tested them and didn't pick up any power increase/decrease outside of the normal noise range. I think all the reported improvements were from swapping old and tired coils with fresh ones. I'll dig up some links, including the one where they showed zero improvement in my car, for you. 

It seems very odd to me that an increase in timing pull was attributed to thermal coating on pistons and valves. Even if the thermal barrier was negligible due to an improper formulation, it shouldn't have affected your knock threshold (at least not negatively). Something is missing from that conclusion! I don't think you need to go a step colder with the plugs, not for your boost target. Going colder is a good thing when need, but can also be a negative thing if the conditions don't require it.


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## 20v master (May 7, 2009)

Marcus_Aurelius said:


> It seems very odd to me that an increase in timing pull was attributed to thermal coating on pistons and valves. Even if the thermal barrier was negligible due to an improper formulation, it shouldn't have affected your knock threshold (at least not negatively). Something is missing from that conclusion! I don't think you need to go a step colder with the plugs, not for your boost target. Going colder is a good thing when need, but can also be a negative thing if the conditions don't require it.


I agree with Max here. A general rule is how much power you are "squeezing" out of a given displacement dictates when to go colder plugs, and even that is too broad of a generalization. You aren't in any kind of insane territory compared to commonly modded 1.8T's, so no you don't need a -8 heat range plug. Also, I had a ceramic thermal barrier on my 10:1 83mm Wiseco's and didn't have abnormal timing pull on pump gas with up to 24 psi from a GT35R. The thermal coating likely had nothing to do with the timing pull you saw.


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## esoxlucios (Sep 17, 2009)

Marcus_Aurelius said:


> It seems very odd to me that an increase in timing pull was attributed to thermal coating on pistons and valves. Even if the thermal barrier was negligible due to an improper formulation, it shouldn't have affected your knock threshold (at least not negatively). Something is missing from that conclusion! I don't think you need to go a step colder with the plugs, not for your boost target. Going colder is a good thing when need, but can also be a negative thing if the conditions don't require it.


Very much appreciate the feedback.

That thermal barrier thread I started is here: http://forums.vwvortex.com/showthre...thermal-barrier-coatings-(TBC)-in-1.8t-motors

The gist was that my engine builder (Clay Witt of TPIS in Chanhassen, MN) strongly recommended that I get all those parts coated. To his list, I added the hot side of turbo, the inconel exhaust mani, and the downpipe. Steve Schoeben, the owner of Headwerks, who was building my cylinder head, strongly advised against it, and Chris at APR also specifically advised not to do the combustion chamber, as that would be thwarting its job of carrying away heat. I even found a thread *before* getting this all done, which warned against pre-detonation problems from TBC on engine internals. My engine builder became really annoyed with the debate, and Imola Motorsports (who was supposed to be overseeing the project) found itself incapable of advising. Thus, it was left up to me, the non-expert, to sort the wheat from the chaff, and to make a decision. I finally decided to go with the Clay's recommendation, and had everything coated.

Anyway, when I got the car back, during the summer, I was getting as much as 10 degrees of CF while running 93-octane fuel on the 93 APR program and was really worried I might be damaging the engine's internals. I *assumed* I was running BKR8EIX plugs, because I read on yet another forum thread that's what comes with the APR kit (as it turns out, they were the platinum 7-heat range plug). So, I resolved this by going with water meth, which has brought me down to 0 degrees CF in winter, and no more than 3 in hot weather. This of course has me wondering whether I needed water meth at all. Maybe I could have mitigated the risk with just a one-step-colder plug? I suppose another option is to go into Lemmi and retard the timing by 2 degrees or so.

[Edit: I didn't yet see Adam's reply to Max by the time I wrote this].


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## esoxlucios (Sep 17, 2009)

Unfortunately, changing the gap to .028 did nothing to help the idle and small hiccups (misfires). LiquidTT is not picking them up on the misfire counter, but they're definitely misfires, and the RPMs, vacuum gauge, and AFR show it. Maybe I should switch to copper or back to platinum (although the plugs might have nothing to do with it).


