ECU Dead?
Thread Starter
|
Novice
Joined: Dec 2016
Posts: 20
Likes: 0
From: Hampton, VA
ECU Dead?
1999 Ultra Classic F/I with Magnetti Morelli parts. I ended up finding a PClll on eBay for 80 bucks so I bought to and installed it. I was riding home the other day and all of a sudden I had no throttle. Bike was still idling but would not accelerate and wouldnt rev or anything. Got to the side of the road and turned off the bike. Turned the ignition back on and hit the fuel switch and the fuel pump didn’t prime. Bike would turn over but it wasn’t getting fuel it seemed. So I got it towed home and pulled the fuel pump out and I hooked it to a power source and the fuel pump still pumps. When I hooked it back to the bike it will prime but only for about half a second then just shuts off. A harley Tech friend of mine believes that the ECU May have gone out.... any inputs on this?
Road Captain
Joined: Jan 2014
Posts: 641
Likes: 48
From: Brisbane
I’m not familiar at all with MM stuff, mine is the Delphi system, but my ECM crapped out at the end of last year. In my case it was pin #4 of the ECM providing an intermittent ground for the fuel pump- again, not sure with your ECM. It was a bitch to diagnose, but before assuming the worst I would be getting some wiring diagrams for your bike and a volt meter and test everything on that circuit. Check ALL your grounds as well and if you can’t find a problem then it may very well be your ECM. But you want to be 100% certain before you go spending that kind of cash on a hunch. Good luck and make sure you post up your fix when you find it!
Seasoned HDF Member
Joined: Feb 2007
Posts: 6,081
Likes: 1,127
From:
1999 Ultra Classic F/I with Magnetti Morelli parts. I ended up finding a PClll on eBay for 80 bucks so I bought to and installed it. I was riding home the other day and all of a sudden I had no throttle. Bike was still idling but would not accelerate and wouldnt rev or anything. Got to the side of the road and turned off the bike. Turned the ignition back on and hit the fuel switch and the fuel pump didn’t prime. Bike would turn over but it wasn’t getting fuel it seemed. So I got it towed home and pulled the fuel pump out and I hooked it to a power source and the fuel pump still pumps. When I hooked it back to the bike it will prime but only for about half a second then just shuts off. A harley Tech friend of mine believes that the ECU May have gone out.... any inputs on this?
What is the history of ownership?
What are all the changes from stock made to the bike? bars, controls, wheels, mufflers, air box etc
What is the mileage?
You report a purchase and installation of a power commander III..Did the motorcycle operate correctly before installation ? for how long did it operate correctly before installation?
You report that bike would idle but not accelerate, rev or anything....do you mean that bike had no response to throttle? Could it be a simple broken throttle cable ?
The fuel pump should prime for a moment and then stop unless bike is running.
There seems to be multiple steps missing in the diagnosis process.
For example: if someone changed handlebars or controls and created a stress point along throttle linkage or cable that broke the cable then you would have a loss of throttle response...on the other hand a simple broken tip on either end of throttle cable would create the same problem as wear and tear over time.
Seasoned HDF Member
Joined: Feb 2007
Posts: 6,081
Likes: 1,127
From:
I will guess you mean operates in the same way (with or without PCIII).. "I did disconnect it and it still ***doesn’t*** the same thing."
Trending Topics
Thread Starter
|
Novice
Joined: Dec 2016
Posts: 20
Likes: 0
From: Hampton, VA
It is rather difficult to follow the situation as presented.
What is the history of ownership?
What are all the changes from stock made to the bike? bars, controls, wheels, mufflers, air box etc
What is the mileage?
You report a purchase and installation of a power commander III..Did the motorcycle operate correctly before installation ? for how long did it operate correctly before installation?
You report that bike would idle but not accelerate, rev or anything....do you mean that bike had no response to throttle? Could it be a simple broken throttle cable ?
The fuel pump should prime for a moment and then stop unless bike is running.
There seems to be multiple steps missing in the diagnosis process.
For example: if someone changed handlebars or controls and created a stress point along throttle linkage or cable that broke the cable then you would have a loss of throttle response...on the other hand a simple broken tip on either end of throttle cable would create the same problem as wear and tear over time.
What is the history of ownership?
What are all the changes from stock made to the bike? bars, controls, wheels, mufflers, air box etc
What is the mileage?
You report a purchase and installation of a power commander III..Did the motorcycle operate correctly before installation ? for how long did it operate correctly before installation?
You report that bike would idle but not accelerate, rev or anything....do you mean that bike had no response to throttle? Could it be a simple broken throttle cable ?
The fuel pump should prime for a moment and then stop unless bike is running.
There seems to be multiple steps missing in the diagnosis process.
For example: if someone changed handlebars or controls and created a stress point along throttle linkage or cable that broke the cable then you would have a loss of throttle response...on the other hand a simple broken tip on either end of throttle cable would create the same problem as wear and tear over time.
Okay sorry its taken so long to respond... Ive been swamped at work.
