Boost issue, Vag log attached. Please help :)

[mxadam]

Hey all, Ive had my car of the road for 8 months and now I have a boost issue. The issue is that when max psi is reached (20psi) it instantly drops to around 10psi. And it feels very weak. In third it will hold 20psi but not for very long and only in very low revs. Car hardly moves. Thinking it could be the n75, maf looks fine from logs. topping out at 90 instead of 100 in third.

Log:

http://imagebin.org/212491

Anything else I should log which could help?

Hope someone can help, Cheers

[mxadam]

the position of the actuator rod on new turbo is about 1cm in from the end ( loosest ) on my old turbo the wastegate was cranked and was around 1cm from other end, could this be the cause? , the idiots have sprayed the threads after fitting nuts so have no idea howto get them loose without the shaft turning

[mxadam]

just tried the actuator, made absolutely no difference

[groggory]

Please post a list of all non-stock engine mods.

Thanks.

Also, please post actual data up next time. I had to transcribe the data from that picture.





http://dl.dropbox.com/u/9842192/mxadam/Log.xls

[mxadam]

fmic,silicone intake + cone filter, forge 007 dv and remap (stock n75c)

[groggory]

I'd do a seafoam exhaust leak test.

Seafoam your intake. Have one friend hold a rag over your tailpipe to create some back pressure. Have another friend keep the revs up to 2k or so. You look for any pre-o2 exhaust leaks. In particular, look for any pre-turbine exhaust leaks.

Your boost curve seems to come on pretty late for a k03s turbo. This makes me think that there are some gases escaping from behind the turbine. Also, what remap do you have? Why would a remap not ask for any boost before 3000 RPM? The k03s can be mostly spooled up by that time! You are missing out on the low RPM goodness of the stock turbo with that remap.

Also, push on the wastegate actuator and ensure that the wastegate rod is moving properly. It shouldn't be jammed up. It should crack at around 5 PSI on a stock k03s.

...I'm kinda wondering why you're boosting so much higher than your specified boost curve. If you're using an n75 you should be following the computer's boost curve closer unless your wastegate has been cranked or something like that.

[mxadam]

cheers groggory ill try the seafoam. I tried the wastegate in centre and 1cm ish in from end and still acts the same.

I dont know who chipped the car as was done before buying. Ever since then it boosted 20psi all day long untill around 5k then tapered of. Now it seems the ecu isnt even requesting 20psi at any point. That spike is to where it should be. What could cause the ecu to request lower boost

[mxadam]

forgot to say i tried an mbc earlier and it would only let me goto 18 for some reason (****ty cheap mbc for testing) and it hit 18 and stayed there as it should. This makes me think its the N75, but then that wouldnt cause the ecu to request lower boost than it should be right?

[groggory]

cheers groggory ill try the seafoam. I tried the wastegate in centre and 1cm ish in from end and still acts the same.

I dont know who chipped the car as was done before buying. Ever since then it boosted 20psi all day long untill around 5k then tapered of. Now it seems the ecu isnt even requesting 20psi at any point. That spike is to where it should be. What could cause the ecu to request lower boost

You don't know for a fact that the ECU has EVER requested 20 PSI boost. All you know is that you were seeing 20 PSI boost.

First, do the seafoam test and be certain there are no pre-o2 leaks. ZERO!!!

You should adjust the wastegate so that the actuator STARTS to move at 5 PSI. Slowly apply up to 5 PSI of pressure to the wastegate via a regulated source. Watch the wastegate actuator as you do this. If it cracks too early, then crank the wastegate a bit. If it cracks too late (higher PSI) then back off the wastegate rod a bit.

Also, your software has a strange boost curve. It seems like you have software written to minimize torque spike for some reason. Personally, I would get your car rechipped to a well regarded tune.

[mxadam]

surely if it was an exhaust leak the mbc wouldnt of been able to hold it at 18psi till 5k, it would drop the same?

[groggory]

No, not surely

[mxadam]

hey all, just got a full leak check on boost/vac/exhaust and no issues. Car seems to be running rich (popping and banging a lot). I think the o2 sensors may be at fault.

Block

Block 030 Oxygen Sensor Regulation - Fluctuates between 000 and 100 (exact numbers)

Block 033 Pre-Cat Oxygen Sensor Control - Doesnt fluctuate at all, just stays on 0.00??

For some reason the tests wouldnt work when i pressed brake pedal in?

Could the pre-cat sensor be the cause here?

cheers

[groggory]

hey all, just got a full leak check on boost/vac/exhaust and no issues. Car seems to be running rich (popping and banging a lot). I think the o2 sensors may be at fault.

Block

Block 030 Oxygen Sensor Regulation - Fluctuates between 000 and 100 (exact numbers)

Block 033 Pre-Cat Oxygen Sensor Control - Doesnt fluctuate at all, just stays on 0.00??

