Help!!! VTX is Sick - Idles Rough - Missing - Runs Hot - Loss of Power - VTXOA
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post #1 of 26 (permalink) Old 05-13-2011, 09:45 PM Thread Starter
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Help!!! VTX is Sick - Idles Rough - Missing - Runs Hot - Loss of Power

Ok I posted this up on the VTXCafe. Im kinda new to the VTXOA, but I need some help, grab your ....

  • I dont need to hear "check the ECM wires". This issue is beyond the obvious disconnected wire. If it is a wire and/or the ECM its not that obvious.

Ok I think the most important thing to note is that all of the problems are intermittent, they come and go with no apparent correlation. When I bought the bike it had 30,000 miles and was bone stock besides slip on exhaust, engine lighting, and alarm.

Some days it runs perfect, absolutely perfect. And some days it doesn't. And I cant figure out why. You win if you can help.

The Symptoms:
  • Idles rough, not terrible just uneven. The exhaust hits a rhythm for a few beats then misses.
  • Engine vibrates more (the girls love it, I dont), its not convulsing just like its out of sync and slightly unbalanced.
  • Engine feels like its missing, or weak has weak spark.
  • Runs hot shortly after the idle starts acting up. Temp light doesnt pop on, just noticeably hotter. Fan pops on constantly at lights.
  • Take off isn't smooth, doesn't bog down, more like its fighting to move, lacks power.
  • Each gear feels shorter, it bogs down at the bottom of the gear and I have to shift earlier than I normally would.
  • The top end lacks power. Doesnt bog down, slowly fights to increase speed.
  • The symptoms almost seem like a burnt or stuck exhaust valve (to give you an idea, dont think this is the problem).
  • It always starts easy, doesn't need choke (since scar), never dies. Just doesn't run right.

The Intermittent Part
  • One day it will purr like kitten and ride like a raped ape, and then one day I will start it up bad,right away the idle is off.
  • It goes away on its own sometimes, other times Ill try to fix the problem. Dozen times I thought I fixed it, but it always comes back.

I Have Tried:
  • Checked ECM and surrounding wires. Because its intermittent electrical seems likely. All wires were plugged in, no corrosion.
  • The wires to the ECM were kinked, straightening them out didnt help at all.
  • The basics like different brands gas, oil, plugs, Seafoam, etc.
  • I installed new vacuum lines, vent line, spark plugs, etc.
  • Scar to tune the carb, with Decap (when it runs good its great, when its bad its the same as always).
  • Changed to HK exhaust and installed new crush gaskets.
  • Rerouted the crankcase vent hose with a filter. Carb was sucking a quart of oil vapor a month.
  • Valve adjustment (mechanic was recommended from a here).
  • I changed the coolant and burped the system.
  • Battery is new, connections are tight.

Things I Noticed That May (or may not) Be Relevant:
  • When I bought the bike it had an alarm system and engine LED's that no longer worked. I have removed the extra wiring.
  • The ECM wires were all intact but were all kinked too. Straightened them out, no change.
  • The spark plugs look ok (lean but Scar shouldve fixed it). Changing plugs didnt help, I tried 3 different brands.
  • The whole engine gets very, very hot. Feels like the Front Left and Right Rear plug areas aren't as hot as the opposite sides.
  • The bike still has the Paired Valve System.
  • The flow from the front cylinder seems much stronger than the rear but, both cylinders feel equally hot.
  • A little coolant leaks from the overflow when its turned off after running hot. Temp light has never come on.

My Thoughts:
  • The intermittent, come & go behavior of the problem makes it unlikely to be anything adjustable, or mechanical failure because some days its perfect.
  • Most likely culprit is the wiring,ignition system, or ECM itself. But thats a big area to troubleshoot.
  • Plausible that its fuel blockage or the air quaility making the difference, seems like that would make is run rough, but not uneven (if that makes sense).
  • The paired valve system could be faulty causing some of the symptoms.

Im at my wits end, if I cant figure out exactly what it is then I am debating just replacing the whole wiring harness and ignition system and hoping for the best....

At this point any feedback, ideas, help would be much appreciated . Whether Im way off or on the right track, Im open to any and all help.

Thanks in advance guys
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post #2 of 26 (permalink) Old 05-13-2011, 10:34 PM
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I would Check the Grounds, Battery terminals and ECM wires again. tug on the ECM wires and make sure they are not broken.

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post #3 of 26 (permalink) Old 05-13-2011, 10:44 PM
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I would take a look at the bundle of ground wires bolted to the front bolt of the front coil. Take the bolt out and clean up all so it's good contact throughout.
The only time I had an issue like yours (bogging down, feeling weak) I cleaned up that and it took care of it.

You get an "A" for typing out your post...nice job.

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post #4 of 26 (permalink) Old 05-13-2011, 10:58 PM
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If you can use a meter. I would start ohming out the throttle position sensor , ig coils.
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post #5 of 26 (permalink) Old 05-13-2011, 11:19 PM
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I had a Ford f150 super crew with the 5.4 V8.

On mornings that there was a lot of moisture in the air the thing would run like crap. if it was raining, getting home from work was going to be a long trip...

Problem was one of the coils. There are 8 of them. one on each plug.

The plastic housing would crack and the spark would short out via the moisture in the air.

Had to remove the fuel rail that went over the top of the coil to replace it.

I wonder if maybe a coil may have cracked and if its a moist day the coil might be shorting out but on dry days it may be just fine.

Do you hear any snapping like an arc?

Could you park it in the garage on a day it is running poorly and take the seat off and close the garage door and look for something arcing.

You have tried a whole lot of stuff to find the issue.

Good luck!!
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post #6 of 26 (permalink) Old 05-14-2011, 12:07 AM
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You were amazingly thorough However, I would check you piston return springs, muffler bearings and flux capacitor. VTX's seem too run as described when these things are out of whack. I'm sure I'm missing more obvious solutions.

Sorry, I couldn't resist. I'm an Asshat sometimes. I hope the VTX gurus offer better advise than me. Good luck in finding the solution to you problem.
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post #7 of 26 (permalink) Old 05-14-2011, 04:46 AM
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will lay money on coil
as a after thought not enough concrete in the heads

always go camping in jan. no bugs,scream kids - yu get the best camp sites and the ladies always snuggle up to you

06 vtx 1300c mainly stock - Hard Krome K2 - darkside (hyro-edge 205/70/15)
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post #8 of 26 (permalink) Old 05-14-2011, 07:05 AM
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Altho I don't have a 1300, I would have to start with all your ground connections should be cleaned especially the one on the front coil.
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post #9 of 26 (permalink) Old 05-14-2011, 07:58 AM
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sounds like a ground problem to me and I would lean more to the charging system

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post #10 of 26 (permalink) Old 05-15-2011, 02:48 PM
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Plug and coil wires

Justin, along the lines klapool brought up.

Can you see anything "weather" related when this happens? Specifically humidity, or impending rain?

I had a 1990 ford ranger. When the weather got to mild humidity, it would run like crap, rough, gutless. But when it was raining out it ran fine. It seemed like a cylinder was gone. But the way it ran, it was obvious it was not the same cylinder. And the intermittent nature of it pointed away from a mechanical issue.

Cleaned all the ignition moving parts, dis cap, rotor, spark plugs. Nothing helped. So then tried the spark plug wires and replaced them all including the coil wire. That was when the problem went away. The issue was the wire from the coil, it was corroded on the end that connected to the coil.

Had that truck for 18 years, and about every 5 years she would do the same thing. Replacing the spark plug wires fixed it every time.

See if there is subtle change in the weather around the time this happens. Could be the wires.
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