Community Forums

azSkier · 05-26-2019, 08:24 PM

This is a follow on to a post in the Newmar forum.

http://www.irv2.com/forums/f103/low-...00-440308.html

I believe I am experiencing something similar. For me, this started at the end of my fall 2018 trip last October.

I got some fuel in Grand Junction... About 3/8 a tank to get to SLC. About 100 miles later, I was climbing a hill and experienced a very brief check engine alarm. 2 seconds and then gone. Happened again a while later. That was it. When I checked, there was no fault and no codes.

I had no idea of what was wrong, so I figured maybe I have some water in my tank. I got my coach ready for storage with an oil change and filter change and filled up my tank and added the necessary fuel additives and left my coach alone for the winter. I experienced the mysterious check engine light 1 more time over 5 hours of driving.

5 months later, I begin the process of using my coach once again. I had some issues, so I drove my coach to a service facility and experienced the check engine light one more time. (4th instance). I am driving rather flat terrain, but I sensed a lack of engine performance. I couldn't put my finger on the issue as I had not driven my coach for several months.

I read this thread (above) in early April and made a note to monitor my turbo boost. Today was that day. I used the spartan display to show the turbo boost while I did some driving. I made it a point to warm up the engine and then begin to aggressively accelerate, especially from stops and while climbing. I drove 20 miles and noticed the max turbo boost as in the 28-32 range. I also experienced the intermittent check engine warning about a dozen times. Almost always while accelerating while climbing.

I stopped at a truck stop to top off my fuel tank. Naturally the engine is at temp and I turned off the engine while adding fuel.

I then drive back to my storage facility and notice the max boost is now ranging from 32 to 39. There are no check engine warnings at all.

So, it appears I am now experiencing a lower turbo boost after starting a cold engine. This situation seems to improve after restarting the engine after the engine is at operating temp.

One other observation. I recently changed my air filter and reset the monitor. After driving I noticed the monitor barely registering any restriction. I worry about this as I want to make sure the air filter is properly installed and there are no intake leaks.

Today, I reset the filter before I drove to the truck stop. At the truck stop, I checked the monitor and the monitor had barely moved from the reset position. I reset the monitor again and drove back to my storage facility. I checked the monitor (with the higher boost) and the monitor was reporting a higher vacuum (this is reassuring to me).

So, it appears my coach is suffering this lower boost situation, but with the mysterious check engine light.

Is there any kind of update on this situation?

Ray,IN · 05-27-2019, 02:26 PM

You may have an air leak at one of the rubber hoses at the air filter, the seal is very critical. The clamps must be torqued to the correct tension-lb/in, and the clamps re-installed to their original position to prevent an air leak. Any air leak will eventually cause what is known as "dusting" the engine, that is unfiltered air is being circulated through the engine, which will eventually destroy the engine.
As to fluctuating boost pressure, that can be caused by a faulty wastegage, either carboned up or rusty.inside, hindering the operation of the valve.A new wastegate is usually ~$60, and must be for your specific engine setup.

skypilot_1 · 05-31-2019, 09:59 AM

OP's 06 ISM should not have a waste gate. The Holset VGT from Cummins Turbo Technologies Variable Geometry (VG) technology. Which eliminated the fixed geometry turbo wastegate. Believe the change came before 06.
Some ISM operators have found "low boost" to be an ECM fault. Air leak on intake side of turbo should not cause a low boost condition. Contaminated the engine.... maybe.
Intake air monitor should indicate about 15 with new filter and move up from there during filter service life. A lower reading than that would indicate open air source, or failing turbo.

https://talk.newagtalk.com/forums/th...splayType=flat

azSkier · 06-06-2019, 02:38 PM

Talked with Cummins about this low boost issue.

The service rep says trouble shooting will take about 4-6 hours and RV rates are $192/hr.

As to the issue, he says when the engine starts up, the turbo sweeps the variable vanes through its range of motion. If there is any kind of resistance, then the turbo is put into some kind of de-rate.

When the engine is started at operating temp, the variable vane sweep is successful and there is no check engine or de-rate.

The problem could be the turbo itself (this turbo is 3 years old) or perhaps the actuator or the actuator shaft.

I barely understand these issues, but will move forward in the next week or so.

vito.a · 06-07-2019, 12:09 PM

Assuming the turbo is in good condition and there are no massive air leaks, a low boost condition is usually caused by a fuel issue.

I would change the fuel filters and check the fuel system carefully before giving it to Cummins.

tom chelbana · 06-07-2019, 09:06 PM

We bought new and had a 04 Essex with the 500 ISM. Had it for 14 years and traveled over 140K miles. Great engine with the only major problem is had to replace the turbo at 130K. We did on two occasions did have low boost and both times it was the EGR valve. The low boost was when going up grades and constant. Might check EGR valve since you tried a number of other checks.

azSkier · 06-08-2019, 09:13 AM

>> a low boost condition is usually caused by a fuel issue.

Thanks.

I have certainly suspected the fuel. Since the problem began, I have changed the filter and have run about 150 gallons through the system. I have also added some Diesel kleen fuel additive.

The only unusual fuel concern is when the fuel filter was last changed. I had filled the tank and then had speedco change the filter. Speedco has changed my filters several times.

When the filter was removed, fuel spilled continuously until the filter was replaced. Hard to tell, but maybe 3-5 gallons spilled. I suspect this happened because the fuel height in the tank and the filling hose were high enough to cause fuel to flow to the filter.

azSkier · 06-08-2019, 09:18 AM

Quote:

Originally Posted by tom chelbana

We bought new and had a 04 Essex with the 500 ISM. Had it for 14 years and traveled over 140K miles. Great engine with the only major problem is had to replace the turbo at 130K. We did on two occasions did have low boost and both times it was the EGR valve. The low boost was when going up grades and constant. Might check EGR valve since you tried a number of other checks.

Thanks Tom.

I bought this coach at 70K miles and just after the turbo had been replaced. Turbo #2 lasted 9 months and 3K miles. So, my coach is on its 3rd turbo and has about 20K miles on it so far.

The EGR was replaced and I have about 15K miles on that.

When you had low boost, did you get any kind of non-latching check engine warnings?

When my EGR failed, I got codes that told me something was wrong.

tom chelbana · 06-08-2019, 12:21 PM

When we had our first EGR valve replacement we did have a check engine light on and that was about 2 years old on a 2004 and 10K miles. The next time we had a EGR valve problem was around year 6 and 40K miles and no check engine light but no boost over 18 psi. Replaced EGR valve and added a methanol/water injection system to keep EGR valve clean and some performance improvement and put 100K with no EGR valve problems.