383 HH missing

[LakeLimo024]

Hey Crew!! First time post, I have a 2006 Wakesetter 247 with the HH 383. The engine started missing pretty bad last day on water last year, so I changed plugs and oil at beginning of this season and it was still missing, and check engine light keeps coming on. I then changed fuel filter, and still not right. I have now changed fuel pump and I guess plugs again to see if that works. Was wandering if anybody could look at my plugs and maybe give some feedback as to what might be the problem. Pics

[Bozboat]

Here is a chart, but your plugs are in a whole new category, especially given seven are fouls and one is not?

 

Edited June 8, 2021 by Bozboat

[oldjeep]

Missing?  It's pretty amazing that it runs.  I'm not sure where I would start, but I guess a leak down test since that looks like a ton of oil.

Could also be bad valve seals, but I don't know how to test for that - pretty much have to look at them.

Edited June 8, 2021 by oldjeep

[LakeLimo024]

Those are brand new plugs lol!! We put 100 hours on it last summer and it ran great, last day started missing so replace plugs and found 2 that looked like maybe running a Lil lean or maybe oil but all the others looked great. These are new plugs with about 2-4 hours running at idle because when I gave it throttle it would start missing and check engine light would come on. Hoping fuel pump will fix the problem

[Blowncoupe]

Any engine codes come up?

[Woodski]

Appears to me a couple of potential things going on, some oil fouling and clearly a rich condition.  I would read the codes as a start.  Have you serviced the injectors, run a compression or leak down test to see if any of those components are not healthy?  How does the distributor cap look on the inside?

@LakeLimo024 - are you saying the problem came on suddenly and all was great on prior run?  Any hints otherwise?  Have you tracked oil and fuel consumption and has there been a change?  Did something happen between the last good run and the first run with problems?  Have you been running the correct oil level, any chance you had too much oil in the crankcase?  Hours on engine?

[LakeLimo024]

On 6/7/2021 at 8:21 PM, Bozboat said:

formulaben

Distributer Rotor and Cap

Here is a pic of the cap and rotor, looks pretty corroded so will be changing that. 

@Woodski it ran great all summer, last day it just started running rough out of nowhere. Will do a compression check and let yall know what I find there. Also gonna check MAP sensor. I'll report what I find. Thanks for all the help guys, it is appreciated!!

[LakeLimo024]

Not sure what the specs are on the MAP sensor but with engine off it was reading 4.5v with it at idle it was reading 2.3v and at 1500 rpm it was 1.5v so it seems to be changing with change in rpm. At 2200 rpm it was 1.05v. @formulaben

Edited June 10, 2021 by LakeLimo024

[justgary]

12 hours ago, LakeLimo024 said:

Not sure what the specs are on the MAP sensor but with engine off it was reading 4.5v with it at idle it was reading 2.3v and at 1500 rpm it was 1.5v so it seems to be changing with change in rpm. At 2200 rpm it was 1.05v. @formulaben

Those MAP sensor readings appear consistent with those RPMs, but you didn't say whether the engine was under load or just revving in neutral.  Looks like neutral to me.

4.5v = ~0.92 Bar = 13.5 PSI = 1.2 PSI vacuum

2.3v = ~0.52 Bar = 7.7 PSI = 7.0 PSI vacuum

1.5v = ~0.37 Bar = 5.4 PSI = 9.3 PSI vacuum

1.05v = ~0.29 Bar = 4.3 PSI = 10.4 PSI vacuum

By the way, the MAP reading should be close to 1 Bar (14.7 PSI) at sea level with engine off unless you are at altitude or in the eye of a hurricane. Specifically, your pressure of 13.5 PSI indicates that you are about 2,300 feet above sea level.  This is why engines lose power at altitude, because the air is less dense.  Even at 2,300 feet you have already lost 8% of the air pressure available at sea level, and hence the power that goes with all of that extra oxygen.  At 5,000 feet, you would be down 17% compared to sea level.

[LakeLimo024]

9 hours ago, justgary said:

Those MAP sensor readings appear consistent with those RPMs, but you didn't say whether the engine was under load or just revving in neutral.  Looks like neutral to me.

4.5v = ~0.92 Bar = 13.5 PSI = 1.2 PSI vacuum

2.3v = ~0.52 Bar = 7.7 PSI = 7.0 PSI vacuum

1.5v = ~0.37 Bar = 5.4 PSI = 9.3 PSI vacuum

1.05v = ~0.29 Bar = 4.3 PSI = 10.4 PSI vacuum

By the way, the MAP reading should be close to 1 Bar (14.7 PSI) at sea level with engine off unless you are at altitude or in the eye of a hurricane. Specifically, your pressure of 13.5 PSI indicates that you are about 2,300 feet above sea level.  This is why engines lose power at altitude, because the air is less dense.  Even at 2,300 feet you have already lost 8% of the air pressure available at sea level, and hence the power that goes with all of that extra oxygen.  At 5,000 feet, you would be down 17% compared to sea level.

Impressive!!! Yes  it was in neutral, and I'm in west Texas which I believe is around 2300 ft!! Learn something new everyday!!!

[LakeLimo024]

OK, so fuel pressure is 58psi at key up and stays there through around 2500 rpm, didn't go much higher but it started missing around 2300 rpm. Sounds better up till then. Compression checked out good on all cylinders at 150psi. 

[Woodski]

Corroded cap and rotor can result in poor spark or cross fire and poorer performance as engine speed goes up.  Between plugs and cap the electrons have a couple of hard jumps to make.

[LakeLimo024]

Distributer

Is the small metal ring that the Rotor connects to supposed to move? It rotates quite a bit on the shaft of the distributer. In the pics I move it from one extreme to the other.

[LakeLimo024]

I know it rotates as the shaft rotates, but should it have that much movement on the shaft itself? Seems like it should be stationary on the shaft

[Woodski]

Not familiar with that distributor although I would think that the rotor and timing ring would not have movement.  Typically, the timing map is in the ECU and not an advance setup like cars in the 80's.  A timing light check to see how much spark scatter you have would be a good test to run.  If you have a lot of scatter, that would contribute to your engine miss.