What causes loss of power?

Scott & Heather · May 30, 2012, 04:02:52 PM

Here's a better video of the full throttle push...not sure if it's even helpful bus this was wide open. I guess there is a bit of a "roll up to wide open throttle" delay...but not sure what's normal and what isn't.

http://youtu.be/36BXdQkLeIQ

luvrbus · May 30, 2012, 04:10:11 PM

Doesn't sound like it going up to 2200 rpm to me is that a NJT bus ?

Hard Headed Ken · May 30, 2012, 04:34:13 PM

Scott,
You need to put the first video back up if possible. Allow someone with more experience than me to listen. I think it was only running on 4 or 5 cylinders for the first few seconds. That's why it was blue smoking so much, that burp you described was the other cylinders kicking in. I've heard this refereed to as "cold ring stick". I don't think it's your problem, you just might want to know. I had this on my 6V92, it was caused by excess carbon build in the ring lands because I was dumping so much fuel in off the bottom and my problem was compounded by a tall first gear.

Ken

luvrbus · May 30, 2012, 04:41:12 PM

It was only running on 5 cylinders Ken it should have never died when it fired the 1st time, not riding a dead horse here but his fuel mixing you can make bet he has carbon build up

good luck

Hard Headed Ken · May 30, 2012, 05:10:25 PM

Kinda what I thought but I hate to say anything, because I know some people seem to get away with it. I will suggest that anyone running or considering running alternate fuels should disassemble some injector pumps and nozzles (maybe a local pump shop might some scrap ones). Try to measure the tolerances with standard micrometer, it's amazing they work with perfect fuel. It will certainly give you an ideal why water and trash is not good. I hate spending money on diesel, I guess I'll keep spending.

Ken

Scott & Heather · May 30, 2012, 07:28:38 PM

It didn't die. It didn't start cause I let off the starter too soon. It normally lights off quick but we are having cold nights here in Michigan. Going to be 46 tonight. But it has been lighting off at the touch of a button no sweat. Also the 5 cylinder then 6 deal literally started a few days ago. What do you think cliff? Oh yes the first video is still up there. First link

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eagle19952 · May 30, 2012, 07:43:35 PM

Ok heres what i think,first you need to listen to whoever said put a tach and pressure gauge on it,and then do it.
I have tuned a lot of Detroits and I am here to tell you you can not build full throttle and discern any thing by pumping the throttle in 2-3 second bursts.
Why don't you hold WTO for 8-20 seconds... jeez the motor was made to run full throttle for days. You'd never set no load gov.speed in that short of time,the engine isn't going to self destruct if it has nothing wrong...and if it does ,well better off it does it where it sits.
we used to shut down our 200kw gens for 30 or 40 minutes every 250 hrs to change oil and had kits put in every 4 years.....
IMO you need to run the piss out of it,AFTER you run a tach on it.
Get you a stobe and a piece of tape.
you won't figure out squat till you do...

eagle19952 · May 30, 2012, 07:47:43 PM

Ps 46* is not cold...I have had Detroits start as good as that at 35 below.
Compresssion and diesel mix REAL well. even in sub zero temps.
Even with 0w30 syn....but thats a whole different can of worms...depends who wants the motors to start....LOL.

thomasinnv · May 30, 2012, 08:55:13 PM

Scott, you are not getting to full throttle by doing your short little spurts. Hold that puppy wide open till it won't go no faster, then take your rpm reading.

Scott & Heather · May 30, 2012, 11:52:38 PM

Eagle and thomas:

Ok I'll do it tomorrow. Scary doing it when standing right there and arm between a spinning belt. Throttle linkage appears to be moving freely and fine so I'm going to have Heather mash the throttle...I'm a bit skittish. I kind of like my arm :-/

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wildbob24 · May 31, 2012, 12:31:01 AM

Scott wrote:

"Scary doing it when standing right there and arm between a spinning belt."

Scott,

Since your bus still has the air operated belt tensioner, this is easy to avoid. You should be able to turn the valve controlling the tension cylinder off and the resulting tension release will allow you slip the belt off the crank pulley and stow it overhead while you perform the rpm tests. A few minutes of running the engine without the radiator fans won't be a problem.

If you're not comfortable doing that, another trick is to use a broom stick to reach in and push the throttle lever.

Bob

RickB · May 31, 2012, 07:55:17 AM

I hope that this entire thread serves a great purpose for folks to pause and research alternate fuels greatly before they start running them because it sure looks like the fuel/waste oil mix may have contributed to this situation. I don't like big government/big oil conglomerations and ridiculously high fuel prices as much as the next guy but getting off the grid has it's inherent issues as well. I don't think it's as simple as folks think it is and i think that some folks dislike for being reliant on anyone for anything sometimes clouds the truth of the matter. We have all heard the "I've driven 200,000 miles on nothing but linseed oil" testimonies and they should be heard but Scott's situation should be added to the mix in future WVO, Biodiesel, WMO discussions. Which we all know will continue until the end of time.

Thanks for keeping us informed Scott.

Rick

eagle19952 · May 31, 2012, 09:55:59 AM

Well heres the deal you NEED to tach the WOT at both places....at the gov linkage AND the pedal. This will confirm linkage and gov problems.
Just sayin.

bevans6 · May 31, 2012, 10:04:44 AM

All I do is put a brick on the throttle pedal (metaphorically speaking, usually I wedge it down with a stick) and check for full lever movement at the governor. Been setting throttle cables like that for 30 years on race cars, I guess it will work with a bus...

As noted, if the belt worries you just take it off, no harm done. Also note Cliffords advice to disconnect the throttle cable from the engine speed lever and lay it aside - you could get it to hang open or otherwise not return cleanly if you leave it connected.

It's odd that we (me definitely included!) just hate to pull max no-load on the engine just standing there holding it wide open when we know they run like that all day long just fine. The first time I dyno'd a race engine and they did a full power full RPM run I literally ducked under the wall, it scared the life out of me! Operator reminded me that I was 10 feet away behind 1/4" lexan and 10" concrete, and that all the other times I'd done full power, full throttle runs with that same engine I was lying on my back with the cylinder head 6" behind my head with 1/8" of fiberglass between it and me, and I was doing 120 mph on a race course...

Brian

Scott & Heather · May 31, 2012, 11:47:46 AM

Interesting experience Brian...those cars are loud as all get out too. Ok, here's my latest video with RPM Tach check. Please note the following:

Idle: 500 RPM + or -
1st WOT CHECK: 2003 RPM
2nd WOT CHECK: SAME
3rd CHECK PUT MY WEIGHT INTO THE BROOM HANDLE AND REALLY PUSHED LEVER: 2253 RPM

These tests were done with the throttle pedal linkage disconnected. I think the lever itself wasn't pushing in all the way. It took some serious umph to get it to almost "click" into full throttle. Something I doubt is happening just from mashing the fuel pedal in the drivers' seat.
Any thoughts?

Notice she started up without the burp (5 cylinder burp). Got down to 44 last night. Cold start. Emptied the slobber tube before starting her. Not sure it made a difference but there was a cup or two of oil in there. Please be sure to watch the second video. You'll see me pushing on the stick and getting it to really reach WOT and you'll see my 2250 RPM reading. SEE VIDEOS BELOW:

http://youtu.be/1dWMNFo5Z34

http://youtu.be/FuDuFCB7oHk