Author Topic: MGX-21 running rough (Read 6514 times)

Luap McKeever · « **on:** July 30, 2019, 06:11:55 PM »

The past several weeks this bike is running bad. Not all the time, but it appears to be happening more when the temperatures are up.

I'm approaching 18,000 miles on it. It's mainly running rough at idle. Once up to speed it is still a rockstar, but idling rough is getting annoying. It's died on me a time or two as well. Today on my home from work pulling into a gas station it almost died and when I lost momentary power, I thought I was going to crash it until I got the engine speed back up.

Having never cleaned the throttle bodies, I'm wondering if I need to do that. The plugs are new as I put them in at the last service, 12,000 I think. I try to run mid range fuel in it.

Thoughts?

Thanks,
Luap

Kev m · « **Reply #1 on:** July 30, 2019, 06:16:04 PM »

Single throttle body, but I hear what you're saying, especially if it carries oil over from the breathers. I'm just not sure what you can and can't do safely when cleaning it.

I was going to ask about plugs... You answered.

You sure about the plug wires? Insulation on them? Connection at coil posts? Insulation of coil itself.

kballowe · « **Reply #2 on:** July 30, 2019, 06:19:08 PM »

Here's a thread for GuzziTech

https://www.guzzitech.com/forums/threads/california-1400-running-rough.17415/

run that thing in pitch black and see if you can find any little blue sparks

Luap McKeever · « **Reply #3 on:** July 30, 2019, 06:20:24 PM »

Quote from: Kev m on July 30, 2019, 06:16:04 PM

Single throttle body, but I hear what you're saying, especially if it carries oil over from the breathers. I'm just not sure what you can and can't do safely when cleaning it.

I was going to ask about plugs... You answered.

You sure about the plug wires? Insulation on them? Connection at coil posts? Insulation of coil itself.

Yeah, the plugs are fine. It's strange. In the cooler mornings all is perfect. Then when the temp rises, it gets rough. Maybe a temperature sensor problem?...

SportsterDoc · « **Reply #4 on:** July 30, 2019, 06:23:03 PM »

Suggest you first pull plugs for a read.
Does your bike have an IACV?
If so, check connection...it may need cleaning or replacement sooner than the throttle body.
Is the mid-range fuel Tier 1?

Good suggestions from Kev M

oldbike54 · « **Reply #5 on:** July 30, 2019, 06:26:27 PM »

Quote from: Luap McKeever on July 30, 2019, 06:20:24 PM

Yeah, the plugs are fine. It's strange. In the cooler mornings all is perfect. Then when the temp rises, it gets rough. Maybe a temperature sensor problem?...

Sounds like a bad temp sensor , doesn't it . Is it loading up at idle ?

Dusty

Luap McKeever · « **Reply #6 on:** July 30, 2019, 06:27:39 PM »

Quote from: SportsterDoc on July 30, 2019, 06:23:03 PM

Suggest you first pull plugs for a read.
Does your bike have an IACV?
If so, check connection...it may need cleaning or replacement sooner than the throttle body.
Is the mid-range fuel Tier 1?

Good suggestions from Kev M

I don't know if it has a control valve or not. Probably so. Yes, mid range fuel is tier1, I usually try and run at least 90 octane in it. Guess I'll pull the plugs again and have a look, but I did that about 1000 miles ago and they looked fine.

Quote from: oldbike54 on July 30, 2019, 06:26:27 PM

Sounds like a bad temp sensor , doesn't it . Is it loading up at idle ?

Dusty

yeah it does load up a bit at idle.

SportsterDoc · « **Reply #7 on:** July 30, 2019, 06:31:08 PM »

Quote from: oldbike54 on July 30, 2019, 06:26:27 PM

Sounds like a bad temp sensor , doesn't it . Is it loading up at idle ?

So that ECM thinks engine is still cold and enrichens mixture?
Quite plausible.
Would expect plugs to so indicate

Bud · « **Reply #8 on:** July 30, 2019, 06:37:31 PM »

How is it starting? Do you have to turn it over several times or does it fire off fairly quickly. Just wondering about the condition of the battery. What does the voltmeter read at idle and or when you start it.

Kev m · « **Reply #9 on:** July 30, 2019, 06:43:12 PM »

Intermittent timing sensor that starts to open sometimes at high temp is a possibility.

