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ahhudgins
07-13-2009, 08:11 PM
I had the intermittent problem with my 95 Maristar 200VRS cranking and not starting a few times during the weekend. I got the manual on the MEFI from Discount Inboard Marine on Friday, read over it this weekend at night, and got the problem fixed on Monday. When it didn't start I had no power to my fuel pump and no firing signals to my injectors. Tach signal from the distributor looked good. I had to sit in the driveway for about an hour starting it until if finally messed up once or twice. When it didn't start, the voltage out on #87 of the MEFI relay was either noisey or 0V. The relay tested good so I monitored the input to the relay on #86. Same thing there, either noisey or 0V. Problem is a bad ignition switch, purple wire. Switch contacts from B+ to run position good, B+ to start position dirty as crap. Simple problem, just hard to find without a schematic. In cheking all of my connections, I found the inside of my distributor cap looked like it had been submerged in salt water for about a month (I can't believe the thing actually ran, and shame on me for not doing a good check this spring). Thanks for everyones help (JimN) and I hope I can help others out in the future.

JimN
07-13-2009, 08:18 PM
I had the intermittent problem with my 95 Maristar 200VRS cranking and not starting a few times during the weekend. I got the manual on the MEFI from Discount Inboard Marine on Friday, read over it this weekend at night, and got the problem fixed on Monday. When it didn't start I had no power to my fuel pump and no firing signals to my injectors. Tach signal from the distributor looked good. I had to sit in the driveway for about an hour starting it until if finally messed up once or twice. When it didn't start, the voltage out on #87 of the MEFI relay was either noisey or 0V. The relay tested good so I monitored the input to the relay on #86. Same thing there, either noisey or 0V. Problem is a bad ignition switch, purple wire. Switch contacts from B+ to run position good, B+ to start position dirty as crap. Simple problem, just hard to find without a schematic. In cheking all of my connections, I found the inside of my distributor cap looked like it had been submerged in salt water for about a month (I can't believe the thing actually ran, and shame on me for not doing a good check this spring). Thanks for everyones help (JimN) and I hope I can help others out in the future.

For future- if a relay won't latch, keep a few test leads in your tool kit so you can latch them manually. It helps to narrow down some problems and could get you home, in a pinch. The relays get DC, so it can't really be noisy but if it buzzes, it's usually a flaky hot or ground, DC on 85 and 86 or AC voltage. You can verify bad grounds by connecting the test lead to a known good ground and likewise, for a flaky hot, as long as it's not a trigger from the ECM.

ahhudgins
07-13-2009, 08:57 PM
Yes, ground on #85 was good but the DC hot on 86 was extremely noisey because the contact in the ignition switch is very dirty. I was monitoring the fuel pump B+ and injector B+ with DVMs and I had the scope on the #86. When the boat didn't start, #86 looked like someone was turning the ignition switch off and on about 100 times a second, so I'm sure the relay was buzzing, just couldn't hear it when it was cranking. I had already pulled the fuel pump and the MEFI relays and tested them off of the boat first.

I definitely agree with the advice you give everyone: Check all of your wiring and grounds! The main ground connection on the rear of the block was a little dirty but not too bad. I have two temp sensors in the manifold and the harness for the wires was pinched between a ridge on the intake and the valve cover. The black plactic of the harness had actually melted and the wires were almost fused together. I guess I'm lucky the boat ran as well as it did.

JimN
07-13-2009, 09:30 PM
Yes, ground on #85 was good but the DC hot on 86 was extremely noisey because the contact in the ignition switch is very dirty. I was monitoring the fuel pump B+ and injector B+ with DVMs and I had the scope on the #86. When the boat didn't start, #86 looked like someone was turning the ignition switch off and on about 100 times a second, so I'm sure the relay was buzzing, just couldn't hear it when it was cranking. I had already pulled the fuel pump and the MEFI relays and tested them off of the boat first.

I definitely agree with the advice you give everyone: Check all of your wiring and grounds! The main ground connection on the rear of the block was a little dirty but not too bad. I have two temp sensors in the manifold and the harness for the wires was pinched between a ridge on the intake and the valve cover. The black plactic of the harness had actually melted and the wires were almost fused together. I guess I'm lucky the boat ran as well as it did.

If the wires that were melted were shorting and they were yellow/black, the ECM would have stored an overheat and a bad ECT code. It also would have run very lean, if it went to high RPM at all. Most likely, it would have gone into RPM reduction and you would never have gotten above 2000 RPM. If you have a problem with low RPM, go back to the pinched wires. The grounds at the rear of the block need to be clean. The ECM, sensors and fuel pump ground there, among others.

ahhudgins
07-13-2009, 10:54 PM
Thanks for the info. I'm going to start paying a little more attention to motor details when I put the boat away for the winter and when I take it out of storage. The horrible condition of the electrodes in the distributor is what shocked me. Hard, crusty, white corrosion and it still ran. Time for a tune up.

JimN
07-13-2009, 10:56 PM
Thanks for the info. I'm going to start paying a little more attention to motor details when I put the boat away for the winter and when I take it out of storage. The horrible condition of the electrodes in the distributor is what shocked me. Hard, crusty, white corrosion and it still ran. Time for a tune up.

If the cap is only a year old, a wire brush can remove most of the crust but if it's much older, the metal is too pitted to really work as well as it should. How did the rotor look? Plug wires should be checked, too.

ahhudgins
07-14-2009, 10:36 AM
The rotor looked fine, and the cap hasn't been replaced since I bought the boat 3 years ago. I put new plugs in it when I bought it so I might as well do the cap and wires as well. I used a dremel tool with a soft wire brush to clean the electodes but I will still replace it. The metal base inside the distributor was covered in the white corrosion and the two screws holding the tach module were rusted pretty good too. The pins on the connector were cleanable. I know the orginal owner kept the boat on a lift under a roof and hardly used the boat (less than 200 hours when I bought it). I only put the boat in the water on the weekends and it's under roof when it's not in the water. There is no gasket under the cap, should there be one?

JimN
07-14-2009, 12:15 PM
The rotor looked fine, and the cap hasn't been replaced since I bought the boat 3 years ago. I put new plugs in it when I bought it so I might as well do the cap and wires as well. I used a dremel tool with a soft wire brush to clean the electodes but I will still replace it. The metal base inside the distributor was covered in the white corrosion and the two screws holding the tach module were rusted pretty good too. The pins on the connector were cleanable. I know the orginal owner kept the boat on a lift under a roof and hardly used the boat (less than 200 hours when I bought it). I only put the boat in the water on the weekends and it's under roof when it's not in the water. There is no gasket under the cap, should there be one?

The cap will often come with a gasket. The "tach module" is the Ignition Control Module, so it's actually more important and you should probably unplug the distributor, unplug it, remove it and clean that up. The IC Module wants good grounds.