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View Full Version : Boost problems. LOGS graphs and pics inside



j2da
09-06-2008, 03:04 PM
let me start by saying thanks in advance to anyone that reads any of this, i am no expert and im just trying my best to include all the info i can to help this shit get figured out. correct me in any place im wrong.

here we go, The problem is, when im WOT, towards redline i am not holding the boost i should be. because of this, it goes into soft limp mode after the pull because its not seeing enough boost. i have the GIAC chip and overall, the power comes on good, but falls on its face after about 1 second.[headbang]

No CEL, but this code shows with vag
17964/P1556 - Charge Pressure Control: Negative Deviation

From Ross-tech-
Possible Symptoms
* Reduced power output
* Limp mode
Possible Causes
* Boost Pressure too Low
* Hoses/Pipes incorrect connected, disconnected or leaking
* Charger Pressure Control defective
o VNT (variable nozzle turbo): nozzles stuck
* Solenoid Valve for Boost Pressure Control (N75) defective

i DO NOT have a boost leak, i tested it multiple times, each with no problems. i also have the ecs n75. the duty cycle seemed alright for that so i dont think thats the problem, but i will rule that out by getting a mbc and seeing if the issue goes away. but until then.

while doing the boost leak test i was looking around and found this
http://i397.photobucket.com/albums/pp59/bullzie08/wastegateactuator-1.jpg
where could this have came from?

j2da
09-06-2008, 03:09 PM
with the help of a friend, we also logged a 3rd gear pull. here are the results:

http://i397.photobucket.com/albums/pp59/bullzie08/logs.jpg

http://i397.photobucket.com/albums/pp59/bullzie08/boost.jpg
boost actually looks fairly decent in this graph but is tapering off more than it should. keep in mind the next pull it was already in limp mode for the lack of boost it saw.

http://i397.photobucket.com/albums/pp59/bullzie08/maf.jpg
the maf readings are actually what made me realize i have a problem. i should be flowing about up to about 170g/s

like i said, i will be getting trying out a differnt n75 soon or a mbc to rule that out. if anyone has any advice or can read the logs and let me know what you see i would really aprreciate it. thanks

mike-2ptzero
09-06-2008, 05:20 PM
Your maf looks like its on its way out causing low readings which will then cause the ecu to decrease boost. Once the actual boost falls below 300mbar from actual boost the ECU will throw the car into limp or close the throttle to 40%.

What does your fuel trim readings look like (block 032)?

j2da
09-06-2008, 05:32 PM
i didnt log 032 but can do that tomorrow hopefully. as for the maf, i had issues back when i got the car and was told it had a bad maf. i took it to KTR performance and they said they had it "rebuilt" or something along those lines. i was always sketchy about it, because i think they just cleaned it and told me it was new. but as im told, the maf should be new. any test to see if its bad?

j2da
09-07-2008, 12:50 PM
So today i cleaned the MAF, and did some sea-foam treatment to clean everything out. I also replaced the air filter to make sure the maf stayed clean. After doing this it seemed to run a bit better but its still having the same issue.

one thing to mention, while i was doing the seafoam i noticed a leak around the exhaust manifold. i could see smoke from the seafoam coming out of it, but its not a big enough leak to make any noise. i cant tell exactly where its coming from but it looks like its from the turbo<exhaust connection. could this leak prevent me from spooling the requested amount, causing the negative deviation code?

mike-2ptzero
09-07-2008, 01:50 PM
So today i cleaned the MAF, and did some sea-foam treatment to clean everything out. I also replaced the air filter to make sure the maf stayed clean. After doing this it seemed to run a bit better but its still having the same issue.

one thing to mention, while i was doing the seafoam i noticed a leak around the exhaust manifold. i could see smoke from the seafoam coming out of it, but its not a big enough leak to make any noise. i cant tell exactly where its coming from but it looks like its from the turbo<exhaust connection. could this leak prevent me from spooling the requested amount, causing the negative deviation code?