Temp sensors, in my experience, tend to show faults more at startup then intermittently hot, but could be.

Any stored codes?!?

Luap McKeever · « **Reply #10 on:** July 30, 2019, 07:08:58 PM »

Quote from: Bud on July 30, 2019, 06:37:31 PM

How is it starting? Do you have to turn it over several times or does it fire off fairly quickly. Just wondering about the condition of the battery. What does the voltmeter read at idle and or when you start it.

Fires up quick...normal. It reads 13.5 volts at idle.

Luap McKeever · « **Reply #11 on:** July 30, 2019, 07:10:37 PM »

Quote from: Kev m on July 30, 2019, 06:43:12 PM

Intermittent timing sensor that starts to open sometimes at high temp is a possibility.

Temp sensors, in my experience, tend to show faults more at startup then intermittently hot, but could be.

Any stored codes?!?

No engine light on, but I can check it this weekend with GuzziDiag. I actually thought about putting the OEM map back on it. I'm running a beetle map right now and it's been fine. But I think the map tweaks the temp sensor a bit to make the bike think it's cold.

Luap McKeever · « **Reply #12 on:** July 30, 2019, 07:23:39 PM »

FWIW, I just went out to verify the volt check and the bike would barely start and stay running until I fluttered the throttle a few times to keep it running. Once it leveled out, it's idling fine. But I believe this has something to do with a temp sensor or maybe the map? It's getting quite annoying at this point.

Kev m · « **Reply #13 on:** July 30, 2019, 07:51:36 PM »

Quote from: Luap McKeever on July 30, 2019, 07:23:39 PM

FWIW, I just went out to verify the volt check and the bike would barely start and stay running until I fluttered the throttle a few times to keep it running. Once it leveled out, it's idling fine. But I believe this has something to do with a temp sensor or maybe the map? It's getting quite annoying at this point.

Is the motor still warm?!?

If the motor is cold and the map tweeked it to read colder then it would just be richer and likely still start.

I dunno... I'm skeptical but let's pull codes, maybe talk to Beetle about the map and go from there. No?

Luap McKeever · « **Reply #14 on:** July 30, 2019, 08:07:31 PM »

Quote from: Kev m on July 30, 2019, 07:51:36 PM

I'd the motor still warm?!?

If the motor is cold and the map tweeked it to read colder then it would just be richer and likely still start.

I dunno... I'm skeptical but let's pull codes, maybe talk to Beetle about the map and go from there. No?

Yeah it was still warm. I've reached out to Beetle. Thanks for the ideas.

beetle · « **Reply #15 on:** July 31, 2019, 12:18:29 AM »

Quote from: Luap McKeever on July 30, 2019, 07:10:37 PM

But I think the map tweaks the temp sensor a bit to make the bike think it's cold.

No so.

I reckon I need to richen it up a bit in the hot weather.

I'll get onto that.

TN Mark · « **Reply #16 on:** July 31, 2019, 05:44:31 AM »

I’d guess the fuel map is fine since it previously ran fine. My Victory will do the same with a weak battery and/or slightly loose battery connections.

s1120 · « **Reply #17 on:** July 31, 2019, 06:59:35 AM »

Quote from: TN Mark on July 31, 2019, 05:44:31 AM

I’d guess the fuel map is fine since it previously ran fine. My Victory will do the same with a weak battery and/or slightly loose battery connections.

Ya a fuel map doesn't "go bad"... well unless the ECU is going, but I doubt that... Any other changes around the time it started acting up?

Luap McKeever · « **Reply #18 on:** July 31, 2019, 01:44:12 PM »

Quote from: s1120 on July 31, 2019, 06:59:35 AM

Ya a fuel map doesn't "go bad"... well unless the ECU is going, but I doubt that... Any other changes around the time it started acting up?

No other changes. It runs perfect in the cool mornings. Afternoons, not so much. Beetle is working on a new map to help lean it out.

TN Mark · « **Reply #19 on:** July 31, 2019, 05:57:13 PM »

I've run a custom map (dyno tune/PCV) on my bike for several years now. If it suddenly started running differently in different temperatures, one of the last things I'd suspect would be the fuel map.

