Ducati Monster Forum

Moto Board => Tech => Topic started by: EEL on March 20, 2015, 09:39:17 AM

Title: Advanced Fueling Issue - Exhaust reversion?? - Need advice
Post by: EEL on March 20, 2015, 09:39:17 AM
Background info:

Intake mods performed:
K&N Air Filter
MWR Power up kit w/ green unifilter replacement

Exhaust mods performed:
SC Project GP-M2 slip on
Completely removed flapper valve from exhaust (this includes leftover bits inside exhaust after servo motor is removed)

ECU Mods
MW Flashed Rexxer to remove O2 sensors and servo and updated to a performance exhaust and intake map
PC-V
Autotune

ISSUE:
By running the autotune for my current setup I was able to determine that even the updated performance rexxer map was way too lean for the MWR power up kit. The bike pulled almost 30% more fuel at certain low RPM and low throttle positions because of the Power up kit. Autotune cured most of the popping but I still have some popping at:

1) From full throttle to zero throttle
2) From zero throttle to just opening the throttle up at cruise range (2% or 5%) throttle

This is what I need help with.

I think item 1 is exhaust reversion. But I'm not sure how to cure it? Dynojet generally says to leave the 0, 2% & half of 5% columns zero on the AFR table but considering the amount of open airbox present, I'm wondering if I need to go the other way and fill in the tables to a pseudo lean condition?

With the autotune, I can poke around to my hearts content but hoping I can get the braintrust to provide a clearer direction on how to proceed so that I can reduce the overall tinkering time.
Title: Re: Advanced Fueling Issue - Exhaust reversion?? - Need advice
Post by: Dirty Duc on March 20, 2015, 09:54:06 AM
Those transitions can be hard to trace without monitoring intake vacuum.  

Does it happen at all RPMs?  What do you consider "cruise range" RPM?

Exhaust reversion is unlikely to affect O2 sensors in the stock location with the rest of a system on.  We had issues at Bonneville that I blamed partly on there being something like an inch between the sensor and the end of the pipe.
Title: Re: Advanced Fueling Issue - Exhaust reversion?? - Need advice
Post by: EEL on March 20, 2015, 10:11:26 AM
Thank you for the insight.

It does not seem to happen at all RPM. I think its primarily low RPM throttle shutoff. It seems to kick in at around 5k to 2k with the throttle off. I will take a test ride and check it out

Aas for the the cruise. I am able to pinpoint that more specifically its seems to happen when I get off the throttle in traffic and then just barely get back on. RPM is about 3900 - 4100.

Bike pops lightly.

THe heavy popping is actually in the 1st condition.
Title: Re: Advanced Fueling Issue - Exhaust reversion?? - Need advice
Post by: Dirty Duc on March 20, 2015, 10:19:03 AM
Where do your 5% bins change to 0?  What target AFR is in the table at whatever comes at the next throttle opening? What target AFR is in the first 5% bin with a non-zero target?

DynoJet question: Does 0 in the table mean "ignore" or does it mean a target AFR of 0?
Title: Re: Advanced Fueling Issue - Exhaust reversion?? - Need advice
Post by: EEL on March 20, 2015, 10:56:57 AM
I have posted an image of Ungeheuer's AFR fuel table below. Provided in a different post but its easier to have it visually here

(https://farm9.staticflickr.com/8751/16252351804_40d827b9f1_z.jpg) (https://flic.kr/p/qLaxY9)

You can see the cruise range established here (with the higher afr's. I'm getting issues at the transition from 0 - 2 to 5 at 4k ish. I'm wondering if this is due to an excessively lean condition at 0 jumping to a much richer value at 2%

The value "0" in the table means ignore. Otherwise it will give you suggestions to modify the fuel table based on the setpoint you indicate in the AFR.

Dynojet says to keep zero's in the 0 throttle an 2% and low rpm range of the autotune. I have attached the youtube video on this. Skip to about 1 min 50 seconds and watch for about a minute.

Using The AutoTune Software (http://www.youtube.com/watch?v=AOi9NHRv7jE#)
Title: Re: Advanced Fueling Issue - Exhaust reversion?? - Need advice
Post by: Dirty Duc on March 20, 2015, 12:35:05 PM
PCV isn't very full-featured, is it?

