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Topic: Too much Biocide on the fuel? (Read 956 times) previous topic - next topic

Too much Biocide on the fuel?

What happens when there is too much biocide added to the fuel. i put the coach in storage a month ago and before doing so added several ounces to the fuel. I tried to start the coach today and it just turns over but wont fire up. I fired up the generator and it ran for about 2 minutes then stalled out. The tank is about 1/3 full.

Suggestions on what to do next?
Rick and Wendy Green
1998 U270 3600 The Coach Formerly known as Princess
Build# 5336
2007 Ford Explorer

Re: Too much Biocide on the fuel?

Reply #1 –
Rick,

Not sure a few extra ounces of bocide will cause a no start.

At only 1/3 tank, the generator fuel pickup may be above the fuel level.

BTW, to reduce condensation, always store with full fuel tank, particularly in humid areas.

Does the fuel (remove filler cap) still smell like good diesel, or has it "turned".

What do you get when you open the drain on the primary fuel filter?
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Too much Biocide on the fuel?

Reply #2 –
The fuel standpipe for my generator only allows fuel to be used from the top 2/3 of the tank, ensuring that I never run below 1/3 for the engine.  The generator should stall at 1/3 tank.  As far as the main engine shutting down, I don't think a few extra ounces of biocide would cause that.  Maybe a clogged fuel filter?

Re: Too much Biocide on the fuel?

Reply #3 –
If your coach still has the original fuel lines they could be the cause.
previous 1984 35 ft ORED 250 HP 3208 Cat       
previous 1998 40 ft U295 CAI 325 hp Cummins
previous 2003 40 Ft u320 build #6140 450 Cummins M11.                                                         
1999 Mazda Miata
Ron, Nancy, Tipper the cat, Max The dog
1997 U 270 36 ft build number 5174 8.3 Cummins

Re: Too much Biocide on the fuel?

Reply #4 –
Checked a fuel fliter to see if algae has it plugged? 

Maybe a bit far fetched since totally stopped flow but sounds one option. 

Urge not stor coach without full fuel tank as can condense water and grow algae

Hope this helps
Mike
2001 U320 4010 Build 5878 (Gus)
Wrangle Unlimited Toad
Nacogdoches

Re: Too much Biocide on the fuel?

Reply #5 –
Quote from: red tractor –
If your coach still has the original fuel lines they could be the cause.

Yup-- check primary fuel filter for AIR in it.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Too much Biocide on the fuel?

Reply #6 –
if it is turning over at a good rate and not starting chances are you have a fuel starvation issue - sounds like you have starvation to both frankly -

I routinely add extra Bio Code with no ill effects -

did you add biocide suspecting or because you have algae or as a preventative measure only?

As Brett said, Always store with Fuel Tank Full ifpossible

Tim Fiedler

Sure Start Soft Start

TCER Direct generator-gas-prod 630 240-9139
Gen-Pro
Tim Fiedler    2025 LTV Unity MBL on Order
2000 Chevy Tracker 2 Door Convertible 4WD Now lifted 4.5"
1985 Citroen 2CV6 Charleston
Murphy Rebel on wheels with 175HP Titan
Cessna P337
1980 48' Westport MY (!/4 Share)

Re: Too much Biocide on the fuel?

Reply #7 –
Thanks for the responses. So its probably not the overdose of biocide thats causing the problem.

I realize it should have a full tank but I wasnt planning on storing it for a whole month when i put it away. plans changed. Actually, I was heading to tank it up when I couldnt get it started.

The fuel lines are original. I had FT check them last year and they said they were OK, but that was last year.  How would I check that. I was in the coach full time from January to september and there was no sign of any issues with the fuel lines. It started right up every time. If the fuel lines were going bad, wouldnt it have difficulty starting all the time.

I agree that it does sound like fuel starvation. I am not at the coach right now. will be back there tomorrow so i will smell the fuel, check the fuel filters and check back.


Rick and Wendy Green
1998 U270 3600 The Coach Formerly known as Princess
Build# 5336
2007 Ford Explorer

Re: Too much Biocide on the fuel?

Reply #8 –
Rick,

If you have a clear bowl primary fuel filter, look for any air in it.

And bad fuel lines often do NOT LEAK, as they are on the suction side of the system.  They let air IN, not fuel OUT.

Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Too much Biocide on the fuel?

Reply #9 –
You could put 5 gallons of biocide in the tank with no effects on starting. You probably have air getting into the fuel system. If you have a hand primer, pump it for a couple of minutes. You could also loosen the secondary filter a couple of turns and then use the hand pump to see if fuel comes out. Yes, check the clear bowl if you have one. Algae usually shows up after the engine has been running and usually under more load than idle.

If your generator ran for several minutes and stopped, your fuel gauge may not be accurate. Using fuel cans, fill the tank higher and then try the generator again. You may have to prime the generator. Easy to do with the electric pump.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Too much Biocide on the fuel?

Reply #10 –
OK, Rick,
I totally agree that it's not Biocide dose and if it were biocide kill related, the engine and the gen. set would have BOTH run for quite some time and then started stumbling as their filters plugged.

