2001 225 Optimax blows 20 amp fuse-Fuel pump fuse

[rock_fish]

Today on the water, my alarm goes off with the intermittent beeps, which I take as a TPS switch issue according to the manual. I shut the motor off and then wait, and it wont restart. It cranks but wont fire. I notice the fuel pump doesnt do its "whirring" noise when you turn the key to "on".


So when i get home I see one of the fuses is blown on the starboard side of the motor and I replace it. I go to start it up, the fuel pump "whirrs" and the motor sounds better, but wont start the first crank, which is no big surprise. Then it blows the fuse again and I get nothing just cranking.


It is the lower left fuse, which I take is the fuel pump fuse.

Is my fuel pump bad? It sounds like it is working just blows the fuse.

Does the alarm and possible TPS switch have something to do with it? I would like to get the fuse issue worked out so I can replicate the warning alarm, and any help would be greatly appreciated.


And I apologize if this is a repeat request on the forum.

[EuropeanAM]

Welcome to BBC!

Your engine has TWO electric fuel pumps- a LOW PRESSURE and a HIGH PRESSURE pump. Very likely that one or the other of them has or is failing.

More "specific" confirmation or assistance might be available if your engine serial number is provided.

[rock_fish]

Hey thanks for the reply!!


I've been digging through the manual about the fuel pump and bench testing it with an inline fuse and a set of leads from a battery. I might try that.


What say you about the alarm?


The old dog's serial number is: OT343110


Thanks!

[rock_fish]

Just a quick update:


I was able to replicate the alarm and the blown fuse while on the trailer.


Motor would start and then the beep beep beep etc would go off and then it would die and a the same fuse was blown.


Thanks

[EuropeanAM]

You'll need to test the two fuel pumps MANUALLY to determine which one is drawing excessive current.

Note: One "quick" diagnostic technique is to unplug the EXTERNAL (low pressure) fuel pump, and pump the primer bulb FIRM. Start the engine (with good fuse in place).

The engine will run for a reasonable amount of time (at idle) with the low pressure pump disconnected (possibly allowing you to determine if the low pressure pump is the culprit).

Another handy technique is to "feel" the low pressure pump (or use a handheld temp gun to "measure" it's temp at or near the outlet fitting). If the temp exceeds 110 degrees- the pump is failing.

[rock_fish]

Is the low pressure pump the square one above the VST or is it the round one attached to the VST?

[Ranger519VS]

its the round one attached to vst. You can trace the fuel line from the pulse fuel pump it goes to the inlet of the low pressure pump.

[rock_fish]

Ok, thanks. I plan to tear into the VST and check both electric fuel pumps in the next couple of days. Drain the bowl, drain/replace the fuel filter.


I will report on what I find out (or break) ;)

[EuropeanAM]

<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by derick881 &raquo;</td></tr><tr><td class="quote">its the round one attached to vst. You can trace the fuel line from the pulse fuel pump it goes to the inlet of the low pressure pump.</td></tr></table>

+1

Recommend before you go tearing into the VST.... simply UNPLUGGING the low pressure fuel pump, and see if the engine will start (with primer bulb pumped firm). If the fuse does NOT blow, I'd recommend testing the LOW PRESSURE PUMP separately (it's would be the likely culprit- and does NOT require you to disassemble the VST).

[rock_fish]

Ok, I will do that today after work and before it gets dark at 5:30 :(


Hopefully this will fix it, and stop the alarm

[rock_fish]

Update:


I pulled the wire harness to the low pressure pump, and started the motor. It started and idled fine for 10 seconds or so with no blown fuse. Bench tested the pump off of the motor, and it ran fine with no blown fuse.

The alarm still went off after 10 seconds. Its the same beep beep beep beep beep etc alarm. Not a constant beep, not 4 every 2 minutes.

I pulled the fuel filter and it had debris in it, looked like leaf pieces. Not sure what they actually were, but bad none the less. So I will replace that.

So now what? :frustrated:



Modified by rock_fish at 6:34 PM 12/6/2011

[EuropeanAM]

Suggestions:

FIRST AND FOREMOST: CAUTION! MAKING ELECTRICAL CONNECTIONS AT OR AROUND THE FUEL PUMP CARRIES INHERENT RISKS. ANY CONNECTION must be SECURE, and you must ENSURE THAT NO FUEL VAPORS ARE PRESENT AT OR NEAR CONNECTION POINTS (RISK OF FIRE OR EXPLOSION).

Specify what amperage fuse you were using when "bench testing" the pump. 20amp fuse is TOO HIGH for this purpose (that only tells you it doesn't draw more than 20 amps... and you have TWO fuel pumps on that fuse circuit of the engine). An ammeter can be utilized to determine the ACTUAL draw of that pump.

Read through the following post CAREFULLY. Check your fuel lines, pulse fuel pump, and filter (recommend ALL be replaced if any component has not been updated):

http://www.bbcboards.net/zerot...first

In regards to your warning horn- I would strongly recommend that you get the engine on the MERCURY Computer Diagnostic System, for printouts of:

-Run History
-Freeze Frame (Fault) History
-Fault Seconds Counters

Information in these reports will help lead to an APPROPRIATE diagnosis for the warning horn (I'm always happy to review reports by email, BTW).

[rock_fish]

I was using a 20 amp fuse, doh! Try a 10 amp or 15 amp? I have a voltmeter I can put on it as well.

And I am heading to get some new fuel lines and a filter this week sometime. Trying to find a place that has it for a good price, that place from out West is outrageous. But that is important to me, I usually change them before I do anything with a new boat. I slipped up there.


And I was trying to ask friends if they knew anyone with a diagnostic kit that could do me a a favor, but I suppose I should take it to the dealer for a printout.

[EuropeanAM]

I'd try a 10 amp fuse FIRST.... then a 7.5. Without a load on that pump, it should NOT blow a 7.5a fuse (bench testing).

An AMMETER is, however, the BEST means of testing the amperage draw of the pump.

We've got plenty of fuel line.... but I wouldn't even begin to say that it's "cheap".

[rock_fish]

Low pressure pump passed the 10 and 7.5 amp test

Next I guess is the high pressure pump

[EuropeanAM]

Daniel:

Since there are definite differences in the load on fuel pumps under "Static" and "Dynamic" conditions, I think it would be a good idea for you to take a few minutes today to give me a call.

I'll be glad to explain a few pointers that may help you with this.

[rock_fish]

Thanks, Don. I need all the help I can get.

I must have missed you in the office today, however.

[EuropeanAM]

Dan- I'm going to be "in and out" through early next week (heat pump problems at home that HAVE to be addressed).

If you miss me- leave a message. I WILL return your call when I retrieve messages.

[rock_fish]

Good talking with you today, Don. Thanks for the help!

I tested those injectors and they all read 1.6-1.7 ohms.


I did unplug the high pressure pump and turned the key with just the low pressure plugged in, and it blew the fuse. I ran out of fuses and could not try the same with just the high pressure, but will this weekend.


Narrowing it down I think.

[EuropeanAM]

Let me know what you find.... you at least (now) know what items are on that circuit, so that you can continue to narrow it down.