V7 III revs pulsing after cold start

[statarchuk]

I have V7 III Stone, 1k miles on it. Just did first service recently.
When starting it on cold (not winter cold, California underground garage cold) it lowers revs down for a moment almost dying, then revs up to normal, then again brings revs down. And keeps pulsing like this for about 40 seconds. Recorded sound of it is here https://www.dropbox.com/s/h204xdjqt3rve5m/MG_revs_pulsing.m4a?dl=1
If to open throttle in this state it dies. I guess it's running very lean.

I didn't have this problem from the very beginning, it developed itself over time. During past winter it was perfect, zero problems at all. Also not related to service, as it started before, just not as severe as it is now.

I really don't want to go to the local dealer, as they are super slow.
Any help would be much appreciated.

[Kev m]

This was common in the I and IIs.

My MkI Stone has done this since new and probably much worse.

Yes it only happens on cold starts, but here's the funny thing, it does it more/worse in hot weather.

It's fine after a minute or two.

Our new V7IIID didn't "seem" to do it, but we bought it in the middle of winter. And since it got really warm and humid recently, it just did it for the first time. Though not nearly as badly as the MKI.

I think it's a case of install a Bettle map or live with it (warm it up for a minute or two). I've been doing the latter since 2013.

[Zinfan]

Ok I cannot help OP but I just sold my 2013 V7 Stone and I had similar issues.  I figured it was maybe a fuel issue as the bike started as normal and even idled normal.  {I should say here that I have a Beetle map installed and have been using it for over a year or two with no issues} Once the new owner took it up the driveway the bike reacted as it always does with a hesitation that requires a few moments to go away and then all is fine for the rest of the time the bike is warmed up. 

However this time the bike decided to go into a very low pulsating idle up and down without throttle input.  Twisting the throttle caused the bike to bog and stall.  I hooked up and ran GuzziDiag and didn't see anything unusual so we tried again and the bike just worked perfect no issues at all during a 15 mile test ride.  I figured maybe it was water in the gas as the bike hadn't run for a few months and it had worked it's way out but when the new owner got it home he is reporting it is doing it again and even when the engine is warm after a freeway ride.

This is an issue as the new owner is a 3.5 hour drive away and I need to get that bike working correctly but have no basis to go on as it has never acted that way before.  I hope that running that tank dry and putting new fuel in might cure it.  Any chance a tank vent line blockage might also result in this issue? 

[statarchuk]

So I bought and installed Beetle map, did the throttle self-learning and reset autolearning parameters.
Didn't help.

[Kev m]

So I bought and installed Beetle map, did the throttle self-learning and reset autolearning parameters.
Didn't help.

Don't give up, talk to Beetle, I hear he'll see your through to satisfaction.

[Pizza Guzzi]

I can confirm Beetle does support his maps totally. I installed a Beetle map in my V7 111 Special and had trouble getting a good idle. Mark was very helpful, tweaking the map until the bike runs just as sweet as can be.

Glenn

[mechanicsavant]

Sure sounds like its going “closed loop” & going lean/rich off the o2 sensors . My v7II does it too when new it was so severe in 40 deg.  Conditions it would often stall . @ 12k mi. It’s a bit better in higher temps .

[roadscum]

So I bought and installed Beetle map, did the throttle self-learning and reset autolearning parameters.
Didn't help.

Perhaps your issue is not fuel map related but instead a mechanical or electrical issue. I go over, in great detail, all the things touched during the service. Valve adjustment?? Ignition wire/plug cap? ?  ?      ?

My V7 III Special does not experience that issue and I find the fueling/throttle response to be good, especially when compared to gen I & 2's. The 1st service on my V7 was performed by the selling dealer, as part of the purchase agreement, before I began my journey from his shop(Hamlin Cycles... he's the best!) in Bethel Ct. to my home in Fl.  He did retrieve me and the bike the day after the service when the fuel filter failed and left me stranded at road side about 300 miles from his shop. The fuel filter is unlikely to be your problem but I suggest you consider changing to an all metal filter to reduce your risk of experiencing a similar event. It's cheap and easy insurance.

Paul

[Kev m]

Hmmm, I wonder if the learning parameters come into play here?

