Air in the system

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Oct 28, 2012 | 01:17 AM

VegiePower

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From: Canmore, Alberta, Canada

Air in the system

I changed a pre-filter before the pump today and must have been sloppy and gotten air in the system. It ran about 5 minutes and then started to chug and knock. Won't restart. I have cycled the pump numerous times. Any other ideas on how to clear air? Do I need to crack each injector or....?

Thanks
Torie

Oct 28, 2012 | 08:50 AM

SkySkiJason

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From: N.GA Mountains

What engine/yr?

7.3 will purge itself of air by cycling the key to 'on' for 30-40secs 2 or 3 times. This pump DOES NOT like restriction in front of it. 100mic strainer is adequate to protect the pump, any 'finer' and you risk killing the pump. WIX 33972 or similar makes a good pre-pump filter.

You can check pump operation by opening water-drain valve and turning key to 'on'. I put a piece of hose on the drain discharge tubing so I can collect/inspect fuel from the filter. A strong pump will give you about a quart of fuel before the pump 'times out'.

Oct 28, 2012 | 10:28 AM

VegiePower

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From: Canmore, Alberta, Canada

Sorry. It is a 2002 7.3L. The pre-filter is for my SVO system and is 10 micron. I changed both veg and diesel filters yesterday. Then drove into the city. Switched over to veg after about 10 minutes and it ran fine for a few minutes and then acted like it had air in it as it slowly lost power and then died. I switched back to diesel but not quick enough. I cycled the pump a dozen times likely. No luck. It turns over great and just knocks on ignition. I didn't have time to look at it much last night and had to have it towed home. I will check the pump and that all drain ***** are closed and pray that my pump is okay. It wouldn't just die would it? I would think it would have been a noticable issue over a number of days or weeks.

Thanks

Oct 28, 2012 | 04:55 PM

VegiePower

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From: Canmore, Alberta, Canada

Update

So I discovered that no fuel was getting to the filter bowl. I disconnected from output side of pump. No fuel. I used my vacuum pump to prime it and its working well again. Strange...

Thanks for the help
Torie

Oct 29, 2012 | 06:38 AM

SkySkiJason

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From: N.GA Mountains

Quote:

Originally Posted by VegiePower

Sorry. It is a 2002 7.3L. The pre-filter is for my SVO system and is 10 micron.

This is too small for a pre-pump filter. ESPECIALLY without adequate heat for the VO. All you want pre-pump is a strainer to protect the pump.

Why did you unhook fuel line instead of just opening water-drain valve on OE filter?

I suspect you have a vacuum leak somewhere or clogged in-tank strainer/filter thingy. The PSD pump does a pretty good job of self-priming. The in-tank strainer is almost a given if you've been 'blending' VO or allowing VO to return ton diesel tank with a poorly designed conversion.

Do the 'in-tank mods' (search Hutch/Harpoon Mods) first chance ya get. This problem will only get worse as the temp drops. The blending will continue to be a problem, but removing the strainer in the tank should keep ya from having this problem...

Are you using stock pump for both fuels? Putting VO thru the stock filter??

My guess is this 'VO system' is not very well designed and your problems are just beginning.

Oct 29, 2012 | 08:40 AM

mtnsammy

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Joined: Jul 2012

Posts: 272

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From: SW Missouri

I agree with a vac leak on line between tank and pump. I did the hutch and harpoon mod on my last truck and it made a big difference. I had about 166000 miles and there were tank issues. On my new Ex I will get around to the tank mods too when it warms up this spring. Many new projects with a new toy.