03 challenger 1800 won't plane out and loses power and rpms

[Butler74]

When it in the water and give it gas it starts to shoot out of the water and then it just bogs down and slows down and will eventually die unless you back off the throttle. Any help is much appreciated.

 

[Butler74]

At wot it will surge.

 

[philipmurphey]

Have you checked the usal things like replacing the plugs ( and check for a lean condition ) and replacing the fuel filters x2? How does it idle in the water and how does it idle on a hose?

 

[Butler74]

The plugs are new. 1 filter is new. It idles good in the water and on the hose for 10 min and then it slowly dies

 

[Butler74]

What do I look for when you say lean condition? On the plugs?

 

[philipmurphey]

you want to have a nice milk chocolate color on the plugs. That will tell you that you are burning the fuel correctly. A black plug or white/clean plug needs more attention to that cylinder- perhaps spark or fuel is missing. Have you checked the compression on each cylinder? Should be 120 or higher to be a "happy engine". Also check your VST tank for fuel pressure. It ahs a "tire valve" on it and should read 36PSI> Also you will need the manual on the engine to help diagnose further issues.

 

[Butler74]

The fuel pressure is 36 psi. And the compression is 120. The plugs are clean looking that's why assume they are new.

 

[philipmurphey]

There is a small black box on the driver side under your storage compartment. It has a lot of wires coming out of it and runs to your motor. It is called a "guardian" and when they start to fail, they can cause weird problems like yours. Most people disconnect them and their problems are resolved. Look around under there and see if you have it and disconnect it and try another sea trial at let us know if that resolved anything.

 

[Butler74]

I will try that and let you know. Thanks

 

[Dr Honda]

Before we can help... What engine do you have?

 

[Butler74]

240 efi v6

 

[Dr Honda]

OK... from that cover... you have a Gen2 engine.

I would start with checking the fuel pressure under a load. I'm guessing the rail pressure is dropping.

 

[Butler74]

Ok so the pressure should stay at 36 psi under a load? I will take it to the lake tomorrow and check. If it is dropping under a load would it be the fuel filter or the fuel pump?

 

[Dr Honda]

It could be:

1) The filter on the bottom of the high pressure pump is clogged.

2) The needle valve in the vapor tank isn't letting fuel flow in. (dirty/clogged)

3) The pump is going bad.

4) The pressure regulator is going bad.


Those are the things I would check out if the pressure is dropping.