# Insane timing pull and low power



## Currancchs (Feb 24, 2011)

*Insane timing pull and low power [updated with logs]*

So, today on my ride to school I randomly logged torque using my LiquidTT (sort of like Vag-Com, but more of a permanent gauge). I noticed I was way down, only logging about 230 ft-lbs, and about 230 horsepower. I next checked timing pull and two cylinders had maxed at 12 degrees, while one was pulling 11.3 and another 9.7. This is on an APR 93 octane tune (with 93 octane in the tank) with a 42dd 3'' DP and high flow cat (rest of exhaust stock). It also has a Neuspeed P-Flo, silicone hoses, new pcv, new motor/tranny and dogbone mounts (BFI Stage I polyurethane). Boost peaks at around 20 psi. The car with this exact same setup last month registered in the mid 260's for torque and slightly less for horsepower (The readings are based off of MAF g/s readings, assuming stock timing, so may be a little low with timing bumped). 

Maybe bad gas? Anybody have any other ideas as to what the cause might be. 

Things I have sort of ruled out: 
Coolant temperature sensor - Reads OK through VCDS 
MAF - Its new, reads about 2.5 g/s at idle 
Plugs - Less than a year old, platinum, one heat range colder than stock 
Just got leak tested (twice) last month, pretty sure that's ok 

Any ideas would be appreciated, thanks guys!


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## Marcus_Aurelius (Mar 1, 2012)

Bad fuel maybe? How are your IATs and coolant temperatures? Can you log actual timing vs corrections and post them?


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## Currancchs (Feb 24, 2011)

Marcus_Aurelius said:


> Bad fuel maybe? How are your IATs and coolant temperatures? Can you log actual timing vs corrections and post them?


 My IAT's are anywhere from high 20's to low 40's (IAT's in Celsius, Ambient here is about 75 Fahrenheit). Coolant temperature stays about 85-89 degrees C on the highway, can rise up to about 98C when stopped for an extended period, then the fans kick on and it cycles from ~87-98C. 

I will try and get some logs and post them later today, hopefully by ~7 PM. 

Thanks!


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## Currancchs (Feb 24, 2011)

Okay, finally got those logs, hope they tell you something, because I am kind of lost as to what they indicate... 






















































Please ignore the Y-axis label, it should be mbar boost (absolute pressure, not gauge, subtract 1000 mbar to see boost gauge pressure)


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## Currancchs (Feb 24, 2011)

Anybody... Bueller, Bueller


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## Marcus_Aurelius (Mar 1, 2012)

Nothing really jumps out of the ordinary except for the dip in your injector time and timing graph at around 4200-4300 rpm. Both curves should be gradually increasing from their lowest point to redline (for example the timing curve should be like a V and not a W). Are you having any hick up at WOT? 

I know you said that your MAF is in good health but it maybe it's playing tricks on you. I would also run this tank of gas nearly dry and try a different source like a Shell V-power to see it the problem persists.


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## Currancchs (Feb 24, 2011)

Marcus_Aurelius said:


> Nothing really jumps out of the ordinary except for the dip in your injector time and timing graph at around 4200-4300 rpm. Both curves should be gradually increasing from their lowest point to redline (for example the timing curve should be like a V and not a W). Are you having any hick up at WOT?
> 
> I know you said that your MAF is in good health but it maybe it's playing tricks on you. I would also run this tank of gas nearly dry and try a different source like a Shell V-power to see it the problem persists.


 Thanks for taking a look at them. I appreciate it. Wonder what could be causing the odd shape of the timing/injector time graphs... I don't notice any hickups at WOT, although the car really doesn't feel like it wants to pull to redline, torque really seems to fall off, not that I've been redlining it at all since I realized it was pulling so much timing. I also logged for misfires and didn't see any. 

I'll see what happens when I put a fresh batch of gas in there, should be close to empty by Tuesday. If that doesn't help I'll take out and clean the MAF and IAT sensor and see if that does anything. On a related note, I actually fill up at Shell (with 93/v-power) about 90% of the time, including last time, but I'll try a different shell station, or maybe Sunoco with 94 octane this time. 

Thanks again!


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## warranty225cpe (Dec 3, 2008)

Have you cleaned your iat sensor or MAP sensor lately?


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## Currancchs (Feb 24, 2011)

I cleaned the IAT sensor ~4-5 months ago, I've never touched the MAP sensor though... Will add that to the list of things to clean if the next batch of gas doesn't remedy things. 

Thanks for the suggestion!


