Go Back   TeamTalk > Maintenance Tips, How-tos and Refurbishing Topics > Engine / Drive Train

Reply
 
Thread Tools Display Modes
  #1  
Old 06-05-2017, 08:58 AM
bdiesel bdiesel is offline
TT Regular
 
Join Date: Sep 2015
Boat: 2003 X10 MCX
Location: Southeast
Posts: 57
Low battery cause fuel pump to shut off?

I took the boat out Saturday to do some surfing & wakeboarding. I idled the motor up and was filling the ballasts and the motor died. I tried to restart but it wouldn't, so I pulled the center cushion and at key on, the fuel pump was not priming. I checked the connection at pump and it was good, but the wiring was warm. Hit key again and it primed and then started and ran fine. It stalled during a surf run but didn't go dead and when we were changing over from surfing to wakeboarding it died again but fired right back up. This was over a 2 hr period.

I get home, pull up TT, and read fuel pump threads until my eyes went crossed. Bought fuel pressure gauge and at key on 3 different times I got 48,50,50 dropping to 42 each time after pump shut off. I'm confused on what the pressure should be on an 03 MCX. Results from my searches said 04 and up should be 57-62 and an 03 should be 38-42. Since I'm in between I'm assuming mine should be 57-62? I live 45 min from the water and weather did not permit an on the water test.

Now to the battery part. I checked resistance from the plug at the pump to the engine block ground and at battery post and both measured .1. I then checked voltage at battery 12.65V, checked at plug on pump at key on 12.48V . Back to battery with key on 12.48V. Left key on checking at battery and it settled at 12.38V. Then I turned a ballast pump on and it dropped to 12.28V. It looks like my battery may be at the end of its life span. Would the depleted battery have caused the issues I was having?

Last edited by bdiesel; 06-06-2017 at 02:07 PM.
Reply With Quote
  #2  
Old 06-06-2017, 02:42 PM
bdiesel bdiesel is offline
TT Regular
 
Join Date: Sep 2015
Boat: 2003 X10 MCX
Location: Southeast
Posts: 57
My thought is that if the battery is at the end of its lifespan and when I turned the pumps on, the voltage dropped low enough to cause problem? I don't mind changing the pump out, but I want to make sure I have properly diagnosed everything before I do. If i'm missing something let me know.

The plan is to take the boat out this weekend and measure fuel pressure while under load. In the meantime, I have ordered everything necessary to replace fuel pump if needed, and I'll keep it in the boat.
Reply With Quote
  #3  
Old 06-07-2017, 06:10 AM
Tilemule Tilemule is offline
TT Regular
 
Join Date: Sep 2016
Boat: 2000 Matercraft Prostar 190, 1990 Ski Brendella supercomp, 1987 Supra Pirata
Location: Se Pa
Posts: 44
Your way of thinking is correct however if the battery was weak enough to affect the fuel pump it would not turn the starter.
Reply With Quote
  #4  
Old 06-07-2017, 09:02 AM
bdiesel bdiesel is offline
TT Regular
 
Join Date: Sep 2015
Boat: 2003 X10 MCX
Location: Southeast
Posts: 57
I agree with that, but a starter is engaged for 3-5 secs and my pumps had been running for about 3 mins. I had the boat idling at 1000 rpms. Another thread recently popped up saying it needs to be at 1500 rpms for the alternator to supply enough voltage for the pumps. Amperage increases as voltage decreases. The battery is 4 yrs old so I didn't want to leave it out of the equation. Just trying to cover all of my bases.
Reply With Quote
  #5  
Old 06-07-2017, 09:24 AM
mikeg205's Avatar
mikeg205 mikeg205 is offline
Moderator
 
Join Date: Aug 2011
Boat: 1995 Pro Star 205 5.7 Liter
Location: Plainfield - Joliet, IL
Posts: 16,683
Send a message via Skype™ to mikeg205
flaky battery even though shows good capacity can cause strange things to happen -how old is battery?
__________________
...A bad day water skiing still beats a good day at work...1995 Pro Star 205....
Reply With Quote
  #6  
Old 06-07-2017, 10:34 AM
bdiesel bdiesel is offline
TT Regular
 
Join Date: Sep 2015
Boat: 2003 X10 MCX
Location: Southeast
Posts: 57
This will be my 3rd season owning the boat & the previous owner told me he replaced both battery's the year before I bought it. Dates were not punched on the battery. I'm going to pull it and have it load tested just to rule the battery out.
Reply With Quote
  #7  
Old 06-09-2017, 10:50 PM
bdiesel bdiesel is offline
TT Regular
 
Join Date: Sep 2015
Boat: 2003 X10 MCX
Location: Southeast
Posts: 57
Took the boat out this evening & put the gauge on it:

Idleing through no wake zone = 40 psi
2500 rpm = 42 psi
WOT = 44 psi

Boat fired right up off of the trailer. I eased away from the ramp & shut it down to hook up the gauge. Hit the key and nothing. Unplugged the connector at the module, plugged it back in, & it primed. It stumbled one time at WOT & pressure dropped to 38 psi then came right back to 44psi. We surfed & wakeboarded for right at 3 hrs with no other issues.

From what I've read on other boats with a MCX it should be 57-62. This is the original pump & the boat has 137 hrs on it. Is it time to change the pump?
Reply With Quote
  #8  
Old 06-10-2017, 05:36 AM
Tilemule Tilemule is offline
TT Regular
 
Join Date: Sep 2016
Boat: 2000 Matercraft Prostar 190, 1990 Ski Brendella supercomp, 1987 Supra Pirata
Location: Se Pa
Posts: 44
I would think at the very least you would want to replace the in tank fuel filter. I would personally replace the fuel pump at the same time because my time is worth more than the 50 or 60 bucks to buy a new pump. When I did mine I actually pulled the whole gas tank to give it a thorough cleaning and basically start new.

I still have a intermittent gremlin in the fuel pump connector at the top of the tank. I have to figure out if it is in the connector or the wire. Sometimes I have to mess with the plug to get it working.
Reply With Quote
  #9  
Old 06-10-2017, 05:44 AM
Tilemule Tilemule is offline
TT Regular
 
Join Date: Sep 2016
Boat: 2000 Matercraft Prostar 190, 1990 Ski Brendella supercomp, 1987 Supra Pirata
Location: Se Pa
Posts: 44
One simple thing you could check is the gas tank breather. I have seen them get a little clogged from wax and I have seen them get clogged from mud wasps.

It is free and easy to check and you never know, strange things happen when dealing with a boat haha
Reply With Quote
  #10  
Old 06-10-2017, 08:32 AM
mikeg205's Avatar
mikeg205 mikeg205 is offline
Moderator
 
Join Date: Aug 2011
Boat: 1995 Pro Star 205 5.7 Liter
Location: Plainfield - Joliet, IL
Posts: 16,683
Send a message via Skype™ to mikeg205
2003 - many posts about those fuel modules failing... read the fuel pump 101 thread for more.
__________________
...A bad day water skiing still beats a good day at work...1995 Pro Star 205....
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


All times are GMT -4. The time now is 07:01 AM.