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## esoxlucios (Sep 17, 2009)

20v master said:


> 0.028" has worked for me from stock 180hp to 550chp on BKR7EIX/8EIX. There's no hidden HP in spark plug gaps; only gaps that are too large. If anything, the larger gap puts more strain on the coil, leading to it's failure sooner rather than later . . . In all your reading, you missed the posts addressing that 2.0T coils don't make more power, don't allow larger gaps, and aren't any more reliable than 1.8T coils.


At the risk of being accused of hijacking my own thread, can you elaborate?

Reason I ask is because NGK's Web site states, in pertinent part:



> A spark plug's voltage requirement is directly proportionate to the gap size. The larger the gap, the more voltage is needed to bridge the gap. *Most experienced tuners know that opening gaps up to present a larger spark to the air/fuel mixture maximizes burn efficiency.* It is for this reason that most racers add high power ignition systems. The added power allows them to open the gap yet still provide a strong spark.


 [bold emphasis added]

The people at HS Tuning claim:



> . . . The secondary circuit on the R8 coils has a higher resistance (more windings) than the stock coils. In fact the secondary circuits were slightly closer to the Okadas we tested than the secondary of the stock coils. We tested these between 12 and 16 volts . . . between 200 and 16,000rpm. The stock coils started to misfire at a much lower rpm than the R8's with a stock spark plug gapped @ .032". The spark was visibly brighter and more intense on the R8's when compared to the stock coils @ every rpm we compared in the stock rev range. We didn't compare anything under 1,000rpm. We were able to open the gap on the plugs much further with the R8's than the stock plug with out misfiring at the same rpm/voltage. . . Here is what we were finding as an AVERAGE on the secondary circuit for each of the coils: Stock: 3.3 M ohms; 5 cylinder coils: 4.75 M ohms; R8's: 5.31 M ohms; and Okadas: 6.2 M ohms


http://www.golfmk6.com/forums/showthread.php?t=45050

Is this just marketing hype?


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## groggory (Apr 21, 2003)

esoxlucios said:


> At the risk of being accused of hijacking my own thread, can you elaborate?
> 
> Reason I ask is because NGK's Web site states, in pertinent part:
> 
> ...


Its all true, but there's more to it than that.

Coils = inductors.

Coil packs = inductors with an electronic switch.

If you want to have more spark energy by having a larger coil, you're gonna have to give it longer to charge. That equals a software change to make those r8 coils sing.

Now, if you threw 20 or 30v on the r8 coils on a stock tune...now we'd be talking. The higher voltage will allow the higher inductance coils to charge more in the same time period.

1 time constant = inductance divided by resistance. Someone should probably measure the inductance and resistance of each coil. Then charge and discharge models for each can be made.


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## Marcus_Aurelius (Mar 1, 2012)

esoxlucios said:


> At the risk of being accused of hijacking my own thread, can you elaborate?
> 
> Reason I ask is because NGK's Web site states, in pertinent part:
> 
> ...


Let's say it's marketing exaggeration! Theoretically speaking, the 2.0 coils, and now the R8 coils, should offer an advantage over the latest revision 1.8t coils because of their construction. However, the practice shows that they don't offer anything really substantial or measurable (at least not where it counts) in terms of performance and with all else equal. At high pressure, 'wide' gap, they get their spark blown out just as easily (in my case for example, they didn't change the psi that I was getting spark blowout with the same gap). Maybe a dwell adjustment would maximize their potential, but we're getting nothing in the real world by just doing the coil swap. 

Check from post 164 in this thread for my experience with the coil swap
http://forums.vwvortex.com/showthre...-Cooling-quot-a-different-approach-quot/page5

And here for Gulfstream's dyno comparison (post 74)
http://forums.vwvortex.com/showthre...echnical-Facts/page3&highlight=2.0t+coil+dyno


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## esoxlucios (Sep 17, 2009)

Now, I have a fcukload of errors:


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## groggory (Apr 21, 2003)

Look them up. I don't feel like searching


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## esoxlucios (Sep 17, 2009)

groggory said:


> Look them up. I don't feel like searching


Sorry, didn't mean to seem like I was asking anyone to. I know what they all are. Crank/cam correlation, too rich at idle, too lean at other than idle, and evap wrong flow direction. My hope is that someone might say, "Bingo! That combination means your cat is plugged!" Or "Bingo, you've got a bad pre-cat O2 sensor," or "your timing is off by a tooth; that's why you have rough idle," or, like Adam suggested, a bad MAF, causing rough idle, in turn possibly causing the cam sensor reading error. But, "randomly" (as Adam puts it) changing parts is probably not a smart or economical approach.


