I had the same thing happen to my '97 Ultra but, it would start to flood out when it idled. I went to a shop who had the scanner and they determined it was the temp sensor. They replaced it and I have ridden over 25K now with out an issue. Solo, I have been averaging 47 MPG.

 

Nice, glad to here that.
I'll see if my local indy has one before I start browsing the web for a good deal.
I did notice that it stumbles when I goose the throttle until it warms up. Then it runs great. It must be messin with the ecu.

 

Ignore the oil pressure gauge....its filled with Mermaid **** and Hen's Teeth....you can't trust them....

 

If you can find that temp sensor anywhere but HD let me know. I've looked long and hard for a cheap version and can't find it. The cheapest online one is from Kutter HD $80. P/N 32446-95a. Be careful you don't get a -99a. It won't work.

The replacement isn't hard to do. Stretch the front fuel crossover tube up over the coil after removing the tank bolts and you can move the tank up out of the way. Hold it up with a block of wood or a few rags stuffed under it. You'll need a small screwdriver to unclip the sensor wire connector. After that it's a deep well socket to get the sensor out and replaced. Torque it per the service manual.

You might want to also check/reset your hot and cold idle speeds. 1500 cold, 1050 hot.

 

Making you an M & M expert quickly.
You have:
98 FLHTCUI with No mods yet
The bike is a magneti marelli fuel injected as explained which was used from about 1995 to 2001 or so by Harley. M & M is a system or brand used in many high end vehicles from europe.
There was nothing wrong with this system but harley decided to go with delphi later on.
Many M & M harley bikes on the road and numerous european vehicles use M & M.
Several large Harley builds were made and are still on the road with M & M injection.
Harley now uses Delphi.
M & M is a very simple and very reliable system BUT since it has not been used for a long time very few new techs. have seen it.
Parts are available easily other than the gas tank itself which is available but takes a little looking.
Again very reliable, very simple but you most know a few things.
First you must own a Harley service manual.
Second you must look at chapter 9 in the manual.
The bike Fuel injection system is rather simple, has few components and if you read chapter 9 you will then pretty much understand almost everything.
Since the bike has been out for such a long time the known issues are well documented.
1- The cam position sensor inside the timer cone. Original melts and the goo is visible under timer cone were the wire exits (located by right foot so take a look) very easy to see with no tools..code 56 and requires lots of cranking before it will start...note a code 56 is triggered for any fart and the code alone is not indicative of a problem..reset computer by disconnecting battery cable.
If sensor is melted replace as a do it yourself for about $180 from Harley dealer or as low as $100 for new ones from EBAY but it must be the correct part number or it will not work...simple tools for replaement
2-VERY IMPORTANT AND MANY GET FRUSTRATED AND CHANGE TO CARB. BECAUSE THEY MISSED THIS...the crank position sensor NOT cam position..the CRANK sensor located by oil filter has a wire that runs along motor and then crosses to opposite side as it goes to the computer (ECM)..There is a connector that gets loose right behind the plastic side cover (throttle side/right side), the cover under the seat. Remove side cover..The connector is black and hidden by frame tube. That connector is a push and turn connector that gets loose and causes bike to shut off or miss..PLEASE LOOK FOR THIS CONNECTOR and zip tie it several times..again many people get frustrated and the techs. do not check for it.. causes all kinds of pissed off folks. THIS IS A FREE FIX THAT COST PEOPLE HUNDREDS $$$ if they go to the dealer since the dealer will not check this and it will rarely throw a code. Several people have been helped by this advice on this forum alone.
3-your fuel lines (2) external under tank will leak fuel at swivel after about 8 years and the originals are NOT serviceable. GOODRIDGE makes HDFL005..The Goodridge lines are at least less than half the $$$ that harley charges..Google the part number as some places sell for under $150 delivered for BOTH fuel lines.
4-Inside the fuel tank..a liner piece inside the tank separates right near the fuel pump and blocks fuel passage at the sock looking filter..bike will suck piece of liner and block fuel flow..you slow down and it releases...then gets stuck again..cycle repeats..repair is simple..open top of gas tank, remove little liner piece..suck fuel out, fill again, drain, wipe inside and close it up..no parts required unless you tear the gasket.
5-The ENGINE temp. sensor is super common and causes surging since the bike gets confused between hot/cold..change out is not that difficult but up to now HARLEY is the only replacement we have seen..very odd your bike is throwing code 14 and that it would run OK?? did you wash the bike? did the bike get washed with a high pressure hose? because it would be odd for it to be running good but the sensor to be bad.
6-The ECM connectors and power commanders...The ecm sometimes has the ground pin get some corosion because the bike is exposed to a high salt content or someone is pressure washing the bike and the connector is not seated correctly.. the ground pin makes bad contact and causes weird stuff.. regarding the power commander some individuals remove the power commander before a sale and keep the rubber protective ECM boot...with no rubber boot contamination from water is very possible.
7-DO NOT USE lowering blocks at rear of bike..The swing arm at the rear does not like lowering blocks..The use of lowering blocks changes shock angle and greatly increases the likelyhood of rear swingarm cracking right at the axle bolt area.
8-Finally some report issues with the throttle body because it must be clean especially the little air bleeds and the connections should all be nice, clean and good to avoid air leaks.

