Audi B5 1.8T ... Slooww .. but whyyy ?!

[The Overclocker]

the car is a 1999 audi b5 1.8t aeb tiptronic , bought the car with 94k , now has 113k

ever since i bought the car list of parts changed because of this power issue ..

sparkplugs
Forged Dv
N75
mass air flow
fuel pressure regulator
new vacum hoses
leak test,ok
added spring to the wastegate to help is close properly
was so despirate i Unitronic it ... did not even gain 1% of power...

im suspecting the cat to be clogged up
or
fuel pump not enough pressure
or
o2 sensor
or
bad turbo... but the car was owned by a old lady and had only 94k ..so i doubt it

im loosing my mind.. on this car but after all ther money ive put into it .... im not going to abandon this power issue but i need tips on what this could be


i have a 2003 jetta 1.8t as well BONE stoke at 100% ..

when i log the audi on vag com it says 126g/s peak air flow tough mass air flow ..

the jetta is at 167g/s .. the jetta DISTROYSS the audi in power .. but the audi is supposed to be at 18psi of boost .. so wtf !?

[ECS Tuning-Audi]

Do you have a boost gauge installed?

Jason

[walky_talky20]

Post long term fuel trims.

Check boost levels with a gauge.

[The Overclocker]

no i don't own a boost gauge but at 2pm im going to a very reputed vw/audi garage , what should i mention ? not that they dont know there shit, i only have a 30min window , then i need a other schedule

[ECS Tuning-Audi]

no i don't own a boost gauge but at 2pm im going to a very reputed vw/audi garage , what should i mention ? not that they dont know there shit, i only have a 30min window , then i need a other schedule

There's nothing they could really tell you that us forum posters could tell you in a 30min appointment. You'll just be out $95 bucks or whatever they charge an hour to hook your car up to VCDS and look at your ECU codes. Unless they are offering to do it for free. But as Keith said without a boost gauge you'll have to log actual boost vs requested and long term fuel trims to really know whats going on with the turbo and your power out put.

Your MAF reading is definitely low so you're not moving much air. Either the cat is logged or there is something wastegate related if your car checked out on a boost leak test.

Jason

[The Overclocker]

There's nothing they could really tell you that us forum posters could tell you in a 30min appointment. You'll just be out $95 bucks or whatever they charge an hour to hook your car up to VCDS and look at your ECU codes. Unless they are offering to do it for free. But as Keith said without a boost gauge you'll have to log actual boost vs requested and long term fuel trims to really know whats going on with the turbo and your power out put.

Your MAF reading is definitely low so you're not moving much air. Either the cat is logged or there is something wastegate related if your car checked out on a boost leak test.

Jason

i own the full version of vcds but i don't know how to use it fully .. its quite complicated lol

tell me what do to and i can do it right now

and this is a reply i gaved to a guy on a other forum

changed my fuel pressure regulator today because yesterday after pushing it for 2 km, i stopped popped the hood and smelled the engine , then i found a gas smell, came from the regulator, removed the vacuum hose and it was smelling preaty bad, diaphram was busted gas was going into the intake , back into the engine ..

im guessing to much excess fuel, some not gething burned, finding its way in the cat then its melt because of excesive heat !?

im just going with logic .. let me know if it makes sence

-------

i'm thinking either clogged cat or wastegate internal flap in the hot side of the turbo broken off

[MetalMan]

...you'll have to log actual boost vs requested...

Jason

Being an AEB, he can't log actual boost.
I too vote for the need of a boost gauge. It's far cheaper than paying a shop for 30mins of time.