I like ung's table better than the DynoJet suggestion.  If you are running a target table that looks like the DynoJet suggestion, I would expect it to act like your description.  If you are using ung's table or something like it, then I would expect to find the problem somewhere else.
Title: Re: Advanced Fueling Issue - Exhaust reversion?? - Need advice
Post by: Speeddog on March 20, 2015, 01:02:37 PM
What does your throttle % show when it's closed?

Title: Re: Advanced Fueling Issue - Exhaust reversion?? - Need advice
Post by: EEL on March 20, 2015, 01:22:33 PM
Are you indirectly asking if I set the range on the PC-V? If so then yes I did.

My throttle shows 0% when its closed. 100% when its WOT. I had a PC-III on my old bike so familiar with that.

Its the second thing I did. First was to turn the bike on and off 3 times in a row as I was told this resets the TPS on the newer models.

Title: Re: Advanced Fueling Issue - Exhaust reversion?? - Need advice
Post by: EEL on March 20, 2015, 01:25:19 PM
Quote from: Dirty Duc on March 20, 2015, 12:35:05 PM
PCV isn't very full-featured, is it?

I like ung's table better than the DynoJet suggestion.  If you are running a target table that looks like the DynoJet suggestion, I would expect it to act like your description.  If you are using ung's table or something like it, then I would expect to find the problem somewhere else.

I am using Ung's table at this time.
Title: Re: Advanced Fueling Issue - Exhaust reversion?? - Need advice
Post by: Dirty Duc on March 20, 2015, 01:50:00 PM
Quote from: EEL on March 20, 2015, 01:25:19 PM
I am using Ung's table at this time.
What does your actual PCV fuel table look like?

How much authority does your autotune have?
Title: Re: Advanced Fueling Issue - Exhaust reversion?? - Need advice
Post by: EEL on March 20, 2015, 02:05:46 PM
I'm not sure what you mean by authority. As mentioned, I have factory 02 sensors removed via Rexxer Flash. Technically the PC-V has full control over the entire fuel range now.

As for the maps themselves, I will have to take a snapshot of the most recent updated map with accepted trim values later today. I've been trying to ride the bike for the last couple of days in various environments (all at approx the same elevation) to ensure I can broaden the mapping range. Currently on the 4th iteration of trim.

Autotune tables aren't showing much change anymore for the already mapped rpm and throttle input locations.
Title: Re: Advanced Fueling Issue - Exhaust reversion?? - Need advice
Post by: Dirty Duc on March 20, 2015, 02:26:09 PM
Definition for this thread: authority = amount of change it is allowed to make at once.

The maps will hopefully tell the story.
Title: Re: Advanced Fueling Issue - Exhaust reversion?? - Need advice
Post by: EEL on March 20, 2015, 04:45:31 PM
20 percent at a time
Title: Re: Advanced Fueling Issue - Exhaust reversion?? - Need advice
Post by: Dirty Duc on March 20, 2015, 04:55:22 PM
Quote from: EEL on March 20, 2015, 04:45:31 PM
20 percent at a time
IMO, that's pretty aggressive with what I believe to be narrow band sensors.

I assumed that part of the reason for the 13:1 target was because of the narrow band range of effectiveness.

Sometimes engines want to be a little richer than that, but a narrow band isn't usefully accurate very far off of stoich.
Title: Re: Advanced Fueling Issue - Exhaust reversion?? - Need advice
Post by: EEL on March 20, 2015, 06:40:43 PM
These are wide band not narrow band
Title: Re: Advanced Fueling Issue - Exhaust reversion?? - Need advice
Post by: brad black on March 20, 2015, 06:51:17 PM
Quote from: EEL on March 20, 2015, 09:39:17 AM
1) From full throttle to zero throttle

do you mean that when you shut the throttle it backfires on the overrun as the revs run down?

put +20 to 30% in the 0 throttle column.  or -100, if it lets you.  see what happens.
Title: Re: Advanced Fueling Issue - Exhaust reversion?? - Need advice
Post by: EEL on March 21, 2015, 08:57:41 AM
Quote from: brad black on March 20, 2015, 06:51:17 PM
do you mean that when you shut the throttle it backfires on the overrun as the revs run down?

put +20 to 30% in the 0 throttle column.  or -100, if it lets you.  see what happens.