A exhaust leak before the turbo will cause the turbo to spool up later, any leak before the 02 sensor can cause it to read slightly leaner then how the car is really running.

j2da
09-07-2008, 02:33 PM
ill have to get the fuel trim readings, i couldnt get my hands on a cable today so i couldnt log it. but how could running rich not let me hold boost?

mike-2ptzero
09-07-2008, 02:44 PM
When you run too rich you make less exhaust gas and thats what spins the turbo.

j2da
09-07-2008, 02:52 PM
makes sense. .

on another note, the front o2 sensor iirc has been replaced with a "generic" one. a shop told me i would save money by them doing it, so i went ahead with it. this was over a year ago and i never seemed to have a problem or throw a code for it. this could be causing lean readings too i bet. hopefully i can see this all when i check fuel trim

and for logging, i just need to read block 032 right?..anything else?

Poopie
09-07-2008, 03:42 PM
i would first replace the maf. how much boost is your car making?

j2da
09-07-2008, 04:12 PM
well i just ordered a mbc to rule the n75 out, ill see what happens when that comes in. as for the maf, ill try to get someone local to swap maf with me and see if that helps things out rather than buying one and wasting money if thats not the problem.

for boost, my gauge reads a peak of 20 but it reads high so id say about 18psi. that log i peaked at 17.9

Poopie
09-07-2008, 04:25 PM
definantly your maf then. That turbo is moving more then 130g's/sec to make 18psi.

bassed
09-07-2008, 04:32 PM
definantly your maf then. That turbo is moving more then 130g's/sec to make 18psi.

Don't you just love having an 01' now[>_<]

j2da
09-07-2008, 04:33 PM
good point i never thought of it that way.

so what you and mike are saying...the maf is reading low, telling the ecu to decrease boost, then the ecu sees decreased boost, and throws it into limp because of it. but why wouldnt i get some sort of code saying bad maf?

bassed
09-07-2008, 04:40 PM
good point i never thought of it that way.

so what you and mike are saying...the maf is reading low, telling the ecu to decrease boost, then the ecu sees decreased boost, and throws it into limp because of it. but why wouldnt i get some sort of code saying bad maf?

There is no bad maf code. They blow, what you're doing is how you determine so.

j2da
09-07-2008, 04:50 PM
i found a maf for 50 from a local junk yard so ill pick that up tomorrow and see how it goes. but kinda pisses me off that i paid 250 a year ago for them to fix my maf issue and now its shot again?

and why would the ecu tell itself to cut boost, then go limp because it sees a lack of boost?

Poopie
09-07-2008, 04:54 PM
i don't trust remanufactured sensors. They blow. My first ford maf on my AEB was a "recalibrated" sensor in a new housing. It was junk. Bought and OEM from the dealership and it was all good.

j2da
09-07-2008, 05:00 PM
well i can go there and buy it, put it in and see if it works. if my car runs good i can just return it to the junk yard and get a full refund and then go ahead and buy the one from the stealership.

and now that you said that, the shop i went to told me they put a re-manufactured maf in. it must have blown over time...

j2da
09-09-2008, 03:42 PM
just installed the "new" maf, buttttttt there are too many cars in my driveway so i can't even leave. sweet. but anyways im pretty nervous about this because it almost seems like its too good to be true...any words of advice?

ill update later, hopefully with good news

j2da
09-11-2008, 06:07 PM
well i put the new maf in, and the results got better. but im still getting the negative deviation code, and still going limp. my maf readings went up to about 160, but boost seems to taper the same amount.

here are the logs:
http://i397.photobucket.com/albums/pp59/bullzie08/log.jpg

i got my mbc too, but want to make sure everything is alright before i go an put that in. by looking at those logs, do you think it will be safe to take out my n75 (for now) and just run straight mbc at 17psi?

also, i have vag-com right now...so i can log anything. let me know what i gotta do, this is starting to get to me

mike-2ptzero
09-11-2008, 10:24 PM
The Race N75 is most likely causing the turbo to boost too high down low which means the turbo peaks too soon and then tapers off way too much. The dbw cars really dont like the race N75 for this reason.

j2da
09-12-2008, 06:29 AM
ill take it out this afternoon and try out the MBC and see if i can hold throughout. another thing i was wondering though. with the mbc running standalone, will that not allow me to go into limp mode?...since ill be controlling the wastegate manually, the car will have no control over the boost, but it will still have control over fueling right?

What im trying to watch out for, is going into limp, the fueling being cut, but the boost staying the same and running lean and doing damage. Or is that now how our cars work?

mike-2ptzero
09-12-2008, 08:14 AM
ill take it out this afternoon and try out the MBC and see if i can hold throughout. another thing i was wondering though. with the mbc running standalone, will that not allow me to go into limp mode?...since ill be controlling the wastegate manually, the car will have no control over the boost, but it will still have control over fueling right?

