Lower power

Topic: Lower power (Read 2621 times) previous topic - next topic

Re: Lower power

Reply #25 – February 06, 2021, 11:10:49 am

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.

Re: Lower power

Reply #26 – February 07, 2021, 11:58:10 am

I put in a gauge to check fuel pressure and it's at 0 with the engine running which makes no sense.

Re: Lower power

Reply #27 – February 07, 2021, 12:10:05 pm

Quote from: oldguy – February 07, 2021, 11:58:10 am

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

Re: Lower power

Reply #28 – February 07, 2021, 12:21:07 pm

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.

Re: Lower power

Reply #29 – February 07, 2021, 12:36:18 pm

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.

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

Re: Lower power

Reply #30 – February 07, 2021, 01:03:17 pm

Quote from: oldguy – February 07, 2021, 12:21:07 pm

In the side of the pump were there is a quick coupler to check pressures.

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

Re: Lower power

Reply #31 – February 07, 2021, 01:48:24 pm

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

Re: Lower power

Reply #32 – February 07, 2021, 02:37:15 pm

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.

Re: Lower power

Reply #33 – February 08, 2021, 12:19:55 pm

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.

Re: Lower power

Reply #34 – February 08, 2021, 12:26:42 pm

Quote from: oldguy – February 07, 2021, 02:37:15 pm

.The only pump before the fuel filters that I can find is 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

Pierce

Re: Lower power

Reply #35 – February 08, 2021, 03:09:47 pm

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.

Re: Lower power

Reply #36 – February 10, 2021, 12:45:35 pm

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.

Re: Lower power

Reply #37 – February 10, 2021, 12:59:27 pm

Quote from: oldguy – February 10, 2021, 12:45:35 pm

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

Re: Lower power

Reply #38 – April 18, 2021, 06:31:24 pm

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.

Re: Lower power

Reply #39 – April 18, 2021, 06:43:00 pm

Is your boost pressure the same? How about lift pump delivery? Air restriction gauge reading?

Pierce

Re: Lower power

Reply #40 – April 18, 2021, 07:22:19 pm

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

Re: Lower power

Reply #41 – April 18, 2021, 11:37:06 pm

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

Re: Lower power

Reply #42 – April 19, 2021, 12:52:12 am

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.

Re: Lower power

Reply #43 – April 19, 2021, 11:58:17 am

Quote from: dsd – January 14, 2021, 01:11:37 am

Donaldson fuel minder fuel filter restriction gauge. Shows filter restriction.
Racor RK32037 FILTER SERVICE INDICATOR-1/8"
Scott

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

I mention it because it's a little less than 1/2 the price of the Racor unit.

As an Amazon Associate Foretravel Owners' Forum earns from qualifying purchases.

Re: Lower power

Reply #44 – April 19, 2021, 12:19:57 pm

And here are the restriction limits for all of our engines in the attachment below.

Pierce

Re: Lower power

Reply #45 – April 19, 2021, 09:17:20 pm

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.

Re: Lower power

Reply #46 – April 19, 2021, 09:32:05 pm

Quote from: WS6_Keith – April 19, 2021, 11:58:17 am

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

I mention it because it's a little less than 1/2 the price of the Racor unit.

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 MinderÂ®

Donaldson EK56501-00410

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

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Re: Lower power

Reply #47 – April 19, 2021, 11:10:38 pm

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

Re: Lower power

Reply #48 – April 21, 2021, 09:43:28 pm

Pressurized the pipes and aftercooler today. There are no leaks. I also got the pre cleaner yesterday and started the install.

Re: Lower power

Reply #49 – December 15, 2021, 12:37:23 pm

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.

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