RPM Jumping, Prop Slipping?

[williemon]

I pulled the injectors myself and did a minor cleaning. I carefully cleaned the junk from the inlet screens and used a battery, a tube, and carb cleaner to force fluid through them as i activated hem using some wires and a 9 volt battery. Not the best cleaning but it got me back on the water. The o rings were in great shape so i just left them on the injector and reused them. Im going to perform a better cleaning and rebuild of them during winter.

[jtight7]

Well, it's been a couple weeks since I have updated and there has been a lot that has gone on. I pulled the boat out of the water and replaced the fuel pump. At the same time I went ahead and changed out the start and ignition switch just so I can eliminate those issues in the future. When it was on the drive way it fired right up and I was able to run it for about 20 min with Fake-A-Lake. The temperature started to slowly creep up past 160 so I stopped. Last night, I put it in the water with high spirits and it ran for about 15 min (going about 25 MPH) and would you know it started to the same thing again. The RPM's would make a small jump then drop down. 

I truly have no idea what to check or replace next. I was really thinking/hoping the fuel pump was the culprit. My next thought is that it has to be the computer. . . thoughts? 

[formulaben]

Well, I'm sure this is certainly frustrating and you've already thrown plenty of time and money at it.  If it was me, I would do the following in order of importance:

• Inspect impeller (change if less than a year old)
• Inspect transmission cooler and verify it is CLEAR of debris
• Change transmission fluid (don't overfill; if your trans calls for Dexron III, go with Dexron IV as it's backwards compatible)
• Replace transmission temp sensor

If those don't fix it, then:

• Replace the 2 water temp sensors (dash and ECU)
• Replace engine knock sensor

Yes, I'm throwing several darts at the board, so feel free to do them one-at-a-time to save money but if you buy the sensors at the local auto parts store it should be under $150 all told and total time to do all of this will be 2-3 hours; sensors being the easiest.  And best of all you can call all of it preventative maintenance...and compared to a new fuel pump, it's a somewhat inexpensive proposition.  Just my 2 cents...YMMV.  Good luck!

[jtight7]

On 7/1/2016 at 0:20 PM, formulaben said:

Well, I'm sure this is certainly frustrating and you've already thrown plenty of time and money at it.  If it was me, I would do the following in order of importance:

• Inspect impeller (change if less than a year old)
• Inspect transmission cooler and verify it is CLEAR of debris
• Change transmission fluid (don't overfill; if your trans calls for Dexron III, go with Dexron IV as it's backwards compatible)
• Replace transmission temp sensor

If those don't fix it, then:

• Replace the 2 water temp sensors (dash and ECU)
• Replace engine knock sensor

Yes, I'm throwing several darts at the board, so feel free to do them one-at-a-time to save money but if you buy the sensors at the local auto parts store it should be under $150 all told and total time to do all of this will be 2-3 hours; sensors being the easiest.  And best of all you can call all of it preventative maintenance...and compared to a new fuel pump, it's a somewhat inexpensive proposition.  Just my 2 cents...YMMV.  Good luck!

Thanks Formula Ben, I did what you mentioned and there was no change. Actually the new fuel pump that I got died. So now I am curious as to what the problem is if it keeps burning up fuel pumps. I dont want to keep throwing new fuel pumps at it and having them burn up in a hour. I'm thinking it has to be something electrical but I am not sure if there is anything mechanical that would make it burn up. Any ideas?

However, when I was ringing out wires and testing voltage I noticed a sensor on top of the transmission that was unplugged. I didnt know this sensor was here but it looks like its a Transmission Temperature sensor. Is it possible that this could be the cause of my fuel pump issues? It doesnt exactly make sense to me but I am not an expert by any means.

I added pictures to a Google Doc at the link below, let me know if you have trouble viewing.

https://docs.google.com/document/d/1REHxK98_3Rxk7djcvi9vvBg4cgfagQt3LFvuq2rMrvs/edit?usp=sharing

[formulaben]

From my Indmar manual:

The Check Engine light may activate if any of the following conditions are noted:
• Low Oil Pressure
• High Coolant Temperature
• High Transmission Oil Temperature
Any of these conditions will also put the engine into Power Reduction mode. If the Check Engine light should go on, or if the engine enters the Power Reduction mode, you should have your dealer check the engine as soon as possible.

