The coach doesn't seem to pull as hard this winter from last. What is the expected turbo boost. I'm getting 24 lbs. boost.
CAT, Cummins or Detroit, 24 lbs should do you well for power. I think we get about that at sea level. You have a waste gate turbo so should get about the same boost at altitude. If you are getting 24 lbs, it can't be a restricted fuel filter. Check air cleaner gauge.
Lower tire pressure now? Might check for an intercooler (CAC) crack or leak.
Pierce
Think I was making 28-29 lbs of boost as I recall. Plan to take it out tomorrow I'll double check.
Scott
Scott I think I was getting that also. Let me know for sure and then I will see what's causing it. Pierce don't want it to be the CAC
I had one rebuilt on my Dynasty. Fuel filters would be the best or and air filter.
Usually, a filter that is starting to clog will show up first by limiting the fuel and power the engine produces. This in turn reduces the exhaust flow through the turbo and limits the boost. This typically shows up on grades or going up an on ramp.
By looking at the air cleaner restriction gauge, you can tell the condition as the reading is a tell tale type with the maximum restriction remaining on the little gauge until it's reset. Driving in wet winter weather can dampen the air cleaner element so it restricts enough to cause power and boost loss. It can also result in higher EGTs especially in mechanical engines.
Pierce
Donaldson fuel minder fuel filter restriction gauge. Shows filter restriction.
Racor RK32037 FILTER SERVICE INDICATOR-1/8" (https://www.racorstore.com/index.php/catalog/product/view/id/11025?utm_source=googleshopping&utm_medium=cse&gclid=Cj0KCQiA0fr_BRDaARIsAABw4EvJ7ZfSN3agsJeNA6FrZtfIWdrDNABQQkypR3LheOvKHEpAAtrWxH0aAjjCEALw_wcB)
Scott
OAT about 70 deg 29 lbs
Thanks Scott I thought I had seen it up there before. On the way back to day it went about 25 lbs when engine was cold and after
engine got hot it was lower. I will check it out tomorrow and it won't hurt to change fuel filters. I might put a fuel gauge in to see
what the fuel pressure is. It would be nice if there was one that could be set up on the Silver leaf.
I put a gauge after our secondary filter but unless you can send the reading to your dash, it does not do much good as you need the PSI at full throttle at max load. Any restriction in the filters won't show up at light or medium throttle.
There are extra wires back there that go to the front so a sensor at the engine and the gauge up front.
Our Pro-Link will read the fuel temperature but not the pressure from the DDEC II.
Pierce
There was a post on this site that talked about how the air filter minder had gone bad and was still showing the filter good. My suggestion is to change the air filter first. At least you then know that is not the problem. If still a problem look at the CAC to see if it has a crack in it that is causing the boost to escape before being pushed in the engine.
Air filter minders are EASY to check:
Remove the hose that goes to the filter minder (the pipe between the filter to turbo) and suck on it. That should peg it in the red and stay there until you reset it. Push the reset button.
Only other issue (and I have never seen it) is if the port the hose attached to on the pipe is clogged. That would probably indicate some other significant issues, as that is on the "filtered" side of the air filter.
How old is the air filter and do you have a Donaldson pre-filter water trap before the air filter,the ones that do not seem to be the ones that get the wet filter.
So the 1/8 hose to 1/8 NPT fitting on the air filter housing has a slintered bronze filter in it. They are very fine and quite subject to clogging up. I am guessing it is to protect engine in case of a sense hose failure? Mine was almost plugged. Cleaned with brake cleaner after removed. So check both directions, to filter minder then to filter housing.
Scott
I noticed yesterday that the evacuator valve on my Donaldson precleaner is very active at idle. It is constantly puffing out air then closing, was quite surprised to see this much operation. I would think it would closed at higher power settings do to increased flow but don't know. I can't express enough how much I like Precleaners. The last six installations have sold me on what a difference they make. I plan to rig up a trap can or bag at the exhaust/vacuator valve to see what is removed.
It's the air filter that's the problem and a pre-filter is next. Anybody have a part number for the pre-filter for the M11.
This filter isn't very old and has 8,000 miles on it.
The air filter has made a difference and I will change the fuel filters next weekend and see if that will also make a difference.
I like doing one thing at a time and then I will know for sure what the problem was.
Pre-filter? Where is that?
If you have one it's in line before the air filter.
Is that in the same "box" as the air filter, inside the tubing leading to the filter box, or a separate housing? I have not noticed anyplace obvious. Is this a stock configuration?
Thanks!
Replay 13 shows picture. I installed in down pipe prior to air filter on my U320. Heard some may have factory installation , I don't know, I do know they work well.
Scott
Donaldson Precleaner (https://www.foreforums.com/index.php?topic=41252.msg411264#msg411264)
Did you notice an increase in boost after changing air filter?
