2008 street glide speedometer reads high

[DTD]

Hello people, I have a problem and am seeing if anyone here can help me.
I have an 08 street glide and a few weeks ago my speedometer started reading high, not a little high but it says I am doing 150mph when GPS is at 65mph and then the ECU cuts fuel. The needle moves a little sometimes when I rev it up also.
I have replaced the speed sensor whith a good used one from eBay and also a new one and it didn't work.
I checked the plug and the grounds and also cleaned them and used deoxit on all connections in the fairing too.
Today I unwrapped the wiring harness and traced the continuity to the ECU and still no joy.
I have an FP3 tuner and tried recalibrating the speedometer and also flashing an old map, it did not work.
I have a used speedometer coming from eBay but I have doubts as to whether it will work, but I am crossing my fingers.
Has anyone ever seen anything like this before? I did wire in a new 6 pin throttle body pigtail right before this all happeneded but I am not getting any codes from it and the engine is acting fine.
Thank you for any help with this

[CndUltra88]

Hello people, I have a problem and am seeing if anyone here can help me.
I have an 08 street glide and a few weeks ago my speedometer started reading high, not a little high but it says I am doing 150mph when GPS is at 65mph and then the ECU cuts fuel. The needle moves a little sometimes when I rev it up also.
I have replaced the speed sensor whith a good used one from eBay and also a new one and it didn't work.
I checked the plug and the grounds and also cleaned them and used deoxit on all connections in the fairing too.
Today I unwrapped the wiring harness and traced the continuity to the ECU and still no joy.
I have an FP3 tuner and tried recalibrating the speedometer and also flashing an old map, it did not work.
I have a used speedometer coming from eBay but I have doubts as to whether it will work, but I am crossing my fingers.
Has anyone ever seen anything like this before? I did wire in a new 6 pin throttle body pigtail right before this all happeneded but I am not getting any codes from it and the engine is acting fine.
Thank you for any help with this

Welcome to HTT.
Rob

[DTD]

Thank you, glad to be here!
Sorry if I just come out of nowhere, I've been lurking but I do have my moments of usefulness.

[rigidthumper]

May be getting AC voltage from the regulator bleeding through the system, easy enough to check- unplug the regulator feed from the stator, and retest ( make it a short trip, as your battery won't last forever)
The other thought I had was spark plug wires can induce an electric signal into wires laying near/against them.

[DTD]

Thanks, I have not checked the regulator so I will when I get off work. I did have a USB charger that stopped working and the lines ran in the same area as the sensor lines, I removed them when I checked the harness thinking it was bleeding ac into the wiring like you said.
I hope that's it and I can get back in the wind.
Thank you!

[C#]

My speedo on my '06 Nightrain started doing the same thing... which was a pre-cursor to total failure. Bad circuit board. Bad manufacture in Taiwan.

[DTD]

Bad circuit board in the speedo or am I going to need a flatbed? 
I am getting worried now

[C#]

The speed sensor is not in the speedo... so mine continued to run until I got a new speedo. I think the speedo is much more complex than a speed sensor (not sure what yours looks like) but due to the moisture that gathers in the speedo if the waterproof dip isn't done well then moisture gets to the board so that would have been my first guess... got a buddy with the same bike that has a working speedo? Do a temporary swap... cheapest way to go.

As for an ebay speedo it must be for the correct model and year afaik. You also are supposed to get it re-calibrated for your actual mileage which is a dealer task.

Don't know if your piggyback ECM interfaces with the speedo. Mine didn't.

[DTD]

Thanks!
The Speedo came in yesterday but it's raining and I have to work. Everything looks the same except the faceplate. I'm at 72000 on the original and I will Mark it down before I try the swap.
I had heard the milleage gets set in the ECU and not the Speedo on my yearmodel but we shall see.
Wish me luck!

[DTD]

Well, the milleage is kept in the speedo and not the ECU. I installed the eBay speedo after work today and it was at 83000. The donor Speedo is off a roadglide and has a 2011 manufacturer date, everything is the same except the black faceplate and ring it slipped right into the hole and powered up.
My problem is still there so I am going deeper into the wiring tommorow. If I don't find a broken wire I'm pulling out the oscilloscope and analyzing the actual data signals from the ECU. My first thought is a bad ground causing a harmonic in the speedo signal from ECU but that should cause other problems as well.

[Scotty]

Check all your earth connections around the bike from battery onwards and make sure they are all clean and tight.
You might need to use a known good speed sensor as well.
Check any electrical work you have done as that is usually the guilty party just disconnect it and re-check you have done it properly.
2 speedos both doing it and your bike never did it before then I would always look at the last thing I did.

[DTD]

Well, problem fixed but I don't know how. I flashed back to my base ECU map but I also moved the crank sensor wire away from the regulator wire at the same time. I am going to move the wire back tomorrow for organization and find out. I had tucked it away neatly after changing the front motor mount.
Thank you everyone for helping me out!

[jmorton10]

Well, problem fixed but I don't know how.

Don't you love it when that happens ??  LOL

~John

[Scotty]

I flashed back to my base ECU map

That there might have been the problem................ worth a check

[CndUltra88]

Thank you, glad to be here!
Sorry if I just come out of nowhere, I've been lurking but I do have my moments of usefulness.

h.


Nothing negative implied.

I didnt have anything useful to add so a Warm Welcome was all I could come up with.

Rob

[IronButt70]

I have another question about speedometers. My son has a sporster 883. He put on a larger better wearing rear tire because he got tired of replacing them every 5-6k. Because of that his speedo now reads about 5 MPH low. Can the ECM be flashed to compensate for that?

[rigidthumper]

Speedo correction can be done if you have a flash tuner (TTS, PV, DL all have that capability) married to that bike.

[DTD]

The FP3 tuner I have is supposed to be able to do corrections, my Speedo always reads  little slow. I have attempted to correct it several times but after I flash the corrected map it never changes so I just live with it.

I believe my problem stemmed from a corruption in the ECU map from my FP3 and going back to the dealer tuned map fixed the problem. I dont know how but the map V&H has for my setup should run great but always performs like a dog compared to the base map. I emailed them about it.
The base map is for a 96" with CVO255 cams, I installed 107 cylinders and S&S 551CE cams now and the engine runs strong until I flash it to the V &H maps then it runs weak.

[kd]

Search FP3 on this site, read and take the advice that is given by the majority of qualified contributors.  Nuff said