How do I Isolate an air leak in my fuel system?

cbird · Post by **cbird** » Fri Jul 01, 2011 2:59 pm

When I start my van up in the morning (or after she has been sitting for a while) she coughs and splutters to life. After I run her for a minute or two the stuttering and shuddering stops and she purrs along as she should. Along with each cough there is also a corresponding puff of grey smoke. I am pretty sure that this problem is that air is getting into the fuel line somewhere. I suspect this is the problem because when I pump the fuel pump on my fuel filter it almost completely gets rid of an shuddering when I start her up. Pervious to this problem I replaced the top seal on my injector pump due to a fuel leakage. It should also be noted that I have converted the van to veggie, although I always start on diesel and purge the lines of veggie oil thoroughly before I shut down.

- I have looked at the fuel lines and injector pump for any signs of a fuel leak and I can find nothing.
- I have recently replaced the fuel filter and tightened all the hose clamps on the fuel lines.
- When I pump my fuel filter priming pump it stiffens up (due to a good prime) but then I am able to further pump it after a minute or two (is that normal or is that a symptom of losing my prime?)

What is happening here? How am I losing my prime if I am not leaking any fuel? How do I go about trying to Isolate my suspected air leak?

Any help would be greatly appreciated as I don't think that the coughing and spluttering on start up can possibly be good for the old van.

Thanks in advance!

negativentropy · Post by **negativentropy** » Thu Apr 05, 2012 9:13 pm

I'm having the identical problem - except now even priming with the pump on the fuel filter wont get the van started - I'm starting to suspect a faulty/crap filter - this all started when I changed the fuel filter a few months ago...

How did you end up solving your problem?

Post by **nxski** » Fri Apr 06, 2012 12:25 am

I had the exact same problem, cvi cleaned the injectors and now it starts with just a tiny puff of smoke.

after oil · Post by **after oil** » Tue Apr 10, 2012 9:42 am

if your fuel lines are original, replace them. replace the clamps too. make sure their tight enough that you cannon spin them on their barbs. when youre priming. make sure the key is in the ON position. on my system anyway, the valve to diesel is closed when unpowered, so when priming it gets stiff because there is no where to pump from or too.

Delica Canada | Mitsubishi Van Club

How do I Isolate an air leak in my fuel system?

How do I Isolate an air leak in my fuel system?

Re: How do I Isolate an air leak in my fuel system?

Re: How do I Isolate an air leak in my fuel system?

Re: How do I Isolate an air leak in my fuel system?