2000 21V Fuel Pump not getting a signal

[Goofyr44]

What's up guys. I'm glad I came across this post. I am having very similar problems and its very annoying. I have a 2000 21V. If any of you have read some of my previous posts you would know that Ive done a bunch to my boat. I'll give a quick run down of the maintenance Ive done and then list the issue I'm having with the fuel pump. So far I've drained the tank, changed the fuel filter, changed plugs, plug wires, ignition coil, distributor cap, rotor, transmission sensor, all fluids, coolant temp sensor, Intake air temperature, and throttle body position sensor. After all the maintenance I thought I corrected the issues I was having.
So long story short after about three hours of running the boat it died on me while running about 35 mph. I got it cranked but the fuel smelled lean. Rode about a 1/2 mile down the river and it died again. After unplugging just about every harness and plugging them back in I was able to get it back started. I made it back to the dock but I never went over half throttle. While sitting at the dock, waiting for the trailer to get backed in, the boat died again. I couldn't get it to crank and had to load the boat without power.
Got back home and changed the TPS, IAT, and Coolant temp sensor. I also checked the fuel pump fuse again, just in case a gremlin caused it to blow, and it was still intact. Normally whenever the key was turned the on position the fuel pump would prime for about 2 seconds. This time it did not. I put a meter on the wires going to the fuel pump and my wife turned the ignition on and still no volts. Just make sure the fuel pump worked I connected it straight to the battery and it came on. I then assumed it was the relays. I changed them and still nothing.
Engine rolls over and starter is strong just no fuel. I haven't checked the oil sender yet but is there anything else that could be causing the fuel pump not to get a signal to turn on? I am beating my head against the wall to trying to figure this out.

[KoolAid]

I'm very fuzzy on mercs. Are you getting power to the fuel pump relay? Is the ground good at the fuel pump relay? If so, check for power (signal) at the relay when key is on. The ECM should feed power to the fuel pump relay as the signal to turn on the pump. To me that area should be your focus.

[boatwakes]

Check the grounds at the back of the motor just to be sure but at this point it sounds like the dreaded ECM failure. I'll pull out the manual here shortly and go over pin testing procedure on the connections. Just for giggles, disconnect and reconnect the ECM, visually checking the pins on the harness and ECM for damage and try again.

[boatwakes]

Okay, on the ECM input (called J1 input connector) and output (J2 output connector) there are specific terminals to test with voltage values for the fuel pump driver. It's possible the fuel pump relay driver is bad. To check, disconnect the J1 connector from the ECM and test terminal 23. It has a dark green with white wire connected to the terminal. Have someone turn on the ignition but not start and measure the reading using a voltmeter set to test DC voltage around 12 volts. It should read battery voltage for the first 2 seconds and then go to zero.

Terminals on the J1 and J2 connectors have two columns of staggered pins. As you look at the connecter's terminals, the column closest to the connector release tab and highest connection is number 1. The second column to its right, which is slightly lower, begins with number 17.

[Goofyr44]

I'm very fuzzy on mercs. Are you getting power to the fuel pump relay? Is the ground good at the fuel pump relay? If so, check for power (signal) at the relay when key is on. The ECM should feed power to the fuel pump relay as the signal to turn on the pump. To me that area should be your focus.

I am getting power to the relay with the key in the in position.


Sent from my iPhone using Tapatalk

[Goofyr44]

Boatwakes. As soon as I get home I’ll go through those checks. Thanks again for the advice and help. I’ll keep you updated.


Sent from my iPhone using Tapatalk

[boatwakes]

Good, disconnect the fuel pump two wire waterproof connector located about 6" from the pump and test for voltage going to the pump there. If its there, the pump is dead and needs to be replaced. Use OEM, cuz the Chinese crap is just that.

[boatwakes]

Has it had trouble turning over and not starting or does it occasionally not even turn over? Turning over means the starter is operating and the engine is spinning but not running by itself.

[Goofyr44]

Yesterday I tested the wire harness going to the pump and it did not have voltage when the key was turned on. I made sure to already have the leads on the plug before the key was on. I know that it only primes for a second. I hardwired the fuel pump to the battery for a quick test and it came on. So I k ow it will come on it’s just not getting a signal to turn on.


Sent from my iPhone using Tapatalk

[Goofyr44]

About the turning over question. Since I’ve owned it I have not had any issues with it cranking. This just all of the sudden happened while out. It normally fires right up without any hesistation.


Sent from my iPhone using Tapatalk

[Goofyr44]

Okay, on the ECM input (called J1 input connector) and output (J2 output connector) there are specific terminals to test with voltage values for the fuel pump driver. It's possible the fuel pump relay driver is bad. To check, disconnect the J1 connector from the ECM and test terminal 23. It has a dark green with white wire connected to the terminal. Have someone turn on the ignition but not start and measure the reading using a voltmeter set to test DC voltage around 12 volts. It should read battery voltage for the first 2 seconds and then go to zero.

Terminals on the J1 and J2 connectors have two columns of staggered pins. As you look at the connecter's terminals, the column closest to the connector release tab and highest connection is number 1. The second column to its right, which is slightly lower, begins with number 17.

Thanks again for all the knowledge and walk through. You have been super helpful and it is very much appreciated. I disconnected J1 and took a reading from 23. I could see the wire color because it was behind the harness. I could have taking the harness apart but your description of the pin location was more than enough. I had my wife turn the key to the on position and I got 12 volts. I also inspected both harnesses and pins and they appeared to be in good condition. I didn’t notice any bends or breaks. I see a few points where wires are grounded to the block on the back of the engine. I am going to take them off and clean them but they don’t look that bad. Is there anything else that could be causing the fuel pump not to get a signal?


Sent from my iPhone using Tapatalk

[Goofyr44]

Has it had trouble turning over and not starting or does it occasionally not even turn over? Turning over means the starter is operating and the engine is spinning but not running by itself.

In my search for the unknown to me, I came across this on the internets. Is this valuable info? I’m at a cross and don’t know what to do. Btw I owe a 6 pack or a bottle of whiskey if that’s your thing.


https://youtu.be/fSEwwa6D2jM


Sent from my iPhone using Tapatalk

[Goofyr44]

Has it had trouble turning over and not starting or does it occasionally not even turn over? Turning over means the starter is operating and the engine is spinning but not running by itself.

Anything else you can think of that I should check?


Sent from my iPhone using Tapatalk

[boatwakes]

Sorry Goofy, been at the lake since Thursday morning and just now enjoying my coffee with internet service. If the relay is getting power but the pump harness connection doesn't get power, it's a blown fuse, bad really or a broken wire between the relay and fuel pump. Sometimes the fuse in the 3 pack of fuses will blow so Check that next. The fuse set has 6 wires, red, purple pink etc.., coming out of the fuse harness and is usually located near the relays. It has a black cap about three inches wide by 1/4" thick on it. Fuel pump is the middle fuse but check all of them.

[Goofyr44]

No worries buddy I appreciate the help. I’m also headed home from a weekend trip. I checked the fuse last time and it was good to go (not blown). I’ll have to look for a broken wire or something.


Sent from my iPhone using Tapatalk