What im trying to watch out for, is going into limp, the fueling being cut, but the boost staying the same and running lean and doing damage. Or is that now how our cars work?

The DBW cars can also close the throttle if it wants.


You can also run the MBC parallel with the N75, this will allow you to decrease the boost a little down low and then allow the N75 to control boost the rest of the way.

DubAudi3
09-12-2008, 09:09 AM
I was running into limp mode and it turned out to be a bad MAF. My buddy told me to unplug it and it would run off the map sensor. I havent gotten my new one and its been unplugged, no limp mode but the car doesnt exactly feel how my 98 a4 did and this one has more mods !! Still havent figured out why it doesnt feel as good [headbang]...
Anyways, you could try unplugging the maf, unless i was told wrong and you shouldnt

j2da
09-13-2008, 04:41 PM
i did some logs with the mbc, in parallel and standalone. maf readings are near 160, and no more limp mode, but still throwing negative deviation code.

here are the results:
these are with n75 and mbc hooked up
http://i397.photobucket.com/albums/pp59/bullzie08/hatemycar4.jpg
http://i397.photobucket.com/albums/pp59/bullzie08/hatemycar.jpg

in this pic, the mbc was at 15psi and it wouldnt go any higher. probably because its the forge bleed valve, and i guess i needed the ball and seat one...
http://i397.photobucket.com/albums/pp59/bullzie08/hatemycar5.jpg

so i got rid of the spike by hooking up the mbc, but i still have the same boost problem, minus the limp mode. what should i look at next? could the small leak on the manifold i found when sea-foaming be causing this? how does the 02 sensor look?

mike-2ptzero
09-14-2008, 07:57 AM
I was running into limp mode and it turned out to be a bad MAF. My buddy told me to unplug it and it would run off the map sensor. I havent gotten my new one and its been unplugged, no limp mode but the car doesnt exactly feel how my 98 a4 did and this one has more mods !! Still havent figured out why it doesnt feel as good [headbang]...
Anyways, you could try unplugging the maf, unless i was told wrong and you shouldnt

The car does not run off the map sensor, that sensor is only used for safety. Your car is just running off the fuel map and timing using load. You are better off getting a new maf into the car.


i did some logs with the mbc, in parallel and standalone. maf readings are near 160, and no more limp mode, but still throwing negative deviation code.

here are the results:
these are with n75 and mbc hooked up
http://i397.photobucket.com/albums/pp59/bullzie08/hatemycar4.jpg

so i got rid of the spike by hooking up the mbc, but i still have the same boost problem, minus the limp mode. what should i look at next? could the small leak on the manifold i found when sea-foaming be causing this? how does the 02 sensor look?

Did you post up the wrong log picture? because it is all done at part throttle. So the readings are all useless.

j2da
09-14-2008, 11:52 AM
oops wrong marker. here are the right ones

http://i397.photobucket.com/albums/pp59/bullzie08/hatemycar6.jpg

j2da
09-14-2008, 12:06 PM
and i cant find a good write up on how to hook the forge 3 prong mbc in parallel with the n75. should i have both of them connected to the tip? i wanna make sure i have mine hooked up right

mike-2ptzero
09-14-2008, 03:32 PM
Yeah you could T the outlet of the MBC to the outlet of the N75 and run both to the TIP.

j2da
09-15-2008, 05:30 PM
ran t, and now still wont go past 15 psi. i can crank the mbc all the way closed and boost like 12, all the way open its still 15. im pretty sure the forge valve is a waste of money, any suggestions before i rip 90 feet of vacuum hose out of my car?

mike-2ptzero
09-15-2008, 05:52 PM
ran t, and now still wont go past 15 psi. i can crank the mbc all the way closed and boost like 12, all the way open its still 15. im pretty sure the forge valve is a waste of money, any suggestions before i rip 90 feet of vacuum hose out of my car?