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## esoxlucios (Sep 17, 2009)

Marcus_Aurelius said:


> Check from post 164 in this thread for my experience with the coil swap
> http://forums.vwvortex.com/showthre...-Cooling-quot-a-different-approach-quot/page5


Max, fascinating discussion on w/m application. I'm using just one 175 nozzle post TB.

Also noted you wrote:



> The top secret stuff is really about going to town with intake manifold testing. Adam did the flow test on them years ago (the one everyone uses as a reference), I plan on teaming up with him and doing something similar but on the dyno. I don't want to give too much details before things get crazy ... as you know it's a touchy subject and some vendors don't like raw unbiased data about their products!


So, what was the outcome? Did you have to go "underground" to carry out the work, lol?


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## lite1979 (Sep 9, 2005)

Check the vacuum lines to/from the FPR. I'm not a BT guy, but like I said; P1128/P1127 scream vacuum leak to me.


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## 20v master (May 7, 2009)

What are your fuel trims? That will tell you if your o2 is dead, or at least point you in the right direction. If you can't see fuel trims with a LiquidTT, they're worthless. :screwy: The cam/crank correlation is an odd one. If nothing changed, I'd chalk it up to cold weather and slack in the cam chain on startup possible due to extreme cold? Clear it and see if it comes back. If it does, it'll make the car very hard to start.


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## esoxlucios (Sep 17, 2009)

20v master said:


> What are your fuel trims? That will tell you if your o2 is dead, or at least point you in the right direction. If you can't see fuel trims with a LiquidTT, they're worthless. :screwy: The cam/crank correlation is an odd one. If nothing changed, I'd chalk it up to cold weather and slack in the cam chain on startup possible due to extreme cold? Clear it and see if it comes back. If it does, it'll make the car very hard to start.


Thanks, Adam. The crank correlation has come back every couple of weeks during the winter, and I also thought that the VVT might not be getting pumped up quickly enough due to the thick oil. I have an engine pan immersion warmer installed, which gets my oil up to 80F when at home, but when I'm at the office, there's no place to plug in. To you give some idea, it was -15F (the dashboard readout) when drove to work this morning.

Unfortunately, the LiquidTT doesn't display fuel trims. I'm going to need to invest in the VCDS for that, or ask my mechanic (David at Nur Technik), again, to do the logging for me. Last time I discussed this with him, I got the impression he did hook up the VCDS and monitored some misfires in cyl 1 & 2, but don't know what other logging, if any, he did. He did not know what the cause of the problem was. At that time, he also bought a smoke machine and found a minor leak at the V-band of the turbo inlet pipe, and another small one in the vacuum line going to the brake booster, and he fixed both. I personally checked and replaced the line going to the FPR recently (I replaced all the small vacuum lines, and long ago eliminated the morass under the manifold and ported to the side, like Max and others have done).

These particular codes (too rich (trim) and too lean (multi)) have been recurring ever since the GTX2860R was installed. 

The EVAP code just started last week (and came back after the new N80 valve was installed). One poster (above) suggested I check a pump in the passenger fender.


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## Marcus_Aurelius (Mar 1, 2012)

esoxlucios said:


> Max, fascinating discussion on w/m application. I'm using just one 175 nozzle post TB.
> 
> Also noted you wrote:
> 
> ...


I never got to doing it. A certain manifold that I wanted to test was playing unicorn at the time and kept delaying the test. To be totally honest, I don't have the drive to do these things anymore. The TT community always was my motivation and it's no longer what it was (I find myself interested in reading/posting a lot more in other sections than here which is bad). I was doing the testing mostly to have the data to share, but I know more or less what the outcome would have been... SEM> the rest overall.


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## 20v master (May 7, 2009)

Marcus_Aurelius said:


> I was doing the testing mostly to have the data to share, but I know more or less what the outcome would have been... SEM> the rest overall.


Yes, but sometimes it's nice to quantify what you already know.


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## Pass18t (Oct 18, 2003)

MAF sensor. Failing, bad readings amplified by cold ambient temps.

Put all your tweaks back to zero, nothing you're tweaking is going to be better than the software.


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