Engine issue
Grand HDF Member
Joined: Jan 2012
Posts: 4,445
Likes: 2,811
From: Oklahoma
Start cheap and simple. If those are the factory plugs, they are due a change, and the appropriate amount (for 5 or six gallons) of Sea Foam (I like Berryman's Chemtool) in a tank of gas are cheap and easy. Then would come plug wires and after that the coil. Separating, spraying cleaner, and reconnecting (dielectric grease recommended) the primary circuit coil plugs, MAP sensor, and fuel injector connectors, big ECM connector, might also help. No hesitation during wide open throttle pretty well eliminates the fuel filter or fuel pump. Also possible are intake leak and worn valve guides, but try the easy stuff first.
3rd Gear
Joined: Jan 2006
Posts: 7
Likes: 0
From: Southern NB
I like what Donnylee said, (paraphrasing) "keep it to the simple stuff first and do one thing at a time (so you'll know what the problem was).
I have a very similar problem on my original owner 2007 SG with 190K kms on it. Hesitation from the rear cylinder only when at operating temp for a long period of time and only appears to be at cruise (2000-2400 RPM). A quick roll-on or roll-off throttle will immediately stop hesitation. No codes at all. TPS was my first thought but I haven't found the issue yet.
Over the past year (lots of premium only gas fill-ups later) I've scrutinized the harness, battery terminals and fuel-related various connectors then systematically replaced the plugs, wires, coil, CPS, TPS, MAT, Head Temp, IAT, Fuel Filter, O2 sensors. Completely drained the tank (coil replacement) and replaced with fresh gas. Notably I just recently noticed my gas cap might be vapour-locking. I'll be looking closer at that soon.
My rational for all those sensor replacements was age and the possibility of near-future failure ruining a good ride.
While performing other un-related work, I also just found one of my (120K kms old) lifters (interestingly, intake rear cyl) was slow to bleed-down (45 mins) and decided to replace the set - again a precautionary measure to avoid cam chest meltdown, but also read on another post here a bad lifter might cause a hesitation as an early symptom before complete failure. As a simple backyard mechanic I can't stand behind that statement.
With these closed loop EFI systems problems can be a result of any one of a multitude of different reasons. To date, guys that have posted their findings are back riding' n' smiling' again. When I find mine I'll post it as a new thread so as to hopefully benefit another.
I have a very similar problem on my original owner 2007 SG with 190K kms on it. Hesitation from the rear cylinder only when at operating temp for a long period of time and only appears to be at cruise (2000-2400 RPM). A quick roll-on or roll-off throttle will immediately stop hesitation. No codes at all. TPS was my first thought but I haven't found the issue yet.
Over the past year (lots of premium only gas fill-ups later) I've scrutinized the harness, battery terminals and fuel-related various connectors then systematically replaced the plugs, wires, coil, CPS, TPS, MAT, Head Temp, IAT, Fuel Filter, O2 sensors. Completely drained the tank (coil replacement) and replaced with fresh gas. Notably I just recently noticed my gas cap might be vapour-locking. I'll be looking closer at that soon.
My rational for all those sensor replacements was age and the possibility of near-future failure ruining a good ride.
While performing other un-related work, I also just found one of my (120K kms old) lifters (interestingly, intake rear cyl) was slow to bleed-down (45 mins) and decided to replace the set - again a precautionary measure to avoid cam chest meltdown, but also read on another post here a bad lifter might cause a hesitation as an early symptom before complete failure. As a simple backyard mechanic I can't stand behind that statement.
With these closed loop EFI systems problems can be a result of any one of a multitude of different reasons. To date, guys that have posted their findings are back riding' n' smiling' again. When I find mine I'll post it as a new thread so as to hopefully benefit another.
Thread Starter
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Novice
Joined: Mar 2017
Posts: 17
Likes: 1
From: Central Louisiana
Unsolved
Well, problem is eluding me still. Took it to a well respected local shop. They rode it for thirty miles, and put it on their Dyno hooked to the computer for 30 minutes. NOT ONE SINGLE HICCUP 😡😡😡
My Ultra is playing me. Lol
The search continues. 😢
My Ultra is playing me. Lol
The search continues. 😢
HDF Community Team
Joined: Nov 2012
Posts: 6,186
Likes: 2,412
From: USA
A dark damp night is a dandy time to run the bike and just sit there looking at the ignition wires. You'll want the headlight disconnected for this, because you want it DARK. You're looking for an odd arcing and such off the ignition wires or coils. Don't get distracted too much by the corona wash, though it is pretty.
In the daylight, let it sit there running, and start running your hands along the wiring. Move flex and shake things. You're looking to see if you can cause the engine to suddenly stumble or such in relationship to wire movement. Pay special attention to the likes of engine sensor wires, throttle body wires, etc.
In the daylight, let it sit there running, and start running your hands along the wiring. Move flex and shake things. You're looking to see if you can cause the engine to suddenly stumble or such in relationship to wire movement. Pay special attention to the likes of engine sensor wires, throttle body wires, etc.
Thread Starter
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Novice
Joined: Mar 2017
Posts: 17
Likes: 1
From: Central Louisiana
Narrowed down
Well folks, after hours of researching this issue of an intermittent miss on the forum and internet, I found theres lots of check this and that (all good advice) but hardly any this is what fixed the issue. Anyway, I replaced the plugs (old looked good) checked what I could without a computer to no avail.
Finally removed the tank and checked map and injector plugs and wires. Didnt really see any problems. Installed the tank but left it raised and started wiggling wires with the engine at 2000rpm. Map wires caused stumble and a code. So, there is a broken wire at the plug or close to the frame. Put at twist in the short harness, put it back together. Test ride was great with no miss. Guess Ill be taking to the dealer to replace the wires. Im assuming they have the tools to replace it with factory connections.
Finally removed the tank and checked map and injector plugs and wires. Didnt really see any problems. Installed the tank but left it raised and started wiggling wires with the engine at 2000rpm. Map wires caused stumble and a code. So, there is a broken wire at the plug or close to the frame. Put at twist in the short harness, put it back together. Test ride was great with no miss. Guess Ill be taking to the dealer to replace the wires. Im assuming they have the tools to replace it with factory connections.
Novice
Joined: Mar 2016
Posts: 23
Likes: 3
From: Wisconsin
This is the exact issue I had a month ago. I replaced the plug with a new pigtail I ordered from the internet. $12.95 an hour of my time and its fixed. 900 miles or so since with no issues. My wire was broken right at the connector so I would have had to shorten the wires, which werent long enough from the factory causing the break in the first place.
Cruiser
Joined: Dec 2012
Posts: 136
Likes: 17
From: sandusky Ohio
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Novice
Joined: Mar 2016
Posts: 23
Likes: 3
From: Wisconsin
I just looked up Harley TMAP sensor pigtail on Amazon and a whole bunch came up. The one I used is for Polaris 4-wheelers but anything that plugs into a Bosch 4 wire TMAP sensor should work. The wire colors on the pigtail wont match the wires in the bike harness but just make sure you match up whats on the old plug and solder it up.
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