Speedster hesitating / missing / breaking up at higher power settings

[marceb16]

Hello - need help. Boat surging slightly as engine starts to break up one off idle and past 1/4 throttle (running erratic, as if fuel or ignition is being pulled momentarily).

I have replaced the plugs, fuel filters, bled fuel at high pressure pump blend valve and verified steady fuel pressure at ~36 psi.

Where should I look next?

Thanks!

 

[ripcuda]

Reading your issue details... the TPS (throttle position sensor)... comes to mind. When it fails, it gives erratic data to ECU and causes issues like you descibe. There are methods to test it is working (service manual has steps if I recall).

Also get an in-line spark checker and verify spark while attempting to throttle up.

Cheers!

 

[marceb16]

I believe I may have it narrowed down to the two bottom cylinders not getting proper fuel, suspect plugged injectors. Is this semi common for these motors, given all the filters, and if so is there even a way to remove the injectors without having to pull the motor out?

If clogged injections, where is the best place to send the injections to be cleaned?

Thanks!

 

[ripcuda]

You have the 240efi (gen1 - round flywheel cover)? The injectors can be removed. You have to unbolt the ECU first, then unbolt the entire intake manifold (injectors inside). Then on the bench you can remove the injectors from the intake. I had injector issues (240efi gen1). Some leaked, some were out-of-spec flow-wise. Had to replace one (couldn't get it to flow right). I sent mine off to BrucatoFIS (online) for servicing. About $20 an injector. Happy with my results. Cheers!

 

[marceb16]

Thank you and yes Gen 1 with a round flywheel cover, installed in a 2000 Speedster. So, you are saying that you were able to remove your ECU and then unbolt the intake while the engine was still installed in your speedster? Seems like that would be a very tough task to bend back around the engine and under the rear seat area. But, boy I really do not want to pull my motor out if I don't have to. Thanks again and in advance for your replies.

 

[Tim75]

I believe I may have it narrowed down to the two bottom cylinders not getting proper fuel, suspect plugged injectors. Is this semi common for these motors, given all the filters, and if so is there even a way to remove the injectors without having to pull the motor out?

If clogged injections, where is the best place to send the injections to be cleaned?

Thanks!

Thank you and yes Gen 1 with a round flywheel cover, installed in a 2000 Speedster. So, you are saying that you were able to remove your ECU and then unbolt the intake while the engine was still installed in your speedster? Seems like that would be a very tough task to bend back around the engine and under the rear seat area. But, boy I really do not want to pull my motor out if I don't have to. Thanks again and in advance for your replies.

Have the service manual in hand. Read it before starting. There are important tips in there that make the job easier.

Be very careful of the fuel rail- it's plastic. There are 2 short hoses on top of the vst. They are $75 to replace them.

 

[ripcuda]

My boat is a Challenger 2k... so more engine bay room than on a Speedster. So pulling the intake is very do-able. I also make life easier by remove the engine hatch cover allowing me to sit on the rear deck and straddle the engine. Not sure the layout on a Speedster... you might be reaching around the front of the engine blind... that would be tougher. GL