Water And The Harley Fuel Injection ECM

Most of us like to keep our rides clean. We take pride in having the chrome polished and the paint spotless. Normally, we just wash and ride with no problem.

More and more frequently we are hearing of Fuel Injected FLT/H models getting water into the ECM and either stranding the rider or quitting in the middle of traffic.

So, here's a few tips and how to trouble shoot this.

First, you need a motorcycle service manual. This is a must have tool if you do your own work.

If you suspect the ECM has water in it, the best thing to do is to remove the ECM and let it dry out over a day or so or gently warm it with a hair dryer. I do mean gentle! Get it too hot and you have an expensive do nothing box.

Removing the ECM is a lot easier than it looks and can actually be done on the roadside if needed.

Remove the right side cover. Some models will require the right saddlebag to be loosened or removed also.

Right behind all that wiring is the ECM it has a large connector right on top.

Inside the same area there should be an approximately 2” wide rubber and plastic connector that looks like it goes nowhere. By squeezing the clip and pulling down you will see the ECM power and Fuel pump fuses. Remove the 5 amp ECM fuse. You can accomplish the same thing by removing the seat and disconnecting the battery if desired.

After removing the fuse look for the two nuts that hold the ECM support bracket in place. Remove the two nuts and slide the ECM and bracket toward the outside of the bike.

After you have the bracket / ECM pulled out you can easily remove the connector and the ECM. The ECM is held on by four rubber supports. If you pull one side back and slip the other side out the ECM is now free.

Now, you need to dry the ECM. You can simply turn it so the connector side is down and let it sit for a day or two. Or, you can gently heat it with a hair dryer and speed it up some.

A couple of additional notes: You are working with Electrostactically Sensitive Devices in the ECM. A simple shock of static electricity can fry the ECM for good. Never touch the connectors with your fingers if possible and try not to shock it. Ground yourself on a water pipe before touching it if possible.

Don’t force the issue! Let it dry thouroughly. A drop of water contains contaminants that conduct electricity easily. A small drop on a circuit or in a small device can render the ECM inoperative. Being that it is not a cheap part, patience and caution are the word.

After the ECM is dried for a while you can reconnect it to the harness and plug in the fuse / reconnect the motorcycle battery. Turn on the ignition and look for the check engine light and listen for the fuel pump. IF you do not have both the engine will not start. Remove the ECM and wait some more. If it still does not work and it is dried out completely, time to take it to a shop.

What can you do to prevent this?

Remove the side cover before washing and cover the ECM with a plastic bag.

Make sure the rubber dust and water boot is installed correctly. If you have installed or had a Power Commander installed make sure the boot was transferred to the ECM connector of the PC.

Never direct full force water in this area. Wash by hand and use gentle flow of water.