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## Currancchs (Feb 24, 2011)

Still haven't ran the tank down enough to put some fresh gas in it, but will hopefully get there tomorrow... In any case, I had a few questions, more to satisfy my curiosity than anything, but they're related to the timing pull, so here goes: 

1.) What would the MAP have to do with timing pull? (I would guess it may be reading lower boost than actual, causing the car to not inject enough fuel and run lean, but you would think that this would be made up for with fuel trims... I'm sure there's a correlation, I'm just trying to be a little more knowledgeable as to what it is) 

2.) Would logging O2 sensor voltage help to determine if I am not getting enough fuel/running lean on a narrow band car, or is this not accurate enough for diagnosis? 

3.) Would a partially clogged air filter cause any sort of timing pul issues (I haven't cleaned mine in quite a while...) 

4.) Do fuel pumps usually quit all at once, or would could a weak one cause fuel starvation/timing pull under boost? (If so, would this present itself if I were to hook a gauge up at idle and look for ~50-60 psi of pressure, or would it only generally present when under boost during driving) 

5.) Is 10.8% multiplicative fuel trim anything to worry about on APR stage I considering that idle trim is 0.8% and I have the 3'' DP (I figured it needed more fuel with the DP, so the higher than normal multiplicative trim didn't really concern me, but you guys would know better than me) 

6.) My injector time graph looks like it puts me over 100% duty cycle (Should it be?) in the higher RPMs, would a 4 bar or 3.5 bar FPR help alleviate this (and the 10.8% multi-fuel trim) or would it be a waste of money/a headache considering the tune isn't meant for it? 

7.) I have heard of the coolant temperature sensor causing issues related to timing pull (since in my understanding pull is calculated using IAT, coolant temp, and knock sensor spikes, not necessarily voltage), but could this be possible if vcds shows normal temps, or would a bad cts still show correct temps to vcds (on a sidenote, my cts is the newer green top, replaced by previous owner, but I will replace anyways if I continue to have problems since its only about 20 bucks) 

As I said before, these questions are more to satisfy my curiosity than anything, as I have searched and couldn't find any definitive answers on these questions, and I trust the both of you more than general forum searching in any case.


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## Currancchs (Feb 24, 2011)

OK, so bear with me. I let the tank run almost dry (filled up about 20 minutes after the gas light came on) and filled up with 5 gallons of Sunoco 100 octane unleaded "racing fuel". I then drove for about ten minutes and logged for timing pull (using Liquid TT, just more convenient than vcds). My initial pull registered 5.2 degrees of pull on two cylinders, and 3.0 on the other two. Another run about 15 minutes after the first registered 3.0 on two cylinders and 0 on the other two, as I would expect for this octane of fuel, maybe it just took a few minutes to circulate the fresh fuel. After that I logged Torque (using the MAF sensor) and was still only making ~230 ft-lbs... I then switched to using the torque sensor to log torque and noticed it jumped up to 253 ft-lbs, but fell quickly... I am thinking this could indicate MAF sensor issues? My reasoning is if the MAF is under-reading then the engine is running leaner than it should be, cutting power and increasing detonation, mitigated by high octane fuel. I also took a look at O2 sensor voltage (Lamdbda in Liquid TT) (I have narrow band) and, under WOT it jumped to 1.022 volts, and settled at 1.018 volts. I would think this would mean it is running severely lean if for a wideband, but does anyone know the conversion for the narrow band? 

I also pulled the hose going to the throttle body and found a small puddle of oil, which I have heard would cause detonation. I plan on taking off the lower IC hoses and dumping whatever oil is in there, as well as cleaning my air filter and MAF/IAT/MAP sensors, but have finals coming up so might not be able to get to this right away  Pictures below:


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## Marcus_Aurelius (Mar 1, 2012)

Marcus_Aurelius said:


> *I know you said that your MAF is in good health but it maybe it's playing tricks on you.*


 The more test you do, the more evident it becomes to me that it is most likely the culprit.


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## Currancchs (Feb 24, 2011)

Marcus_Aurelius said:


> The more test you do, the more evident it becomes to me that it is most likely the culprit.


 I completely agree, just seems weird since it is pretty new, but stranger things have happened. Thanks for the help Max. 

P.s. Nice writeup on 225 exhaust manifolds a couple threads above this one, I always enjoy reading your explanations.


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## Currancchs (Feb 24, 2011)

*Update*

So, just in the way of an update, I am getting a new MAF sensor. The one in there currently is only about 8 months old, and had a twelve month warranty apparently, so it is being swapped for free! (@$195 from Audi I'm pretty happy!) Thank you Audi of Nashua! 

I previously cleaned the MAP/IAT/MAF sensors, dumped a small amount of oil out of the intercooler piping and cleaned and aligned the throttle body. After doing this I cleaned the air filter and defaulted the ECU (I unplugged the +/- cable for about 36 hours). 