The ECM also provides for a tapered engine RPM reduction if engine coolant temperature approaches the high operating limit. If the coolant temperature exceeds 176° F (80° C), the engine RPM is gradually reduced until a safe temperature is reached. If the engine RPM should decrease due to high coolant temperature, stop the engine and inspect the raw water intake, sea c*** and sea strainer (if equipped) and hoses for blockage or problems.

Edited July 5, 2016 by formulaben

[jtight7]

11 hours ago, formulaben said:

From my Indmar manual:

The Check Engine light may activate if any of the following conditions are noted:
• Low Oil Pressure
• High Coolant Temperature
• High Transmission Oil Temperature
Any of these conditions will also put the engine into Power Reduction mode. If the Check Engine light should go on, or if the engine enters the Power Reduction mode, you should have your dealer check the engine as soon as possible.

The ECM also provides for a tapered engine RPM reduction if engine coolant temperature approaches the high operating limit. If the coolant temperature exceeds 176° F (80° C), the engine RPM is gradually reduced until a safe temperature is reached. If the engine RPM should decrease due to high coolant temperature, stop the engine and inspect the raw water intake, sea c*** and sea strainer (if equipped) and hoses for blockage or problems.

I have never been in power reduction mode before, could you describe its behavior? Do you think that it is similar to what I am experiencing?

I guess I will buy another pump and test it with this sensor plugged in.

[formulaben]

How do you know your pump is dead?!  Seems VERY odd to have a new pump die.  Please explain what is happening, e.g. how are you diagnosing that it is dead?

IMHO you are describing 2 separate problems (assuming I'm reading the thread correctly.)  If the reason your boat died is because of the fuel pump as described here then your problem should have been fixed...but you still have the original problem, yes?  I think in that case you have vapor lock which is very common in that era of boat...but that's a separate issue of which you'll find plenty of advice here on how to permanently fix it (I added the Carter pump and wish I had years ago.)  I'm guessing your boat is going into power reduction mode, and as stated above it takes an overheat to do that...you already said it appears your transmission temp sender isn't even connected.  FIX THAT. 

You have water temp and oil pressure left.  I assume (bad thing always) that you have full oil, and if surfing you should go a quart over.  If so, then that leaves water temp.  High water temp can also overheat the transmission, so that's why #1 on the list was inspect/replace impeller.  The fact it acted weird after you slowed down and then tried to speed up could point to a bad impeller or bad water circulation and the ram effect of the water intake is augmenting your cooling, but when slowing down you get an overheat.  I went back and re-read the thread and never once did you mention how the water temp looked. 

To answer your question, the ECU will reduce fuel in an effort to cool the motor...doing exactly as you describe.  You said you did everything on the list...tell us, what did the impeller look like?  What about the transmission cooler?  And you changed the transmission fluid?  And which of those sensors?  The only thing I would add to that list is double-check oil level.  The oil pressure is reading fine when running, yes?  If not both oil sensors are relatively cheap...and the one that sends a signal to your dash is known to fail.  And lastly, WHAT IS THE WATER TEMP when you duplicate this?

[jtight7]

Responses in Red

 

How do you know your pump is dead?!  Seems VERY odd to have a new pump die.  Please explain what is happening, e.g. how are you diagnosing that it is dead? When I put the key in the ignition and put turn to the "start" position (to the right one position) the pump is supposed to primer for 2-3 sec. When in this position I do not hear or feel the pump running. I took the pump to work today to bench test it with a power supply but have not had time to do so yet. What other methods are there to test the pump?

IMHO you are describing 2 separate problems (assuming I'm reading the thread correctly.)  If the reason your boat died is because of the fuel pump as described here then your problem should have been fixed...but you still have the original problem, yes?  I think in that case you have vapor lock which is very common in that era of boat...but that's a separate issue of which you'll find plenty of advice here on how to permanently fix it (I added the Carter pump and wish I had years ago.)  I'm guessing your boat is going into power reduction mode, and as stated above it takes an overheat to do that...you already said it appears your transmission temp sender isn't even connected.  FIX THAT. I believe it is one issue but is resulting in over running the pump. I'm not 100% sure about this but I think that the constant sudden change in RPMs and effectively the power to the pump is burning it up. I will look into the vapor lock issue and installing a Carter Pump. Would the Carter pump be in place of or an addition to the existing pump? The transmission temperature sender is now connected.

