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Author Topic: What causes loss of power?  (Read 5570 times)
Scott Bennett
Scott & Heather MCI-9
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« on: May 19, 2012, 08:07:35 PM »

As many of you know, I have a coach that wasnt running right on
Our trip from florida to Michigan. I had
Mixed motor oil in with the diesel. Long story but here is the latest list of things I've done and  I'm still
Missing some hwy top end. Can't get the coach over 65 mph:

1. Drained fuel tank and added 15 gallons of b100 biodiesel to clean tank and fuel system. Ran it on that for a couple of hours then added $200 worth of diesel to the tank. Coach exhaust is now invisible. Can't see it at all.

2. Motor oil looks great and so does tranny fluid.

3. Checked turbo at inlet and outlet and looked perfect. Spins as it should with no play.

4. Pulled off muffler running straight pipe now and can hear turbo Smiley love that whistle.

5. Blew air in all fuel lines to eliminate any obstructions.

6. Changed fuel filters

7. Checked to be sure throttle linkage is working properly.

Coach doesn't even smoke a teeny bit on full throttle on the hwy. where is my power? Seems to me like it still isn't getting enough fuel. Anything in the fuel system that would obstruct or reduce flow?


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Scott & Heather
1984 MCI9 6V92-turbo with 9 inch roof raise & conversion in progress.
http://www.scottmichaelbennett.com/p/our-bus.html
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luvrbus
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« Reply #1 on: May 19, 2012, 08:39:52 PM »

Wow, start by checking the rpm with a hand held tach your 6v92 should be 2100 to 2250 no load then check the fuel pressure should be 55 to 70 lbs at full throttle ? does your engine have a fuel modulator sounds like you are not getting full fuel position at the injectors.

You really cannot tell if the engine is at full throttle by checking the linkage on the governor housing,the rpm check is a good place to start   
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HB of CJ
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« Reply #2 on: May 19, 2012, 09:40:18 PM »

If practical, try changing out all your rubber fuel lines with one size larger.  Old rubber lines constrict like clogged people heart arteries and restrict fuel flow.

It would sound like your restriction/power problems MAY be waste oil caused....or at least influenced somewhat?  "Abandon All hope Ye Who Enter Here."  HB of CJ (old coot) Smiley Smiley Smiley
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Eric
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« Reply #3 on: May 19, 2012, 09:50:29 PM »

Totally unrelated to fuel issues.....but how about the air filter... Ours plugged and it was a dog discovered some crafty inhabitants Wink


Have fun !

Eric
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niles500
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« Reply #4 on: May 19, 2012, 11:48:48 PM »

clogged fuel system --> cleaned out with bio --> now under powered = clog moved further down line = blow out fuel lines, filters, injectors - see what caused Sean Welsh's problem a few years back - HTH
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Scott Bennett
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« Reply #5 on: May 20, 2012, 02:35:36 AM »

Cliff, I think this is the only way I'll know definitely what my power loss is. I'll work on this. Going to have to purchase the tach. Where does it connect? At the alternator?

HB, problem Exhibited only recently so I doubt my lines are constricting flow enough to cause this but it will be a good idea to replace the rubber lines anyway since I ran on B100 for a couple of hours. I'm not sure the waste oil caused my issues but the jury is still out on that. If so, I'll be the first to share this and save others the aggravation of trying to use it as fuel.

Eric, true true. I forgot to mention it in the above list but we replaced the air filter two weeks ago. Took entire housing apart too and cleaned it and made sure there were no obstructions. Good point and yes did it.

Niles, we did blow out the entire fuel line system all the way back to the tank. Had to reprime but it was worth it to be sure the lines were clear.

Two thoughts:
1. I took apart my engine stop lever/throttle plate assembly to unseize the engine stop lever when we were parked in florida. Any chance I could have put it back together wrong? I merely unbolted the Lid, unseized the stop lever washer and put the lid back on.

2. When changing fuel filters, I noticed that there was a small actuator or little round metal electric solenoid that is attached to the secondary fuel filter housing that has two wires attached with nuts. Does it control pressure or something along those lines?

