bad fuel injection pump or something else??

jgagnier · Sep 16, 2017

Hi.

I have a 310c which will turn over but will not start. I am suspecting a fuel injection pump failure but not sure. I am getting fuel to the pump however its not getting to the injectors (or out of the pump for that matter). I have tried bleeding the lines over and over again but will not get a drop out of the pump but there is fuel pumping through the return line back to the fuel tank. Any suggestions before i pull the pump and assume its bad?

thepumpguysc · Sep 17, 2017

Remove the return line & fitting from the top of the pump.. All the way down to the alum. top cover.. NOT JUST THE LINE but all the fittings..
What happens to those pumps is either the fuel went bad & stuck the pumping parts/fuel delivery parts or the plastic flex ring broke up & clogged the fuel return system..
By removing the check ball fitting from the top of the pump, your allowing fuel to escape & more fuel to come in the pumping circuit..
IF you can remove the top cover with out breaking the screws.. do it.. you may just have a stuck metering valve.. they normally just loosen up w/ a flick or 2 of your finger.. google it.. "roosa master stuck metering valve" it'll give you an idea of what to look for..
Good luck.. TPG

jgagnier · Sep 17, 2017

ok...I removed the cover and found what seemed to be a stuck metering valve as you said. It would push down but not release. I played with it for a minute and seems to be working as it should. I press down and it releases on its own...Is this correct? I hooked everything back up and still not getting anything, now not even out of the return. I took it back apart and rechecked the metering valve and it seems ok if this is indeed how it works

jgagnier · Sep 17, 2017

The metering valve arm itself will move freely to turn the metering valve but will not by pulling the throttle. Seems as if the linkage is bad??

thepumpguysc · Sep 18, 2017

The metering valve turns by flyweight force & spring force.. it wont turn just sitting there stationary while working the THROTTLE..
IF you pump has a MANUAL shut off[ pull cable] it will turn by operating the shut off..
IF the mv turns with your finger.. that's good enough..
IF IT TURNS w/ your finger & your still not getting fuel out of the pump.. the problem lies deeper..
IT SOUNGS LIKE the pumping plungers are stuck also.. they're deeper inside the pump & cant be reached from the outside..
It requires the pump to be dismantled & cleaned.. Sorry for your bad luck.. TPG