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Engine Hesitation, Momentary

Yahoo Message Number: 115054
Experiencing momentary hesitation of power for about one second. So, I depress accelerator and power seems to return to normal. This occurs intermittently at random times. Does not seem to be related to engine load like steep climb or hard acceleration. This happens about 3-4 times in a 250 mile trip.
Coach was in storage with about 60 gal of diesel in the tank for about 18 months with no trips. I suspected clogged fuel filters due to possible algae. So, I had both filters changed with my last oil change and lube about three weeks ago (450 Miles) at Speedco/LovesTruck Stop, Ripon, CA.
I added a quart of PS, "Diesel Kleen" fuel additive at my last fill up. So far, after about 250 miles I have not seen any improvement. Still hesitating intermittently at random.
How long should it take for the additive to work? I do not even know if this additive will do the trick as I do not know the true source of the problem.
What else should I consider?
Daron Hairabedian, 98 Allure 30226 with Cummins, 325 HP (6CTA 8.3 Ltr)

PS: BTW, Speedco used to be very reasonably priced. But, now that Speedco is owned by Loves, they have added a $70 surcharge for RV oil change & lube service. Total service was $328 (Including $13 CA sales tax).

Re: Engine Hesitation, Momentary

Reply #1 –
Yahoo Message Number: 115055
Thought Diesel Kleen was for when it gets cold, however randomly add since I was told it was the right thing to do. Maybe change fuel filters again? I have heard chatter on one of these forums regarding a solenoid and the emergency stop button going south. I think you should hop on the IRV2 forum and poke around.

Re: Engine Hesitation, Momentary

Reply #2 –
Yahoo Message Number: 115061
I am in favor of trying a second filter change. The fuel additive may have increased contaminants to the fuel line from the old fuel and the tank. Always add a diesel biocide to your fuel every time you fill up. The biofuel they dispense nowadays seems to love to grow algae during storage. Fuel treatments rarely have biocides in them. Safe travels.

Jeff Thurston
2003/4 Intrigue 42ft Ovation
400ISL 11630

Re: Engine Hesitation, Momentary

Reply #4 –
Yahoo Message Number: 115063
I have followed 3 rules for years now with no problems.
1. Alway store the coach with a full tank.
2. Always add the appropriate PS product with every fill.
3. Change fuel filters every 12 months. The one time I went over the one year filter change rule, they clogged.
Lee Zaborowski

Re: Engine Hesitation, Momentary

Reply #7 –
Yahoo Message Number: 115066
Don't use fuel dry in a diesel. It has alcohol in it to absorb the water and pass it through the system, this is only used for gas engines. We have fuel/water separators that will allow the water to settle out. If you get water in your injection pump or injectors it can cause major damage. You can get it at Wal-Mart but don't use it LOL.

Re: Engine Hesitation, Momentary

Reply #8 –
Yahoo Message Number: 115067
Try turning off your exhaust brake, If its hanging up it can cause the smptoms you are talking about. It should be lubed once a year. TWInsall 98 Allure 30255 now 2004 Intrigue 11731

Re: Engine Hesitation, Momentary

Reply #10 –
Yahoo Message Number: 115069
Lube the exhaust brake? Sorry, have not heard that one before.

Wally & Elta Mae
2007Allure 470 Sunset Bay #31535

Re: Engine Hesitation, Momentary

Reply #11 –
Yahoo Message Number: 115072
Wally - Suspect your era coach has the Jake Compression(?). Some era coaches, with different engines, have Exhaust Brakes (PAC) vs Compression Brakes. And part of the regimen is keeping all the moving pieces of the Exhaust Brake moving freely - thus, lube (With appropriate high temp lubricators.)

I do not believe any ISC every had Jake Compression.

I believe all CC's with ISL's and C9's had Jake Compression.

Some Other Brands, have ISL's with Exhaust Brakes. (Not sure about the C9, suspect they always have Compression Braking(?).

OP - Like Lee. Full Tank in storage. If sitting for a period of time, and especially in humid parts of the country, adding additives to that last tank is cheap insurance. I use Biobor JF for final storage. I also run Optilube in every tank, due to my CAPS era engine was designed for pre ULSD fuels.

Suggest you try to Power Systems products:

- Bio Kleen Diesel Fuel Biocide

- Clear-Diesel Fuel & Tank Cleaner

You may have an injector sticking from time to time? And the Fuel & Tank cleaner may help loosen that back up, if it is gummed up. Or, Diesel Kleen + Cetane Boost would also not hurt to run thru a tank.

- Diesel Kleen +Cetane Boost

Hope it clears up, and nothing more the bad fuel:)!

Smitty

04 Allure 31017
04 Allure Sold to a nice new owner! Now enjoying a 07 Magna Rembrandt 45' ISX600 #6775
"We're ONDROAD for THEJRNY!" (Toad and Coach license plates, say Hi if you see us!)

