Tige 22V (2004) Runs only on 4 zylinders

[Andreasmartet]

Hello
I apologize for my English, English is not my first language, but i will try my best.

I bought a used Tige 22V Riders Edition (2004) with the 5.7 liter V8 Vortec engine last year.

Now to my problem:
The first ride this year was about 2 weeks ago and after 3 hours of riding, the engine started whistling loudly (extremely loud intake noise) and the engine had no more power (8MPH) maximum.
I then checked a few things and found that the engine runs only on 4 cylinders. 2,3,5,8 do not work

I have checked the following:
The ignition distributor and the ignition cables everything worked fine, then I checked the spark plugs, they also work but I noticed that the spark plugs do not get wet. Therefore, I suspected that the high pressure fuel pump is not working.
So I checked the fuel pressure and I have around 60 PSI so that also fits.
After that i talked to a mechanic and he said that maybe the idle air control is not working. I also changed that.
No boat mechanic I called has a diagnostic tool for the MEFI 4.
so I can't read the errors either.
I did build a diagnostic tool with an LED and compared the LED's tektimes.
This has output that the TPS has low voltage, as well as the IAC and the knock sensor is not detected:
I have replaced everything and it still does not work.
Does anyone have an idea what else I could control or what the error could be.

I thank anyone who can help me

[boatwakes]

Welcome and hello!

How did you determine only those cylinders were firing?
Engines need 3 things to run: fuel, spark and compression. Check spark by using an inline spark checker like this one... https://www.amazon.com/OBDResource-I...zcF9hdGY&psc=1
Check compression using a compression tester.
Check each fuel injector by individually disconnecting the power connector to each.
Report back with what you find out and don't replace any more parts until you have a clear idea what is wrong.

[Andreasmartet]

Thanks for your answer

I know they don't work because I have disconnected one at a time on the ignition distributor while the engine is running to see if there is a change or if the engine behaves differently.
When I disconnect 2,3,5,8 the engine runs with no change.

I ckecked the spark plugs, they are working at all cylinders.

I also tested the compression, on the outer cylinders I have 8 bar and on the middle two 7,5 bar.

I also measured the current output on the injector cables, when I turn on the ignition I have 5 volts (so they are triggered) but when I start the engine they no longer get a signal.

[boatwakes]

It sounds like dirty fuel that lead to fuel injectors getting plugged with debris. I suggest removing and replacing the fuel filter and inspecting the old filter and fuel inside it for debris or water. Furthermore, the injectors will need to be removed and cleaned, flow tested and then re-installed. This procedure is pretty easy if you're confident of your mechanical abilities but requires attention to detail because you're involving a flammable liquid. Find a shop that does injector cleaning and I'll do a write-up on how to remove the injectors if you need. In the future, and for all reading this, it's best to disconnect the injector leads while the engine is running instead of removing the spark plug wires for multiple reasons (explosion from gas fumes, shocking yourself or others, etc...) when trying to find a dead cylinder.

[Andreasmartet]

Thank you I will try that.

It would be very nice if you can write me such an instruction, then I will try it right this weekend.
I think I will manage that without burning the engine completely

Thank you for your help

[boatwakes]

I will write a separate thread in the "How To" section.

[hfreak100]

Andreasmartet were the fuel injectors your issue? I am having very similar issues with my '00 21V Riders. Thank you boatwakes for this and the writeup!