Rough running/misfiring at constant rpm&throttle - SV1000 Portal
 1Likes
  • 1 Post By RecoilRob
 
LinkBack Thread Tools Rate Thread Display Modes
post #1 of 13 (permalink) Old 23rd April 2017, 07:16 AM Thread Starter
Moped rider
 
Join Date: Jan 2016
 ♂ Czech Republic
Posts: 89
Garage
Rough running/misfiring at constant rpm&throttle

All of sudden my SV1000S K4 started running rough at 3-5t rpm range, while having constant throttle at cruising position (~10%). It is literally kicking back and forth with the whole bike and it appears even in neutral. Actually here is the sound...most noticeable at 20-30s as misfires/little pops:
Vocaroo | Voice message

When the issue kicks in, the STV move/jump around quite significantly...but not really sure, if that is the cause or consequence of a problem...yet seems important.

Last time I rode her everything was fine (2 weeks ago), on this Friday the issue appeared immediatelly and getting worse with warming up the bike.

Got:
PC V, O2 sensor gone, stock headers, STORM/MIVV cans, K&N filter.

Tried:
Moved with spark plug cables and PC V ignition harness.
Removed quickshifter switch from PC V temporarily. QS itself is working.
Checked intake for vacuum leak - exchanged a cracked rubber cap and tightened one little loose airbox clamp.
Did synchronization of throttle valves + TPS and STV adjustment.
Tried to completely mis-adjust the STV sensor.
Exchanged sparkplugs.

Nothing helped so far. Will try:
Different PC V maps or tweak fuel in the affected range...to rule out bad tune. Yet both maps, I have used before, were just fine.
Check for vacuum leak in Scottoiler vSystem...as I didn't focus on this part yet, it is few months old.
Pretty sure the TPS and STP are OK, so I will re-do the synchronization again....while swapping hoses for more precise measurement.

After these I am out of ideas, so any other suggestion is welcome. Thanks in advance.
Hasha is offline  
Sponsored Links
Advertisement
 
post #2 of 13 (permalink) Old 23rd April 2017, 01:29 PM
Forum whore
 
Join Date: Feb 2011
 ♂ United States
SW Pennsylvania, USA
Posts: 1,850
Do you have a spare set of TB's laying around? If not...Ebay is your friend and they can often be found for very little money and are great to have for just such a problem. I'd guess that your TPS is starting to act up and about the only way to be sure is to substitute a known good one...but they're pricey. That's why I got the spare TB's as they came with injectors and all sensors for under $50 which is much less than a single sensor. The TPS has to get really bad before you'll get a code or be able to easily see it on an ohm-meter and we've had several members with weird surging type issues that they finally tracked down to TPS after pulling out much hair and checking/changing about everything else. Good luck to you!
RecoilRob is online now  
post #3 of 13 (permalink) Old 23rd April 2017, 05:55 PM Thread Starter
Moped rider
 
Join Date: Jan 2016
 ♂ Czech Republic
Posts: 89
Garage
Different maps neither zero map helped...so didn't bother with fuel adjustment.
There are none vacuum leaks in the system.
Synchronization is kind of weird...when I set idle rpm equal and then rev the engine, levels are off. When I set levels at reved engine (4-5t), idle levels are off. Kept the setting, where the engine is idling smooth. I should definitelly look up more info about synchronization later on.

Thanks for the tip.
The TPS...hmm, ye, that could be the problem. I already checked the voltage on multimeter...yet haven't found any drops or floating value. Gonna try osciloscope later on, to have closer look. Unfortunately, I do not have second TB at my disposal, yet I will contact some local SV guys to borrow me their temporarily, after I am done with the scope.
Hasha is offline  
 
post #4 of 13 (permalink) Old 23rd April 2017, 06:58 PM
KNEE DRAGGER
 
schmidt314's Avatar
 
Join Date: Nov 2005
 ♂ United States
Portland Oregon
Posts: 4,317
Garage
Quote:
Originally Posted by Hasha View Post
Different maps neither zero map helped...so didn't bother with fuel adjustment.

There are none vacuum leaks in the system.

Synchronization is kind of weird...when I set idle rpm equal and then rev the engine, levels are off. When I set levels at reved engine (4-5t), idle levels are off. Kept the setting, where the engine is idling smooth. I should definitelly look up more info about synchronization later on.



Thanks for the tip.

The TPS...hmm, ye, that could be the problem. I already checked the voltage on multimeter...yet haven't found any drops or floating value. Gonna try osciloscope later on, to have closer look. Unfortunately, I do not have second TB at my disposal, yet I will contact some local SV guys to borrow me their temporarily, after I am done with the scope.


What is the vac delta from idle to the slightly higher rpm? They will vary, but how much is key. I would think if perfect at idle they should be under 10mm of Hg delta. One bike in the past I worked on that had big deltas, I actually fixed by realigning the primary throttle plates in the bore. It made a big difference. This should not be the main problem though.

