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View Full Version : 1995 LT1 fuel pump issues... HELP!!


djobarefooter
07-22-2011, 01:06 AM
In 2008 and 2009 JimN walked us through fuel pump problems.. Back then, we replaced our safety switch, blown fp fuse, tested our fp relay, replaced our alternator, and repaired an electrical drain. We have changed as of today 3 fuel pumps. We have, according to our testing light, power at the fuel pump, but the new pump won't hummm. We have cleaned the fuel tank and the pick up screen and added aan inline filter before the pump thinking debris was causing failure. At a loss what to do next. Thes fp fuse is not blown and relay seems fine since we have power on the one side of the pigtail. HELP!!!! Any ideas?

Thrall
07-22-2011, 02:49 AM
Maybe you have the worst luck in the wold with fuel pumps. If you have 12V to the pump during the 2-3 sec priming cycle and 12V when the engine is running (if it ran I guess), then everything else works. You have another bad fuel pump.
Not sure why it's eating pumps if the tank is clean and there's a filter before the pump as well.
Could it be getting starved for fuel and heating the pump up? Run it out of gas ever/often?
My '96 190, LT-1 had a hidden in line filter just off the fuel pickup on top of the tank. Have you found one there? Could be old and plugged up causing fuel starvation, making the pump work harder.

Just some suggestions.

djobarefooter
07-22-2011, 10:46 AM
Thanks for input. We just cleaned the tank and screen and installed an inline filter on or near the top of the tank before we put this last pump on this week. Now we seem to have juice, but no hummm. When we took the old pump off, sth screen was dirty as well as the screen in the tank, so if debris can help in overheating the pump, I think we cured that now.
Does anybody know if we need juice on both sides of the pigtail to the pump. Light is dead ,on one contact and lights the other side. Assuming this is neutral side? Also pigtail look to be almost melted a little bit inside. We did clean the little bit of corrosion on the contacts. We'll test the pigtail issue today. Yes, we do feel like we have the worst fuel pump luck!!! Master Craft owners since 1980 never any issues. Love our boats!!!!

JimN
07-22-2011, 11:16 AM
Thanks for input. We just cleaned the tank and screen and installed an inline filter on or near the top of the tank before we put this last pump on this week. Now we seem to have juice, but no hummm. When we took the old pump off, sth screen was dirty as well as the screen in the tank, so if debris can help in overheating the pump, I think we cured that now.
Does anybody know if we need juice on both sides of the pigtail to the pump. Light is dead ,on one contact and lights the other side. Assuming this is neutral side? Also pigtail look to be almost melted a little bit inside. We did clean the little bit of corrosion on the contacts. We'll test the pigtail issue today. Yes, we do feel like we have the worst fuel pump luck!!! Master Craft owners since 1980 never any issues. Love our boats!!!!

Have you checked the resistance from the FP relay to the fuse, pump and the ECM? If the voltage drops on the + lead, it causes electrical devices to fail earlier/more frequently. The + starts at the red lead attached at the starter solenoid. All terminals and connectors need to be checked. If you see ANY corrosion on a terminal, replace it with a new crimped-on terminal and solder the joint.

djobarefooter
07-22-2011, 02:35 PM
Thanks. Will check it out this afternoon. Will post results of troubleshooting .

JimN
07-22-2011, 03:32 PM
Thanks. Will check it out this afternoon. Will post results of troubleshooting .

I would also re-check the fuel line and any hardware, from the fuel pickup tube to the pump. Yours may have a metal screen at the end of the pickup tube and the screen is very fine. I have seen some weird stuff clogging fuel pickups, so make sure yours is clean. Blow air through it from the aluminum block. Also, make sure the shutoff valve is actually open and the anti-siphon valve isn't sticking.

Thrall
07-22-2011, 07:07 PM
Here's some troubleshooting literature. Poor copies but readable if you blow them up

Thrall
07-22-2011, 07:08 PM
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