Engine Power Decrease... HELP

[ilyafish]

hey all,

Well as some of you have read, me and one of my band mates finally got our MCI MC-9 home from st. louis to NJ. We ran about 80% of the time on Veggie. There were a couple of issues I am wondering about. Wondering if you fellas could help out.

1. at 70 MPH the bus started to vibrate a good amount. Is the normal or is it some in the aliment or other wheel issue?

2. This is the big one, About 95% of our trip we had to floor the execrator the whole way home. Is this how the transmission is geared?
Also we found a decrease in the engine power and switched out a fuel filter thinking we hit a little bit of dirty veggie. It seem to pick up a little.  but we had half the seats already and going 35 MPH up pretty small hills. we switched to deisel no improvment, so i dont think it has to do with the veggie.

I hope this is a small issue that can be solved because we plan on having 10 guys and towing 2,500 LBS trailer.
I figured they are made to carry 44 people at a avg. of 170 LBS, all the seats and other junk that = up to about at least 2,000 LBS that shouldn't be a issue but. there was only 2 of us and half the seat out and it seemed to be already a issue. HELP. ha ha

thanks again fellas i eagerly await you answers!

Peach

[lostagain]

Make sure your are getting full fuel. Check the filters, supply and return fuel lines for  leaks, a leak on the supply side will not show visually as it is suction. Make sure the fuel lever on top of the governor moves all the way to full fuel, the linkage might be out of adjustment. The buffer screw might be out of adjustment and that would screw things up too. These are the first things that come to mind.

The vibration is not normal. It could be a wheel out of balance, a misalignment, a bad bearing, maybe a U-joint on the drive shaft...

Once all is fixed, it will be a good, reliable and cool rig!

Let us know what you find.

JC

[Hartley]

If your NJT MC9 is one of the 83 models, The cruise speed sweet spot is about 64 mph, You can top 70 but that's about all given the rear end ratio and engine output. I have had mine to 75 mph but it doesn't like it much. The 277 Hp settings are OK for flats and open road but are terrible for high end cruise.

They don't like long grades or hills at all. I went over signal mountain at 5 mph and almost rolled backwards a couple of times towing 8,800 lb trailer.

The shakes on yours may be caused by two things, or maybe 3 things.

Front Tires out of balance or out of round is the usual reason.

The front end needs bushings which may or may not have that effect.

The Tag axle downforce pressure is messed up and you are not getting
a proper amount of air pressure to the tag axle air bags. Should offset
about 6,000 lbs. Regulator is up at the back of the engine on the
cieling almost dead center. Takes about 30 to 35 psi for tags.

Lacking tag axle pressure makes the coach wiggle and wobble on the road
especially on uneven pavement. Your tag brakes will also tend to lock up
if not enough pressure.

Just the quirks I have found...

Dave...

[CraigC]

You are no longer driving a car a bus or truck slows down on hills.  I do not know exactly what you are referring to as a small hill. If you stated the exact route you are talking about probably someone that is familiar with that topography can tell you if you hill climbing performance is correct. It does not take a big hill to slow down a bus and trailer. The good news is even with more band members it probably will not slow down much more if any. I assume you know what lugging a diesel engine is. If you can not accelerate any faster in the gear you are in then you need to down shift. If you have a tachometer I do not climb hills at full speed, I run about 1800 to 1900 rpm's at that speed you are letting the engine loaf  along[ not making max. heat ] and still running fast enough to get maximum engine coolant water flow. Example my bus is a lot lighter the yours and I have re powered it with a higher hp engine then yours. Let me add this also for comparisons a friend has a engine just like mine in the exact same bus, same gear ratio's but he has 40+ less horse power. We run together a lot the only difference he pulling a ford ranger pickup and I am pulling a 8,000 trailer.  I can run away from from a dead stop maybe a little less then a quarter mile getting up to 60 mph. Because of the limited number of gears in a stock bus going through rolling hills, major mountain grades he is always right on my back bumper I can not pull away from him nor is he able to gain on me. There are a few minor exceptions to this when we find a hill match to my extra hp. and trans. ratio. We both climb the steepest mountain in Calif. at 30 mph. On a cold day without pulling anything I pulled it once at 50 mph the last 1/4 mile it gets steeper and I was lugging it there.  The point I am typing to make with the last statement if I had 13 speed or more we could of us could find a gear to go over a grade "a little faster".
Without extra gears it takes lotsa of hp to jump up a gear.
I hope the about makes sense. I know you are in a hurry but there are times when climbing a hill you just have to learn to be patient and enjoy the scenery. That particiliar hill climb only last a few minutes. Some times less then 5 minutes slower then a car on a fairly long hill.

Yes you may very well have a problem that is why I suggested if someone else could tell you what they do on a particular hill. Remember the following differences will make an exact comparison difficult unless you were running together. Tire size, rear end gear ratio, engine hp, maybe different transmission, weight of the 2 buses, extra rolling resistance of the trailer, outside air temperature.

Sorry for being so long winded.
If you have a problem good luck in getting it fixed!!! If not enjoy your travels, we only get to travel through this life once and it passes way to fast.