Is the TPS setting in the PCV correct?
You can also sometimes see a bad TPS using the PC unit by having key on, bike not running, and open the TPS dialog box in the software. Now very slowly open throttle and watch the feedback. A bad TPS you will see the values jump around a bunch open when you near 10%.

-ms


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
schmidt314 is offline  
post #5 of 13 (permalink) Old 24th April 2017, 08:30 AM Thread Starter
Moped rider
 
Join Date: Jan 2016
 ♂ Czech Republic
Posts: 89
Garage
Quote:
Originally Posted by schmidt314 View Post
What is the vac delta from idle to the slightly higher rpm? They will vary, but how much is key. I would think if perfect at idle they should be under 10mm of Hg delta. One bike in the past I worked on that had big deltas, I actually fixed by realigning the primary throttle plates in the bore. It made a big difference. This should not be the main problem though.

Is the TPS setting in the PCV correct?
You can also sometimes see a bad TPS using the PC unit by having key on, bike not running, and open the TPS dialog box in the software. Now very slowly open throttle and watch the feedback. A bad TPS you will see the values jump around a bunch open when you near 10%.
Used DIY liquid based synchronization jig with coolant liquid. Max level difference with reved engine was 12cm-ish, which (depending on coolant density from datasheet) should give slightly below 10mm Hg. I guess I am on the edge.

Yes, every time I did the syncro, I re-adjusted the TPS (- C00) and calibrate the PCV. Also noticed yesterday, that the voltage for 0% throttle changes when engine stopped and idleing (something like 1,14...V vs 1,15...V)...used idleing value. Anyway, I will be using zero map for testing, until I solve the issue, so PCV is out of game.

I will just get the osciloscope with data logging...to be absolutely sure, if that is the cause. Both the multimeter and PCV can have some low pass filters to smooth out the TPS signal...so they might not show the drop out, I will be looking for.

Thanks for inputs.
Hasha is offline  
post #6 of 13 (permalink) Old 24th April 2017, 10:28 AM
One man & his dog
 
Valves's Avatar
 
Join Date: May 2004
 ♂ England
Farnham, Surrey, UK
Posts: 1,568
I had this with my K3, only got it cured by increasing fuel in at cruising setting. You've disconnected O2 sensor, which i also had to do.
I do wonder if you just have 'wear' and need to increase fuel a little


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

You can live more in 5 minutes on a bike... than some people will live in their whole lifetime (Burt Munro, World's Fastest Indian)
Valves is offline  
post #7 of 13 (permalink) Old 24th April 2017, 01:02 PM
Forum whore
 
Join Date: Feb 2011
 ♂ United States
SW Pennsylvania, USA
Posts: 1,850
The significant clue here, IMHO is the STV's moving around when the problem happens. They only respond to the main throttle movement which is translated to them by the TPS and if they're moving around it's because they're trying to follow the inputs they're getting. If the physical throttle isn't moving...but the STV's are...then I'd think the TPS is sending them erroneous signals. Hopefully you'll be able to see on the scope if the TPS is flaky, but others have tried and failed to positively ID when this has happened and replacement was the only way to prove that the sensor was bad. That's why it's SO nice to have a spare on the bench...just in case.
trumindgame likes this.
RecoilRob is online now  
post #8 of 13 (permalink) Old 9th May 2017, 06:19 AM Thread Starter
Moped rider
 
Join Date: Jan 2016
 ♂ Czech Republic
Posts: 89
Garage
So, bad news and good news.

It is not the TPS. I swapped TPS from SV650 and the situation was exactly the same. Also tried to bypass the TPS sensing of PCV and the situation got little better...so my focus went to interference.

I compared the datalogs of the TPS signal from both bikes reved at 4k rpm (mine and the 650). Noticed a pretty much same noice levels, yet significant difference in interference spike levels on mine.

Spikes had rpm*6 frequency, so maybe a regulator. Voala, the issue completely disappeared with regulator disconnected from the SV harness.

Now I would need a little help with these ideas:
1) Is it a bad regulator? Like about to get broken? The regulator is just the 3-phase rectifier or also contains some voltage regulator?
2) By adding PCV to the system, isn't the harness simply inducting more interference?
3) Worth re-wiring alternator directly to regulator (not to use SV harness) and also patch the regulator output directly to the battery (as described here on forums already)?
4) Worth hard-wiring PCV to the SV harness to prevent double-wiring TPS, injectors and ignition coils?

Anyone encountered something like this before?
Hasha is offline  
post #9 of 13 (permalink) Old 9th May 2017, 07:08 AM
KNEE DRAGGER
 
schmidt314's Avatar
 
Join Date: Nov 2005
 ♂ United States
Portland Oregon
Posts: 4,317
Garage
Quote:
Originally Posted by Hasha View Post
So, bad news and good news.

