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Author Topic: AHHHH!!! 1000 miles @ 50mph...and no hill climbing power....HELP!  (Read 3531 times)
Eric
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« on: October 23, 2009, 08:22:31 PM »

HELLO ALL! long time no chat! just finished a nice cross of the country with "Endeavor" all was great except it's gov is 50mph according to my gps and to make things worse on the slightest incline i have no power....i'm dropping down to nearly 35mph climbing the little hills in iowa....any ideas? I don't really mind the 50mph however hill climbing would be great.... no smoke no problems...just no giddyup.. oh yeah the important stuff.. lol Bumping up the MPH to say 60-65 would be great is somebody can help me with this as well!

1985 Neoplan an440 6v92ta with an alison v731
also if it matters current GVW is 29,880lbs

Thanks in advance...!
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Nick Badame Refrig/ACC
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« Reply #1 on: October 23, 2009, 10:32:03 PM »

Hi ekhedge,

Change your fuel filters. They are Clogged!

Good Luck
Nick-
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TomC
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« Reply #2 on: October 24, 2009, 02:20:55 AM »

Very important-if you've never changed the fuel filters before, make sure you refill the new fuel filters with clean Diesel fuel to the tops before rescrewing them back on so not to loose your fuel prime.  Good Luck, TomC
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« Reply #3 on: October 24, 2009, 04:58:43 AM »

if the filters were pluged , would it not be smoking black from running lean???
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« Reply #4 on: October 24, 2009, 05:04:59 AM »

Check your engine shut down cylinder it is probably not returning keeping the throttle from full open


good luck
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« Reply #5 on: October 24, 2009, 05:38:01 AM »

if the filters were pluged , would it not be smoking black from running lean???

I don't think so.  Black smoke is incomplete combustion of diesel fuel (such as when you open the throttle all the way climbing a hill and engine rpm is slower causing all the fuel to not burn).  Plugged fuel filter will not allow enough fuel to develop power, but what fuel is injected will totally burn (just not enough to create adequate power).  Jack
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« Reply #6 on: October 24, 2009, 06:13:25 AM »

Once you have changed the filters as per previous instructions..if it doesn't work I had problems with a transfer pump not hard to change or real expensive.. Huh
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« Reply #7 on: October 24, 2009, 06:36:11 AM »

As Luvrbus said, the simplest things first.  Make sure you are getting full throttle at the governor.  Install a fuel pressure gauge to check out the fuel system.
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RickB
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« Reply #8 on: October 24, 2009, 07:09:33 AM »

All of the above but I would check the air filter and housing as well, make sure you have a good filter and no birds nest cutting off your DD's oxygen supply.


RB
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baker4106
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« Reply #9 on: October 24, 2009, 01:30:52 PM »

Happened to me last fall.   No speed or power and no black smoke.   Fuel filters were plugged.
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gus
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« Reply #10 on: October 24, 2009, 01:53:14 PM »

As others have posted this is a classic clogged fuel filter symptom. Mine is showing this so I'm going to do it next week.

I notice it when it takes more throttle to get the same power as before, the engine simply isn't getting as much fuel as it should.

It is usually the primary filter since it is first in line, but if you've never changed/cleaned yours it is way past time.

Fortunately I still have the original primary filter and it just has to be cleaned off, no expensive filter to buy.
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johns4104s
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« Reply #11 on: October 24, 2009, 08:18:02 PM »

Ditto on the air filter and fuel filters, I have twice the power after changing my air filter. Boy was it blocked.

John
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Garymci5
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« Reply #12 on: October 24, 2009, 09:54:13 PM »

I would guess that a '85 bus would run at least 65mph on the govenor....my old '76 Eagle ran 80mph on spec RPM (at least it sounded like it).

Must have fuel and air:

My even older GMC Fishbowl was gov'd to 55mph (under RPM at 1850; DD 6V71), but turned it up and would run an indicated 72mph on oversized tires. Like the old man said "when it sounds like a sewing maching, it's just right". That's about 2400+ RPM. He was right. Ran the same route 4 years, ever year a different change, every year a little faster. Final year ran the same hills at 12mph faster, minimal speed lost from flat cruising. Same load, same weather, same same.

I'd also take a gander and say that with a turbo one could install bigger injectors for a slight bump in power.  If'n it were me a water injection kit would find it's way under the hood, to both keep temps down and to facilitate complete combustion during WOT (starting out or climbing hills).  Would also wrap the exhaust to preserve all the exhaust energy possible. Lost heat is lost power due to lost velocity, THE key factor to turbo performance is velocity.

Also recommend to ensure the exit tract is flowing well. Diesel's flow A LOT of air/CFM. Want to be scientific? Install a back pressure tester. I didn't, but did make a quasi dual exhaust and noticed a difference, besides all the noise. Previously, at WOT, the backpressure was so great, that even at speed, the pressure was great enough to part heavy water on the road at 65mph!..! Holy Sacred Cow Bat Bird!

My last little trick, not sure if it actually helped, was to use ATF for the oil bath filters. It's lighter than engine oil (SAE 30 for a 6V71) and the theory was less resistance equals more flow ='s more power. Never got around to making intact ram air ducts.....

Nowadays one has BioDiesel to help increase Cetane among the many other benefits. The 'race fuel' for compression igntion technology (or lack thereof).

So there you have it.... A full report is expected Monday morning of what was done and scientific results to back up the theories. Shocked Grin
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Cheers,
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RJ
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« Reply #13 on: October 24, 2009, 11:17:25 PM »

EK -

After doing the maintenance that the others have suggested, be aware:

1.  92 series engines do not like running much over 2100 rpm.  71s can, but don't risk it with a 92.

2.  You've got a transit.  Most are set up for 57 - 62 mph max, but really decent 0 - 30 times.  So, the only way to get more top end out of your bus, after having the rack run to make sure the bus is hitting on all six, and that it's governor is set correctly, is to replace the rear axle's ring & pinion pumpkin.  More than likely, you've got a 5:38 gearset in there.  To obtain 70+ mph with the angle drive gearbox, you'll need one of the coveted 4.10:1 gearsets.  Last time somebody here checked, those were special order and would also set you back about $2,000.

FWIW & HTH. . .

 Wink
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RJ Long
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« Reply #14 on: October 25, 2009, 07:59:46 AM »

RJ has a good point, transits usually don't have highway gears unless someone has already changed them or it was originally a suburban model.

On the other hand there is still a power problem that must be dealt with first.  If it is having trouble climbing hills with a transit rear end, it would be worse with highway gears.
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