Cleaned MAF, and car is slow again :(

[dylan8]

Maybe silly question, but has anything other then the MAF been checked? Has your fuel economy gone up?

[McDub]

Maybe silly question, but has anything other then the MAF been checked? Has your fuel economy gone up?

a brief vag-com check, that's about it.
and yes fuel economy does seem like it went up actually, but i don't have a good comparison of this because i never drove it slowly after i got it chipped, so this may or may not mean anything.
only comparison i have is pre chip to work i could get low-mid 7L/100km, and i tried a few slow runs after i stuffed around with the maf, and i can't get it below 8.
but that could simply be because of the re-map. or i am still driving quicker.

[dylan8]

when you disconnected the battery to refresh the ecu, did you notice it drive ok for the first 5mins, then go back to sluggish? probably to late to ask now. reason is, i replaced MAF, o2 sensor, temp sensor, and one other part i cant remember the name of, they didn't show up as being faulty on the vagcom or whatever my mechanic has. just showed there was a fault with my rear sensor in the exhaust system. (something the 2lt Bora doesnt even have!). this then lead to a fault being logged, and fuel usage going up.
So what im trying to say is it could be many parts and it may not log a fault under the right one.
Thats probably not bad fuel usuage for a gti (as far as im aware)...
How about your temperature guage? does it read right on 90 after 10mins or so or driving?

[McDub]

hmmm can't say i noticed it change after 5 minutes, though it does seem to have gotten worse the last few days but that could be in my head, not sure.
well that's comforting that they don't log errors properly! sounds like this may be a timely/costly problem to diagnose...
and yeah everything else seems fine, temperature goes to 90, idles at around 8300rpm...
although once again i may be imagining it, but a couple times the past few days, i have felt a small surge/bump in power delivery while accelerating very gradually, as though the fuel delievery was being messed up... but this could just be me noticing things that aren't there as i'm paying more attention to how the car is running!

[dylan8]

hmmm can't say i noticed it change after 5 minutes, though it does seem to have gotten worse the last few days but that could be in my head, not sure.
well that's comforting that they don't log errors properly! sounds like this may be a timely/costly problem to diagnose...
and yeah everything else seems fine, temperature goes to 90, idles at around 8300rpm...
although once again i may be imagining it, but a couple times the past few days, i have felt a small surge/bump while accelerating very gradually, as though the fuel delievery was being messed up... but this could just be me noticing things that aren't there as i'm paying more attention to how the car is running!

idles at 8300rpm...?

what yr and how many km? haha that sucks when you dont know if its just in your mind or not, do that all the time.

Dont know about the surging, i had big power downs with a broken MAF, would take off, and it was like your stalling, but it didnt shake etc, not fun when crossing busy roads etc

[McDub]

yeah i think 8000 is normal for the car, it might be just a touch higher than it should but has been like that since i got it at 85k, and its now at 105k. Year 03/04
edit: haha i just realised what i was doing. i obiously meant 830 and 800rpm...

[kaneda]

Have you preasure tested the intake track to see if there are any leaks ?
Cheep , easy and quick to do .............
Ive had a few issues of late and found 2 leaks in areas i wasnt even looking in just by slapping together a tester from bits around the garage and minute mend .

[McDub]

Have you preasure tested the intake track to see if there are any leaks ?
Cheep , easy and quick to do .............
Ive had a few issues of late and found 2 leaks in areas i wasnt even looking in just by slapping together a tester from bits around the garage and minute mend .

that's probably a decent possibility, it is what i suggested might be the problem in the OP, but no-one seemed to comment on it. As the only thing i touched was the air intake, naturally you would think this is where i introduced a problem?
saying that, the other possibility is that after playing around with the MAF, it made me pay attention to the cars performance, meaning it actually could have been running bad for say a week and i could have been oblivious to it IYKWIM

so maybe it's sucking in un-metered air, meaning it's running lean...
i don't exactly have the means of doing this test though (well i probably do but this whole thing has put me off touching my cars organs!)
but i've got some parts coming from ecs so i plan to take the car for some work very soon, will let you know how it goes.
(14lbs clutch, R1 d.valve, boost guage)

[McDub]

finnally got around to putting the car in for a service!

can't wait to get it, will post back hopefully late next week with positive news!

[McDub]

i might just be talking to myself now...

picked up car this morning. really hard to tell if performance has changed, partly cos i've been driving a diesel ute to work for the past week, but also most of my attention is drawn to all the cabin sound as a result of i'm guessing a combination of the single mass flywheel, and the yellow BFI dogbone inserts. it seems to just find the harmonic frequency of the cabin and *****s me a little! But at the same time i sort of like how i can feel the engine working... just not the feel of it between 1000-2000rpm... eeek

will do some more sprint times to see if the times are changed.

oh and no major problems were found, other than a faulty coolant sensor. sparkies were replaced too, they were still the originals from the factory. looked like they had been running rich, likely due to said faulty sensor. car was driven and logged and everything seemed in order.

i'm getting a new N75 valve put in in a couple days so will see if that has any effect also.

still noticed my idle drop to 500-600 rpm very momentarily when i was sitting at the lights this avo. no idea why it's doing that, it's probalby the 10th time i've noticed it do it now.
and yep the throttle body was cleaned incase someone was going to suggest cleaning it.