Ownership - Ive had the bike since February and I got it from a brother in my MC, and he got it from another brother in the MC. The person I got it from had it for 6 years or so and put about 2500 miles on it because he was always riding his FXR.
Changes - I added a PCIII (Used off Ebay. Seller said it came off a bike he carborated) , 16" Paul Yaffe Monkey Bars, Eagle 204 Cams, The bike had a Bassani 2 to 1 exhaust when I got it, and I put a K&N air filter. The bike was running ridiculously lean when I got it because it was never tuned for the exhaust. I ended up burning up the rear cylinder exhaust valve so I rebuilt the whole top end.
Mileage - 40k
PCIII - The bike ran before installation but it ran so lean the rear exhaust pipe would glow orange when running 80-85 for any kind of time. So I got the PC to put in to get the bike from running so lean. The miles I rode before it died on me this time the bike did perform much better.
Accelerating - I was on the highway and I went to pass a car before we got to an area of construction and when I came off the throttle to slow down I went to speed up again and there was just nothing there. The bike was still running but there was zero throttle. I pulled off the side of the road and turned the bike off. I went to restart it and there was just nothing. When I normally turn the bike on the fuel pump would purge for about 3 seconds or so and when I tried to restart it just clunked. Once I got it home and pulled the fuel pump out of the tank I hooked it up to power and ground wires and it ran just fine. Put it in a bottle of water and it pumped the water out of the bottle. Hooked it back to the bike and it ran for a half second and stopped. Tried it multiple times and it did it every time.
Hope I covered everything you asked.
HD Forum Stories
The Best of Harley-Davidson for Lifelong Riders
7 Surprising Harley-Davidson Products that Are Not Motorcycles
Verdad Gallardo
8 Best Harley-Davidson Motorcycles Ever
Pouria Savadkouei
10 Worst Harley-Davidson Motorcycles Ever
Pouria Savadkouei
Killer Custom's Jail Break Is The Breakout That Refused to Blend In
Verdad Gallardo
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?
Verdad Gallardo
Harley-Davidson Reveals Super Cool Cafe Racer Concept
Verdad Gallardo
Engraved Rebellion: Inside Bundnerbike's Glam Rock II
Verdad Gallardo
10 Motorcycles You Should Never Buy
Joe Kucinski
10 Things Harley-Davidson Needs to Fix in 2026
Verdad Gallardo
Stellar HDF Member
Joined: Jan 2009
Posts: 2,578
Likes: 463
From: On a Lake, not far from the Gulf
I don't think you did your fuel pump any favors by running water through it. I also doubt that the ECU is deas as it is probably the ECU shutting off the fuel pump after it primes. The pump should prime for 2-3 seconds then shut off prior to ignition. The ECU will shut off the pump if it does not get ignition pulses, meaning something in the system is not working.
As always with a M&M EFI bike try pulling any trouble codes that may be stored in it. Also make sure that your ECM, and fuel pump fuses are good. They are located in a fuse holder behind the right side cover by the ECM. Next make sure that your battery is in good condition and fully charged. You may want to load test it at an auto parts store. Next take the PCIII out of line and hook the ECM up directly to the harness. Next check the fuel pump relay. You can try swapping it out with the stop lamp relay. They are the same part number.
As always with a M&M EFI bike try pulling any trouble codes that may be stored in it. Also make sure that your ECM, and fuel pump fuses are good. They are located in a fuse holder behind the right side cover by the ECM. Next make sure that your battery is in good condition and fully charged. You may want to load test it at an auto parts store. Next take the PCIII out of line and hook the ECM up directly to the harness. Next check the fuel pump relay. You can try swapping it out with the stop lamp relay. They are the same part number.
Last edited by larsfum; Oct 8, 2017 at 11:10 AM.
Seasoned HDF Member
Joined: Feb 2007
Posts: 6,081
Likes: 1,127
From:
Trying to follow your notes:
Multiple owners.
Last owner had it for 6 years/road 2500 miles
Mileage - 40k
You owned it since February but road it for an unknown number of miles.
Added used PCIII from Ebay at some point but unknown how long it has worked .
16" Paul Yaffe Monkey Bars
Eagle 204 Cams
Bassani 2 to 1 exhaust
Bike was running ridiculously lean
Added K&N air filter.
Burned rear cylinder exhaust valve so rebuilt the whole top end.
I will guess you added the PCIII after the rebuild and that you entered a map for your bike.
Test fuel pump power line with digital multi-meter.
If bike sat for a long time then pump might be getting stuck and require replacement.
Multiple owners.
Last owner had it for 6 years/road 2500 miles
Mileage - 40k
You owned it since February but road it for an unknown number of miles.
Added used PCIII from Ebay at some point but unknown how long it has worked .
16" Paul Yaffe Monkey Bars
Eagle 204 Cams
Bassani 2 to 1 exhaust
Bike was running ridiculously lean
Added K&N air filter.
Burned rear cylinder exhaust valve so rebuilt the whole top end.
I will guess you added the PCIII after the rebuild and that you entered a map for your bike.
Test fuel pump power line with digital multi-meter.
If bike sat for a long time then pump might be getting stuck and require replacement.