You have water temp and oil pressure left.  I assume (bad thing always) that you have full oil, and if surfing you should go a quart over.  If so, then that leaves water temp.  High water temp can also overheat the transmission, so that's why #1 on the list was inspect/replace impeller.  The fact it acted weird after you slowed down and then tried to speed up could point to a bad impeller or bad water circulation and the ram effect of the water intake is augmenting your cooling, but when slowing down you get an overheat.  I went back and re-read the thread and never once did you mention how the water temp looked. The water temp sits exactly at 160°F and stays the entire time. I just changed the oil and the oil level reads a little on the higher side 

To answer your question, the ECU will reduce fuel in an effort to cool the motor...doing exactly as you describe.  You said you did everything on the list...tell us, what did the impeller look like?  What about the transmission cooler?  And you changed the transmission fluid?  And which of those sensors?  The only thing I would add to that list is double-check oil level.  The oil pressure is reading fine when running, yes?  If not both oil sensors are relatively cheap...and the one that sends a signal to your dash is known to fail.  And lastly, WHAT IS THE WATER TEMP when you duplicate this? The impeller only has a few hours on it, maybe 10, it looked like a new impeller with all blades intact. The transmission cooler screen was clear of debris and the hoses looked to be in good shape. I did not replace the Transmission Temp sensor because I had just found it and noticed it was unplugged. This is the sensor on top of the transmission, underneath the wiring harness. Were you able to see the Google Doc that I posted several posts back with pictures of it? I also replaced both water temp sensors and Knock sensors at the beginning of the year when I first started having these issues. The oil pressure floats around a little bit when accelerating and decelerating, it may need a little more oil. The water temperature is in the mid 70's to low 80's.

[formulaben]

5 minutes ago, jtight7 said:

 I believe it is one issue but is resulting in over running the pump. I'm not 100% sure about this but I think that the constant sudden change in RPMs and effectively the power to the pump is burning it up. I will look into the vapor lock issue and installing a Carter Pump. Would the Carter pump be in place of or an addition to the existing pump? The transmission temperature sender is now connected.

The fuel pump runs (primes) for 2 seconds at key up, then during start and after it start it runs continuously (I believe it needs to see cranking RPM and >4psi oil to run)...changing engine RPMs or throttle doesn't really have much effect on the pump, it runs continuously; but the fuel injectors change their routine and the fuel regulator acts accordingly.

Here is a retail version of the supplemental pump.  You can DIY for about 1/3 the cost.  It is only 5-8psi but keeps the primary pump primed so it doesn't vapor lock after running and sitting a while.

 

7 minutes ago, jtight7 said:

When I put the key in the ignition and put turn to the "start" position (to the right one position) the pump is supposed to primer for 2-3 sec. When in this position I do not hear or feel the pump running. I took the pump to work today to bench test it with a power supply but have not had time to do so yet. What other methods are there to test the pump?

OK, just to verify you tested the connector and you get power to the pump on key up?  What about when cranking?  If it's not priming I guess it could start but I'm definitely missing something here...

Anyway, correct me if I'm wrong, you have NOT replaced the water temp sensor that sends info to the ECU?  If not, I would do that next (fuel pump issues, not withstanding.)

[jtight7]

Ok, so the pump runs at a constant speed, its not a variable speed based on current or voltage. I was not sure. 

Yes, I have tested the connector and I get 11.8V at key up on the connector. I just looked up the location of the fuse for the fuel pump but I have not checked it yet. It should be good if I am getting power to the connector but I am going to double check and buy a handful of those fuses. 

I have not replaced the water temp sensor to the ECU this year but I did change it at the end of last year. It should have no more than 25 hrs on it. I can order another one and replace it again.

[formulaben]

1 minute ago, jtight7 said:

Ok, so the pump runs at a constant speed, its not a variable speed based on current or voltage. I was not sure. 

I'm not positive if its constant speed or variable, but the pump is constantly running with the engine on.

[jtight7]

Does this year have a mass flow sensor on the intake? If so, is this something to consider?