Re: Engine Hesitation, Momentary

Reply #12 –
Yahoo Message Number: 115073
Thomas, Thanks for responding. The problem occurs whether the PacBrake is on or off. Yes, I keep it lubed with Synco "Super Lube" synthetic as recommended by Mfr.
Daron

Re: Engine Hesitation, Momentary

Reply #13 –
Yahoo Message Number: 115074
Sure its a Exhaust brake with a ISL 400, something to add to my maintenance list.

Already use Bio Kleen Diesel Fuel Biocide, will check out the Clear-Diesel Fuel & Tank Cleaner

Re: Engine Hesitation, Momentary

Reply #14 –
Yahoo Message Number: 115076


Thanks to Smitty, Lee, Whit and all others who kindly responded with good suggestions.
Here are the suggested possible solutions that I will do or investigate:
1. Will add "Biobor" biocide.
2. Will add second treatment of PS "Diesel Kleen" on next fill-up.
3. Will add PS "Clear-Diesel Fuel & Tank Cleaner".
4. Keep fuel tank full while in storage.
5. One forum member, Whit Byers, advised that the ABS warning light does not always illuminate with intermittently faulty ABS sensors or connections. Replacement of two ABS sensors solved this same problem for Whit. I will have a Tech diagnose ABS sensors with test device.  In addition, I am guessing that ABS fault could perhaps also explain intermittent problems with my King Cruise Control engage/disengage that has been haunting me for some time.
6. Will change fuel filters again after I run through another couple of tanks of good fuel and work through the additives.

Hopefully these "Shock" treatments will work. I shall report results later.

BTW, What does "Optilube" do? Similar to Lucas?
Daron Hairabedian

Re: Engine Hesitation, Momentary

Reply #15 –
Yahoo Message Number: 115079
It was an issue on coaches built in the 90's. By the early 2000's with the ISL engines the problem was no longer an issue because the ISL use an engine Compression brake, or Jake Brake. Sticky exhaust brake diaphragms can cause all sorts of issues, from poor starting to severely increased fuel consumption and all other sorts of intermittent issues. It could also be the King throttle control module that were used on earlier ISC engines.

What I liked about changing the most was the coaches were similar in many ways but totally different. The more advanced engine and transmission allowed me to almost maintain the same fuel milage with a 8,000 lb heavier coach. It would climb the same grades a few MPH faster. So a ISL 400 with a 3000 world transmission is a better deal that the ISC 330 with the lder 3060 transmission. It also shifts smooth and can be programed to work better in hill terrains. Instead of having 1.7 bays I now have 3 full bays. Instead of having one slide I have three. And instead of having 800 lbs more weight on the left front tire versus the right the coaches is perfectly balanced. I much preferred the 12 R tires which lowers RPMs and the 315's I now use are much quieter. Having the genset up front and not under my drivers seat is a big improvement. The refer is a big step up as is the Advantium oven. I can turn sharper and get out of tighter spaces with my IFS front end versus the I beam on the Much shorter Allure. 42 ft 10 " Intrigue vs. the 37 ft 4 " Allure. Though they said it was only 36 Ft. Prefer the larger shower and bath room space and the larger linen, clothing and closet spaces. Easily double the Allure. The 42" Intrigue is also quieter and love having the heated floor for late fall, winter, and early Spring weather. The coach originally came with A&E Awnings but after a year I went back to zip dee except for the powered patio awning. Having larger holding tanks and fuel tanks is great and the tag axle really stabilizes the coach with high cross winds and prevents 18 wheelers from pushing your coach to the side as they pass at high speeds. All the electronics need to be replaced as they are both outdated, but nothing lasts for ever. Hoses become issues as do the circulating rear pimp for hot water to the heater up front. The only negative I can think of is the pre 2000 coaches don't have radiator cooling and charge air radiator issues as the coaches built from 2001 to 20o6 or so. The DF fan controller is a big pain in the pocket book. I love diesel heat and water heat compared to propane. But my Marine toilet can be a pain in the neck sometimes. But at least you never have to worry about sewer gas issues. My 3m coating on the front is beginning to fail/ I'll have the front repainted, but will leave the 3M off.

Re: Engine Hesitation, Momentary

Reply #16 –
Yahoo Message Number: 115081
Walter, Thanks for the lead. I researched and read the old post about the malfunctioning emergency stop button on our CC forum. I will inspect this switch, clean parts, reassemble, check for good continuity and report results.
Is the stop switch normally open with circuit continuity when fully depressed?
Daron

Re: Engine Hesitation, Momentary

Reply #17 –
Yahoo Message Number: 115086
Stop button, really? I am having the same intermittent issue and it's not the filters. I am hoping it isn't the CAPS pump either. We have had the lift pump replaced too. Anyway let us know what you find with the switch etc. that is very interesting. I wonder if there is a simple replacement available. That switch is referred to as an E stop switch, emergency stop. Used on ski lifts, all kinds of machinery etc. I bet grainger carries them. This really lights a light bulb with me because ours is so intermittent that I think it seems electrical in a sense. Wow.

Re: Engine Hesitation, Momentary

Reply #18 –
Yahoo Message Number: 115089
https://opti-lube.com

I carry XPD and Summer Blend from Opti-Lube.

