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Mdhcols · 03-06-2016, 08:18 AM

Hi all! First let me thank all of you who have responded to me in the past. Having been a desk jockey during my working life, I'm not the best mechanic and your info has been very helpful.

I have a 2000 Allegro Bus with the 300 HP Cat engine and 99K. While not a speed demon, it has been very reliable the last 20,000 miles I have owned it. Every 12 months I have all all filters and oil changed. Yesterday, while coming up I-95 the engine started to back off on power. After awhile my top speed was 45-50 on flat highway. There was nothing in the accelerator when I pushed on it. The engine sounded normal to me outside listening to it but no punch.
We finally limped to our destination in Southern Georgia. When I parked, I revved it very slightly and got lots of black smoke coming from the exhaust. Never had any before ever. I have always taken that to mean running too rich and not enough air mixture. Honestly I know little about the engine. Someone asked me if I had water in the filter and I am scratching my head on that one.

Just wondered if there were any things I could check before I get the courage to take it to some local shop down here? BTW it has been 12 months and about 7K since last oil and filter change so it is due now.

As always, thank much for any input.

Mike.

Skip426 · 03-06-2016, 08:30 AM

There are some possibilities, but a few questions first.
Were you driving in the rain / wet road conditions ?
Did the problem start shortly after a fuel up ?
How far had you driven before the problem started ?
Is your coach equipped with a turbo , boost gauge ? or a Scan-gauge D or Silverleaf to check for codes in the Engine Control Module ?

Bigd9 · 03-06-2016, 08:43 AM

Everything Skip426 said.

I would be looking at the air filter (there should be a air gauge in the rear near the radiator - see picture_ and I would be looking at fuel filters. There could be two of them, one back near the radiator with possibly a plastic cup on the bottom of it, and another filter "could" be installed on the engine itself. There was a period of time where Cat had their own filter on the engine and Freightliner installed another one near the radiator. Then there was a period of time where Cat did not install the engine filter.

Check the air restriction gauge after you answer Skip426 questions. They are important...

G Schulz · 03-06-2016, 08:46 AM

Sounds to me like it's a turbo issue. Could just be in the ducting. Do you have a boost gauge? Should be in the mid twenties.

2009 Safari Cheetah 40'
350 HP Cat
2014 Ford Focus
Air Force One

laj · 03-06-2016, 08:48 AM

i would check to see if you have a hole in the line to you cac. somewhere you have lost your boost.

Mdhcols · 03-06-2016, 04:16 PM

Thank you,
No rain for long time, no boost gauge, had not fueled in two months. Been sitting in northern Florida. I had driven maybe 100 miles or so when it started to get really bad. In retrospect, I think it was a little sluggish when I left Florida and gradually got worse the farther I went. FYI, I had filled up in Southern Georgia going south at Pilot which is the only place I buy fuel. Also had put Lucas Oil injector cleaner in as I was going to be sitting for a while. No problems with engine on way down to Silver Springs.

Mr_D · 03-06-2016, 04:43 PM

Bad turbo
Stuck exhaust brake
Plugged fuel filter(s)
Bad CAC
Leak in turbo to CAC hose/tubing
Collapsed air cleaner element

JFXG · 03-06-2016, 04:47 PM

It sounds like you may have gone into limp mode. First call should be to the hot line for either Freightliner or Spartan, whichever chassis you have. They can talk you through a method of reading engine/trans error codes if you don't have a reader. If you can easily get it to a shop, that's better.

There are several areas that could be problematic, some already mentioned. Another area is that your Cat engine is equipped with a very high pressure fuel pump called a HEUI pump. These pumps can be very sensitive, and one thing they sometimes don't like is dirty engine oil. Just one possibility. Best bet is to check error codes.

plewis2447 · 03-06-2016, 06:14 PM

Had this same engine and had the same problem. It is the Heui pump and it is putting metal shavings out. You need to have the rails cleaned and injectors changed that are bad. If you do not clean the rails throughly then you will have the same problem within 100 miles. CAT is very aware of this issue.

super_rep · 03-07-2016, 07:38 AM

Sounds like one of the hose clamps connecting the air after cooler to the turbo has come loose. This will let the turbo boost air dump out before the engine intake. Has happened to me twice on two different vehicles. Symptoms exactly as you describe.

twinboat · 03-07-2016, 08:02 AM

The first thing to check is for plugged air intake or wet and collapsed filter. Did something move in and build a nest ?

Next, look around at all of the hoses and lines around the engine for something disconnected.

Then spend a few bucks changing the fuel filters. 90% of low power is fuel related. If you have never changed them yourself, get a road service guy to do it.

From there, it's probably, off to a shop.

Skip426 · 03-07-2016, 08:48 AM

Quote:

Originally Posted by Mdhcols

Thank you,
No rain for long time, no boost gauge, had not fueled in two months. Been sitting in northern Florida. I had driven maybe 100 miles or so when it started to get really bad. In retrospect, I think it was a little sluggish when I left Florida and gradually got worse the farther I went. FYI, I had filled up in Southern Georgia going south at Pilot which is the only place I buy fuel. Also had put Lucas Oil injector cleaner in as I was going to be sitting for a while. No problems with engine on way down to Silver Springs.

2 month old fuel, may have developed algae and started plugging the fuel filters, check the label on the injector cleaner for algae control additives.
Check the air filter, to see if something set up a nest in the intake duct work, while the RV was parked.
Then check all the connectors and clamps, from the turbo to the CAC ( Charge Air Cooler) and from the CAC to the intake manifold. A split flex connector or broken clamp can cause the issue you have.
Start looking into those items you can do yourself , before you take the coach to a shop, a $7 clamp, or a $20 flex connection, isn't so cheap if a shop charges you $200++ to locate and replace it.
Hopefully because your not reporting problems starting the engine this will be an easy fix.
I see from other posts that most of these possibilities have been mentioned, but start with the items that you can deal with , filters and connections, before heading to the shop.

GA Navigator · 03-07-2016, 08:54 AM

I'm leaning toward a filter/intake blockage or a boost problem. OP stated lots of black smoke so it seems to me it's getting fuel.
I had a clamp come loose on my Cummins intake and had similar symptoms except for no smoke but I think I read that my Bosch P7100 pump won't add fuel without seeing the boost pressure. Maybe Cat is different.

1994 Holiday Rambler Navigator
Cummins 8.3
Allison MD3060