MK5 Golf GTI
All Things Mk5 => How to Guides / Troubleshooting => Topic started by: bigmig95 on October 02, 2014, 01:43:01 pm
-
After a few pointers. Car had lack of boost and change in exhaust pitch when the last problem occured three weeks or so back, had Alex at AKS change the N75 valve and she's been running great since until this morning.
Lack of boost again :sad1:, slightly different feel to this issue than before the N75 was swapped. Just done a couple of 3rd gear accels with VCDS and noticed the pedal position is 100% but the throttle position is backing off.
Any pointers as to common causes of the throttle backing out on the TFSi even on 100% demand.
Car is 2005 Gti stage 1 REVO with Full milltek TBE and forge twintake.
Booked in for a remap in 3 weeks and this happens FFS. How to fall out of love with a car :sad1:
-
For Clarity this is my main area of concern
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2Fjj45%2Fgodsy1969%2FCapture2_zpsfabcf6e8.jpg&hash=7bde433ca313dc7bd836b9d47d1bf965f6990633)
-
Does she idle ok? Any errors?
I've read a number of threads regarding the throttle body but they also get surging.
-
Throttle body?
-
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Ffarm3.static.flickr.com%2F2706%2F5714519882_5c38bd5eb7_b.jpg&hash=a8c8a6782f50b977a786e32825cf46aee8c574c1)
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Ffarm3.static.flickr.com%2F2748%2F5713959495_3178eb414c_b.jpg&hash=efb02e009bf7e851d41b0e3204e66d6ac23c0503)
I'm probably wrong but isn't the Throttle drive angle sensor built into the throttle body?
-
Does she idle ok? Any errors?
I've read a number of threads regarding the throttle body but they also get surging.
Bloody car ran fine today :fighting:
No faults on VCDS, idles fine even when I had problems yesterday.
Only thing i know of that closes the throttle is left foot braking at that closes it completely AFAIK so that eliminates brake pedal switch as the throttles partially closing.
Could be throttle body Rich?.........any checks for this. ECU is seeing 100% demand from pedal.
IIRC the throttle body gives a couple of positional signals from potentimeters and the ECU uses them as a comparitor (correct me here, it's been a while since I had any electrical dealings with this motor) if there are any discrepancies outside normal running conditions it closes the throttle and throws up a MIL light. Problem is MIL light already on due to new Milltek sports cat (not remmed out yet)
To me it could be two areas if it's the throttle body. Motor drive to throttle plate or throttle position issues. Anyone know how do run any checks / adaptations etc to check the throttle body. Don't want to change it and fork out under pure guess work if I can help it. :happy2:
-
cant you monitor
Sender 2 for -
Acc. Pedal Pos.
Throttle Drive -
Angle Sensor 1
with ignition on but engine off?
http://wiki.ross-tech.com/wiki/index.php/Throttle_Body_Alignment_(TBA)
-
Thanks Dazza. Will look it the monitoring of those parameters later. Adaption process all good according to software
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2Fjj45%2Fgodsy1969%2FCapturexxx_zps83fda780.jpg&hash=d10c5fcbbae835f84c9d4fd38831785f94a055ef)
Only issue is it looks and intermittant fault at the moment which if it carried on is gonna prove a ball ache to pin down.
-
I think the TB throws up a G88 sensor fault.(off the top of my head)
-
Thanks Dazza. Will look it the monitoring of those parameters later. Adaption process all good according to software
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2Fjj45%2Fgodsy1969%2FCapturexxx_zps83fda780.jpg&hash=d10c5fcbbae835f84c9d4fd38831785f94a055ef)
Only issue is it looks and intermittant fault at the moment which if it carried on is gonna prove a ball ache to pin down.
Just wait and see if it happens again.
-
Problem seems to be changing slightly. More consistant issues over the weekend and it feels similar to what I had previously so the n75 swap may have been a red herring. Just done a couple of pulls to check the boost and timing. Boost seems very on off and thats proven by the specified v actual below, airflow into the engine is similar which may be due to the turbo demand being spikey also.
Car idles fine and behaves as normal off boost.
Boost specified v Actual
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2Fjj45%2Fgodsy1969%2Fboostlog1_zpsd2390fd3.jpg&hash=d2225c812f755f17a769a9f49575b37ac6532d55)
Mass air flow from 2 runs.
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2Fjj45%2Fgodsy1969%2Fairflowlog_zpsba38ea04.jpg&hash=60e65ef708d488b295623083e3c6b48ad7284e4a)
Apologies @dazza (http://www.mk5golfgti.co.uk/forum/index.php?action=profile;u=10457) for not using your fancy import function for the data. Can't get it to run properly (probably me bud :grin:)
-
It's not you mate it wont show in preview. And not set up for multiple logs in one file. Next time post it any way send me the link so i can take a look.
-
Well after a week of thinking about it and chatting with a couple of guys one of the areas to investigate was the theory that there must be some kind of torque cut closing the throttle on this one. I'd eliminated any interference of the ABS or brake system and no fault codes were being flagged up so pretty unlikely to be an electrical fault with the throttle body.
I decided to plug in my REVO SPS switch but now connected to the PC so I could actually see the setting rather than relying upon the switch to do its job.
Acquiring the settings my numbers were B9,T9,F9 !!!!!!!!! And before you ask these numbers are not even set on my switch. I then set them at the original numbers that were set by REVO and the car performs as it should. :happy2: It's weird that the SPS (well the one I have) is a bit hit or miss and occassionally decides to put random numbers into the ECU :fighting:
The intermittant issue here was quite likely to have been I'd been running very close to the torque limit that has been set and only going over it occassionally, with the recent colder weather the issue had become more regular with the cooler intake temps and subsequent increases in torque it kind of made sense. You should be able to see from the logs @dazza (http://www.mk5golfgti.co.uk/forum/index.php?action=profile;u=10457) kindly put up that the throttle closing starts at around peak torque area.
Guess the moral of the story for me is I won't be relying on my SPS to put in the numbers its had preset on it, I'll always use the PC through the SPS to set the numbers