VP 8.1 GX-i running like crap

[DFWcobalt]

Last year I was getting water in the bilge. Local Cobalt dealer traced it back to outdrive, and in order to repair the leak they pulled the drive and engine. When they gave me the boat back I dunked it immediately and it ran so rough, stalled, and would not even come close to planing. I took it right back to the shop, and they called me 30min later saying it was fine. We then went for a ride together, and it was fine.

Winterized and stored all winter.

Got her on the lake today. Same engine issue. Rough. No power. Almost Sounds like its running on one bank.

What should I check? How should I check it?

Oil and filter are new.

Help!

Thanks

 

[Dillusion808]

What did they do to make it run last time?

I'd start there.

 

[DFWcobalt]

They said that they didnt do anything

 

[Dillusion808]

Air fuel spark

Really hard for us to help over the internet without much information honestly.

 

[alldodge]

Welcome
In most all cases when the motor has issues it will need to be scanned to determine what is happening. The scanner needed is one made by Rinda and will need a adapter to plug into the PCM. Can use the Techmate or Diacom software on your laptop

There are some basic checks that can be done prior. One issue with my following comments is I can no longer look up your motor to view it's configuration.

Remove the fuel filter and dump fuel into a clear container to see if there is anything but clean gas

Check fuel pressure at the rail to see if you have 40 psi +/- 4 psi

With motor being removed it could very well be one or more the the harness connectors are loose. Disconnect battery, then remove and reconnect connectors all over the motor

 

[DFWcobalt]

Thanks so far. Will do what i can.

How can i confirm spark? Pull plugs one at a time and ground them on block while cranking?

 

[Dillusion808]

I like to use my test light so I don't get zapped.

 

[DFWcobalt]

Fuel filter drained. Some sediment in bottom

 

[DFWcobalt]

This harness was loose. I pulled it apart but it was def not fully seated. Not sure what its for

 

[Scott Danforth]

Compression numbers? All 8 cylinders should be between 145 and 155

Fuel pressure?

Have you sent the injectors out to be cleaned and flow checked?

Beyond that, you need Rinda

 

[alldodge]

There ya go, a connector not even connected.
My guess is there is another one somewhere

and gas looks fine

 

[DFWcobalt]

There ya go, a connector not even connected.
My guess is there is another one somewhere

and gas looks fine

For clarity, It was connected…just barely. I easily pulled it apart then took pic.

Will keep looking for more.

Thx

 

[alldodge]

ok, but since it ran fine, motor removed it no longer runs fine, then it starts running fine again, and now it doesn't

I would bet it's an electrical issue and a bad connection. Fuel pumps, injectors, sensors, ECM, don't do things that resemble and light switch on/off/on/off