Just as Brett, Ron, Tim and Pierce have said, when a diesel engine refuses to start, it has to be that the engine is starved for one or the other - fuel or air - or both.  Air is highly unlikely so it's most likely fuel.  When you turn the key on, does the Auto Stop solenoid move and stay pulled up?  If it does, then most likely, with a tank at 1/3rd, the fuel has drained (siphoned) back to the tank.  Like Brett said, suction lines leak air IN and return lines are under such little pressure, there's seldom any significant evidence of fuel leakage OUT.  Occasionally a return line will show some small leakage at the tank top fitting because that is a line restriction that develops a little back pressure.  Usually quickly evident to the average bear's nose.

So look for any loose fitments at the fuel filters and at the engine driven fuel pump (I replaced that a year or two before you purchased).  Anywhere in the fuel lines, that you can get your eyes on them, check for linear cracking along the axis of the fuel hose covering, especially near the end fittings.
 
You had the fuel lines checked a year ago and I had them checked by FOT before our sale and they were OK then but you are really getting out there in time on the original hoses.  The engine and gen. set always did well deep into the low 1/4 tank level range.  That may have changed with time, of course (gauge calibration shift), but if you normally store the coach near full and this time it was 1/3 or so, that's another indicator of lines aging.  The siphon effect at full tank level is minimal as compared with a low tank.

But what is kind of the biggest clincher is that the engine and gen. set both bothering simultaneously when the tank is about 1/3 which really sounds to me like fittings allowing air in and the lines siphoning back to the tank.  The gen. set would run for a bit due to the fuel trapped in the downhill side of the lines, but if the two sets of lines are leaking, they might well be all starting at the same time (same spool of material and the same exposure history of biofuel burden accelerating the aging.

Whenever mechanics changed fuel filters without filling the new filter or if they allowed the engine supply line to drain back, they always had a really hard time getting the engine line primed again.  If there is a primer bulb, I never found it and no tech could ever show it to me.  They were always successful in getting it started by removing the line at the first filter, priming the filter and the line (trying hard to not let it siphon back on reassembly) and then cranking the engine.  Once it caught, there would be some stumbling but it would run fine after that.  If you don't discover catastrophic line weakness and you can get it started, keeping the tank full should minimize the problem until you are ready to tackle the replacements.

Good luck,
HTH,
Neal
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Neal (& Brenda) Pillsbury
'02 U320 SPEC, 4200, DGFE, Build #5984
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Re: Too much Biocide on the fuel?

Reply #11 –
Update: Got it running this morning. I added fuel to the tank and topped off the chassis battery overnight just to make sure. It took several tries before it finally took off so I am thinking that fuel must have drained out of the injector pump.  Took it straight to the fuel station and then to LazyDays Tampa to get the windshield replaced. It ran the entire time without any problems. 

I didnt have time to check further into the cause because I didnt want to miss my appointment at lazydays. I will check further when I get it back.

Thanks again for all the help.

Rick and Wendy Green
1998 U270 3600 The Coach Formerly known as Princess
Build# 5336
2007 Ford Explorer

Re: Too much Biocide on the fuel?

Reply #12 –
Finding air leaks can be what turns a technician's hair gray. Isolating one component after another in the fuel system and using a MityVac can eliminate one possibility after another until the culprit is found. Could also be as simple as the injection pump return valve leaking some fuel back to the tank if it's not low fuel in the tank. Tough to clamp off the supply line at the tank and then pull a vacuum at the other end.

With both the main engine and the generator stopping, low fuel in the tank is a good possibility. Since they have different pickups, a bad hose seems less likely but both could be related to low fuel level. I've had several diesel cars develop a fuel sender problem. One car was getting incredible mileage with the fuel gauge not really moving once it got to a quarter tank. The engine suddenly quit while I was on the Autobahn. Lucky it was downhill for several Ks and I was able to make it to a station. 

If the generator stops again, you can pull the supply line off the electric fuel pump and blow back into the line. With the fuel cap off, if you can hear bubbles, the line may be bad. No bubbles means the pickup is above the fuel level. The same could be done to the engine feed line but slightly more difficult to do from the primary filter.

Pierce

Before I replaced our generator supply line, I noticed it was damp but not dripping or anything.
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Too much Biocide on the fuel?

Reply #14 –
Quote from: AncloteJoe –
Update: Got it running this morning. I added fuel to the tank and topped off the chassis battery overnight just to make sure. It took several tries before it finally took off so I am thinking that fuel must have drained out of the injector pump.  Took it straight to the fuel station and then to LazyDays Tampa to get the windshield replaced. It ran the entire time without any problems. 

I didnt have time to check further into the cause because I didnt want to miss my appointment at lazydays. I will check further when I get it back.

Thanks again for all the help.


A similar thing happened to me me in the past few months, (see my prior posts).  I had to replace the fuel lines as there were cracks at all couplings and also at bends over the fuel tank.  You asked how to tell if you have air leaks.  These cracks are very visible, and a symptom is being harder to start, then no start.
97 U295 40, Build #5040, 6C8.3 325 HP
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