Gas in Fuel Return Line

[brg]

My 1998 Isuzu Wizard diesel (4JX1 engine) has recently experienced severe loss of power when under load. The same symptoms were experienced 18 months ago, and were fixed by replacing the injector O rings.
This time the mechanics have found that when the engine revs, gas bubbles appear in the fuel return line. They are reluctant to take the injectors out until they are sure that O ring failure could cause the gas in the fuel return. Is there anyone out there who knows if this is possible?
Thanks in advance.

[geeves]

Yuc
With that engine your stuck with whatever the mechanic tells you. Only deal with a Holden dealer or a mechanic that realy knows his way round that engine.
I would be checking the whole fuel system as far as the pump first as the air is either being sucked into the line or somehow getting blown in at the injectors. My money is on an air leak between the tank and the pump or at least it would be if we still had 5c pieces

[brg]

The mechanic has already checked out the fuel line from the tank to the pump and there is no leak. Its just that it doesn't show the usual symptoms of O ring failure (poor starting and sump oil rise), and they don't want to touch the injectors unless this could be the cause of the gas in the fuel return.

[geeves]

One very horrible thought that will probably have your mechanic checking the injectors first. The fuel lines on that motor run through the block and head. A leaky head gasket could be the cause.
Only other thing you can do is fit a sight glass at various points in the system and work out which area the bubbles come from

[brg]

Problem solved. O rings and injector sleeves have been replaced and the engine is now running sweet. Thanks geeves for your input.

[geeves]

Did they fix under a warrentee or did you need a mortgage?

[brg]

$1099 all up. Could have been worse.

[geeves]

After all the horror stories about injectors Ive heard in the past thats not that bad. Its about 600 to do injectors on the much simpler 4jb1