Usually mix things up a bit, using Summer Blend for 2 out of 3 fill ups, and XPD for 1 out of 3 fill ups. (We fill up from the top half of the tank, as we like to full when pulling into a park or campground, in case of power outages, etc.). So this blend is probably just a bit higher on the Lubricity of our Summer Blend, and a bit less then Summer Blend. (The costs of Summer Blend are so much less, is why I do this mix.)

I also carry Amsoil Cetane, and if I expect to be traveling at higher altitude and heavier mountain grades, will add some extra cetane to the tanks too.

Once a year, I do a tank of PS Kleen, as preventative maintenance.

I use Biobor JF if in humid conditions for the full fill up before parking the coach between trips.

Why do all this? Well, because I consider it a low cost insurance for an engine designed to run on Pre ULSD fuels. Our ISL is the CAPS era, and the extra lubricity 'may' help it live a bit longer. (I've bypassed the Lift Pump with a FASS Electric Pump, but retained the excellent dual fuel filters that CC installed. On one test of four tanks, with Cetane added (Above what is in the Opti-Lube XPD and Summer Blends.), the four tank MPG was about like .4x higher then the norm. I attribute that to more power per gallon of fuel. If I recall correctly, ULSD lowered the power per gallon yield by ~10% (If it's important, fact check this, as my memory sure could be off:)!). Thus the reason I add the Amsoil Cetane for heavy mountain/altitude driving. (Nope, not scientific. But gee, it's my money and makes me feel like I'm helping the engine work a bit easier, as well as protecting the CAPS:)!)

Lucas? I've not researched additives for over 7-8 years now. But at the time, Lucas was not as high of Lubricity as Opti-Lube. I do add their Oil Additive at yearly LOF. Again, because I want to:)!

Best to all, be safe, have fun,
Smitty
04 Allure 31017 (CAPS era ISL370 (Now 400)
04 Allure Sold to a nice new owner! Now enjoying a 07 Magna Rembrandt 45' ISX600 #6775
"We're ONDROAD for THEJRNY!" (Toad and Coach license plates, say Hi if you see us!)

Re: Engine Hesitation, Momentary

Reply #20 –
Yahoo Message Number: 115091
Jesse,
I have no boost info available on my 6CTA mechanical engine. But, what is relationship to charge air cooler. Not sure how momentary hesitation would be affected.
Daron

Re: Engine Hesitation, Momentary

Reply #21 –
Yahoo Message Number: 115092
I also have a 8.3 mechanical and expirenced momentary loss of power climbing larger hills, taking your foot off the pedal and reappliying throttle would spool up the boost again. This eventually got worse and worse until I knew I had a major issue. Turned out the charge air cooler developed many small holes throughout the years reducing the Air flow. Not much help that CC didnt include a way to monitor your boost on our mechanical 8.3's without installing an aftermarket boost gage. Not saying its your problem just something to keep in mind with our vintage of CC.

Jesse 97 Intrigue 10357

Re: Engine Hesitation, Momentary

Reply #22 –
Yahoo Message Number: 115093
FunJnt,
Thanks for your interest. I checked the Emergency Stop switch in my engine compartment yesterday. I checked for continuity with my multi-meter. It is spring loaded to maintain an open circuit. Continuity across the terminals is accomplished by depressing the switch all the way to the end of its travel. Apparently this completes the circuit across internal terminal contacts. Spring seems plenty strong enough. I am still waiting for someone to advise if this is normal operation. I have not road tested yet. Plan to be on the road in about a week.
I will report whatever I learn.
BTW What is your coach model and year?
Daron Hairabedian

Re: Engine Hesitation, Momentary

Reply #23 –
Yahoo Message Number: 115094
As I remember it should be about 22 lbs at higher RPM.s. When I had charge air cooler issues it always affected my midrange performance first. And my Fuel milage would start to sag, too. But I never had any hesitation because of it. TWInsall Allure 1998 # 30255. ISC. 330.

Re: Engine Hesitation, Momentary

Reply #24 –
Yahoo Message Number: 115095
Jesse,
Thanks for your time and concern. I am keeping this discussion on the forum as others may benefit from the dialog.

I am still in hopes that some of the other simpler solutions suggested by other members on the forum will bear fruit.

Nonetheless, I appreciate that you are giving me the advantage of your own personal experience. The problem on your coach sounds very serious...and very expensive. I have much to learn about this.
A few questions, if you please:
Were you told that this is this a common issue with the 6CTA? How was the problem diagnosed and verified by the tech that you used? Was the problem related to age, miles driven, atmospheric conditions,i.e, humid climate? What had to be finally repaired or replaced by the tech? Since you still have the coach I assume that you went ahead with the corrective surgery. Did you need to have the charge air cooler replaced? Any ancillary parts? If you don't mind relating, what was the parts and labor cost of the job on your '97. I am just curious to know what I may be facing before I take it in for diagnosis.
BTW, my coach has about 81,000 miles on the odometer and has spent the last 10 Years in the Palm Springs, CA area (desert) for about for about 8 months of each year. The balance of its life is spent along the Oregon and Washington coastal area.
Daron