I did some logging immediately after this and was getting slightly less timing pull (8-9 degrees). After putting another 100 or so miles on it, timing pull increased again to ~12 degrees across all cylinders (one seems to only pull 11.3, but close enough). 

My understanding at the moment is that when a MAF is failing it reads lower than true airflow. This causes a tuning map to be selected that has increased timing to correspond to this lower airflow. When the airflow is artificially low because of a failing MAF this extra timing has to be pulled back out to prevent detonation. This makes sense as to why I was seeing less, but not non-existent, timing pull with race gas, and less timing pull after defaulting (because, until it adjusted, it was running the correct maps)... 

I throw this information out there because this is just my understanding of it, and I'm sure it isn't entirely correct, so please correct if I'm wrong! 

When I get the new MAF in a couple of days I will default the ECU again and wait a day or two then report back here with the results. 

Thanks for your help guys.


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## Currancchs (Feb 24, 2011)

Installed the new MAF sensor today, still getting pretty bad timing pull, seems to run a bit better though (could just be me). I did not disconnect the battery, but I did clear fault codes to zero trims. MAF readings through Liquid TT don't include decimal places, but I saw 1 g/s at idle with the brand new MAF (Bosch, NIB from Audi dealership), old MAF would also show 1 g/a though, although this might be a screwy Liquid TT thing, because I remember in Vag-Com the g/s value seemed marginally higher (0.5 or so). 

I guess I'll be moving on to vacuum leaks... 

Looking back to fuel trims, it seems that my idle fuel trim is just about perfect (0.8), whereas multiplicative was high (10.8)... Also, I remember the week before multiplicative was up around 16%, with idle normal. Also, I unplugged my MAF sensor on the way to school yesterday and wound up with a 17544 code - Bank 1 System Lean, which I'm assuming is triggered when fuel trims max out at +25%. This seems to me to indicate that under high vacuum the system is solid, but under boost (or heavier vacuum on TIP side) it is not. Could this also possibly be indicative of a TIP leak, seeing as how at low flow a leak may not be as apparent as when the turbo is really trying to suck a lot of air? 

I'll get a can of brake cleaner tomorrow and spray everything in sight hoping for an idle change. I took a look at the TIP as best I could today and it was pretty oily looking, so maybe time to upgrade...


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## Currancchs (Feb 24, 2011)

OK, so I had a shop check today just to make sure there was nothing wrong with the tune (Verify it was not somehow corrupted/a 100 octane file), nothing was wrong with it. I also read the MAF g/s through VCDS and it shows ~2.9 g/s @ ~760 RPM, which I believe is nicely within the expected range. Fuel trims are now at ~1.8% idle and ~7.0% multiplicative. The shop went through my symptoms and logs with me and came to the conclusion that it could be a partially clogged/melted cat (I have the 42dd one, bought within the past 6 months or so) or a bad ground somewhere... I also sprayed carb cleaner on every hose and gasket area I could find with no change in idle...

My plan of attack is to unhook the cat and take it for a test drive to see if the timing pull lessens, then take the battery tray out and make sure the ground strap under there (as well as other grounds in other places) are OK.

Any additional ideas for me to check would be appreciated. This problem is getting pretty annoying...:banghead:


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## 20v master (May 7, 2009)

Bad ground wouldn't cause timing pull. Your MAF idle value is good.


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## Currancchs (Feb 24, 2011)

20v master said:


> Bad ground wouldn't cause timing pull. Your MAF idle value is good.


I didn't think so either, but the shop I went to today mentioned to check my grounds because they had an S6 come in that had a single cylinder misfire that they apparently spent 25 hours diagnosing only to come to the conclusion that the ground strap was corroded, replaced that and car ran great. I think they just always check and reccomend checking grounds after that experience :banghead:

Sent from my PG06100 using Tapatalk


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## Marcus_Aurelius (Mar 1, 2012)

Just to throw it out there, when was the last time the fuel filter was changed and how is the fuel pump health? Did you ever log AFR under full load (WOT pull)?


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## Currancchs (Feb 24, 2011)

I changed out the fuel filter a couple months back. I'm not exactly sure how to go about checking fuel pump health though, I would assume I would just measure rail pressure at idle with a guage, but is there a better way/way to do it through vag com? I took a look at "lambda" values through Liquid TT, but they don't make much sense (less than 1 off throttle, 1 steady, more than 1 on - I always assumed, and still assume, lambda*14.7=AFR). Fwiw the wot value jumped to 1.022 then steadied to 1.018 and held there until redline, ill try to log afr tommorow with vcds, but all I have is the narrowband o2 since its an AMU.

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