We are guessing it is a 20 year old fuel pump. I realize not cheap. There are cheap after market ones, I chose not to buy those, since they can leave me straned, and all odd ball companies.

 

It actually looks pretty new, is definitely aftermarket. I was just not sure if these pumps can kind of be working?

 

If your hoses, pump all check out, maybe check for an intake leak as E98 suggested. Check to see if the flanges are tight and the flange seals are intact.

 

Ok guys and gals sorry for the delay, have been waiting for parts and the time to jump in. So, I replaced the fuel pump and all of the internal tubing and it almost seems to be worse now. I double checked everything (not my first rodeo) so I have to assume the previous assembly was probably working ok. So, now what? Well I noticed the gas in the tank is on the yellow side so am going to drain and replace that (duh, don't ping me for that it does not look that bad) and then run some injector cleaner through it and see if any of that helps. The current symptoms are: starting from cold, cranks but struggles to turn over, when it does idle is very low and then stalls, crank again and does not turn over, let sit, crank and same as the first time. When I do rev the throttle is revs the engine but in a few seconds it seems to loose power and the second time I did it I get a back fire. I know it must be a fuel to air ratio thing so will put in some new gas and see what that does. Also, the kit came with a replacement fuel pressure regulator but I am not sure where it goes exactly. Need more research on that.

Regarding the comments about an intake leak, if that still sounds feasible to you please let me know specifically where to check, I know my way around many bike but this is my second harley.

One other quick thing, I did need to reuse the existing fuel filter (not the screen, the metal one) because the one that came with the system was too small and did not fit properly in the bracket. I shot some air up in it and reinstalled with the new pump. Not sure if that could be an issue, just the whole thing is very erratic.

Thanks.

 

You originally said you could hear fuel "splashing" when you turned on the bike. Did that stop?

 

Yes, but I figured that was from the fuel return system displayed in the diagram earlier in this thread and confirmed that is where the sound is coming from.

 

Ok another interesting addition, when the PO traded the bike with me they gave me an additional ECM. They said the Harley dealer installed a new ECM and this was the old one. However, when I just called the same dealer, they said that they diagnosed a bad ECM in October but then never heard back. So, are assumption is the PO bought one on the used market. Since the ECM controls the fuel/air mixture we assumed that the ECM being bad is what is causing the rough running bike. So, I cracked open the side panel to pull the "new" ECM only to find that it looks like the original is still installed (assumption based on the amount of grit and grime). So, I hooked up the other ECM that they gave me with the bike and the problem persisted. So, now I am taking both ECMs to the local Harley dealer for testing to see if either one of them work.

With that, HOW DO YOU REMOVE THE ECM FROM THE RUBBER MOUNTING!!!! That is making me a little batty right now. I know there must be a trick but.....

 

If you are dealing in aftermarket fuel pumps, make sure you get one that flows the same as OEM, or you could have problems from the new pump...

Did you ever check your fuel pressure before diving into the tank and replacing parts...?

You are planning your repairs based on second hand info from a guy who sold the bike, rather than fix it.... Big red flag there... I would take anything he said with a grain of salt...

That MM EFI system was good in it's day, but is old, out of date, and has been problematic as those bikes get older... It is hard to get parts for it, few know how to adjust/tune it, and many have swapped out an MM EFI for carb.... You took a big gamble buying an MM EFI bike that has "fuel delivery" issues.... Hopefully it is not the MM EFI itself causing the issues..

But that is now all water under the bridge... You need to start from scratch, do your own diagnosis of the issue, or give it to an expert with fresh eyes... hopefully one who is familiar with the MM EFI system.

If I was in your shoes, first I would get a copy of the proper HD Factory Service manual for the bike.

Then based on symptoms I observed, I would do a systematic diagnosis of the possible causes, trying to check/isolate the cause, and then fix it.

I don't "throw parts" at a problem, yet on a 20 year old bike, I'd be more apt to replace wear parts along the way... but every time you change something that doesn't fix your issue, especially if it's an aftermarket solution, you are adding another variable that could complicate the search for the actual issue(s).....

Start with the easier cheaper checks, like an intake leak, then progress through to the more involved/expensive ones...

Without actually getting hands on your bike, I'm can't offer a checklist for you to follow... but you have been given some good suggestions...

The first thing I would do is make sure the gas tank parts you replaced aren't adding to the problem, as you mentioned the fuel pump seems too small for the bracket and made the matter worse.... so you are now committed to make sure that was a good, proper replacement... then you can start your systematic diagnosis..

It can seem daunting, but if you are thorough and systematic, you will eventually find the problem, and learn a ton about your new bike in the process...

Good luck, and keep us posted in your progress....

 

Thanks for the ideas, direction and encouragement. I agree starting from scratch is probably the best course of action. Also, to be clear, unless I posted it wrong, the fuel pump was the right size, the fuel filter they sent was not so I had to resuse the one I had.

 

check the fuel pressure to see if it is adequate. The back fire could be intake gaskets. cheap and easy.