Here is exactly what happened

[tomloans]

Motor Data
1B737378
FEB 2009
PRO XS L

Started her up in the morning to back out and tie up at the dock. I had the normal surging that got better as the engine warmed up. Killed the engine to park the vehicle. Came back to this....




So I ignored it and put it in gear and in a few seconds it was mostly gone. Got on plane and all was well. Hit 5800 RPM from time to time and no problem..

The sound came back once or twice more for a few seconds at start up through out a very long day but once I gave it gas no problem. But what I did notice is that I have a very rough idle nearer the end of the day. This is newer as well.

On plane, no issues and have no problems at all.

So all I can say is, SIGH...

Please help.

Again, new fuel rail and plugs with no problems for the first 8 hours and then this starts happening.

[Another Distraction]

Wow. How do you ignore that. Lol...
Look at the EZ stuff at the top of the motor....belt, pullies, tensioner, compressor.

[castforcash]

Have you checked the reeds in the compressor?

[tomloans]

Wow. How do you ignore that. Lol...
Look at the EZ stuff at the top of the motor....belt, pullies, tensioner, compressor.

I agree, but the noise goes away almost every time after warm up and I drove this for 2 hours at 4500 to 5500 RPM all day long. Whatever it is, it is the same problem over and over again. I had both Fuel regulator and air regulator torn and so I replaced these and it ran great for awhile. then it started this nonsense on the last trip. this was after first start up.

I am going to lose my mind.

[tomloans]

Have you checked the reeds in the compressor?

Compressor is good. I will have to check the reeds. I read something about the reeds that could cause strange things like this. It wont hurt to take a look. Never done it so I will Youtube it.

Thanks.

[castforcash]

Compressor is good. I will have to check the reeds. I read something about the reeds that could cause strange things like this. It wont hurt to take a look. Never done it so I will Youtube it.

Thanks.

I'm talking about the reeds in the compressor, not the main reeds in the air plenum.

[tomloans]

I'm talking about the reeds in the compressor, not the main reeds in the air plenum.

Well I guess I could take it apart. I have really fussed with it pretty good. The compressor is the updated one and has about 120 hours on it. Seems super tight.

[castforcash]

Well I guess I could take it apart. I have really fussed with it pretty good. The compressor is the updated one and has about 120 hours on it. Seems super tight.

Ok, don't take it apart if it is the updated compressor. Wait for better advice from the experts. Hope ya get this figured out soon.

[tomloans]

Ok, don't take it apart if it is the updated compressor. Wait for better advice from the experts. Hope ya get this figured out soon.

Thanks - me too... It is just bizarre. Maybe that knocking is a missing cylinder? Or maybe when I stopped it to park the car, one of the air injectors was stuck open and flooded a cylinder ( this seems reasonable ). This would then cause a hydro lock of sort causing that horrible knocking until it bleeds out of the cylinder. Hence why I have no issues at higher RPM's.

[Another Distraction]

Does it go away when you shift into forward?

[tomloans]

Does it go away when you shift into forward?

No it didn't at idle but as I gave it a little gas it would go away. I was hitting 5800 Rpm with no issues.

[tomloans]

Don,

Just so you know. First start was just a surging I have been having on the first start for last two trips. When I went to park the truck, I turned the motor off. I didn't leave it running. When I came back I restarted ( after about 5 to 10 minutes ), the surging was replaced with the sound in the video. It is somewhat a surge as well with a serious knocking sound.

Is the ECU messing up. Can it relearn? I am just completely baffled here. If it were the compressor, the noise would be all the time. But most of the day it was fine except after a particularly long stop. Also as the day continued. I noticed the Idle was getting rougher as every start up.

And as reminder, the spark plugs are super dark. Not wet but rather dark so it appears it is running rich.

[Savage]

I would run the motor with:

1.The lower unit removed. Supplying water with a garden hose.
2. The air compressor belt removed. Supplying regulated air with a shop air compressor.

See if the noise is eliminated.

[tomloans]

I would run the motor with:

1.The lower unit removed. Supplying water with a garden hose.
2. The air compressor belt removed. Supplying regulated air with a shop air compressor.

See if the noise is eliminated.

Savage, the problem is that it is not always making that noise. So if I take the lower unit off, I could have a false positive.

Also if it is the compressor ( which feels solid to me ), wouldn't have the noise all the time?

Also you will notice in the video that the engine acts like it was missing. It noticeably shakes when the sound comes. It sure looks like hydro lock.

C

[EuropeanAM]

Ok, don't take it apart if it is the updated compressor. Wait for better advice from the experts. Hope ya get this figured out soon.

“Updated” doesn’t amount to much. Take the belt off the engine and check it for lateral or up-down movement in pulley, or for
any knock or rattle at the bottom of the stroke.

If all there is as it should be, engine reeds and compression test would be the next locations to look.

[tomloans]

..

[Another Distraction]

Will you fix this already, I'm dying to see what made that crazy noise.

[EuropeanAM]

Is there any evidence of anything rubbing the bottom of the flywheel cover perhaps?

I too am quite curious... reminds me of a prank video (tech trying to find tapping in a wheel bearing or rotor) I saw recently.

[bob p]

have you looked at inside of cowl to see where its hitting,sounds like belt against the cowl

[tomloans]

I actually heard it with the cowling off. Now have a no start situation. I started new thread for this. Not sure if both issues are related but likely they are. I will video this too for fun and thrills. Yesterday would have been a real good day to fish.... Sigh...

http://www.bbcboards.net/showthread.php?t=1150467