Well a leak type MBC is never really closed since your just limiting how pressure is being leaked off. You need a MBC that is designed to block off the pressure when fully closed. My friend uses one of those on his GT35r and is able to run 16-32psi without a problem.

j2da
09-15-2008, 07:37 PM
so theres no way i can get this bleed valve to hold more than 15psi? can i block off one of the 3 prongs or something? i really dont feel like buying another mbc.

but, i acutally had it boosting over 15psi when i had it hooked up wrong, which made no sense. i had the mbc inline, after the n75. but instead of the n75 beind hooked into the tip, it was just venting to atmosphere (probably not good), the mbc's 3rd prong was in the tip, then it was connected to the wastegate. this worked good for boost, but the car wanted to die when between vacuum and boost.

mike-2ptzero
09-15-2008, 10:02 PM
so theres no way i can get this bleed valve to hold more than 15psi? can i block off one of the 3 prongs or something? i really dont feel like buying another mbc.

but, i acutally had it boosting over 15psi when i had it hooked up wrong, which made no sense. i had the mbc inline, after the n75. but instead of the n75 beind hooked into the tip, it was just venting to atmosphere (probably not good), the mbc's 3rd prong was in the tip, then it was connected to the wastegate. this worked good for boost, but the car wanted to die when between vacuum and boost.

When you had it hooked up in series you were just decreasing how much pressure was being sent to the wg once the N75 let pressure thru. That is how you hook it up if you want to run more boost then what your ecu is tuned for, the way you have it installed now(parallel) will only allow you to run less boost then what the ecu wants to run since you now have 2 paths for the boost to reach the wg, thats the way to install it if you are trying to decrease boost spikes.

j2da
09-16-2008, 12:03 PM
im gunna go put it back in series, but this time with the n75 venting to the tip. when i originally had it in series the spike went away and it seemed to hold more boost.

j2da
09-21-2008, 10:56 AM
mbc is back in series and car seems to have smooth power, but the boost is still tapering off. the negative deviation code also showed up too. these are the logs from a 3rd gear pull i did yesterday. i will only have vag-com for the rest of the day so anything that i need to look at let me know today and ill try to get it posted.

fyi, the 3 prong mbc is hooked up in series after the ecs "race" n75. the ambient pressure prongs from each valve are connected to the TIP with a t-fitting.

tapering too much...
http://i397.photobucket.com/albums/pp59/bullzie08/mbcseries.jpg

whats up with this?
http://i397.photobucket.com/albums/pp59/bullzie08/mbcseriestimingangle.jpg

3rd and a little of 4th here:
http://i397.photobucket.com/albums/pp59/bullzie08/mbcserieslog.jpg

what should i be looking at next?

mike-2ptzero
09-21-2008, 02:50 PM
Timing graph will always be up/down, you will never see one that is very smooth since the timing map is always being adjusted.

Your 02 readings are very rich, you want to be in the .85-.88 range with anything over .9 very rich.


How old is the turbo, could just be worn out causing it to run at a lower efficiency and that would cause the boost to hold less boost in the higher rpms then it would brand new.

j2da
09-21-2008, 03:53 PM
As far as I know, turbo is 120k old...I doubt the previous owner replaced it. Could the exhaust leak coming from the manifold, or a crappy O2 sensor be causing the rich readings?

mike-2ptzero
09-22-2008, 08:51 AM
Leak and a worn 02 sensor will usually give a lean condition.

j2da
05-03-2009, 02:54 PM
bump after a nice winter of snowboarding and forgetting my car had any problems...anyways i still got this boost issue and id like to get it sorted out for good.

ive been out of work for a while with a broken wrist so i got a bit of time to get this fixed and done with. on that note i just installed my second MBC, this one being a ball valve to rule out my n75 for good.

heres a pull:
http://i397.photobucket.com/albums/pp59/bullzie08/newMBC.jpg

as mike said above anything above .9 for my o2 readings is rich, what can be causing this?

also, im aware my turbo could be out of efficiency days. is there any way i can see if its going out?

mike-2ptzero
05-03-2009, 05:42 PM
Boost leak somewhere after the turbo could be causing the car to run rich.

j2da
05-04-2009, 12:27 PM
i did a boost leak test and neither saw or heard any leaks. heres another log, this time with block 032.

http://i397.photobucket.com/albums/pp59/bullzie08/mbc2.jpg

mike-2ptzero
05-04-2009, 01:52 PM
032 is a worthless block to log. You want block 031 for 02 sensor, 032 is just fuel trim and it isnt going to change much if at all during a log. Log block 022 in its place for timing correction.

