[Chris B]

It's 80 degrees and sun shine here, our boating season is pretty much year round. So right now I am wasting sun shine. I am narrowing down the problem and it seems to be pointing to the ECM. Per the repair manual diagram the ECM controls the warning buzzer sensor and the fuel pump relay along with many other sensors and relays. If I turn the ignition to the on position and the buzzer sounds the engine will start. If I turn the ingition to the on position and the buzzer does not sound, I do not here the fuel pump pressure up and the engine just spins over but will not strart. It is not getting fuel. It does have spark in either situaton and since the spark is also controled by the ECM it make the ECM suspect. I am still checking all wires and connections but may have to have the ECM checked. Big problem is boat is not on the trailer it is on a lift in my boat shed and even if I get it on the trailer nearest service center is over 50 miles away. Trying to find a local mechanic that can test the ECM, may have one in our Motor Cycle Club. Will keep all posted on what I find.

[DCB_MINDED]

Just a thought, but have you looked to see if there is a fuel pump relay (by itself) If so, it could be as simple as the relay going bad.... I have seen them get a little spot of corrosion on them and not make contact. My apologies for the bad info earlier on the fuel pump. Aparently the 7.4 is set up differently than my 5.7.

[Chris B]

No problem on the info. The fuel pump relay is on top of the engine, I will check it shortly and try to find the warring buzzer sensor to check it. I talked to the mechanic I thought may have equipment to check the ECM but he does not. I will chase a few more things but it is looking like I will take it to dealer and let them go through it and fix what they find. They have a check up special for 225.00 plus parts they go through and check everything.

[DCB_MINDED]

I had a car that did that with the fuel pump relay. It wouldn't start for anything but if you pecked on it with something, the pump would kick in, and it would fire right up. the relay was over 100 bucks, so I took a chance on tearing it up (actually it was broken anyway, so no real risk) and took it apart. Took a little 320 grit sandpaper to the contacts in there, and used some terminal cleaner on it. Worked for another year until I sold the car! I guess it's still running to this day.

[Chris B]

Swapped fuel pump relay with another one that was next to it and nothing changed. Also checked the fuses again. All terminals have power with the ignition switch on and all fuses check good. I am still looking & checking. Tapped on everything that looked like it needed tapping on, even the ECM and nothing. Did not spend a lot of time on it today, had to mow the yard.

[Hudson River Steve]

Chris,

Did you verify that you have battery voltage on the Grey wire coming off the Fuel Pump Relay? You should be able to hear the fuel pump buzz immediately after turning the ignition switch on. I believe it runs for about a second or two to prime the fuel rail and then the ECM shuts off the pump until the motort starts running...after which it runs continuosuly.
If you want to take the ECM and fuel pump relay out of the equation, you can remove the Fuel Pump Relay from its socket and using a short piece of wire jump the terminal with the pink wire to the terminal with the grey wire. You shoud now hear the pump run continuously. If you don't hear it then either the pump is bad or the wiring to the pump (Grey is positive or Black is ground) is bad. As you say, the pump is tough to get to.

P.S. The sound that you hear when you turn the key off is the Idle Air Control valve.

Steve

[Chris B]

Hi Steve,

Pink wire has power, jumped pink wire to grey wire and fuel pump runs. The ECM does not signal the relay to turn the fuel pump on. I checked the relay by swapping it with the spark relay and the fuel pump relay works in the spark socket. Put spark relay on fuel pump and nothing. Also checked the kill switch, it's working properly, shift sensor is working properly and can not find any problems with the ignition switch. I turned the ignition to on, moved the shifter and can here the relays clicking, except that the fuel pump relay does not click. Turned the kill switch on an off and same thing. With the ignition switch on I disconnected and re-connected the main connector from the boat to the engine and can here the relays click, except for the fuel pump, also the warning buzzer does not sound (buzzer is good). So I am back to suspecting the ECM and looks like I will take it to dealer and let them go through it. Befoe that I will find the pink wire coming out of the ECM and test it at the ECM to make sure it is not broken between the ECM and the relay, also I did not check the ground wire in the relay connector so will do that also. There's a ton of wires on this engine and none easy to access.

I did fix one thing, the electronic compass was not working and while tracing wires behind the dash, found a broken wire. Compass works now.

[DCB_MINDED]

Sounds like you are getting it narrowed down at least. Hopefully that will save you some big cash in diagnostic fees. It's a shame it couldn't be something simple like a bad relay Best of luck getting it all worked out!

[Chris B]

Sprayed it with WD-40 and put duct tape on it and it still won't start. . Tried jumping the fuel pump to make it run, starts up will not stay running. Also when I checked the wires coming into the relay they are all grounded except for the pink hot wire. I talked to the mechanic at the repair shop today and as soon as I can get it on the trailer I am going to bring it to him and have him to go through it and fix what he finds along with doing the yearly service. The engine oil and drive oil are fresh so he does not have to do that part. The trick is going to be towing it to the lanch and winching it onto the trailer as have only driven it on the trailer, never had to winch it on. While it is in the shop I am going to have the seats in the cock pit re-upholstered except for the drivers seat as it is in good condition. Will have them done in white tuck & roll so they all match and look fresh. After that a wax job and hopefully I am done except for putting gas in it and cruising. No issues in cabin, every thing works, it's very clean and all upholstery is in great shape. Thanks all for the advise and help, it's just more than this old shade tree mechanic can handle.

[Chris B]

It was the ECM. Did not take to dealer did all the trouble shooting myself in the boat lift, was about 99% sure it was the ECM after all the testing. Ordered new one, changed out and it fired up. I learned a lot doing this myself and now know why dealer charges so much to work on one of these. Perfromed some other task while working on the engine, like change out the belt and re-wire the 12V batteries and system the PO had this thing tuned into an electricians night mare. Few things left to do as the isolater is bad and the on board battery charger is not working, will change them this week. Other wise all is working fine and boat is running great (knock on wood).