2004 Wakesetter VLX - Stalling & Surging

[paulhey]

17 minutes ago, Bozboat said:

Have you checked the fuel pressure ?   Maybe the fuel pump is sucking air into the line near the area of the leak l repair posted friday describing a fix next to a fuel distribution block?

 

I'll be sure to check the fuel pressure tomorrow and report back. I have not had any leaks on the suction side of the fuel system.  

If it's like it was on the water, the fuel pressure may fluctuate a bit during this. I'm also going to look at whether I can just push it past the 2300 rpm point, which was the case on the water  

One thing I am wondering is whether it makes sense to continue to pursue the injector work.  Would this particular symptom be indicative of injectors.  

Edited August 19, 2022 by paulhey

[Bozboat]

You may have multiple problems but generally they are either fuel delivery or spark. Double check the work done to date and then verify fuel pressure, replace the injectors and clean the throttle body. If fuel pressure is not good, then you have a problem with the pump or air in the lines or getting in the lines.

Edited August 19, 2022 by Bozboat

[paulhey]

Sounds like a plan of attack.  While I have the plenum off and working on the injectors, I'm wondering if the TPS or IAC make sense to replace given the symptoms?

[Bozboat]

9 hours ago, paulhey said:

Sounds like a plan of attack.  While I have the plenum off and working on the injectors, I'm wondering if the TPS or IAC make sense to replace given the symptoms?

A good mechanic would only replace parts that are not working. But personally, it makes sense to me  replace the TPS and IAC because you are already there. 

[paulhey]

Guidance needed: On the 2004, the plenum is held in place by 6 bolts. Easy. 
 

The throttle body is on the forward, starboard side of the plenum. 
 

It looks like, to be able to remove the plenum, I take out the 6 bolts.  Next - the only thing that see that is physically connected is the throttle.  Just remove the bolt that holds that to the throttle body?

Then there are the connectors for the IAC and TPS, as well as on on the forward side another sensor connector. 
 

Is that correct??

 

Happy to hear from anyone who knows. @SmoothYou seem to have the same engine. 

Edited August 19, 2022 by paulhey

[paulhey]

Ok. In process update. Rechecked everything I did. Looks good. 
 

Put the fuel pressure gauge on. Same behavior as yesterday.  Solid 62 throughout - except when I got to appx 2300. While revving up and down, the pressure was "vibrating" between 50 and 65 or so. 
 

I then decided to push it up a bit - and I heard a beep. Realized the perfect pass was on, and I was in rpm mode. 
 

I turned it off - and she worked like a champ up and down the RPM. 
 

Onto the injectors. 

Edited August 19, 2022 by paulhey

[paulhey]

@justgary or anyone else. 
 

This plenum isn't budging. Any tricks?

[paulhey]

Never mind. It popped. 

[paulhey]

Ok. Status report. Old injectors out. New injectors in. Cleaned the heck out of the throttle body and everything plenum. Put it all back together. Keyd up a couple of times to prime - pressure solid at 62.  Started her up - doing really well. Solid pressure at 62. Zero vibration up and down the RPM chain. 
 

Next step is a water test.

[paulhey]

First water test complete. Tubing with 11  kids for a couple of hours. She did fine. It had been so long since I had driven it without a problem, I forgot some of the feel of the ride. I kept expecting it to stumble. Felt a rumble - just waves. Thought it was stalling - just the load after a turn. 

So far - so good. 

The next test will be a wake-surfing day, fully loaded, plowing through the water.

I'll report out after that, hopefully wrapping this one up, and thanking everyone who helped. 

Fingers crossed!

[Smooth]

That sounds great about the boat running! Thanks for the updates on it and keep us posted on the wake-surfing. From what I can tell, is that the only thing you have done different from me are the injectors. My engine seems so strong and runs so smooth that I never would have thought of testing the injectors but have heard they can get 70% clogged and the engine still run good. Maybe that 70% clogged injector could cause vapor lock because fuel is not running through the line enough. I'll try to keep my injectors numbered with their cylinders then get them tested and add it to your post if my engine can run without a blower.

[paulhey]

Second water test complete.  

Just my son and me - boat fully loaded for surfing. I've not posted on what we did (probably will in a separate one), but fully loaded means two 850's that replaced the stock tanks + center standard full + wedge down.

1:15 hrs of surfing and the problem did NOT happen!

I'll tell you what - after 2 months of trying to get to the bottom of this - we were both expecting it to happen. My son though it sounded like it was happening while he was surfing, but it didn't. I kept thinking I may have heard or felt something -- but she kept on going strong. 
 

Before we call this one done - I do have a couple of questions. Stand by for some very non-specific observations. 
 

1) Still being a new-to-us boat that has been really out of commission for some time. When idling in the water, I can feel the engine. Just the rumble. Not rough. Just feel the engine while I'm in the seat.  This is my first inboard, so trying to figure out if that's normal, or perhaps do I need to do a timing check after all of this work. 
 

2) Particularly while surfing - I can really feel the system working. It's not too rough. And it's not like a vibration from a bent prop (that's something else I'll post about separately too). Just what I think is the system working to plow through the water. Hard to describe. Not cavitation - never loses power or grasp of the water. If there are words that can describe what normal feels like versus abnormal - would love to hear. 

[Smooth]

ACME 2773 4 BLADE 15" X 13" PROPELLER 

This is the prop that I run with my boat but lost some top speed. Doesn't make engine lug, hesitate or rumble. You will loose top speed and engine will run a higher rpm because the prop is easy to turn so go easy on the engine when running out to your destination.

[Smooth]

 

12 hours ago, paulhey said:

Just what I think is the system working to plow through the water. Hard to describe.

Bought my boat used and it came with a prop size of 13.5"X17.5" and could run with it but... the Acme 2773 seemed to make the boat respond better all around even the cruise control holds a better consistent speed with it.

[paulhey]

2 hours ago, Smooth said:

 

Bought my boat used and it came with a prop size of 13.5"X17.5" and could run with it but... the Acme 2773 seemed to make the boat respond better all around even the cruise control holds a better consistent speed with it.

Thx. Appreciate that.  Similar situation with me. Stock ACME 537 was on it (dinged up and needing repair) so I went with a 1235 (14.5 x 14.25) not knowing exactly what we were going to be doing with it most. Perhaps an upgrade to something else will be in the future and another post 😂