[The Overclocker]

im really suspecting either Clogged cat or broken wastegate flap located in the hotside of the turbo

good thing is, separating turbo back from turbo will reveal both suspected issues

edit:

i think thats what i'm going to do , i have a Rdv in less then a hour at a reputed shop, im going to tell him to seperate those two for inspection and if all ok do a fuel pressure test

all this in 30 min should be possible in my guess and will be well worth it

edit:

& do a boost test wile where at it , i dont want to buy a gauge because i dont want to install one i like the Oem look of the car and dont want to invest in a 400$+ setup to have a clean oem look installed boost gauge

[ECS Tuning-Audi]

i own the full version of vcds but i don't know how to use it fully .. its quite complicated lol

tell me what do to and i can do it right now

and this is a reply i gaved to a guy on a other forum

changed my fuel pressure regulator today because yesterday after pushing it for 2 km, i stopped popped the hood and smelled the engine , then i found a gas smell, came from the regulator, removed the vacuum hose and it was smelling preaty bad, diaphram was busted gas was going into the intake , back into the engine ..

im guessing to much excess fuel, some not gething burned, finding its way in the cat then its melt because of excesive heat !?

im just going with logic .. let me know if it makes sence

-------

i'm thinking either clogged cat or wastegate internal flap in the hot side of the turbo broken off

Go to the channels function where you can enter individual measuring blocks. I forget off hand which is the long term fuel trim but you'd want to log that.

Also check out http://www.ross-tech.com/vag-com/vag-com-faq.php this will give you a run down on how to get you started.

I'm not quite sure I understand exactly what you're trying to explain with the regulator. The regulator shouldn't allow raw fuel to enter the engine other than the fuel rail.

Misfires can cause excess un-burnt fuel to ignite in the converter which will cause it to over heat and possibly melt the catalyst cells eventually clogging it.

Being an AEB, he can't log actual boost.
I too vote for the need of a boost gauge. It's far cheaper than paying a shop for 30mins of time.

Forgot he has an AEB. You are correct.

Jason

[The Overclocker]

the regulator was poring out raw fuel from the vacum outlet, diaphram was busted so i replaced it , hoping it was the reason for bad performance... but it wasent

[The Overclocker]

i'm off to the shop, i'll update ones i come back

[The Overclocker]

ok the update is that i forgot to mention that i hade 2 dtc that i cleared p1136 + p1556

cleared it .... came back just in time for the mecanic to see it ..


he told me usually thats related to the crank case pcv valve

at idle i'm at 14.8% over fueling ... thats wayy to much according to him

he test drove the car , wot couple of time and he didint feel like the cat is clogged up he told me the car would be moving a lot less

so now i'm leaving the car cool down

then attacking that crank case pvc valve !!

please share toughts and ideas on what else should i check

[ECS Tuning-Audi]

Sounds like a good plan of attack. If your PCV isn't supplying enough vacuum to your N75 valve it can cause it to hit limp mode. Which would only allow you to build 3psi and it would feel very very slow.

Jason

[MetalMan]

Sounds like a good plan of attack. If your PCV isn't supplying enough vacuum to your N75 valve it can cause it to hit limp mode. Which would only allow you to build 3psi and it would feel very very slow.

Jason

PCV and N75 are unrelated on the B5 1.8T. N75's references are only the compressor housing pressure tap and turbo inlet pipe.

I actually don't see the PCV system causing the low power issue, unless the PCV/PRV valves are physically damaged. I imagine a clogged PCV system causing oil leaks, though. It's definitely a good idea to refresh the PCV system if it hasn't seen any maintenance in a while, even if it's not the source of the problem.

The Overclocker: do you have any more information on the leak test? Your persistent fault codes kinda point toward an air leak somewhere (since you already replaced the N75).

[The Overclocker]

i took the hose the connects to the pvc 035103245A , blew air inside as strong as i could and was shut closed , and pulling air in was fine

is my mouth strong enough to test this or i need real 15 psi testing

[ECS Tuning-Audi]

PCV and N75 are unrelated on the B5 1.8T. N75's references are only the compressor housing pressure tap and turbo inlet pipe.

I actually don't see the PCV system causing the low power issue, unless the PCV/PRV valves are physically damaged. I imagine a clogged PCV system causing oil leaks, though. It's definitely a good idea to refresh the PCV system if it hasn't seen any maintenance in a while, even if it's not the source of the problem.