It is not the TPS. I swapped TPS from SV650 and the situation was exactly the same. Also tried to bypass the TPS sensing of PCV and the situation got little better...so my focus went to interference.

I compared the datalogs of the TPS signal from both bikes reved at 4k rpm (mine and the 650). Noticed a pretty much same noice levels, yet significant difference in interference spike levels on mine.

Spikes had rpm*6 frequency, so maybe a regulator. Voala, the issue completely disappeared with regulator disconnected from the SV harness.

Now I would need a little help with these ideas:
1) Is it a bad regulator? Like about to get broken? The regulator is just the 3-phase rectifier or also contains some voltage regulator?
2) By adding PCV to the system, isn't the harness simply inducting more interference?
3) Worth re-wiring alternator directly to regulator (not to use SV harness) and also patch the regulator output directly to the battery (as described here on forums already)?
4) Worth hard-wiring PCV to the SV harness to prevent double-wiring TPS, injectors and ignition coils?

Anyone encountered something like this before?


Make sure all your grounds are happy.

1. Regulator might be going bad, but what was magnitude of the ripple you saw?

2. It is possible, but PCV units were better grounded than the PCIII usbs. I have had issues when passing the harness near the HT lead for the rear cylinder.

3. By doing this you will get less DC loss and slightly better voltage response and take out a few connectors that are known to be problematic.

4. No, do not hard wire it. It makes things a total nightmare to service later on. Most people's units work fine and we have used them under race conditions w/o issues do to plugs.

Again, make sure the continuity of the ground between frame and engine are super low resistance. Then also check between cable at battery and engine. I have see. The ground lug that bolts to the engine near the counter shaft area gets loose or get corroded and cause all kinds of issues.

-ms


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
schmidt314 is offline  
post #10 of 13 (permalink) Old 10th May 2017, 01:36 PM Thread Starter
Moped rider
 
Join Date: Jan 2016
 ♂ Czech Republic
Posts: 89
Garage
I used simple digital USB scope, which was available in the job. Unfortunately it had minimum sampling interval 2us (for consistent sampling), so getting the true spike value was a bit hard.

At 2% of the throttle the nominal voltage was 1.24V, spikes were going as high as 2.8V. The SV650 had like half spikes - around 2V.

Thanks for tips.

I will re-wire the regulator output to the battery today and as well check grounds...to be honest, didn't think about grounds yet. If that doesn't help, next step is trying out new/another regulator. And then re-wiring alternator to regulator.
Hasha is offline  
post #11 of 13 (permalink) Old 14th May 2017, 02:23 PM Thread Starter
Moped rider
 
Join Date: Jan 2016
 ♂ Czech Republic
Posts: 89
Garage
Issue fixed.

It was the interferrence from the alternator/regulator.

I've split the alternator cable, crank sensor wires routed as original. Alternator wires routed directly to the regulator connector and trimmed to length. Regulator output routed directly to battery terminals via 30A fuse.

Not even the issue was fixed, but the engine got much better running....very smooth idle, instant reaction on gas popping, etc.

I highly suggest to do this mod. More about it here:
Regulator Interference
Hasha is offline  
post #12 of 13 (permalink) Old 14th May 2017, 04:25 PM
Forum whore
 
Join Date: Feb 2011
 ♂ United States
SW Pennsylvania, USA
Posts: 1,850
Sounds more like a PC-V problem than something actually with the bike. If left with the stock ECU...no problemo. Add the PC-V...and the problem was created or it became more susceptible to the normal electrical murmurings of the bike.
RecoilRob is online now  
post #13 of 13 (permalink) Old 14th May 2017, 09:22 PM Thread Starter
Moped rider
 
Join Date: Jan 2016
 ♂ Czech Republic
Posts: 89
Garage
Quote:
Originally Posted by RecoilRob View Post
Sounds more like a PC-V problem than something actually with the bike. If left with the stock ECU...no problemo. Add the PC-V...and the problem was created or it became more susceptible to the normal electrical murmurings of the bike.
Well exactly. By adding PCV harness you increase the overall length of wires and therefore increase the sensitivity to induct interference from alternator/regulator.

And I wouldn't say without the PCV the bike was fine. The engine seemed lazy and/or hesitating. I simply thought, that the bike is supposed to run that way. When I blipped the throttle, the STV followed with much longer delay and somehow feeling confused about its position. Now the response is instant and precise. And it is not caused by the PCV, as I am running zero map without acceleration pump.

I simply give credits to much less interference in crucial ECU signals (TPS, STV, MAP, engine temp, maybe GPS as well...who knows what else). Exactly as described by other guys in the interference topic...."the bike so smooooth now".
Hasha is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the SV1000 Portal forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes Rate This Thread
Linear Mode Linear Mode
Rate This Thread:



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome