Ugly Fix? Yes or No? Comments.

[Venturer]

I've been reading of the EGR valve regularly failing in the Cummins ISM 500 engine. Some have gone with the "Ugly Fix" which keeps the EGR closed. It will stay closed on its own above 7,000' anyway, so I'm wondering what harm could come if it remained closed all the time?  The engine oil will stay cleaner without the exhaust soot contaminating it. Some claim the engine will run cooler as well. Any on the forum have firsthand experience with it?  

[Mocephus]

I installed it on my DD60 three years ago when we first purchased our '05 Sig. I noticed a significant improvement in acceleration from a stop. I do not know if there was a change on engine temp only because I didn't document it before the install. I saw no noticeable difference in mpg.

[BradHend]

I looked into doing the EGR delete on my ISB as a means of trying to save some money and time sourcing parts as only re-mans are available for my rig.  I believe my reman EGR valve alone cost me 1200 Canadian plus core. 🫣

Unfortunately every mechanic and tuning shop that knew what it would take said it wasn’t possible on my 2005 ISB as the ECM couldn’t be programmed for it - but 2007 and up would be doable.  I had called about a dozen or so places and after being turned down for the same reasons from most shops I decided to just replace it and be done with it as I wasn’t sure what to believe.

However I also came across two shops that argued quite firmly that my 2005 ISB engine never had an EGR valve or a VGT turbo and that I must be mistaken.   

I do envy you if you are able to do this on your ‘06 ISM engine.  Best of luck!!

[Chargerman]

I installed the Ugly Fix on my DD60 about 3 yrs ago also.  I haven’t noticed any difference in acceleration but I have recorded about .4 increase in mileage. What I like most is that my oil stays so much cleaner. After thousands of miles it is still translucent. Previously I couldn’t drive down the road without it becoming jet black. 

[Just Jim]

What year did they start with the EGR.  Mine is a 2003.

[JDCrow]

55 minutes ago, Just Jim said:

What year did they start with the EGR.  Mine is a 2003.

That’s when production pickups (Ford anyway) first got a diesel EGR. The glorious day the 6.0 powerstroke was born. 
 

You’ll read on here sometimes Monaco had “holdover” chassis. That is they had an older but new engine/trans laying around. I know a few on here have say an 05 coach with an 03 engine. 

[Venturer]

Is there a downside? Will it potentially harm the engine on a long full throttle climb? I can't imagine that it would as it's already closed above 7,000'. Has anyone ever reported engine damage directly related to the EGR being permanently closed?

[Tom Cherry]

40 minutes ago, Venturer said:

Is there a downside? Will it potentially harm the engine on a long full throttle climb? I can't imagine that it would as it's already closed above 7,000'. Has anyone ever reported engine damage directly related to the EGR being permanently closed?

https://www.irv2.com/forums/f123/anyone-install-the-ugly-fix-for-ism-327522.html

Interesting read.  DEFINITELY not for a DPF.  Some issues and some concerns about higher temps and engine issues.  My take….need a good temp probe for Turbo.  BUT am NOT the engine guru….  Read every comment….seemingly good info.  No other major write ups as comprehensive as this one..

At least you have a lot to review….

 

[vito.a]

EGR was introduced to most Cummins engines in 2003.  I think you are correct in looking at alternatives.  The Cummins ISM has an issue with developing leaks in the EGR cooler.  

I've tested the Ugly Fix on both a 2007 and a 2004 Cummins ISX.  On the 2007 model it caused an occasional check engine light.  On the 2004 it worked without issue.  

About the hardest part is finding the barometric sensor in the engine wiring harness to plug in the Ugly Fix.  It is buried under the intake manifold and taped up and zip tied back out of the way. 

Some good reading: 

The Ugly Fix for Cummins ISM (coming soon) - iRV2 Forums

Anyone install the ugly fix for ISM - iRV2 Forums

[Venturer]

I had read all of the posted articles (a couple of times) and am considering installing it. My concern is not knowing the EGT on a long mountain climb. Would a long climb at 3,000' be much different than 7,000' when the EGR valve is closed anyway? Yes, the air is denser, but the turbo should compensate for that. 

[dl_racing427]

13 hours ago, Venturer said:

I had read all of the posted articles (a couple of times) and am considering installing it. My concern is not knowing the EGT on a long mountain climb. Would a long climb at 3,000' be much different than 7,000' when the EGR valve is closed anyway? Yes, the air is denser, but the turbo should compensate for that. 

Denser air results in higher boost, which reduces EGT in diesel engines.
I see no downside to eliminating EGR on diesels, other than the possibility of causing a check engine light, and the ECU possibly derating the engine.
As long as that doesn't happen, I'd do it.

[Tom Cherry]

All good comments, but remember that if the engine has the DPF and the ECM is programmed to operate with it, from what folks say, they can have a very expensive issue.  Ugly is NOT, based on what that forum and many others say, for a DPF. Now, if someone has successfully run them with the DPF and had no issues....GREAT...but it can be a sizeable repair bill....think $6000 or so.  That is WHAT I read.....and therefore, if I thought I needed to try to "Trick" the emissions....on my DPF. I would NOT DARE.  Like some of you here, I'm assuming, have had my share of fun and experimentation with cheating the emissions on cars that had the "DUMB EGR" and put in plates with small holes or orifices to decrease the amount of EGR fed in or totally taking it out. Certainly those have have had good results, with a few hiccups, on NOT DPF engines attest to it being a "performance enhancer"....just don't tell certain members of certain environmental groups....  LOL, they WILL picket you and DOX you.....and I am NOT kidding...  An ex inlaw in our family once got into a shouting and almost shoving match because she did not think that it was appropriate for a 5 year old to be auditioning for "I Want to be an Oscar Meir Weiner" and wanted to call 911 and have child protective services come out and she was willing to swear out a warrant for the Grandfather's child abuse...as he was coaching the child and excited that she was a finalist.....  YES....that did happen and that was the LEAD Google Search on her.....

OK....back to sleep.....

 

[Bliksem]

I installed the Ugly on my '09 HR with a ISM,  I moved 50 feet and the check eng light came on. Unplugged and no more light so I returned it for a refund. I have since had the ECM programed by Diesel spec inc and have removed the EGR injection tube that causes a restriction in the intake. More power and a 1mpg gain in milage. 

 

[Venturer]

Tom, one source stated that the ISM did not have a DPF. Another stated that the DPF was introduced in 2007 on the ISX engine, but it didn't say it was added to the ISM. Where would it be located? An engine serial number check with Cummins would confirm yes or no.   

[Frank McElroy]

One thing to keep in mind is that at low altitudes, Cummins factored in EGR operation as a way of lowering exhaust temperatures.  So, if you are climbing long grades at full throttle (something you shouldn't be doing even with EGR - you should be climbing at max HP RPM), without an exhaust temperature pyrometer, you do run a risk of eventually burning a valve seat or burning a hole in a piston.

[Venturer]

16 minutes ago, Frank McElroy said:

One thing to keep in mind is that at low altitudes, Cummins factored in EGR operation as a way of lowering exhaust temperatures.  So, if you are climbing long grades at full throttle (something you shouldn't be doing even with EGR - you should be climbing at max HP RPM), without an exhaust temperature pyrometer, you do run a risk of eventually burning a valve seat or burning a hole in a piston.

What did Cummins do for exhaust temps at lower altitudes before adding the EGR to the ISM in 2002. If one keeps the RPM at 1800 on a long climb, would that be enough to avoid a problem. On my Bus with the 450 ISL, I would back off 2-3 mph from maximum speed on a long (1/2 mile or longer) climb. No problems in 84,000 miles. 

[Frank McElroy]

53 minutes ago, Venturer said:

What did Cummins do for exhaust temps at lower altitudes before adding the EGR to the ISM in 2002. If one keeps the RPM at 1800 on a long climb, would that be enough to avoid a problem. On my Bus with the 450 ISL, I would back off 2-3 mph from maximum speed on a long (1/2 mile or longer) climb. No problems in 84,000 miles. 

Before EGR, engines were not as computerized with high pressure common rail injection and lower engine coolant temperatures.  Internal engine metallurgy and valve timing were also slightly different.

If you're climbing grades at full throttle, then you are putting max load/wear on the engine and generating lots of heat going into the coolant system. 

I like to climb long grades with my ISL at about 2,000 RPM, and NOT full throttle.  If needed, I'll manually downshift the transmission and climb at a slower speed. 

You never want to climb long grades at full throttle and let the transmission downshift for you.  A good rule of thumb is that if you are passing almost all 18 wheelers,  you are climbing too fast and putting lots of wear/strain on your engine.  It's all a matter of how long you want the power train to last.  In a motorhome's life, probably just lower fuel economy.  In an OTR truck, shortening mileage on an in-frame by a few hundred thousand miles is real money.

[Venturer]

It looks like I will be ok with the Ugly Fix, as I have always driven conservatively. I run about 62-65 and try to keep the RPM at 1800-2000 on the long uphill pulls mostly for cooling. On shorter 1/2 mile hills, I generally let the transmission pick the gear. The ISM is new to me, but hope to find the sweet spots after a few trips. Thanks to all for the informative comments.      

[Tom Cherry]

My experience and also written up by Cummins and several others with technical and engineering backgrounds, including one of our founders who was a top notch Mechanical Engineer.

The 5-6 shift point is based on the max torque RPM, PLUS say 50 - 100 RPM.  if is a function, calculated as well as tested, sort of seat of the pants, by Monaco.  Allison and the engine manufacturer have to evaluate and sign off.  So, if you pay attention to when, in either mode….normal (performance) or economy mode, on a level stretch with medium throttle (not a rompin’ stompin’ drag racer or gramma, assuming she ain’t the descendent of the little ole lady from Pasadena), then add about 1 - 2 MPH to it and set your cruise there.  Leave the tranny in ECONOMY.  The Allison will downshift less and you will get the best MPG.

For example, my 425 ISL with the higher ratio rear end will $@#! into 6 around 60 - 61…maybe 62.  I set the cruise to 63 or so.  If there are a few gradual but noticeable grades and it drops down and frequently down shifts, I bump it up one MPH.  The Allison will not, in ECONOMY, downshift into 5th until say 57 or so MPH.  BUT, the cruise will not “floorboard” it on a gradual grade, so it drops down, in 6th, to the upper 50’s, but eventually gets back to the cruise set point.  

HOWEVER, if i use the NORMAL or Performance mode, it quickly downshifts.  i also abandon the Cruise coming up on a grade and get a running start….maybe a few MPH higher….but then manually shift to keep the RPM at least 1800 or so.

NOW….HAVING SAID ALL THAT.  The 5-6 shift point is rear end ratio dependent.  A 2008 Dynasty, with the same 425ISL comes with a lower ratio read end due to the heavier body. The rear end ratios in a model year USUALLY, at least in the Camelots and Dynasty do NOT change based on 40 (non tag) or 43 (tag) configurations.  So a 2008 Dynasty will shift in the upper mid 50’s….say 57/58.  Then, you have to run where you are comfortable for cruising….which might be 60 MPH.  If that doesn’t suit you on a typical interstate….adjust for your tastes.

That’s my take….lots of reading papers and such and talking to experienced Monaco owners and experimentation and also Allison and Cummins tech support.

 

[Venturer]

Just took our maiden voyage with the coach and the Ugly Stick.  Great acceleration, with no hesitation off the line. After 140 miles, the Aladdin said 8.6 mpg, however, we had a nice tail wind much of the way and it was flat going.  At arrival, overall, it averaged 7.7 mpg. We started at 450' elevation and ended at 4200 so it was up hill. We'll return home on Sat and average out the trips. I have no history to compare it to, but I'm not expecting any issues with the U.S. We're very pleased with this, our first Monaco, and first ISM engine. The interior workmanship and quality is amazing. I can see why owners have kept them long after the company failed.

Travel Safe  

[96 EVO]

Ugly Stick 🤣!

I used to fly one of those in the 80's!

[Paul J A]

20 hours ago, 96 EVO said:

Ugly Stick 🤣!

I used to fly one of those in the 80's!

Lear  55E

[96 EVO]

1 hour ago, Paul J A said:

Lear  55E

I wish!

The 'Ugly Stick' was a bare bones, easy to build, radio controlled airplane!

Just a box fuselage, no windows or any real shape to it, but it flew well, and preformed great stunts!

[Venturer]

Guess I have to be more careful with my words here. However, I learned there was a model plane called the Ugly Stick. I didn't know that before. 🙂    

[Gweedo]

My ugly stick works awesome, I pull it out from the bay put on some bait n catch fish.  Merry Christmas n good luck