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Author Topic: Having our first mechanical issue...  (Read 1307 times)
DriverGT5
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« on: August 07, 2014, 07:13:10 AM »

When we got out Series 5 a few months ago I was shocked as to how much power it had and how well it accelerated for a 35,000 lbs vehicle.

We have taken it on two trips since covering about 1000 miles but on this recent return trip I noticed it was really slow from a stop and took a very long time to get up to speed. Like it's missing about 1/2 the power it once had. I managed to get home and pulled the fuel filters to find them full of what looks like some oil sludge and water. I changed both filters and ran around the block twice but it's still the same, no real power.

What should I be looking for on this 8V71? Air throttle opening all the way? I guess I don't know the best place to start.

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1968 Eagle Series 05 - 7616
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dukegrad98
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« Reply #1 on: August 07, 2014, 08:51:22 AM »

What's your fuel level?  If you're sucking the bottom of that tank for the first time in a long time, I'd check the filters again -- fuel first, but also air.  May still be a lot of gunk making its way through your fuel system.

Cheers, John
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ol713
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« Reply #2 on: August 07, 2014, 09:51:12 AM »


Hi;
   yea  - - - I agree with what John said.   If your coach has set a long time with a partial
   tank,  you will find algae  growing in there.   Also check your air cleaner. There is diesel
   conditioner available at most truck stops.   Undecided
                                          Merle.
                                           
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bevans6
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« Reply #3 on: August 07, 2014, 11:03:27 AM »

Any smoke that is different than before?  If no smoke then odds are not the air filter, but it doesn't hurt to check.  Also doesn't hurt to establish that the air throttle is achieving full travel.  But it's probably the fuel system.  If gunk got through the filters you could have to clean the injectors and the fuel rails in the heads, etc.

Brian
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1980 MCI MC-5C, 8V-71T from a M-110 self propelled howitzer
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DriverGT5
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« Reply #4 on: August 07, 2014, 11:27:57 AM »

That's the sort of place to start I was looking for. The bus sat for at least a year before I got it. I filled the tanks up and drove it about 1000 miles with 240 gallons give or take that would put me just under 1/3 of a tank. I did put some Diesel Kleen or what ever the stuff is called when I filled up. Maybe I dislodged a bunch of crap in the tanks?  Huh

I know I have a good bit of smoke when it starts from the right bank and it sounds like at least one injector isn't working all that great until it warms up. Maybe now is a good time to clean all the lines and check the injectors. I'll let you know what I find. Any suggestions on the best way to go about all this? Just pull stuff off and spray the crap out of it with brake cleaner or carb cleaner?
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dukegrad98
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« Reply #5 on: August 07, 2014, 11:59:28 AM »

That's the sort of place to start I was looking for. The bus sat for at least a year before I got it. I filled the tanks up and drove it about 1000 miles with 240 gallons give or take that would put me just under 1/3 of a tank. I did put some Diesel Kleen or what ever the stuff is called when I filled up. Maybe I dislodged a bunch of crap in the tanks?  Huh

That's exactly my bet -- it's practically a recipe for clogging a filter when you mix a tank that hasn't been used in a long time, a full load of fresh fuel, and a fuel treatment that is basically a solvent.  It could be tar / algae / sludge / water / unidentified gunk in there, but you just want to hope the filter caught most of it.  Start there, then move through the rest of the system as necessary.  

Any suggestions on the best way to go about all this? Just pull stuff off and spray the crap out of it with brake cleaner or carb cleaner?

I don't have great advice here, but I will say that I would NOT use brake cleaner.  I have personal experience with this being a bad idea on injector parts.  Your mileage may vary, but that was a costly learning experience for me on a smaller diesel engine.

