2013 VP 380-C Fuel pump whine

[1000 Islands]

New guy here, new to us boat, 2013 Cobalt 262 380-C 6.0L. First VP, and it had 228 hours when we picked it up a couple of weeks ago. Freshwater only. I started noticing a fuel pump whine not long after putting some hours on it. The engine runs great, no performance issues except for an extended crank when hot (happened twice so far). Seems like the extended crank situation is a shot across the bow.

Prior to launching the boat, I replaced the water pump impeller, fuel/water separator, oil and oil filter and drive oil, all with OEM VP parts/fluids. The engine does not run hot. I noticed judging by the witness marks on the bolts, someone at one time replaced the entire seawater pump and housing assembly. The impeller looked fine when I changed it.

I have the manuals now and Rinda scan tool now (I'm an auto tech/shop owner 35+ years), and using a stethoscope, the noise is coming from the low pressure pump. This is the pump on the starboard side of the fuel module asm with a Schrader valve near the bottom. Of course, I forgot to bring a fuel pressure gauge to the river house, which is where the boat is on a lift (100 miles from home). The whine is evident when cold starting the engine, and gets worse as the engine warms up to operating temp (closed cooling).

I removed the 5/16” water hose on the starboard exhaust nipple in the rear on the Captains Call exhaust, which is the outlet from the fuel module cooler. No water comes out of it when running the engine to 1500 rpm. I then removed the 5/16” hose at the bottom of the heat exchanger. This hose is the feed for the fuel cooler. Water falls out of the heat exchanger like it should, but blowing through the fuel cooler with my mouth does not result in any water coming out of the previously removed outlet hose in the back. I used a Dewalt cordless inflator to try to blow through the fuel cooler. Nothing comes out the other end. This is very strange only because it does not appear that the inflator is struggling or “dead heading” when attached to the 5/16” hose. I need to bring a compressor and fuel pressure gauge up on my next trip.

Does anyone know what year VP stopped having the paint chip issues (or did they)? Where would you go next? I am not against replacing the entire fuel module with a new VP one, but it’s a tad on the spendy side. I am also not against fixing what I have, but I’m not sure I like the idea of Chinese replacement pumps nor do I understand the fuel cooler situation (the cause of no cooling water flow). I just don’t want to miss the reason of the pump's demise if I use a new VP fuel pump module. I don't know if I'm not understanding the fuel pump cooling system, or if there is indeed a fuel cooling issues causing a vapor lock on the couple of long crank situations that I've experienced. The You Tube channel for ManCave is interesting, but I’m not sure he addresses low pressure fuel pump whine unless I missed it. Thanks

 

[1000 Islands]

Engine #A218739 or 40869452

 

[BRICH1260]

I think you need to figure out why there is no water going into or out of the fuel cell for cooling. This could lead to the low pump overheating. I dont have your engine but my cooling water comes from the Tstat housing, perhaps its clogged. Your fuel cell is post the pump paint problems so that should not be the issue.

 

[1000 Islands]

Good to know on the paint issues. Do you know when they figured that out? Sounds like I need to figure out the fuel cooling water flow situation and replace the LP pump, since paint contamination is not very likely.

The cooling water for the fuel cell comes from near the bottom of the heat exchanger. There is a nipple there. When I took the 5/16" hose off of this nipple, the seawater drained from the heat exchanger. That hose leads directly to the fuel cell inlet, and blowing through it and the fuel cell didn't lead to any water or air coming off of the removed hose at the Captain's Call pipe.

I need to bring some more testing equipment with me next weekend. I would like to also run the engine for a few seconds with the fuel cell inlet hose off of the heat exchanger to see if water comes out. I am unsure how the system is supposed to work - a good, steady stream of seawater from the heat exchanger port anytime the engine is running, cold or hot, or???

 

[BRICH1260]

Like I said, I dont have that engine and mine is seawater cooled but I would think there should be a steady flow of cooler water through the lines and fuel cell. Check and make sure water is flowing, check for a clogged line or nipple. Hopefully you will find it.