I hope new map somehow fixes what went wrong without masking over another possible cause.

Bulldog9 · « **Reply #20 on:** August 01, 2019, 06:36:27 AM »

Dirty injectors? Bad fuel? Plug caps? Sometimes its the simple things.

Also, I wonder if it could be that aux air injector system with the reed valves near the exhaust ports. This is the small octopus system on the front left and front of motor just above the horns. I think the MGX is the only model with it, I've not seen it on any Eldo or Cali's. If the contraption works like it does on other vehicles it is supposed to put air into the exhaust stream when the engine is cold. If that system is malfunctioning it could be injecting air into the exhaust stream when hot and confusing the O2 sensor?.

Never mind... I just remembered you're running a beetle map and he shuts off the O2 sensors.

Still may be worth a look as well as checking over all the sensors and connections, and reflashing the map.

Luap McKeever · « **Reply #21 on:** August 01, 2019, 11:57:41 AM »

Beetle sent me a new map and I installed it yesterday evening. I was able to ride it around just a little and couldn't ride today due to rain. But, the preliminary result was encouraging. I'll have to wait until the weather clears and try again.

Stay tune :)

SportsterDoc · « **Reply #22 on:** August 01, 2019, 12:13:52 PM »

Quote from: Luap McKeever on August 01, 2019, 11:57:41 AM

Beetle sent me a new map and I installed it yesterday evening. I was able to ride it around just a little and couldn't ride today due to rain. But, the preliminary result was encouraging. I'll have to wait until the weather clears and try again.

Good, did you check plugs before and after?

If the map is not the full solution, suggest diagnostics on (1) oil temp sensor and (2) IACV.

Oil temp sensor is simple resistance measurement

Luap McKeever · « **Reply #23 on:** August 01, 2019, 12:20:52 PM »

Quote from: SportsterDoc on August 01, 2019, 12:13:52 PM

Good, did you check plugs before and after?

If the map is not the full solution, suggest diagnostics on (1) oil temp sensor and (2) IACV.

Oil temp sensor is simple resistance measurement

I checked the plugs about 1,000 miles ago and they looked good. If the map don't help, I'll chime back in for more guidance on those other things. thanks.

Tkelly · « **Reply #24 on:** August 02, 2019, 10:47:03 AM »

How about mid grade gas in a Stelvio,any one have experience?I have always used premium an wonder if I am wasting money.

jbhotchkiss · « **Reply #25 on:** August 02, 2019, 02:42:54 PM »

Quote from: Kev m on July 30, 2019, 06:16:04 PM

Single throttle body, but I hear what you're saying, especially if it carries oil over from the breathers. I'm just not sure what you can and can't do safely when cleaning it.

I was going to ask about plugs... You answered.

You sure about the plug wires? Insulation on them? Connection at coil posts? Insulation of coil itself.

Long shot, but I'll chime in anyway. When replacing the airbox with a pod filter on my Cali14 Custom, I noticed the center spark plug wire on the left cylinder was being pinched between the blow-by collector box and the cylinder, such that the insulation was wearing noticeably. I widened the gap between the cylinder and the collector box and re-wrapped the wire in the area of wear and I think I'll be OK. Worth a look I believe.

Luap McKeever · « **Reply #26 on:** August 03, 2019, 09:58:34 AM »

Quote from: jbhotchkiss on August 02, 2019, 02:42:54 PM

Long shot, but I'll chime in anyway. When replacing the airbox with a pod filter on my Cali14 Custom, I noticed the center spark plug wire on the left cylinder was being pinched between the blow-by collector box and the cylinder, such that the insulation was wearing noticeably. I widened the gap between the cylinder and the collector box and re-wrapped the wire in the area of wear and I think I'll be OK. Worth a look I believe.

Thanks. I checked this and all is well.

Luap McKeever · « **Reply #27 on:** August 03, 2019, 10:00:02 AM »

online gambling craps

jbhotchkiss · « **Reply #28 on:** August 03, 2019, 12:54:17 PM »

Looks like one good and three a tad rich?

beetle · « **Reply #29 on:** August 03, 2019, 05:42:42 PM »

I agree. A tad rich.

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Author Topic: MGX-21 running rough (Read 6514 times)

oldbike54

beetle

beetle