Cheers, John
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Dave5Cs
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« Reply #6 on: August 07, 2014, 12:37:36 PM »

Use diesel solvent or clean diesel to clean them with. Always blow dry with filtered air.
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luvrbus
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« Reply #7 on: August 07, 2014, 02:54:58 PM »

Install a gauge on the secondary filter it should read above 40 lbs at 1200 rpm if you have the old canister type with a sock type filter you will find out the new fuel and the sock type filter are not compatible we just went through this on Tom's MCI 
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Oonrahnjay
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« Reply #8 on: August 07, 2014, 03:18:26 PM »

       Algae in diesel fuel almost always happens if you have water in the fuel -- a weird kind of algae sits at the layer between the two, it lives in the water and gets nutrition from the fuel.  What happens is that you "burn down" to the level of that layer and it all gets sucked into your filters in a single gulp.  There is a fuel treatment called "BioCide" which will kill the algae but if they're there, it doesn't matter if they're alive or dead -- they'll still clog up your filters again and again.
       Unfortunately, probably the best way to deal with the problem is to drain the tank and refill with clean fuel.  You can reuse the fuel you drained if you filter it externally and put a little BioCide in the fuel.  In fact, if you had algae in the tank, it's probably a good thing to use a small amount of BioCide as a preventative even if you fill with 100% clean fuel.  If there has been algae in there before, it will try to grow back anytime there's water and fuel in there.  The bottle of BioCide has directions for the amount to use as a preventative mix.

HTH,   Bruce H   southeastern NC  USA
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Bruce H; Wallace (near Wilmington) NC
1976 Daimler (British) Double-Decker Bus; 34' long
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Oonrahnjay
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« Reply #9 on: August 07, 2014, 03:41:26 PM »

     Oh, yeah.  If you do have algae, you have two different problems -- the algae that was (and probably still is) in the tank and the stuff that's in the lines, filters, pump, injectors etc.  My discussion was taking care of the tank, other posts have talked about the other.
« Last Edit: August 07, 2014, 03:45:12 PM by Oonrahnjay » Logged

Bruce H; Wallace (near Wilmington) NC
1976 Daimler (British) Double-Decker Bus; 34' long
6-cyl, 4-stroke, Leyland O-680 engine

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muldoonman
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« Reply #10 on: August 07, 2014, 04:51:16 PM »

Talking about algae, bought my bus over 3 years ago and the thing had been sitting for about 7 years and not started. Had about half tank when I got it and topped it off and drove it home 400 miles.  Never had a problem with mine. It has a Racor filter in front of the stock Detroit filters. It was in a climate controlled barn though. Might have made a difference.   Good luck.
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lvmci
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« Reply #11 on: August 07, 2014, 05:24:51 PM »

Hi Driver, since you found junk on your filters, I would blow hi air pressure back from the primary in, fuel line, then empty your tank with the drain, have 5 gallons of fresh fuel ready to rinse again. As Clifford said, the spin on filter seems to handles newer fuel, including the biodiesel mixes better,  not to mention so much easier. Tom, lvmci...
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luvrbus
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« Reply #12 on: August 07, 2014, 05:30:32 PM »

What are you guys calling algae doesn't algae require sunlight to grow, a fungus will grow in dark places but I don't believe algae will   
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DriverGT5
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« Reply #13 on: August 07, 2014, 05:35:53 PM »

Just when I thought I was done learning about vehicles... Cool

Sounds like this is going in the right direction. The blackish goop I remember in my filters that I thought might have been oil is probably crap in the tanks.

I have spin on filters so maybe I'll pull the new ones back off and have a second look to see what's in there. I'll also install a fuel pressure gauge. I'm sure that will come in major handy down the road also.

I'll go through the fuel system in the next few weeks and let you know what I find. This will be the first time I've pulled 8v71 injectors but this will be the 4th vehicle I've owned with clogged injectors. I seem to have a knack for purchasing cars with rusted gas tanks... I was happy this bus had aluminum tanks.... Roll Eyes
« Last Edit: August 07, 2014, 05:40:03 PM by DriverGT5 » Logged

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gus
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« Reply #14 on: August 07, 2014, 06:26:12 PM »

Don't let the tank level get low. Keep it near full so the old fuel/crap will gradually get diluted.
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