Strange low speed "chug"

Posts specific to the 2.5 litre turbo engine

Strange low speed "chug"

Postby flySTi » Sat Jul 23, 2016 1:09 am

While sitting in traffic today and slowly creeping along at 5km/h the car started chugging along somewhat half way between a top fuel dragster and a Harley softail. I stomped on the brakes to pull it up (mainly because I was laughing so hard I couldn't see) and then the brake pedal felt like a sponge cake. I slowly accelerated again and the lumpy chug was still there and so was the spongy brake pedal. By this time the a gap had opened up in front so I did what all god diagnostic mechanics would do and went WOT. It lagged to boost and then snapped my head off. :roll:
It seems ok now but can anyone tell me wtf that was.?
Stock + VF52 + AVO Dump + 3 port.
Ta.
User avatar
flySTi
 
Posts: 26
Joined: Sun Dec 09, 2012 9:44 pm
Car: Obsideon Black MY07 GT-Spec B Wagon
Real name: Darren

Re: Strange low speed "chug"

Postby flySTi » Mon Aug 01, 2016 9:27 pm

I can actually make this happen now. If i drive for 10 mins and push the ac button it does it immidiately. The car drives percectly without it. What happens to the engine when the ac is on. Something opens up and gets stuck!
Seriously what is happening.
User avatar
flySTi
 
Posts: 26
Joined: Sun Dec 09, 2012 9:44 pm
Car: Obsideon Black MY07 GT-Spec B Wagon
Real name: Darren

Re: Strange low speed "chug"

Postby flySTi » Sat Dec 24, 2016 2:07 am

It was obvious in the end. Logs showed something was pulling the timing. Heaps of it gone. Turns out the AC compressor is creating a knock. Every time it cycles on - knock knock. (its quite violent) What a joke. After an hour of driving with it off, pulls like a porn star.
Now I just need to get the AC compressor "fixed".
User avatar
flySTi
 
Posts: 26
Joined: Sun Dec 09, 2012 9:44 pm
Car: Obsideon Black MY07 GT-Spec B Wagon
Real name: Darren

Re: Strange low speed "chug"

Postby andy_mac » Sat Dec 24, 2016 2:05 pm

Hmmm mine does something similar when idling along in traffic or town with heaps of on/off light throttle. Always assumed there was just a heap of parasitic loss at low RPM's in these cars. Should probably do a few logs too to be sure.
2000 JDM Legacy B4 RSK - SOLD
2006 JDM Legacy BP5 GT Spec B wagon
2011 VW T5 van 2.0L of turbo diesel awesomeness
User avatar
andy_mac
 
Posts: 480
Joined: Sun Jan 19, 2014 2:30 pm
Location: Tauranga, New Zealand
Profile URL: viewtopic.php?f=10&t=30298

Re: Strange low speed "chug"

Postby flySTi » Sat Dec 24, 2016 4:02 pm

I just need to rewrite the knock threshold tables and should be good to go. Now I just need a dyno, oscilloscope and a real knock. I ain't getting that for xmas!
User avatar
flySTi
 
Posts: 26
Joined: Sun Dec 09, 2012 9:44 pm
Car: Obsideon Black MY07 GT-Spec B Wagon
Real name: Darren


Return to 2.5T engine specific

Who is online

Users browsing this forum: No registered users and 6 guests