j2da
05-04-2009, 04:46 PM
ill log block 022 in a bit.

quick question tho, with my new mbc im still having trouble boosting anywhere above 17-18psi...even with it cranked all the way closed. the internal spring might be to weak, but can i disconnect the wastegate, clamp it and see if i can boost more...or is that too dangerous?

mike-2ptzero
05-04-2009, 05:52 PM
You can do that but make sure to do it in 5th gear at low rpms so the rpms dont climb too quick.

j2da
05-04-2009, 09:17 PM
i didnt disconnect the wastegate but heres 022 logged
http://i397.photobucket.com/albums/pp59/bullzie08/mbc3.jpg

mike-2ptzero
05-05-2009, 05:23 AM
The deviation code is most likely being caused by the Race N75 valve. That valve does not work on the dbw cars because running more boost causes the turbo to taper sooner and this drops you below the requested boost in the higher rpms and when the ECU sees close to 300mbar difference in boost it throws the deviation code and goes into soft limp. So you either need to learn to short shift or put the stock N75 valve back in, you could try doing a diode on the map sensor wire but it not might not fix your deviation issue.

The deviation could also be caused by the turbo itself if the effiency has decreased over time which happens.

j2da
05-05-2009, 08:50 AM
well im running just MBC right now, no race n75. the n75 is just connected to the tip, still plugged in to the car but with the t connecters looped together..so there is no more big boost spike, yet im still tapering more than i should. so it could just be a dieing turbo. but what about a small exhaust leak around the manifold/turbo area, could that cause any of this?

mike-2ptzero
05-05-2009, 09:24 AM
well im running just MBC right now, no race n75. the n75 is just connected to the tip, still plugged in to the car but with the t connecters looped together..so there is no more big boost spike, yet im still tapering more than i should. so it could just be a dieing turbo. but what about a small exhaust leak around the manifold/turbo area, could that cause any of this?

Well a leak at the manifold before the turbo would cause the turbo to spool up slower, I dont think it would cause it to taper.

j2da
05-05-2009, 02:57 PM
yeah, it spools fine. back to the rich issue, is this related to the lack of boost? what else could be causing rich readings?

WonPointAteTea
05-05-2009, 03:48 PM
hmmm... i just started getting similar problems with my 2000, and the boost taper and the same neg. dev. code...

I was going to try most of what you have to rule it out

i have been getting a cat inefficiency code as well. could a bad cat be causing all of this to happen? It would seem to maybe make sense, less flow, equals less spool, and then less boost? maybe?

j2da
05-05-2009, 04:12 PM
really wish i knew. you running a stock tune or got a chip? i was thinking about getting a test pipe and exhaust and seeing how much more it would breathe...maybe that could solve some issues

mike-2ptzero
05-05-2009, 05:10 PM
hmmm... i just started getting similar problems with my 2000, and the boost taper and the same neg. dev. code...

I was going to try most of what you have to rule it out

i have been getting a cat inefficiency code as well. could a bad cat be causing all of this to happen? It would seem to maybe make sense, less flow, equals less spool, and then less boost? maybe?

Yes because there would be too much back pressure causing a restriction of flow and not allowing the turbo to spool up like it should in the mid to higher rpms.

j2da
05-25-2009, 11:06 AM
called up GIAC to talk about a possible reflash, in the instance i have a bad tune. they said look at IAT saying extensive heatsoak was a common issue with the 2000.

in these logs i had the mbc cranked closed (still wouldnt boost over req). ambient temp was about 32c. MAF readings low too, and it feels slower and slower every time.

im still trying to pinpoint the exhaust leak around the turbo too, dont really know where its coming from. on another note, it almost sounds like my turbo is going...doesnt sound like a dentist drill, but sounds a lot "raspier" than it should. it sounds clean when im around 5psi, but once i go anywhere above 12 the sound comes on.