[McDub]

Finnally got around to doing 0-100 sprint times.

pre-chip: 8.7 sec
post-chip: 7.3 sec
post-maf replacement: 8.0 sec

So it's sitting somewhere in the middle.

ok since then i've had it looked at reasonably thoroughly, replaced diverter valve, replaced the N75 (J type), new sparkies, cleaned throttle body, new coolant temp sensor cos old one was apparently faulty, and the time is still:

post-service: 8.0 sec

so it didn't improve it the slightest bit!
this is really sh**ting me big time. what the hell is going on???

If it's of any use, the unitronic program is supposed to run the car at a nominal 16psi.
Reading off my crappy NewSouth guage, in 1st it gets to 10psi, in 2nd it gets to 15psi, and in 5th it actually gets up to 18psi and sometimes a little more!

Just so much about my car is shi77ing me right now. For one the installation of the boost guage seems to have stuffed up the Dim circuit on my dash, the new single mass flywheel n clutch seems to chatter when it starts to engage under 2000rpm which is moderately annoying... We took the hard dogbone bushes out and returned to stock cos it was terrible IMO.
the boost guage needle vibrates at max boost which is an easy fix but i havn't got round to it yet...
my gearbox is di*ky and rough between gears and sometimes even at the lights it physically won't go into first...
i just want someone to steal the car so i can start over!


I'm gonna get it inspected on a dyno to see if that will help shine some light on the matter...

[fuzion]

ok since then i've had it looked at reasonably thoroughly, replaced diverter valve, replaced the N75 (J type), new sparkies, cleaned throttle body, new coolant temp sensor cos old one was apparently faulty, and the time is still:

post-service: 8.0 sec

so it didn't improve it the slightest bit!
this is really sh**ting me big time. what the hell is going on???

If it's of any use, the unitronic program is supposed to run the car at a nominal 16psi.
Reading off my crappy NewSouth guage, in 1st it gets to 10psi, in 2nd it gets to 15psi, and in 5th it actually gets up to 18psi and sometimes a little more!

Just so much about my car is shi77ing me right now. For one the installation of the boost guage seems to have stuffed up the Dim circuit on my dash, the new single mass flywheel n clutch seems to chatter when it starts to engage under 2000rpm which is moderately annoying... We took the hard donbone bushes out and returned to stock cos it was terrible IMO.
the boost guage needle vibrates at max boost which is an easy fix but i havn't got round to it yet...
my gearbox is di*ky and rough between gears and sometimes even at the lights if physically won't go into first...
i just want someone to steal the car so i can start over!


I'm gonna get it inspected on a dyno to see if that will help shine some light on the matter...

anyone reading this?

did you reset your throttle body firstly through vagcom/vchecker?

have you checked all your hoses? the vacuum hose going to the fpr tends to be very brittle and leaks/breaks.

did you install the boost gauge correctly with no boost leaks?

are you sure you put the right spark plugs in?

oh and regardless what ive read or heard, maf needs to be replaced usually not cleaned. and do you have a oil based filter?

[Golf Loon]

Also worth checking the O2 sensor as a stuffed MAF often finishes them off, which will make the car run rough and slow.

Sounds like you have been taking it to the wrong people mate, get someone competent who understands VWs to check it over.

[McDub]

fuzion, i assume it's been reset etc... though i thought that was just for DBW.
hoses havn't been inspected properly, however no obvious leaks can be heard. and yes no leaks with boost guage... well apart from when a hose came off while driving resulting in the guage reading atmospheric...
sparkies were put in after problems happened so their not the problem, but yes they would be the correct ones
Golf Loon, yes the O2 sensor has been considered. it is going to be looked at again though. unfortunately when i got the car dynoed today, we couldn't get a readout from the OBDII port to compare with the figures from the probe.

so yeah i got it dynoed today at MRC in Castle Hill because it was near work and someone recommended them

http://www.mrcdyno.com.au/

assuming generous 30% losses for the stock 110kw motor, you would get 77kw atw
with the unitronic program that claims 145kw in the states, you would get 102kw
And as i expected, i got somewhere in the middle:

All figures are plotted with RPM on the X-axis...

KW and Nm (i think the torque is an estimate at the flywheel, no idea why...)


Boost and AFR


KW and AFR


And here, the lead to the N75J was unplugged because he wanted to see how it would react under just the normal spring force of the actuator... cos i think he thought it was loosing too much boost, but may not of realised at the time that it's likely just because it's a small turbo...


as you can see, it seems to be running very rich at high rpm's.
the old spark plugs where quite black so that agrees with that i suppose.
and the power curve looks very rough too.
this was the 3rd run. the first run the power curve looked a lot smoother and it got 94kw. 2nd run it got 91.

so from here, the O2 sensor is going to be looked at again, these images are gonna be sent to Unitronic in Canada to see if they can shine any light on the matter, if not much happens of that mark from mrc suggested an exhaust back pressure test incase the cat is stuffed... and yeah that's about it. but he reckoned it's more likely a problem with the program (as i have wondered all along...), but time will tell... hopefully

[kaneda]

Sure its not a boost leak ?
Kinda strange how the boost stays so level across the range as you would expect it to go up n tapper off .
Running rich mean there is too much fuel but maybe its not enough air ?
Did you do a leak test ,only takes a few minutes and can save a lot of hasel
.