I changed the fuel filters, cut the primary filter apart and it was fine so no difference in power. Last night I went to start the engine
and it wouldn't start. Went out and pushed the air purge button and the engine started immediately. One other time the engine
was hard starting, like there was air in the system. When I get home today I will change the fuel line between the pump and the
primary filter.
If that doesn't help, next logical step is replace fuel line between fuel tank and first filter.
"Air in the system" is classic symptom of failing fuel lines. Based on my reading here. No personal experience....yet. Our fuel lines still OEM, and seem to work fine. Knock wood.
If your coach has the Racor style primary filter with the clear plastic bowl, you might check the bowl for cracks and replace the four o-rings. I have not experienced it, but others have reported air leaks at those locations.
The Racor has 4 - 6 O rings, any one of which can leak and lead to poor running or no start.
I have changed the fuel filters, no difference but after I cut the primary fuel filter apart I didn't expect any. I want to pull any codes
off the ECU, any own let me know how to do that.
I put in a gauge to check fuel pressure and it's at 0 with the engine running which makes no sense.
Where did you install the gauge?
Pierce
In the side of the pump were there is a quick coupler to check pressures. There is also another one in the elbow going into
the pump that I will try that I think is to check the vacuum lift.
I installed ours in the discharge side of the secondary fuel filter. It only shows idle fuel pressure because you can't read it when driving. ;D Nice to fasten a smart phone with video running to check it going up an on ramp or grade. That way, you can tell if there is a filter restriction.
At a 600 rpm idle, we get about 36 psi.
Pierce
I don't know if your newer Cummins big block fuel system works like my 8.3L small block, but FWIW I did a write-up several years ago wherein I investigated fuel pressure and what controls it. On my engine the two key components are the lift pump (transfer pump) and the overflow valve. The lift pump produces the pressure, and the overflow valve controls the pressure. I installed my fuel pressure gauge in a special fitting
between those two components so it reads the pressure at the
inlet of the injection pump. More info below if this is of any interest:
Fuel System Science Project (https://www.foreforums.com/index.php?topic=21795)
My installation is a little different as there is no main injection pump like Cummins and CAT but as the fuel leaves where my gauge is, it goes through the ECU where it cools the electronics and then into the cylinder heads where internal passages take the fuel to each cylinder where a unit injector (combination injection pump and injector) is operated by a lobe on the twin camshafts with push rods up to the special rocker arm. So, no main injection pump, no fuel lines. Also no intercooler (CAC) as there is a aftercooler below the big blower.
The discharge on the secondary filter pressure should be about the same as the pressure reading at the pump intake. The overflow/return valve is designed to return any fuel to the fuel tank where the pump pressure is more than the specifications call for plus unused fuel at the injector itself where it also helps cool the injector. In the case of the 2 cycle, the fuel return is internal in the cylinder heads and travels close to the four exhaust valves so carries a lot of heat back to the fuel tank.
So, if the return valve seat is pitted or has valleys formed by the fuel flow through it, the main injection pump may not get full design pressure. Low pressure may mean lower and uneven spray pressures, poor pump cooling and poor pump lubrication resulting in shortened lifespan.
Another reason to put a fuel cooler in the return line as our fuel tanks don't get any air cooling while driving. Good to keep tank fairly full so the tank itself can radiate more heat.
Pierce
There's a picture of where I put the gauge. After lunch I will put it in the other gauge place and see what happens. This is not at
all like an 8.3 Cummins or at least the mechanical one. The injector is in the head. The only pump before the fuel filters that I
can find is the electric purge pump.
Right now I'm trying to talk to a tech at Cummins. The person I have been talking to before is retired so I have lost a really
good source of information. I checked the other port on the elbow going into the pump and I would get pressure from the
electric purge pump.
But the gauge has to be right after the secondary filter for it to give an accurate reading on the discharge pressure from the last filter.
Check this post for possible solution: Cummins ISC 8.3 Stalls and heals overnight. Fuel pump? ECM? - iRV2 Forums (https://www.irv2.com/forums/f123/cummins-isc-8-3-stalls-and-heals-overnight-fuel-pump-ecm-469287.html)
Pierce
I've worked on the 8.3 mechanical engine so I don't know if it is anything like the electronic 8.3 is anything like the M11. Going into
Cummins tomorrow and have them check it out. It will be a good time to program the ECU so the jake will work in cruise.
Cummins checked it out and everything seem to check out and they set the Jake to come on and off in cruise. Hopefully I am
good to go. Next drive is 400 miles on Friday.
Did they see what your update level was on your ECM at the same time? People have spoke about the additional updates over the years, makes me curious. My ECM was replaced and they said it was updated to the most current updates, but who knows what I actually ended up with. I would really like to have my coach on a Dyno to get a baseline performance numbers. I have no clue were it is in regards to were I am and what it should be. Probably don't need but would be nice to know.