3rd gear...
http://i397.photobucket.com/albums/pp59/bullzie08/iatboostmaf-1.jpg

j2da
05-27-2009, 04:26 PM
what im wondering for the iat, are they way too high (even for the smic)?

heres another one..
http://i397.photobucket.com/albums/pp59/bullzie08/iatboost3rd.jpg

willowtreexx
06-08-2009, 04:08 PM
any news on your issue? I am having the same issues with mine. 2000 1.8t ATW with 126,000 on the turbo and new motor... i want to fix this

KBB5
06-08-2009, 07:05 PM
Could have a clogged cat, or turbo might have slight play, or wastegate might not be actuating properly,

WonPointAteTea
06-09-2009, 12:28 AM
called up GIAC to talk about a possible reflash, in the instance i have a bad tune. they said look at IAT saying extensive heatsoak was a common issue with the 2000.


i wonder what would make the 2000 more susceptible to heatsoak??

j2da
06-21-2009, 02:06 PM
not too sure but i did notice the fog light was clearly blocking every ounce of needed airflow to the stock intercooler. i took them both out and noticed a bit of improvemtn but havnt logged to confirm any actual gains yet.

KBB5
06-21-2009, 09:25 PM
either your cats clogged, the MAF u have is trash, or your turbo is loosing its long term strength, the K03 is a small turbo and will taper at the higher rpms , im actually thinking you wastegate flap is weak, good luck man I have similar problem but aint getting over 13psi

j2da
06-23-2009, 01:33 PM
funny you say wastegate because i was just looking at anohter thread where people were talkig about fluttering/bad wastegate and how it sounds like an exhaust leak at times (mine sounds like it has an exhaust leak around turbo). im hoping to find a cheap k03 this way ill be able to tell if the wastegates bad or if the turbo has had it days. also lookig to get test pipe so that will rule out cat too.

willowtreexx
07-20-2009, 09:46 AM
any update on this? i still havent found my issue yet and i got the car rechipped with a new file...

j2da
07-20-2009, 10:34 AM
still havnt pinpointed it, kinda just been ignoring. ill be installig a k04 this week ill let u know if the code goes away.

what chip u get?

willowtreexx
07-20-2009, 10:47 AM
still havnt pinpointed it, kinda just been ignoring. ill be installig a k04 this week ill let u know if the code goes away.

what chip u get?

I got the Unitronics Stage 1 and have been running a 710N DV. im 100% stock other than those two things.

j2da
07-20-2009, 11:31 AM
did you check and eliminate the possibility of a boost leak? thats the most common. if you getting the negative deviation code check this out...http://wiki.ross-tech.com/index.php/17964/P1556/005462

willowtreexx
07-20-2009, 11:57 AM
did you check and eliminate the possibility of a boost leak? thats the most common. if you getting the negative deviation code check this out...http://wiki.ross-tech.com/index.php/17964/P1556/005462

yeah i checked all my hoses, IC hoses, MAF... The only thing that i didnt check and dont know how is the VNT on the turbo and the N75.

It just strikes me as stange that this issue happened only right after i got it chipped...[confused] makes me want to think its a software problem

willowtreexx
07-20-2009, 11:58 AM
i wish i was going K04... [:(]

j2da
07-21-2009, 12:29 PM
haha yeah im stoked on the k04 i had to do something i was sick of dealing wtih k03 problems, at least now ill have somehting to look forward too.

but if you want to diag your n75, i have a mbc im not using i can sell you for cheap. its a bleed type and will hold up to 15psi but that way you can see if your n75 is junk.

j2da
07-21-2009, 12:34 PM
and the reason you noticed this when you got chipped, is beacsue it wasnt requesting high boost in stock mode and your turbo had no problem holding the stock 9psi. when you got chipped it was tryping to hold somewhere around 15 and thats when you need everything to be working perfectly.

j2da
09-14-2009, 02:14 PM
Negative deviation returns.[headbang]

Since the last time ive posted on this I put a k04 on, got a tune, did FMIC, test pipe, and im running a mbc right now. I did pulls with my race n75, a stock n75, and mbc and all still show the negative deviation code.

I just pressure tested to 15psi and heard no leaks either, all i heard was some bubbling into the engine somewhere. I did block off the pcv valve too.

I want to buy a maf maybe thinking thats bad, because my readings arent going above 160g/s...but at the same time im only boosting 18.5psi. Should values be above 160g/s on a gpopk04 @18.5psi?
Here are some simplified maf readings:
RPM ; MAF g/s ; BOOSTpsi
3600 129 18.9
4500 149 16.3
6000 160 11.3

Also, the o2 readings are starting out perfect @ .85 but by the end of the pull are at .89 (somewhat rich).

Theres a forge 007 on its way, so well find out if the divereter was the issue in a day or two. Not thikning this is too probable tho seeing i have a fairly new 710n in there now.