 

The main issue with MM isn't reliability (although in reality they are suspect) but the fact that you cannot easily tune them to match your engine mods.

 

ETS is one of the base inputs of fuel control sent to the ECM, if not in specs the ECM is telling the injectors to close early or stay open longer and it is usually the longer which floods the engine. Change it and not overthink this because it is EFI.
Don't worry about a carb change until the MM becomes undependable or doing a bigger engine and the ETS failure is common so don't get nervous.

 

I have a 97`Roadking,had the same problem except no code.Changed out the temp sensor,runs perfect.All HD dealers carry this sensor because it is a comon problem.Thanks to this forum my baby runs great.I also found the temp. sensor problem and help no here.Good luck.Skip

 

The MM as implemented by HD sucks. It is an open loop system with no trim or feedback. Even Ducati dumped MM. When they went to Delphi and added EGO and feedback, they had a good EFI system. The MM is **** poor as used on HD. and unless you have a scanalyzer and breakout box of your own, it will be hard to find someone to actually work on it.

 

It's been a fun Harley week for me, Here's the run down.

I fallowed IM's run down list and went over everything.
The original ET sensor code didn't come back after I disconnected the battery and re connected.
So I called a buddy of mine and we went for about a 100 mile ride over to the coast and back.
About half way there I notice a waft of smoke coming up the right side and the smell of burning oil. sure enough, leaking push rod tubes. It wasn't to bad so we just stopped every 30 miles and I wiped it off. Well, by the time I got home it was a mess.
But no engine codes.
So I pulled the front tube apart and to my delight there's an adjustable push rod. So while i'm inspecting the seals I notice that the middle o ring is on top of the spring contacting with the cover???? I couldn't see how this setup would hold back oil. So I referred to the service manual. Sure enough, it was installed incorrectly, I checked the other three, yep, all of them were wrong.
So I picked up a set of o rings from the local indi as well as an ETS from HD, (100$) just in case.
I read up and watched videos on setting the adjustable push rods since I had no instructions from the PO who probably didn't even know she had them.
Feeling some what confident (i've been a back yard mechanic for 25 years) I tackled the job this morning.
Did the base circle, brought the rod down to touching the lifter then did three full turns. Let em bleed down and they all spun. Also put the tubes and o rings on the correct way.
Fired her up, She rumbled like an evo. So......I washed her .....Didn't use high pressure, just a garden hose with my thumb over the end. Let her sit for about an hour before i started her. run good, at first.
I rode her from the back yard to the front, let her idle while I got my helmet on to go around the block. Hopped on and....thawump..thawump..thawump. Idle started to lope between 900 and 1500rpm. Engine light comes on. Sooo I check the code, yep..14 ETS. What the hell, I have it, so I changed it right then. Fingers are just a little singed.
All changed, I did disconnect the battery then reconnect when I finished and I also pulled all the plugs I coulod find and put dielectric grease in.
Fired right off. Ran great. Went around the block,(about 4 miles where I live) Not a drop of oil from the rockers.
But, she's idling at about 1200 rpm now, was 900. I liked it better at 900. I have read that 1050rpm is normal.
Is there an adjustment for the idle on the MM system?
I did have the air cleaner completely off and cleaned the throttle body with carb cleaner and a rag. Maybe I moved something.
Anyway, Thanks for all the input from everyone. It was very helpfull.