Power on the 6v92 , long grades playing tricks on me.

[neoneddy]

So what got me thinking about this was my experience today.

We're coming back from the Dells of Wisconsin going on I94 towards MSP, we started going up a grade but at some point I thought we leveled off or where actauly going down hill but in fact we were still on an uphill grade. I feared the worst as I had my pedal to the metal as I felt our speed decreasing down to almost 40mph.   Then I recalled we hit something similar on the way there.

I was pulling our Chrysler town and country (4200lbs) as well.

Questions :

1) should I be worried at all?
2) would an older fuel filter(s) cause loss of power?
3) would air filter be an issue?
4) is this all just normal and I need to deal with it?

We managed a tick over 6 mpg over 523 miles pulling the t&c and trying to keep up with traffic hitting 70 when we could .  I'm running 100-110 psi on my tires.  Temp never gets over 185f , it was in the 70s ambient air temp.


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[Utahclaimjumper]

 Your a worry wart,,BUT,,if you were down that much you should have dropped a gear to keep up the engine RPM and fan speed.>>>D (In other words, don't lug it)

[neoneddy]

Your a worry wart,,BUT,,if you were down that much you should have dropped a gear to keep up the engine RPM and fan speed.>>>D (In other words, don't lug it)

Mine is.an auto trans and around 50mph it will drop, sometimes I drop it down if I know that we need to take it low and slow.

This one just surprised me.

I don't mind being worry wart :-)


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[uncle ned]

Huggy will pull the long hill from Knoxville to Nashville On I40 at 55 miles per hour.

But I look down and the temp slowley creeps up.  I have to slow down and keep her in second under 50 to keep the rpm's up.

Just have to drive by the temp. guage not the speed.

If it is freezing rain I can cross fancy gap at 60. If it is 90 i will cross it at 25 to 30 in  low gear.

uncle ned

[Geoff]

If you want to go up hills without slowing down pulling a toad you will need twice the horsepower you have now.

[chessie4905]

Get misters if you don't already have them. Cuts the stress on engine instead of running near overheat at times. Cheaper than a cracked head or more.

Restricted fuel filters creep up at first, being not so noticeble till they fully restrict. Look for normal rate of black smoke on hard grades, then notice it doesn't produce any on similiar climb. Some engines with turbo and smaller injectors may be hard to tell. The more wear in a 71 or 92, the better they run. Back the day, truckers used to say their engine ran the best before it "blew"

[TheHollands!]

Neo, I pull the same vehicle with same bus and I find that the slow inclines are trickier to negotiate than the steep climbs. I installed a pyrometer and drive by that rather than my speed. It can be easy to push it too hard thinking your on a flat and overheat the engine in a spot where you start relaxing. I usually drop a gear to keep the rpms up and just go a little slower.  Craig

[neoneddy]

Get misters if you don't already have them. Cuts the stress on engine instead of running near overheat at times. Cheaper than a cracked head or more.

Restricted fuel filters creep up at first, being not so noticeble till they fully restrict. Look for normal rate of black smoke on hard grades, then notice it doesn't produce any on similiar climb. Some engines with turbo and smaller injectors may be hard to tell. The more wear in a 71 or 92, the better they run. Back the day, truckers used to say their engine ran the best before it "blew"

I recall seeing black smoke once while leaving a light in the spring when everything was cooler.

I've never seen black smoke from her since, doesn't mean it's not happening, just I don't see it.

The temp sits around 185 indicated, didn't rise much even on the grades.  Last month we took a trip to Austin,mn and the temp would rise some but not much over 195 , it was in the mid 80's ambient temp.

This is leading me to think my fuel filters might be clogging up, what is the usual interval on changing? I just bought it in April / May of this year.



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[chessie4905]

Try by replacing primary filter. They usually plug faster than secondary. GM recommends 5000 mi. on primary and 10,000 on secondary . You may need to service more often due to dirty fuel, coach parked for extended time, dirty tank, etc.

[neoneddy]

Done.  Here is a video I shot on doing it, a quick inspection of the filter and finally a test drive. Everything seem fine? https://youtu.be/hHZVaQXDFkI


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[azdieselman]

That is NOT the way to fill a filter.

[neoneddy]

That is NOT the way to fill a filter.

It was the best I could figure by watching a few other videos. Care to enlighten me for next time?




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[azdieselman]

In an ideal world, You would put the filter on dry and prime with a pump.

If you want to put them on wet, Plug the center hole (filter outlet) with your thumb. Fill it through the small holes around the outer portion of the cover plate.

You can defeat the purpose of filtering by allowing contaminants to enter the outlet side of the filter.

[lvmci]

Hi neon, check your fuel pressure, my 8V71 had it's first tank of 20% biodiesel, with new fuel filters it dropped to 6psi, with no other outward signs of problems. lvmci...

[Iceni John]

Several folk in the RV storage yard where I keep my bus have commented to me about how their RVs want to overheat when driving north on US395 through California.   The reason is very simple  -  the elevation gradually changes from about 3000 feet in the Mojave Desert to almost three times that near Mammoth Lakes, but so imperceptibly that most drivers merely push the accelerator pedal slightly further to maintain what they think should be a normal flat-land cruising speed.   Add to this the usual high temperatures and sometimes strong winds there, and the result is a lot of RVs with overheated engines.   It doesn't matter if the terrain looks flat and level:  if the map says that you're climbing, you need to drive appropriately.   At times like that you have to drive by your gauges, not by how it feels to you.  A pyrometer is good (but some folk will question just how hot a 2-stroke's exhaust can ever get compared to a 4-stroke's like a Cummins where a pyrometer is almost a necessity).   I have a turbo boost gauge, and when climbing I drive according to what it tells me, not by the speedometer  -  there is a direct correlation between turbo boost, i.e. the amount of fuel being burnt, and coolant temperature.

Even driving on I-15 between Corona CA and the foot of Cajon Pass the elevation gradually increases enough that I get 1 MPG less driving northbound than when coming back southbound, and my engine always runs a few degrees hotter when going north.   These long gradual changes in elevation can be almost as bad for buses and RVs as shorter and steeper upgrades.

And talking of gauges, I've installed a fuel pressure gauge and a primary fuel filter restriction gauge.   The more information you have, the easier it is to diagnose problems.

John