Here are some logs from 003, 033, 115:
http://www.audizine.com/gallery/data/500/k04_maf_boost_o2.jpg

what tha f. let me know if you got some ideas

j2da
09-15-2009, 12:53 PM
bump with some fuel trim values. I was reading a writeup on ross-tech about maf diagnosis and it mentioned checking block 032 as well as 003. and this i did. if anything at least i got some more data, useful or not. what do you think?

http://www.audizine.com/gallery/data/500/fuel_trim_and_maf.jpg http://www.audizine.com/gallery/data/500/fuel_trim_and_maf2.jpg

j2da
09-15-2009, 06:08 PM
just installed the forge007 (yellow spring) aaaaaand the boost is still tapering.

mike-2ptzero
09-16-2009, 07:46 AM
Block 032 is just the fuel adjustment and you dont need to log those, just read them to see how much the ecu is pulling/adding. As you can see from your log they dont move. The readings you do have tends to suggest a boost leak.


Boost is always going to taper in the mid/higher rpms with a K03/K04. But your MAF readings should be much higher then 160 g/s with a K04 pushing 18+psi. Even the GIAC X chip on the 2001 with a K03 will hit near 180 g/s, but this also depends the elevation(DA) and outside temps.

j2da
09-16-2009, 11:43 AM
Block 032 is just the fuel adjustment and you dont need to log those, just read them to see how much the ecu is pulling/adding. As you can see from your log they dont move. The readings you do have tends to suggest a boost leak.

-i did a boost leak test to 15psi and heard nothing, should i go to 20? I dont see how id miss a leak when i would clearly hear it. What am I missing? I block off the pcv, put a pvc cap on the intake after the MAF w/ a hole and hold a rubber airhose tip to it while someones watching the gauge go to 15. No clear leaks but the boost does taper out in about 10 seconds, all i can hear is some bubbling into the block. Am i just not testing high enough? Also, i cant crank the mbc anymore, the boost tops off at 19psi no matter what.

mike-2ptzero
09-16-2009, 11:55 AM
No 10psi is enough. If you dont hear anything at that or 15psi then there isn't a leak.


You might want to try a new maf.

walky_talky20
09-16-2009, 09:37 PM
The oil bubbling sound (with pcv blocked off) is caused by pressure leaking through the journal bearing inside the turbo. Boost leak down is normal especially on an older turbo (slightly worn bearing and seals) and doesn't necessarily point to a problem. This is also why you should remove the oil cap during the test to gaurd against pressure building in the crankcase.

You may want to try pressure checking everything after the turbo. Either starting at the pipe that goes across to the intercooler, the bottom of the IC itself, or right at the throttle body. Doing this, it should hold the pressure for longer and allow you to detect any leaks.

j2da
09-17-2009, 08:12 AM
The oil bubbling sound (with pcv blocked off) is caused by pressure leaking through the journal bearing inside the turbo. Boost leak down is normal especially on an older turbo (slightly worn bearing and seals) and doesn't necessarily point to a problem. This is also why you should remove the oil cap during the test to gaurd against pressure building in the crankcase.

You may want to try pressure checking everything after the turbo. Either starting at the pipe that goes across to the intercooler, the bottom of the IC itself, or right at the throttle body. Doing this, it should hold the pressure for longer and allow you to detect any leaks.

ill have to try that, maybe ill redo the piping on the fmic and while im there just pressurize right into the inlet iself. but as mike said above, i would have most likely heard a leak by now. are there any hoses that only get flow once the car is running? due to a check valve or something? or do they all see boost once pressurized? And im not talking about the big hoses as much, more the smaller vac lines.

and mike, as far as my maf being bad..how would that even cause any of this? I know my car isnt running to potential, i was getting pulled on by a 250hp legacy gt (it should be somewhat even, correct?) Its underboosting, and thats why i think the readings are low. I SHOULD be able to get the turbo to spike higher than 20psi, and i cant.

on antoher note, both my k03, and new k04 sound pretty loud. almost louder than it should. the turbo literally SCREAMS, but doesnt sound blown...just screams. both of the turbos had the same sort of sound, so i dont think its anything specific to the turbo, my old k03 had 130k on it..the k04 has about 2k on it.

