NefMoto

Technical => Diagnostics => Topic started by: hunter3899 on April 02, 2019, 01:16:45 AM



Title: Large amount of timing pull at the start of throttle input then tapers off.
Post by: hunter3899 on April 02, 2019, 01:16:45 AM
Hello everyone.

I was wondering if anyone has had an issue that seems to have popped up after tuning my 2008 VW GTI FSI. I get a weird large spike in timing pull whenever the throttle is applied especially in low rpms but drastically tapers off when I hold that throttle position so the load isn’t really changing. Another possibly related issue is when cruising at highway speeds it will also go into full timing retard (-12) when very small throttle input is applied. Full throttle power runs from above 3,500 rpm don’t have any or very little timing pull. Just trying to decide if the timing is too aggressive in the low load ranges or if I’m having an issues like false knock or even possibly a maf issue. I have been pretty stumped on this issue for a few months now, any help would be appreciated.


Title: Re: Large amount of timing pull at the start of throttle input then tapers off.
Post by: adam- on April 02, 2019, 01:49:55 AM
What fuel?  What load?  What timing request?  Logs?  Who did the file?  Try adding more fuel?  AIT?  Bad knock sensor?


Title: Re: Large amount of timing pull at the start of throttle input then tapers off.
Post by: hunter3899 on April 03, 2019, 01:04:25 AM
Fuel 91 octane, Load usually around 30, timing around normally 30 degrees btdc  after initial corrections, will post logs soon, my file but using eurodyne maestro, lambda at .93, Air intake temp is irreleavant, no codes for a bad knock sensor or short to ground but knock sensor is in an unknown. All I'm trying to do is find possible causes from others experience to go in a more direct route of diagnosing the issue instead of chasing my tail like I have for 6 months. I know there is a lot of variables that effect this issue just wondering if anyone else has fought a similar issue. The timing pull goes away as load increases after 30. Thanks for the reply.


Title: Re: Large amount of timing pull at the start of throttle input then tapers off.
Post by: Blazius on April 03, 2019, 02:08:09 AM
Fuel 91 octane, Load usually around 30, timing around normally 30 degrees btdc  after initial corrections, will post logs soon, my file but using eurodyne maestro, lambda at .93, Air intake temp is irreleavant, no codes for a bad knock sensor or short to ground but knock sensor is in an unknown. All I'm trying to do is find possible causes from others experience to go in a more direct route of diagnosing the issue instead of chasing my tail like I have for 6 months. I know there is a lot of variables that effect this issue just wondering if anyone else has fought a similar issue. The timing pull goes away as load increases after 30. Thanks for the reply.


air intake temp is not irrelevant, it reduces timing based on IAT, also 30 degreees on 91 octane and that lambda  is wayyyyyyyyyyyy too much,..


Title: Re: Large amount of timing pull at the start of throttle input then tapers off.
Post by: adam- on April 03, 2019, 03:05:53 AM
30 degrees btdc  after initial corrections,
After corrections?  So it's even higher at cruise?

Air intake temp is irreleavant
It's not.  Heatsoaked manifold and then high load with no chance to cool?  It'll knock.

knock sensor is in an unknown.
Too many unknowns.

I know there is a lot of variables that effect this issue just wondering if anyone else has fought a similar issue.
Could be solved with a log and not 6 months.

The timing pull goes away as load increases after 30. Thanks for the reply.
Probably because timing request gets better.  % tuning?


Title: Re: Large amount of timing pull at the start of throttle input then tapers off.
Post by: fukenbroken on April 03, 2019, 03:10:25 AM
91 octane should not be used on turbocharged engine at all


Title: Re: Large amount of timing pull at the start of throttle input then tapers off.
Post by: hunter3899 on April 03, 2019, 09:39:34 AM

air intake temp is not irrelevant, it reduces timing based on IAT, also 30 degreees on 91 octane and that lambda  is wayyyyyyyyyyyy too much,..

By saying air intake is irrelevant im saying the timing pull does not change whether its -15f to 105f same amount of timing pull. the tune is running 91 at 5000 ft altitude so air density is significantly lower and 91 is all that is offered at this elevation unless your buying 50 gallons at a fuel distributer.


Title: Re: Large amount of timing pull at the start of throttle input then tapers off.
Post by: hunter3899 on April 03, 2019, 09:59:39 AM
After corrections?  So it's even higher at cruise?
It's not.  Heatsoaked manifold and then high load with no chance to cool?  It'll knock.
Too many unknowns.
Could be solved with a log and not 6 months.
Probably because timing request gets better.  % tuning?

Yes after corrections, the interesting thing about that is the timing maps haven't been changed from the base file I received from Eurodyne at all. In the low load like 30% in the optimal timing maps its requesting about 35 to 39 degrees btdc. Which is supposedly fairly conservative for a direct injection setup.

I have logged it and it tells me at around 30% load  it pulls -10 (KW*) at any point along the rpm when the throttle is opened up until 6000 rpm. Possibly might need to log the knock sensor V because I didn't run that in the log but it may not be that important to know the V because it probably wont tell me the if the sensor is functioning properly.





Title: Re: Large amount of timing pull at the start of throttle input then tapers off.
Post by: hunter3899 on April 03, 2019, 10:02:42 AM
91 octane should not be used on turbocharged engine at all

The car runs on methanol injection as well but for this purpose its not useful because at the load i'm getting the issues i'm not even in boost, still in 15 in/hg at the manifold. It runs fine at WOT.


Title: Re: Large amount of timing pull at the start of throttle input then tapers off.
Post by: hunter3899 on April 03, 2019, 10:28:07 AM
Will post logs soon, Windows had a melt down on my laptop and had to reinstall everything. Thanks for the replies.


Title: Re: Large amount of timing pull at the start of throttle input then tapers off.
Post by: vwaudiguy on April 03, 2019, 11:25:26 AM
I've seen what Hunter is describing. It was so long ago, I forgot what it was, but I believe it was on an MED9 Audi with an automatic...


Title: Re: Large amount of timing pull at the start of throttle input then tapers off.
Post by: hunter3899 on April 03, 2019, 11:39:42 AM
yep im running med9.1 with a dsg trans and k04 turbo.


Title: Re: Large amount of timing pull at the start of throttle input then tapers off.
Post by: Blazius on April 03, 2019, 12:01:06 PM
Huh interesting, in/hg thats something I havent heard in a while :D


Title: Re: Large amount of timing pull at the start of throttle input then tapers off.
Post by: hunter3899 on April 06, 2019, 10:40:58 PM
this is a narrow window of the occurrence on the log. I cant see anything out of the ordinary imho. Any info would be great.