When my crankcase breather and PCV were busted on my B6 I kept getting kicked into limp mode. Once I replaced both it hasn't flinched. Only reason I drew this conclusion.

Jason

[The Overclocker]

i took the hose the connects to the pvc 035103245A , blew air inside as strong as i could and was shut closed , and pulling air in was fine

is my mouth strong enough to test this or i need real 15 psi testing

any news on this ?

[MetalMan]

When my crankcase breather and PCV were busted on my B6 I kept getting kicked into limp mode. Once I replaced both it hasn't flinched. Only reason I drew this conclusion.

Jason

Lots of differences between AMB and AEB engines (MAP sensor, DBW vs DBC, etc) so your B6 could have been in limp mode from some sensor value that doesn't exist on AEB.
Regardless a busted PCV system falls under my statement "unless the PCV/PRV valves are physically damaged" so I'm not saying you're wrong

i took the hose the connects to the pvc 035103245A , blew air inside as strong as i could and was shut closed , and pulling air in was fine

is my mouth strong enough to test this or i need real 15 psi testing

This is a pretty basic check of the PCV valve you performed. Chances are it may still be good, but this is only one component within the whole PCV system that needs to be checked.

any news on this ?

Any news on this: ?

The Overclocker: do you have any more information on the leak test? Your persistent fault codes kinda point toward an air leak somewhere (since you already replaced the N75).

[ECS Tuning-Audi]

Lots of differences between AMB and AEB engines (MAP sensor, DBW vs DBC, etc) so your B6 could have been in limp mode from some sensor value that doesn't exist on AEB.
Regardless a busted PCV system falls under my statement "unless the PCV/PRV valves are physically damaged" so I'm not saying you're wrong

Oh I know, not discrediting you either. The differences over the years are borderline ridiculous, which makes it very easy to mix up.

I need more coffee lol.

Jason

[walky_talky20]

ok the update is that i forgot to mention that i hade 2 dtc that i cleared p1136 + p1556

P1136 = Long Term Fuel Trim Additive: Bank 1 System too Lean
P1556 = Charge Pressure Control: Negative Deviation

The first code means you have a low MAF reading at idle. Usually due to a leak.
The second code is a low boost pressure code.

at idle i'm at 14.8% over fueling ... thats wayy to much according to him

He is correct. That is way too much. But the idle (additive) trim is half the story. What is the part throttle (multiplicative) trim? That would be the number right beside the 14.8. That other number will help us internet-diagnose your car a little better.

As it stands, I can say you have a leak somewhere. Air is getting into the manifold at idle, but is bypassing the MAF. Could be in the Turbo Inlet Pipe, could be in any hose connected to the manifold. Or anywhere in between those 2 things.

You also have low boost. This could be due to the leak. The turbo could be perfect, but you are just leaking all the boost out of somewhere. So one leak could *potentially* explain both issues. It could be sucking air IN at idle, and the blowing air OUT when in boost. All from the same tear in a single hose. It could even be a hole in the intercooler.

BUT, if you were losing that much boost (which, to trigger a low boost code on an AEB, would have to be like...all of it) we should also see a VERY NEGATIVE part throttle (multiplicative) fuel trim. It should be adding fuel at idle, and then pulling it back at the top end. We don't know that yet until you get us the part throttle trim details. Not to mention you said you did a boost leak test and didn't find anything. So while this theory is neat, it may not explain your problem.

So you may have a different reason for no boost (ie: missing wastegate flapper, dead N75, etc.) and the wonky additive trim could be due to a vacuum-only leak that a boost leak test will never catch. Meaning a leak that is behind a check valve. Like a broken evap line or something.

So those are my 2 theories. 1 leak that explains both things, or 1 vacuum leak along with some kind of turbo/wastegate/control issue. The part throttle trim information would be helpful to narrow it down.

