CM570 compression in fuel

[jdrmx]

(04-17-2016 )Rawze Wrote:  Things that come to mind...

* Bad Injectors.

* Leak in fuel lines (pressurize fuel tanks to 10 psi and see if it clears up).

* Cracked or worn out head.

* Bad fuel pump that is sucking air.

It is normal to get some bubbles into the return line. It is due to cavitation at the regulator. -- It will usually stop if you pressurize the fuel tanks a bit.

Have you boroscoped the engine while the injectors were out? -- Check for cracked valves, head, and signs of washed out cylinder walls or washed out carbon ring.

Also check temps at exhaust ports. that will usually reveal a lot too, and run the engine on only one cylinder at a time to see how it does.

I have not boroscoped the cylinders. I did check cylinder temp with infared gun and it certainly agrees with the performance test. I also checked a good running cm870's return fuel last night to compare. Like you said, there was some small bubbles, but nothing like this cm570 is doing. With the diagnostic tool I have it does not allow me to run it on 1 cylinder at a time, only 1 "off" at a time.