Scott
Well I went for a drive yesterday to check out the coach and give it a run. I was hoping changing the fuel lines would have given
back the power but I'm still 10 Kilometers and hour slower on this hill. The trans was shifting rough. I will have the coach off the
road for a month and then I will be taking it into the Allison Dealer hear to check it out and to set up it shifting down when the
Jake Brake is applied.
Is your boost pressure the same? How about lift pump delivery? Air restriction gauge reading?
Pierce
I thought my boost pressure was higher and Cummins said the fuel pressure was fine. I might take it in and have them dyno it.
When I was there last time the dyno wasn't available. The is a hill going to Whistler that I used to go up at 85 km and now I
go up at 75 km
Make up some intake plugs and pressurize the entire intake. Neighbor had a intake bellows failed and was difficult to see. Check CAC also. So what was the boost? Lots of contributing factors Altitude, temperature, humidity, RPM, but you still should be seeing 28lbs of boost in balance at what your EGT is at. Yes dyno should give you these parameters but your hill does also short of no torque info. Dyno will also give you a base line for future checks, but checking the intake is a good practice. Plugged air filter? I also installed a fuel minder for the fuel system to see suspect fuel filter restriction. See reply #5
Scott
That's a good idea Scott. Cummins said the intake system was fine but I think I will check it out anyhow. The highest boost was
around 24.
Hey Scott, what's the range on this guy? The one on my coach as a "red" area of 25in-Hg. I did find this one on (ugh) Amazon that has a red zone at 20in-Hg:
Amazon.com: Air Filter Restriction Gauge: Automotive (https://www.amazon.com/The-Filter-Pros-Restriction-Gauge/dp/B07CT821B1/ref=sr_1_3?dchild=1&keywords=Air+Filter+Restriction+Gauge&qid=1618847332&sr=8-3)
I mention it because it's a little less than 1/2 the price of the Racor unit.
And here are the restriction limits for all of our engines in the attachment below.
Pierce
I have in new fuel filters, new fuel lines and new air cleaner. I went out this afternoon to start to check that there isn't a leak in the system and I think I threw away the end cap I made when I had the Monaco to put air into the pipe so I will have to make another.
The Monaco aftercooler was shot and I had it re cored.
Attributes
Thread Size 1/8-27 NPT
Length 2.52 inch (64 mm)
Diameter 1.26 inch (32 mm)
Pressure Drop (Hg) 13.90 inch Hg (353 mm Hg)
Brand Filter Minder®
Donaldson EK56501-00410 (https://shop.donaldson.com/store/en-us/product/EK56501-00410/prod430201)
It typically runs in the middle of the scale with a new fuel filter. Looks to same indicator in appearance.
Also oddly is stays full of fuel. Doesn't seem to leak, just odd. Donaldson says this is acceptable. I never did figure out the exact one to get but this seems to meet my needs so far.
Scott
Makes no difference what the brand or red and green markers are. Only the amount of restriction matters that you take off the chart I posted for your engine brand. I've not seen a liquid filled model but if they have a liquid, they are typically filled with glycerin for normal temperatures and silicone for higher temperature environments. All coaches should have one as OEM. I bought a new one to put in the engine compartment so I could check it when I checked the oil. If you follow the black tube from the air cleaner, it will lead to the gauge.
Ours never moves until the air cleaner element starts to get enough dirt in it to cause a restriction. A damp element will also cause a high reading. You just push the end or a button to reset it.
Pierce
Pressurized the pipes and aftercooler today. There are no leaks. I also got the pre cleaner yesterday and started the install.
Went to Whistler Monday night and climbing a hill my turbo boost went up to
30. First time that has happened since I opened this post. Then about an hour
later is was down to 26 and coming home last night the highest it got was 26.
OAT (outside air temperature) and elevation can effect the boost. You should be at full throttle for a few seconds.
Pierce
The temperature was the same and elevation wasn't much different. There is a lot
of up and down going to Whistler and When I noticed the boost not going above
26 I was still way under 1,000 ft. Whistler base is just over 2,000 ft.
Oldguy,
It's a long shot but have you verified that you are getting full travel out of the throttle mechanism?
On a older coach (SOB) I actually found that I was put into a semi-limp mode by the throttle controller (not full throttle) because it monitored the brake light circuit for cruise control purposes and I had a bulb out.
Some times it can be something completely out of left field.
From your description of the symptoms it sound like it drives good on the flat? just an issue on a climb?
Good Luck,
Doug
I have had that problem when I had the King Control in the Monaco Dynasty I had
also. This is not limp mode, just lost a few ponies. I had limp mode on my last trip
home but I think that has to do with a oil pressure sensor which I'm going out to
check on soon.