 

[ripjmk]

You need to take the fuel cell off and dismantle it as shown on the Mancave videos. The fuel cell is double walled with the cooling water passing around the cell, the passages are very narrow and prone to corroding/ silting up. You might get lucky and find just the inlet or outlet plugged up but most likely its inside the cell water passages. The cell needs a good water flow out of the cell even at idle to cool the fuel by-passed back to the cell from the fuel rail (hence, more cooling needed at idle than full throttle).
Other than that if the LP pump is whining when starting from cold you have another problem as well, either fuel suction issue (filter or anti syphon valve) or bad LP pump.

 

[1000 Islands]

That fuel cell is an odd set-up. The high pressure fuel regulator is incorporated into it, and there is no fuel return line from the rail. The actual high pressure fuel circuit to the engine is returnless, and no fuel is ever returned to the fuel tank. I don't know what the float does either. I need to take the module off and apart and figure out how it works. I doubt there is a suction issue on the LP side, because that would lead to a fuel starvation issue @ WOT, and that is not occurring.

 

[ripjmk]

Is your fuel cell similar to that show on the Caveman Videos? If so the float is there to allow any vapor (air or gas) to flow out to the inlet manifold to to ensure the fuel cell stays full of liquid gasoline (low liquid level allows float to fall and open the vapor valve).
I'm not familiar with the later EFI to comment on the fuel rail particulars.

 

[1000 Islands]

I'd have to watch the videos again, but a lot of things he says don't make sense. For example, if that float sticks, how will the engine run richer? It can't. The fuel pressure regulator controls the pressure. It isn't a carburetor lol. I'll figure it all out and post the results. Troy seems to know what he's doing, but I think that music and all of the "clubbing" he does on the fuel cell should have been edited out, and maybe substituted with how the thing really works and how he cleans the parts. Does the LP pump fill that bowl and "park" the fuel at the inlet of the HP pump? How does the water cool the fuel pumps if the pumps are on the outside of that still? Is just the fuel cooled??

 

[1000 Islands]

I stand corrected! I watched his video on how to test the float and needle/seat. If the needle and seat leak fuel, it ends up being drawn into the engine. However, nowhere does he explain what the purpose of this system is. Like you stated, maybe it allows vapors to be pushed out so the low pressure pump can fill the bowl? I thought this system was tied to the HP fuel feed side, which it's not.

 

[1000 Islands]

Fixed. I tried to blow through the fittings for the cooling seawater with compressed air - no go. I removed the fuel cell and took a peek into the inlet (lower) and outlet (upper) fittings, and there was an obstruction in the lower fitting. I drilled it out, and it was apparent that parts of the rubber impeller from a previous failure was the obstruction. More compressed air, and I got a little bit of air/water out of it. One more air toot and and the rest of the obstruction shot across the room.

I mentioned when I changed the water pump impeller a few weeks ago before launching the boat, I noticed that the entire water pump housing had been replaced at one time. The impeller cover plate bolts were red still with no chips, but the mounting hardware definitely had witness marks. I don’t believe the Cobalt dealer where this boat was only serviced at ever went any further. All of the water hose crimp clamps were still intact, and I doubt someone would use those style clamps again.

Since I didn’t have a seal kit, I didn’t take anything else apart. The housing appears to have a black oxidize-type coating, so paint chips are not a concern here. Back together it went, and I removed the hose at the exhaust nipple and now there was good water flow. During a 2-hour water test, there was no more whine, and no more hot-soak crank extended crank situations.

I had mentioned that there was a cold fuel pump whine. With the hatch open, you can hear a little whine which is consistent with an electric fuel pump, esp not being submerged in a fuel tank. Now it’s whisper quiet, hot, at trolling speeds.

 

[BRICH1260]

Glad to hear that you got the problem resolved.

 

[1000 Islands]

Me too - those OEM VP fuel cells are $2K!

Hindsight being 20-20, the cooling water inlet fitting on the fuel cell is restrictive at the elbow, but the elbow is easily accessible w/o fuel cell removal. So this whole "fix" could have been just a few minutes, rather than taking the scenic route.