Thanks once again for the assistance and helpful dialogue.


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Scott & Heather
1984 MCI9 6V92-turbo with 9 inch roof raise & conversion in progress.
http://www.scottmichaelbennett.com/p/our-bus.html
˙ǝɯoɔlǝʍ suoıʇɐuop ˙snq ʍǝu ɐ pǝǝu ʎlqɐqoɹd ll,ǝʍ 'sıɥʇ pɐǝɹ uɐɔ noʎ ɟı
Hard Headed Ken
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« Reply #6 on: May 20, 2012, 05:10:21 AM »

Scott,
 If you don't have these gauges, turbo boost, exhaust pyrometer, and fuel pressure gauge. I think they could really help you keep an eye on your engine functions. They are the original DDL, no laptop required.

Ken
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Utahclaimjumper
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« Reply #7 on: May 20, 2012, 05:34:34 AM »

Scott,, the wires from your filter are for the water detector system,>>>Dan
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Scott Bennett
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« Reply #8 on: May 20, 2012, 06:31:24 AM »

Ken, I would love to get kitted out with that set of gauges! Love to monitor stuff like that. I will start looking around for them and as we get the $$$ I will start buying them. Can you or Cliff or someone recommend a good place and brand to purchase the following:

1. Pyrometer
2. Tach
3. Fuel pressure
4. Analog or manual water temp.


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Scott & Heather
1984 MCI9 6V92-turbo with 9 inch roof raise & conversion in progress.
http://www.scottmichaelbennett.com/p/our-bus.html
˙ǝɯoɔlǝʍ suoıʇɐuop ˙snq ʍǝu ɐ pǝǝu ʎlqɐqoɹd ll,ǝʍ 'sıɥʇ pɐǝɹ uɐɔ noʎ ɟı
lostagain
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« Reply #9 on: May 20, 2012, 07:21:51 AM »

For now, buy yourself a hand held tachometer at Harborfreight or similar place. Less than $100. You stick the little white strip of tape that it comes with onto the main pulley, and aim the tach at it, and it shows your rpm right away. Handy tool to have.

And yes, it sounds to me too like it is not getting full fuel from the racks. Look at your stop cylinder and levers again.

JC
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JC
Invermere, BC
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luvrbus
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« Reply #10 on: May 20, 2012, 08:12:50 AM »

Scott make sure you have clearance between the shut down cylinder and lever run it awhile and check that clearance making sure it hasn't closed up MCI's are bad about the skinner valve leaking and let the shutdown cylinder start to close taking away power
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thomasinnv
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« Reply #11 on: May 20, 2012, 08:28:42 AM »

Also Scott, I beleive the sensor wires you are talking about on your secondary filter are not a water sensor, but a fuel pressure sensor. It is part of the emergency override system. It disengages the starter when there is fuel pressure. The MCI's have an emergency override system that you can hold the start button to keep the engine running after the safety shut down system has activated.
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Hard Headed Ken
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« Reply #12 on: May 20, 2012, 08:35:30 AM »

I've used egauges.com. They carry most brands. If you have some extra wires running up front it would be easier if you used electric senders. I think it might be some benefit if you installed pyrometers in both exhaust manifolds
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RickB
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« Reply #13 on: May 20, 2012, 03:48:18 PM »

I would IR gun the exhaust manifold and see if all your cylinders are firing correctly. Although you would probably be seeing something if that was the culprit.

Rick
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Scott Bennett
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« Reply #14 on: May 20, 2012, 05:27:55 PM »

Yes. I see nothing at the moment. Exhaust is literally invisible. Is my gear pump dying?


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Scott & Heather
1984 MCI9 6V92-turbo with 9 inch roof raise & conversion in progress.
http://www.scottmichaelbennett.com/p/our-bus.html
˙ǝɯoɔlǝʍ suoıʇɐuop ˙snq ʍǝu ɐ pǝǝu ʎlqɐqoɹd ll,ǝʍ 'sıɥʇ pɐǝɹ uɐɔ noʎ ɟı
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