For some reason the tests wouldnt work when i pressed brake pedal in?

Could the pre-cat sensor be the cause here?

cheers

Would you mind posting the data up instead of just your interpretation of the data?

[mxadam]

do i just log like usual for a sec as its only idling? didnt think log would be needed, the second block just stays on 0. no data will show any diff. The first just go, 000 then few seconds later 100 then back to 000 then few seconds later the second does the same , and it just loops like that.

[groggory]

do i just log like usual for a sec as its only idling? didnt think log would be needed, the second block just stays on 0. no data will show any diff. The first just go, 000 then few seconds later 100 then back to 000 then few seconds later the second does the same , and it just loops like that.

What numbers are in your block 032?

What is your block 031 at idle?

What is your block 001 at idle?

A 3rd gear pull from 2k-6k of block 001-031-032 would be helpful


....

The reason I asked for your exact data was that your analysis didn't make sense to me. Block 030 has two values. Block 033 has two values. Your explanation sounds like you're only looking at one value. I didn't understand, so I felt the data would explain it more clearly.

[mxadam]

heres a bit of the data you needed. I done this before seeing your post. This was weird, car was warm the whole time. For about 5 minutes the numbers were as I said (wrong) then I done a second log and they were the same but after a few minutes the numbers changed and the precat became active. As said the car was fully hot the whole time.

I will do the other logs tomorow on way home from work

You will see it in this log

http://www.filedropper.com/idlelog2

[mxadam]

do you want me to do a quick log of 001 on idle?

[groggory]

do you want me to do a quick log of 001 on idle?

What is your block 032 at idle?

What is your block 031 at idle?

What is your block 001 at idle?

A 3rd gear pull from 2k-6k of block 001-031-032 would be helpful

[mxadam]

heres the log you need. I cant do the log while driving untill tommorow (im in uk, tomorow i work till late so roads will be empty. plus its raining hard). Again it took ages for the sensor to become active.

http://www.filedropper.com/idlelog4

[groggory]

heres the log you need. I cant do the log while driving untill tommorow (im in uk, tomorow i work till late so roads will be empty. plus its raining hard). Again it took ages for the sensor to become active.

http://www.filedropper.com/idlelog4

It looks like your car was warming up through that log...

Here's my notes...

* The log starts with your coolant around 77C and tapers up to your coolant around 90C. You are going to run rich while the car is warming up. The engine does this to help your car warm up faster. Your car is 'cold' when it's below 80C coolant temp.

* Once you've reached 80C your lambda control didn't kick in for another 3 minutes.

* Your cat never came to temperature as far as the computer is concerned. This was after about 7.5 minutes. This is too long. I'm wondering if your cat is bad or your rear o2 sensor is bad.

* Once you're reached around 85C your car is in closed loop, as can be recognized by the lambda adjustment in block 001. This is good. This means your front o2 is working.

* Your block 032 fuel trims are withing +/- 5%, which is GOOD! This means your car is running pretty darn well.

* At idle your block 031 is showing roughly 14.7:1 once in closed loop, which is good. However, it is stumbling around. You say you checked for vac and exhaust leaks, and I hope you did a good job, because those can definitely cause this problem. I would try unplugging the MAF and seeing if the block 031/1 values stop stumbling with the MAF removed. This would point to a bad/ dirty MAF. Also, I'd pull your plugs, take a picture of them, and check their gaps. Please take a picture of your spark plugs w/ no flash, on a white background, in good lighting. Also, check gaps. Report back on this.


So in short, unplug your MAF.

Do another set of 001-031-032 idle logs for 10 minutes.

Pull spark plugs, take a picture of them (in cylinder order). Check gaps on all of them. Post up pictures and report gaps.

We'll do some load testing once the rain stops for ya.

[mxadam]

cheers for all the info greggory, I am clueless when it comes to finding problems. I will have to do the log for idle with maf disconnected tommorow as its 11pm here, dont want to annoy the neighbors

The maf was giving me issues when I put the turbo on (very limpy idle). I cleaned it and the idle disappeared. May still be buggered tho (the maf was brand new from dealer then sat in garage for a good year)

The cat was a new cat when I put the turbo on. Did look strange its like 2 little bulges instead of 1 long wider cat. Supposidly the right cat for the car tho but def doesnt look like the stock one, thought it may be an updated cat?

I changed the spark plugs and gapped them to 0.28 about a week ago to see if that was the problem, but nothing changed. Did feel slightly smoother but maybe just me

The leak tests were done by a friend at his garage, I wasnt there at the time. If nothing else comes up I will get him to do it again while I watch.

[groggory]

cheers for all the info greggory, I am clueless when it comes to finding problems. I will have to do the log for idle with maf disconnected tommorow as its 11pm here, dont want to annoy the neighbors

The maf was giving me issues when I put the turbo on (very limpy idle). I cleaned it and the idle disappeared. May still be buggered tho (the maf was brand new from dealer then sat in garage for a good year)

The cat was a new cat when I put the turbo on. Did look strange its like 2 little bulges instead of 1 long wider cat. Supposidly the right cat for the car tho but def doesnt look like the stock one, thought it may be an updated cat?