I will try this to see what happens. I dont know if -100 will be allowed.
Title: Re: Advanced Fueling Issue - Exhaust reversion?? - Need advice
Post by: EEL on March 21, 2015, 09:02:45 AM
As requested here are the autotune maps from the last iteration

Horizontal Cylinder

(https://farm8.staticflickr.com/7610/16882371871_d0ccf48e82_c.jpg) (https://flic.kr/p/rHQyZ6)

Vertical Cylinder

(https://farm9.staticflickr.com/8684/16882184402_82f912a7f6_c.jpg) (https://flic.kr/p/rHPBfS)
Title: Re: Advanced Fueling Issue - Exhaust reversion?? - Need advice
Post by: EEL on April 13, 2015, 09:11:54 AM
LENGTHY UPDATE:

ITEM 1-------------------------------------------------------------------------

Exhaust leak at the horizontal cylinder head was a significant culprit to the backfiring issue. Unusually, it wasnt easily identified. I quadrupled checked that the exhaust was seated properly and and quadrupled checked that there was no leak.

HERES A LESSON FOR ALL OF YOU (or maybe i'm the only one that didn't now know this)

You need to treat the exhaust flange nuts that hold the exhaust to the head as pretty much one time use.

What would end up happening is everything would be nice and tight when I would check in the garage and the bike idling. When I would go for a ride, the nuts would physically back out about 1 full turn over the course of about 50 miles due to the exhaust pulses from riding!

Apparently these things are called "tension lock nuts". I went to the local ducati dealer and picked up 2 for dollar. I immediately noticed that they were a lot hard to install back on. Significantly less popping but some still exists. I dont think I'm going to ever get rid of it all but now its only in extreme cases and pretty much only on decel.

ITEM 2--------------------------------------------------------------------------------

UNGEHEUER's KISS AFR TABLE:

Its a good AFR table but I found that the leaner afr during cruise resulted in a less smooth ride for my 1100 EVO. I think you could go two ways:

1) Keep the KISS AFR and Install a 14T sprocket as MANY people do. This essentially bumps the RPM levels up and changes your cruise range. Essentially getting the bike to smooth out. This generally results in worse fuel economy.

2) Don't use the leaner ARF range at all. I tried a very simple map. Took all the lean values and changed them to 13.2 to match the rest of the values around it. I noticed immediately that the bike was able to run a lot smoother thru the entire rpm range. Even lugging it (3500 rpm) seemed to work fine in 6th gear. Again slightly less gas mileage (just like the 14T sprocket) but I dont have a 14T sprocket and I feel the power delivery is more linear.

ITEM 3---------------------------------------------------------------------------------

POWER COMMANDER VALUES AT 0% and 2% Throttle

With the exhaust leak issues resolved. I decided to start characterizing how my bike ran at idle and at 0% and 2% throttle. Rather than putting in random values into the PC-V I set the AFR target in the autotune to 14.0 at 0% and 2% columns just for $hits and giggles.

Turns out, the bike pretty much runs 14.0 for both these setpoints for the rexxer performance exhaust and intake flash I have from motowheels.

Only at idle was the bike running super lean. I was able to diagnose an afr of 15.5 using the live readings with the laptop plugged in. The rest of the setpoints showed no real changes (minor 1% - 3% changes in the columns.

After accepting the fueling changes to achieve 14.0 AFR from the autotune, the first thing I noticed was a much smoother idle.

Still need to experiment with a richer mixture (maybe 13.7 instead of 14.0) and see how the bike reacts. Right now I'm still getting the current map fully vetted.

If anyone is interested, PM me and I will send you the .PVM map. I dont mind sharing.

My bike is aggressively modded; no flapper (with butterfly completely removed), MWR power up kit, K&N filter, GP-M2 exhaust, Rexxer performance flash. So they may be very few that would make use of it.

Title: Re: Advanced Fueling Issue - Exhaust reversion?? - Need advice
Post by: 3G on April 18, 2015, 05:23:40 AM
I had similar problems with pcv auto tune on my m1100. The OEM fuel cap breather was too restrictive causing fuel starvation, I  disassembled the cap and removed the restrictor washer. The  bike runs smoothly now and autotune has leaned itself out due to improved fuel supply. I have also added 13% fuel in the 0% throttle line this improved on/off throttle transition.