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5-600+hp BIO users any issues with fuel pressure?

972 views 3 replies 2 participants last post by  erbilabuc 
#1 ·
I get fluctuating fuel pressure when I run my bio up to aproximately 45-50%. The percentage is rough I always just do a quick calculation in my head. Anyhow my airdog gives me 17-18 psi normally. When I run say over 35% of bio it usually drops down to 14-15 psi. Then when I approach 45-50% the fuel pressure will hold at 14 then drop to 5 or sometimes even zero. Then pop back up to 14 and repeat seemingly without a pattern. Sometimes it may take a few minutes to do this and others it will do the whole deal in 10 seconds. If the fp falls to zero my rp will still usually hold until about 50% of load (just a guess).

When it does this I usually just add a few gallons of #2. It quits fluctuating and everything is happy again.

My theory is that my airdog just doesn't like the viscosity of this bio. My buddy brews it. He does a very good job as far as I know and can tell. His setup is legit well filtered and all that.

So my main question is are any of you pushing as much fuel as I am or more (sorry I can't quantify how much fuel beyond saying it is 600hp+ worth) with an Airdog, Fass or similar fuel delivery system and having issues with fuel pressure? Airdog is a 150 BTW. Supply line is run to the stock filter housing and pressure sensor is installed just after the factory filter.

Also I want to add I can easily see the difference in how thin or thick the fluid is when I'm having issues by sampling some of the fluid. Also temperature seems to have no major effect on this problem. IIRC I've had a 42% mixture in weather down to 25 degrees.

Today the mixture was thick enough that after the fp dropped to 0 the cp3 was starved and the truck died.

You don't need to have a 600hp truck to respond, I just threw that out there to possibly draw someone with a similar setup. If you've seen issues like this and or have alot of experience with bio, lay it on me.

Thanks
 
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#2 ·
stupid question but what truck do you have? Airdog has a hard time handling 100% bio and is definitely not meant for veggie oil. Only way to solve your 100% biodiesel fluctuation problem is to heat the biodiesel somehow and bring the viscosity down.
 
#3 ·
Not a stupid question, it should have been in my sig. It's a dodge with a 5.9 cummins.

I've never ran 100% bio, only up to aprox. 50%. Probably won't be adding a heater, so I guess I'll just try to always run a lighter mixture.

I just thought it was odd that I've never seen any posts or talk about these pumps and bio not getting along all that well. Thanks for the reply.
 
#4 · (Edited)
I have a fass HPFP and it has no problem keeping 60psi even with 80degree cold oil. Not knocking the airdogs but when Ii was in the market for my fuel pump I called airdog and their sales and tech's both told me their pumps are not meant to handle any type of bio or veggie oil mixture (this was January 4th of 2011). FASS pretty much told me the same thing but did state that they have had success with their pumps but b no means are they meant to handle it. I went with the FASS due to the lifetime warranty no matter what you run through it.
 
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