[jtight7]

SO! After trying everything that I can think of and taking in all of your suggestions, I broke down and took it to someone. I described my problems and was on the correct path but I dont think that I would have ever come up with the issue. The mechanic that I took it too found that the fuel line pick up inside the tank was clogged and letting a lot of dirt through. This was the cause of the RPMs sporadically dropping. The fuel pump burned up because there was so much dirt let through the fuel lines due to the fuel filter before the pump. This fuel filter (WIX 33033) that is before the pump is under sized by a lot from what I have read and been told by the mechanic. It is a 21 micron filter and according to him and other sources I have read the minimum should be 10 microns. Is was letting a lot of dirt and debris through that was burning up the pumps. 

Our solution was to clean out the fuel line pick in the bottom of the tank and the replace the WIX33033 fuel filter with a fuel water separator ( I will update with pictures and p/n's later). We also replaced all of the fuel lines from the tank to the fuel filter after the pump (GF111).  It took my mechanic about 2 hrs to replace everything and he ran the boat for about an hour on the water and everything checked out!

In all I really think i would have spent the same amount of moeny trying to get this fixed by the dealer had I gone to them initially because when I talked to them they didnt have any other ideas than what everyone on here suggested. The mechanic that I took it to was recommended by the dealerships in town when they couldnt figure out the issue. If anyone lives in Knoxville, TN and has had a difficult time finding quality service for their malibu this is the guy to go to. . .

Jeff Hughes

Roane Marine Power Sports 

http://www.getrmp.com/

Thank you everyone for all of your help. I will update with pictures and part numbers of the fuel water separator this weekend!! If there are any questions let me know. 

Edited July 14, 2016 by jtight7

[jtight7]

Took the boat out this weekend after I got it repaired and I couldnt have been more happy. It ran like a dream all weekend! So I think the fuel pick up was the issue! 

[williemon]

What are the specs on the water seperating filter? Ive read that some filters may be marked 10 micron but are only 90 percent efficient at it. Several of the ones i saw have 25 micron ratings. 

[jtight7]

On 7/25/2016 at 2:08 AM, williemon said:

What are the specs on the water seperating filter? Ive read that some filters may be marked 10 micron but are only 90 percent efficient at it. Several of the ones i saw have 25 micron ratings. 

I will grab the part number this weekend and pull some specs and let you know

[jtight7]

On 7/25/2016 at 2:08 AM, williemon said:

What are the specs on the water seperating filter? Ive read that some filters may be marked 10 micron but are only 90 percent efficient at it. Several of the ones i saw have 25 micron ratings. 

Sorry that this took so long but here is a link to a quick doc with pictures that I wrote up. The fuel water separator is a Serra 18-7845. You can get the kit with a filter from west marine. The second link is the kit with a similar filter, just keep in mind that you want to have a minimum of a 10micron filter before the pump.

https://docs.google.com/document/d/1pKSXAHyvvfYk0zTpttPuG5HdV_9C7ylMJcWLY_zT3NY/edit?usp=sharing

http://www.westmarine.com/buy/sierra--10-micron-fuel-water-separator-filter-replacement-element-kit--9399478?recordNum=14

Hope this helps!

[williemon]

Hey, quick question, how does your fuel pickup tube route inside the tank? My pickup tube in the tank "points" to the observer side of the boat in the tank. Is that its correct routing or should the tube be pointing toward the front of the boat? I fugured you might would know since you had to clean yours. Thanks for the writeup and pics. I will install my filter that way as well. I also want to put a high pressure 5 to 10 micron after the pump just before the fuel rail. After reading about fuel systems on performance cars, I believe there should be one there even though indmar chose to not put one there for my year. 

[jtight7]

30 minutes ago, williemon said:

Hey, quick question, how does your fuel pickup tube route inside the tank? My pickup tube in the tank "points" to the observer side of the boat in the tank. Is that its correct routing or should the tube be pointing toward the front of the boat? I fugured you might would know since you had to clean yours. Thanks for the writeup and pics. I will install my filter that way as well. I also want to put a high pressure 5 to 10 micron after the pump just before the fuel rail. After reading about fuel systems on performance cars, I believe there should be one there even though indmar chose to not put one there for my year. 

Mine was pointing to the port side of the boat so I think yours is ok in the direction it was pointing. I dont know how old your boat is but if you are going to add a filter and fuel water separator I would suggest changing out the fuel lines as well. In total, the fuel separator and new fuel line were $80. Mine lines were 15 years old and filled with debris. Good luck!

[williemon]

Yea, mine is an 01 and i have already replaced the fuel line so i just need to add the filter.