[The Overclocker]

i think i found one of the problems


the 034-129-101B valve , if i blow both ways or pull both ways there is no restriction .... could this be the issue im having !?

and second issue -->

and did the leak test , removed the 034-129-101b valve, blocked the port

i found a small leak i fixed it , but i hear bubbling sound from the engine , don't know if its the oil or antifreeze bubbling

is this normal as well ?

[The Overclocker]

i just did a driving log

my 02 sensor's voltage flikers ..


goes from lets say 0.6v to 0.1v to 0.8v back to 0.6 then 0.2v ect ect all that wile maintaining same speed or rpm .. !? normal

[MetalMan]

i just did a driving log

my 02 sensor's voltage flikers ..


goes from lets say 0.6v to 0.1v to 0.8v back to 0.6 then 0.2v ect ect all that wile maintaining same speed or rpm .. !? normal

It's normal for O2 sensor voltage to fluctuate lean-to-rich and then rich-to-lean, which shows up as 0V to near 1V or anywhere in that range.

[The Overclocker]

but that must be on the first 02 sensor .. i just tough of that i didn't monitor the other one

its very confusing understanding what is what in vcds .. i'm still learning

is there any way some one could guide me on this

[The Overclocker]

what do you guys think i should do next ?

and is the pancake valve normal to breath from both ways ? how can i test it or know if its still good

[The Overclocker]

P1136 = Long Term Fuel Trim Additive: Bank 1 System too Lean
P1556 = Charge Pressure Control: Negative Deviation

The first code means you have a low MAF reading at idle. Usually due to a leak.
The second code is a low boost pressure code.



He is correct. That is way too much. But the idle (additive) trim is half the story. What is the part throttle (multiplicative) trim? That would be the number right beside the 14.8. That other number will help us internet-diagnose your car a little better.

As it stands, I can say you have a leak somewhere. Air is getting into the manifold at idle, but is bypassing the MAF. Could be in the Turbo Inlet Pipe, could be in any hose connected to the manifold. Or anywhere in between those 2 things.

You also have low boost. This could be due to the leak. The turbo could be perfect, but you are just leaking all the boost out of somewhere. So one leak could *potentially* explain both issues. It could be sucking air IN at idle, and the blowing air OUT when in boost. All from the same tear in a single hose. It could even be a hole in the intercooler.

BUT, if you were losing that much boost (which, to trigger a low boost code on an AEB, would have to be like...all of it) we should also see a VERY NEGATIVE part throttle (multiplicative) fuel trim. It should be adding fuel at idle, and then pulling it back at the top end. We don't know that yet until you get us the part throttle trim details. Not to mention you said you did a boost leak test and didn't find anything. So while this theory is neat, it may not explain your problem.

So you may have a different reason for no boost (ie: missing wastegate flapper, dead N75, etc.) and the wonky additive trim could be due to a vacuum-only leak that a boost leak test will never catch. Meaning a leak that is behind a check valve. Like a broken evap line or something.

So those are my 2 theories. 1 leak that explains both things, or 1 vacuum leak along with some kind of turbo/wastegate/control issue. The part throttle trim information would be helpful to narrow it down.

i'm really not sure on how to get thats information on vcds

too many options

and my n75 is new

[Avant Nate]

Yes pancake can flow both ways, but in reality is always under negative pressure. You need to inspect all vacuum lines, and the pcv system. See walky's post above, pretty much explains it all. Run a boost leak test. If the leak is in the pcv system, where you pressurize it may or not detect it.
Edit: lol, see you saw Walky's post,

[The Overclocker]

Yes pancake can flow both ways, but in reality is always under negative pressure. You need to inspect all vacuum lines, and the pcv system. See walky's post above, pretty much explains it all. Run a boost leak test. If the leak is in the pcv system, where you pressurize it may or not detect it.
Edit: lol, see you saw Walky's post,

if it does then i have to cancel my order ! i ordered one thinking pancake would be no good

[The Overclocker]

vcds is standing by for instructions ! i need this car boosting !

