mercruiser 350 EFI won't start. help!

[dumpster]

Hello I have a 2001 mercruiser 350 EFI that will turn over but not start. the fuel pump runs, fuel injectors don't inject fuel, and I have no spark. I already swaped coils with my starbord motor and still no spark. please help!:huh:

 

[OldSkool]

Hello I have a 2001 mercruiser 350 EFI that will turn over but not start. the fuel pump runs, fuel injectors don't inject fuel, and I have no spark. I already swaped coils with my starbord motor and still no spark. please help!:huh:

Sounds like a short in the harness going back to that engine. Pull the key switch and make sure all the connection are good. Check you harness from the computer to the engine.

 

[poormonkey]

I have the same year boat but with the 5.0 EFI's, this summer I had the same exact issue. I was getting plenty of fuel, but a weak spark. For me it turned out to be the coil, so I put in new coils for both motors. Also, I put in new distributor caps as well, and changed the plugs.

How does your distributor cap look? Did you pull a plug out and leave it attached and see if you were getting spark while cranking over the motor? The old school route of putting the plug close to some metal and look for some spark?


I remember reading this as well, someone pulled it from the manual.

Tests for Thunderbolt Ignition:
W/ignition key on AND BILGE WELL VENTILATED OF GAS FUMES!!!

#1 - Connect your voltmeter neg. lead to the engine ground and pos. lead to the white/red wire terminal at the dist. It should read 12 volts.

#2 - If 12 volts is present, remove the coil spark wire from the distributor and connect it to a spark gap tester to ground. Remove the white/green lead from the dist. terminal. Turn the ign. key to on and strike the white/green lead to ground. If there is spark, replace the ignition sensor in the dist.

#3 - If there is no spark, substitute a new coil and repeat test #2. Now if you get spark, install a new coil. NO SPARK, replace ign. amp.

#4 - In #2, if there is No voltage present, disconnect the white/red wire and check it again for 12 volts. If 12 volts is present, replace the ignition sensor inside the dist. cap. If no 12 volts present w/it disconnected--ignition amplifier is shot and must be replaced."