I changed the spark plugs and gapped them to 0.28 about a week ago to see if that was the problem, but nothing changed. Did feel slightly smoother but maybe just me

The leak tests were done by a friend at his garage, I wasnt there at the time. If nothing else comes up I will get him to do it again while I watch.

The only leak tests that I've found to work are:

1) Pressure test the intake to around 10 PSI using the method at the top of the forum

2) Seafoam test the exhaust + the rag trick.

Commercial smoke machines also work well, but they only get I'd say 90% of leaks.

Spraying carb cleaner and whatnot on the lines is a crap shoot. Sometimes it works, sometimes it doesn't.

These cars are picky about leaks. Before you go down the rabbit hole, be 110% certain it's not a leak first.

[mxadam]

hey, here are the 2 files

http://www.filedropper.com/run
http://www.filedropper.com/idlenomaf

while cruising around i was watching the lamda and it was bouncing all over the place 0 > -10+ , it was all over the place

sorry i dont know how to do those graphs you did

[mxadam]

if you think this still looks like a leak ill take it to somewhere with a proper smoke tester

[groggory]

if you think this still looks like a leak ill take it to somewhere with a proper smoke tester

You're lambda correction is a bit heavy on that run and your AFR is always lower than your AFR request.

I have a gut feeling you have a leak. You just need to use methods to find the leak that are standard and work.

[mxadam]

ok cheers grog ill take it to somewhere else with a smoke tester to get it rechecked, have no idea what my mate was doing if they find a leak

cheers mate will update after

[groggory]

ok cheers grog ill take it to somewhere else with a smoke tester to get it rechecked, have no idea what my mate was doing if they find a leak

cheers mate will update after

There are nice tutorials stickied at the top of the forum with how to do both of these tests. It's not rocket science...

For the intake:

1) make a pressure test coupling
2) Remove your air box
3) clamp off your pcv hose just before the TIP
4) Apply 10 PSI regulated pressure and listen for leaks. Feel free to use a sprayer to look for leaks.

For the exhaust:

You guys in the UK don't have seafoam. But I know you have something like seafoam...

1) Have a friend hold the rpm's at 2k
2) suck about 8 oz of 'seafoam' into the intake via a vac hose slowly without stalling the engine
3) let the car sit for 5 minutes
4) fire the car back up. Have a friend hold a rag over the tailpipe to create some extra pressure.
5) look and feel aroudn the back of the engine with a flashlight and mirror to find the leaks. The car will be smoking, so you just have to find out where the smoke is coming out from

...easy procedures.

[mxadam]

hey just an update. done smoke test again today (he did it from charge pipe last time!!) smoke came out of the seal on the silencer on the turbo, like this http://forums.vwvortex.com/showthrea...ilencer-outlet

gotta get that welded and then we will see, was hard to get pressure in there with it pouring out of that seal

[mxadam]

hey, ive made a pressure tester to stop paying for someone else to do it

last time we done it we didnt clamp of pcv as ive removed it and use a catch can. We heard oil bubbling in the oil sump. Which part do I clamp, the outlet on the catch can or the outlet on the rocker cover. would the crankcase pressurize if clamp the outlet on catch can?

cheers

[groggory]

hey, ive made a pressure tester to stop paying for someone else to do it

last time we done it we didnt clamp of pcv as ive removed it and use a catch can. We heard oil bubbling in the oil sump. Which part do I clamp, the outlet on the catch can or the outlet on the rocker cover. would the crankcase pressurize if clamp the outlet on catch can?

cheers

If you have a recirc catch can, clamp the outlet of the catch can.

[mxadam]

Hey. Car was in for mot today, no leaks at all. Changed maf as it was reading low but no change, changed n75 still no change. Only really Evap, o2's and map sensor or worst case car running without turbo working for a couple years has made ecu loose tune? It lost the key and alarm and had to be re programmed, not sure if this is pos?

Where would you go from here? Driving me crazy lol

[mxadam]

Oh yeah I gave it some in 3rd earlier. Full boost 2.5k then down to 10psi at 3k!

[mxadam]

And if wastegate is run strait from pressure source it boosts to 5psi only. So this mean actuator is working fine?

[groggory]

And if wastegate is run strait from pressure source it boosts to 5psi only. So this mean actuator is working fine?

If your wastegate actuator is connected directly to your charge pipe and you're only boosting 5psi, then your wastegate is shot.

[mxadam]

something which may help. I can do this at any point in rev rage. U can boost 2k-3k and get the drop, back off accelerator and the boost will peg 20psi then drop instantly to 10 again. U can do it at 5k rpm and same still happens.