mike-2ptzero
09-17-2009, 08:21 AM
ill have to try that, maybe ill redo the piping on the fmic and while im there just pressurize right into the inlet iself. but as mike said above, i would have most likely heard a leak by now. are there any hoses that only get flow once the car is running? due to a check valve or something? or do they all see boost once pressurized? And im not talking about the big hoses as much, more the smaller vac lines.

and mike, as far as my maf being bad..how would that even cause any of this? I know my car isnt running to potential, i was getting pulled on by a 250hp legacy gt (it should be somewhat even, correct?) Its underboosting, and thats why i think the readings are low. I SHOULD be able to get the turbo to spike higher than 20psi, and i cant.

on antoher note, both my k03, and new k04 sound pretty loud. almost louder than it should. the turbo literally SCREAMS, but doesnt sound blown...just screams. both of the turbos had the same sort of sound, so i dont think its anything specific to the turbo, my old k03 had 130k on it..the k04 has about 2k on it.

Maf will effect your WOT AFR which will in turn effect boost levels, a low reading maf will also have lower load readings.

Looking at your AFR readings it seems your car is running a bit rich at WOT up top. You want to be close to .85 and up top your seeing .875-.89, .9 is around 10:1. Which seems odd because that combined with the high fuel trim reading at part throttle it looks to be a boost leak even though you say you cant find one.

walky_talky20
09-17-2009, 09:19 AM
Yeah, retest at the intercooler inlet. Maybe try a bit above 15 psi as that is your problem - can't get above 15 psi. Also, have you tried just removing the vacuum line to the wastegate actuator altogether, to make sure the wastegate never opens? Then go for a test drive - build boost slowly in a high gear and see if you can exceed 15 psi.

j2da
09-25-2009, 02:51 PM
I finally did a good boost leak test, ended up making a nice boost leak tester at the shop w/ a regulator valve to stop air from creaping back out. i connected it right after the diverter. i was able to crank it to 22 psi and walk around the car and listen for leaks while spraying soapy water at any noise.

anyways i found a few small leaks at 20psi, none that seemed too big though. the first series of leaks were coming from the fpr line where i Td the boost gauge in...replaced lines and re ziptied them.

the second leak i found to be coming from this valve: (top right is the coolant reservoir):
http://www.audizine.com/gallery/data/500/valve_leak.jpg

now the leak was pretty small and didnt seem like it would cause boost to taper that much, it wasnt really hissing TOO loud at 20psi but it was definintly leaking. think it could be the culprit? what valve is this anyways?

j2da
09-26-2009, 10:06 AM
bump for coffee

walky_talky20
09-26-2009, 11:49 AM
That is the "suction jet pump". I have seen an updated design for these. It appeared that they made the plastic thicker around the edge where yours is leaking. That is exactly where mine failed - only it sheared clean off all around the circle there. Blew apart and the car stalled instantly. I was in the middle of nowhere so I taped it together and stayed out of the boost for a week until I got a new one! Ah, good times.

http://www.ecstuning.com/Audi-B5_A4-Quattro-1.8T/Engine/Intake/ES3223/

j2da
09-28-2009, 01:07 PM
i ordered the "suction pump" valve so well see how it turns out. but really how could that small amount of leaking air from the valve account for any negative deviation? im having a hard time believing this will fix anything but well see, fingers crossed

willowtreexx
03-02-2010, 03:02 PM
question about the vacuum test. when you pressurize the system, does it hold at 15psi? i can pressure my system to about 8psi and then the moment i stop charging it it goes away right away. so I have to have two people to test my car. one putting pressure on the system and one walking around listening to leaks. Is this normal?!

2001A4QUATTRO
03-02-2010, 03:04 PM
Do you have the valve on the TIP blocked off? You would have to have a very large leak for that to happen. You should be able to hear it..

willowtreexx
03-02-2010, 03:31 PM
yeah i have the valve blocked off. I assume youre talking about the "hockey puck" black thing? if thats the case yes its blocked off. I cant hear the leak if i do have one. I have all new hoses, and tracked down everything other leak. its dead quite when i charge the system cant hear it leaking out anywhere. I usually sit in the car and watch the boost gauge while someone charges the system. i see it register 8psi and then once he stops forcing air into it, it goes back to zero...

willowtreexx
05-26-2010, 07:23 PM
I am going to be replacing my wastegate tomorrow and I will let everyone know if that fixes my LIMP issue