Misfiring on startup? Calms down after a while.

Remember we tend to err on the rich side but light grey on the later fi bikes is deemed ok as they tend to run hotter anyway and they dont look deathly white 🤷🏻‍♂️
 
watchman said:
Given where he is i would leave be with the crap fuel down here they are not blisteringly white and altitude will change em again and i think the bike is a fi model 🤔
Click to expand...
Yes efi. I'm trying to get to Harley dealership in Seville, but am tempted to leave until I get back home
 
Thanks guys, an update for you:
I'm now in Seville, a Harley dealership opened just 4 months ago here, and over the phone they were the most responsive, so I took the motorbike in , i asked then to check compression, sensor readings, fuel injection pressure, General oil levels etc.
They told me that they had found some codes on the memory and cleared them, but didn't tell me what they were.
They put the diagnostic computer on and rode it too.

They've given it a clean bill of health after changing both spark plugs and air filter (the air filter was old but had been cleaned, so i assumed that an older air filter, more blocked than a new one, would make the motorbike run richer, but that's old thinking and maybe the sensors reduced fuel consumption because of lack of air flow?).
They told me that one of the spark plugs was worse than the other, and I'm now wondering if that was the cause. Now that's annoying as I bought a pair of HD gold plugs at the start of the trip, I wish I'd stuck with the previous iridium ones now.

The one thing thats hasn't been explained away is the fuel sender telling me low fuel at 100 miles instead of 80 miles that for the last 12 years it has, but of course that could be explained away as a faulty sender, however it has been doing that consistently for the last 2000 miles.
 
Ok, so to update you on how it was, it ran a bit better with the new plugs and air filter to the point where I wasn't having to change down a gear to keep it from bucking and kicking like you're in fifth trying to do 30mph.
From Seville I got as far as Salamanca before I noticed the old signs creeping back in.
Caveat: There's two of us on the bike plus camping and cooking, luggage etc so we're right up to GVRW.
I'm sure when anyone rode it with no luggage it would seem ok apart from that small amount of misfiring after startup (it always starts well).
The Seville HD dealership, I had asked to give me compression and injector readings, sensor, check oils etc, all to try and get a picture of what might be causing the issue, but they only said that they were ok, and didn't print out readings.
They only reported that it was running fine (after putting it on their computer) and they rode it, presumably one-up and that it performed OK.
They did say however, that there was oil in the air filter, that coincides with me smelling hot, not burned, oil whilst riding, or at least stopped at lights etc.
I'm now back home and 4200 miles later I can say that it ran well for aroiund 200 of that, the rest I had to nurse-30mph 2nd gear, 40mph 3rd gear and 4th seemed to have a bandwidth greater, 50-65, no more no less, 5th gear would only work at above 65mph (all these speeds as per HD clock not true speeds).

So now I'm thinking, could a sensor be giving info to efi making it lean, where are these sensors, and what resistances at 20 degrees should I be looking at?
Soon I'll take the plugs out that they put in and photograph them accurately so you can take a look.
I can't remember who said it-one of yourselves, or one of the mechganics that looked at it in Spain, but it was reported tha one plug was whiter than the other.

One last note, to check fuel consumption accurately, I would note number of litres I'd fill up (to neck) after a 100 miles.
Consistently it would be 8.5-8.8 litres for 100 miles (this would coincide with the low fuel light coming on, which for the last 12 years would always come on at 80 miles), by my calculation that would equate approximately to 2/3rds of the tank, so i'd get 150 miles out of a full tank to empty, or saying it another way 50mpg, remember, fully laden.
I've never previously got more that 120 miles out of the tank.
I'd appreciate any other input anyone could add to the above. TIA
 
The bike has a Temperature Manifold Absolute Pressure (TMAP) sensor. It does the job of a MAP and IAT sensors.

The MAP part provides instant manifold pressure information to the engine's electronic control unit. The data is used to calculate air density and determine the engine's air mass flow rate, which in turn determines the required fuel delivery for perfect combustion.

The IAT part shows air temperature at intake. Temperature affects how much petrol is required for cold starting or economical running on warm days. It is also used in calculating engine timing.

The resultant petrol injected will then be modified based on what the O2 sensors indicate.

Before deciding on whether to start changing stuff I would recommend you get an electrical diagnostic manual as it shows how the sensors can be tested.
 
Thanks Andy, would the workshop manual be sufficient, or are we talking something else?
Also, does that sound like a good place to start testing based on anecdotal evidence?
 
There is a separate electrical diagnostic manual. Some of the download sites for pdf files include it with the service manual if you don't have one of them either. Did you ever tell us what year the bike is?

Your fault on the surface seemed like an air leak. It is clearly something strange so before getting a shop involved I would try and test as much stuff as possible myself.

There is a lot of information here and it might have all you need to test the sensors saving you the cost of the manuals.

EVO: Engine Control - Sportsterpedia

sportsterpedia.com sportsterpedia.com
 
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Thanks guys, wow it's complicated! Ask me what's wrong with your boiler and I can tell you, but the amount of testing here is beyond me, and I'm OK with a Fluke multimeter too.
I think I'm gonna take it to a dealership and just ask them to do all the testing of sensors for me.

But before I do that, reading through the testing regime there I noticed a recurring theme (the battery ground).
Now I did put a lithium battery on the bike about a year ago, and recently I was informed here that an odd issue that appeared (the speedo dropped its reported speed by 5-7 miles per hour when the horn was pressed) might be linked to a bad ground, so I'll check the ground first.

Thanks for your input.
 
The year of the bike is also in question as I bought it brand new in December 2010, but some have said it's a 2011 Nightster-I have to check that out.
ALSO, I have had issues with the speedo itself occasionally, and reading through that "sportsterpedia" link, I see there's a relationship between VSS and ignition.
At the start of this journey 2 up and luggage, the speedo stopped working completely, briefly.
It's happened before but I wasn't 2-up so if it happened to affect the ignition I wouldn't necessarily have noticed as I barely rode the bike, even less went fast (above 70) on it.
It righted itself after a few miles and an ignition/restart of engine cycle, and didn't reoccur.
 
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