[The Overclocker]

02 sensor logs, before & after cat


Before Cat ---->

Second / Voltage








After Cat ----->


Second / Voltage











note that when you see the log writen 0 , its right after a WOT when i completely release the gaz pedal for the engine to resume idle

[MetalMan]

O2 sensor logs don't give us very useful data. The ECU uses the primary O2 sensor as a "watchdog" on fueling... so if it detects that the fuel mixture is too lean, it adds fuel. But it will always try to keep the mixture so that the O2 sensor reads between 0-1V.
Secondary (post-cat) O2 sensor is only used for emissions monitoring.

Try logging fuel correction trims while driving normally (non-boost), which is when the ECU will be in closed-loop fueling. I don't know which measuring block it is, but I think it should be in the 30's.

[gmx]

If you have VCDS, you've read enough which cable to get. You've probably come across Ross-Tech's own documentation - read it.
Block 032 for trims.

There is a rough test for the WG actuator/flapper operation. Without a boost gauge you shouldn't be doing it. Get it hooked up, then disconnect the WG-N75 line.

[The Overclocker]

UPDATE !!!

i installed a Boost gauge to know exactly whats going on with boost ...

im at 5 psi peaking at 6-7 psi ... should be at 18 psi ... im unitronic chipped ..

got that p1136 code again .. cleared it .. at idle im at 3.20G/S according to the mass air flow ... thats way to low .. should be around 15 g/s !?

should i still open the cat to see if the turbo's flap is still nicely shut and in place ? or is this my pancake valve doing this ? ?

i need to know i have a schedule at the shop today in 1 hour , if its now the wastegate valve inside the turbo please someone tell me so i make the guy do something else !



thank you !

waiting on some input

[MetalMan]

Glad you opted to use a boost gauge; we have a much better reference now.
At that boost level, you might not be in limp mode. So that may point to something mechanically preventing higher boost.

A quick test is to unplug the N75 valve's electrical connector. This will essentially only allow the turbo to boost to wastegate pressure, which should be 3-5psi. It's a quick and easy check.
You can also follow gmx's advice on basically what amounts to a wastegate test. Since you have a boost gauge you can back off the throttle if boost exceeds ~20psi (if boost reaches this level, the wastegate is fine).

got that p1136 code again .. cleared it .. at idle im at 3.20G/S according to the mass air flow ... thats way to low .. should be around 15 g/s !?

Is this in drive or park/neutral? In park/neutral, that's about right (3-5 g/s is normal).

[Avant Nate]

I don't think you would be able to get that much boost if your flapper wasn't there, itd be around 0.

[The Overclocker]

update


i took off the cat and the flap is still there and its preaty tight so thats good, and the cat looks in good shape as well


i even performed a smoke test leak and its not leaking anywhere ..

i went to check on the pancake valve i ordered and it performs like mine, if you blow both ways flow will pass true , so no point on changing that, i returned it

but wile we pulled out the cat and the 02 sensor .... i noticed something strange ....

the 02 sensor bong was 100% white .. why is that ?!

and the vag com reading are weird .. too much fluctuation .. , i will upload a video later of this ... its weird

and the knock sensor cyl #4 is weird .. all of cyl 1 , 2 , 3 are about in the 0.600v h +-, the cyl 4 0.950v is weird and when i rev it get even worst

[Avant Nate]

Inspect the PCV hoses coming out of the block. unscrew the coolant tank and lift it up a bit to gain better access.

[The Overclocker]

Inspect the PCV hoses coming out of the block. unscrew the coolant tank and lift it up a bit to gain better access.

i'm not even going to waist my time , the code came up again .. and p1136 = vacuum leak and i have no leak .. and p1136 = if no leak = pcv crank case ..


i'm going to order the tube coming out the crank case, the T , the pcv + the line from pcv to Y connector ... i'm donne fucking around ..

[The Overclocker]

[The Overclocker]