One bike is run at cooler temps for a few months, suddenly there's a hot humid day, current trim values make it sputter on cold start.

Another bike is run at warmer temps day after day, no problem with cold start on warm temps.

I'm thinking our III didn't seem to do it today, though it did the other day right after the first service. Coincidence or some other variable we haven't considered yet?

[roadscum]

Hmmm, I wonder if the learning parameters come into play here?

One bike is run at cooler temps for a few months, suddenly there's a hot humid day, current trim values make it sputter on cold start.

Another bike is run at warmer temps day after day, no problem with cold start on warm temps.

I'm thinking our III didn't seem to do it today, though it did the other day right after the first service. Coincidence or some other variable we haven't considered yet?

Almost every day here in SW Florida is hot and humid and I've not had any issues. 97 degrees now and a real feel of 110 and the V7 starts just fine.

Paul

[Kev m]

Almost every day here in SW Florida is hot and humid and I've not had any issues. 97 degrees now and a real feel of 110 and the V7 starts just fine.

Paul

Yeah my theory takes that into account you see.... But it's just a swag. Could be other variables. Individual build differences or other ambient conditions.

Either way it's nothing like my MkI which will often sputter/stall if you try to pull away too soon (under a few minutes) after a cold start in certain conditions.

[twowheeladdict]

I have not seen this with my bike that I have had for a year.   It is all stock. 

I always run non-ethanol, and it is always on a battery tender when parked.  I also always park it with a full fuel tank because I top it off after every ride at the non-ethanol station 1/2 mile from my home. 

If it runs normally after warm up, I would investigate the fast idle circuit, but I have no idea how that functions on the V7III.  I would think the ECU is looking at various sensors to determine what to do so sensors is where I would start my research to make sure they are all functioning correctly. 

[PrajwalKale]

Thank you for the reply

[vintagehoarder]

Had a similar problem on a 2014 V7 special, turn out to be spark plug caps grounding out. Replaced them, problem went away

[Kev m]

Ironically my Stone didn't do it this morning either. About 80°F, but low humidity. < Shrugs > another reason I've just lived with it.

[statarchuk]

Thanks everyone for responding.

I spoke to my dad about this, he's a car mechanic. He said that this sounds like there could be an intake leak.
Looked through the service manual and the most probable place where it can leak on this engine is the evap system.
So I removed it and the bike started to idle as smooth as it used to.
Should have done it from the very beginning as everyone recommended.
Super happy about this.

[SmithSwede]

Excellent!!!    And thanks for reporting back with a solution to the issues you raised.   So we aren’t left hanging. 

I’d also check the two hose clamps on the rubber intake runner from the air box to the intakes.  You would not think these could loosen, but mine have several times.

Also check the cross over tube between the exhaust headers under the engine. The clamps on each side are notorious for getting loose, and apparently air gets in and confuses the sensors and screws up the fueling.  Had this happen to me a few times as well.

[Kev m]

Interesting.

5 years ago when we were chasing down the cold start problem I clamped off the purge line from the EVAP canister and so did some one else here. It didn't help in either case.

I guess it would depend on where the leak was, but color me skeptical that the OP has found the source. I hope he has... But if that was true in my cases they shouldn't come and go no?

Or maybe a tiny leak that can vary with temp/humidity can make a difference?!?

[statarchuk]

I've tested this in various temp conditions: from 65F in underground garage to 85F outside in the afternoon. No issues so far.
Now I'm tempted to reattach EVAP and try if the problem will come back.

[Kev m]

Ooopps, sorry totally meant to respond today.

Hey anything is possible and it was a logical place to look.

Just because clamping the purge line didn't help in a few MkI's doesn't mean it couldn't help on a III. Hell who knows.

Hopefully it's gone and never comes back.

I'm pretty sure I can count on my 13 to do it again, but the 18, maybe not we'll see.

[stimpoff]

I have had leak in seal between head and manifold. Use carb/brake cleaner or propane torch (without flame:-) to detect it

[Kev m]

Ours hasn't done it again. I wonder if I should have reset the fuel trim after adjusting the valves. Maybe that first start right after adjustment was the ECM reacting to the slight difference in valve clearances. Hmmmmm.