RV Trip Planning Discussions

Go Back   iRV2 Forums > POWER TRAIN GARAGE FORUMS > Cummins Engines
Click Here to Login

Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
Reply
 
Thread Tools Search this Thread Display Modes
 
Old 02-17-2019, 10:17 PM   #1
Junior Member
 
RV_rob's Avatar
 
Join Date: Feb 2019
Location: Dallas, TX
Posts: 14
ISC 8.3 - is boost readout from Intake Manifold Pressure

Hi all, after using the site extensively to solve many, and I mean many issues, it's time to ask a few questions (at the end of post)
MH was running okay my last trip (didn't seem like full power, but okay enough to not raise a flag) but my last few moves(from storage to my house) I've noticed a complete change and it's a dog off the line and takes long time to get to hwy speeds

ScanGauge Readings:
1. HPR - Idle 16.1, Max @2200rpm 129.2 (jumps to about 80 off the line then runs up to about 130 till I let off pedal.

2. BST - Idle 0.1, Max 0.1 (never changes)

Inspection**with engine OFF **
a. Pulled jacobs e-brake and butterfly is fully open, check.
b. Spun turbine by hand and it spins freely, checked compressor blades and
they spin with turbine just fine, check.
c. Stuck my inspection camera (plumbing tool) in and wastegaste is fully
closed, check
d. hooked air hose to wastegate actuator and istead of pushing diaphram, it just blew out of a hole made by corrosion. I sealed with JB weld, waiting for it to fully cure before testing the actuator again.
e. Air filter has not been changed in a while, but filter minder is half way
closed and says it's still fine (i know that doesn't mean too much)

**with engine ON**
a. had dw push pedal to about 1600 rpm and inspected turbo to make sure
it's spinning up on both ends (again, no load, only in park)
b. found large crack in exhaust manifold



-Does this engine use Intake Manifold Pressure to give boost reading, or
another sensor, like the line going to wastegate actuator?
-Can that crack be the cause that my Boost is literally at Zero, or is that
probably a bad sensor. I know my boost says 0.1, and my power output seems to agree, so if it's a bad sensor, is the ECM derating and that's the cause of NO power?
-What should my boost typically be at idle, and same for horsepower
reading?
Attached Thumbnails
Click image for larger version

Name:	Capture.JPG
Views:	39
Size:	124.6 KB
ID:	235308  
__________________

RV_rob is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free!

iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 02-18-2019, 02:38 AM   #2
Senior Member
 
Join Date: Jul 2014
Posts: 15,971
Boost is a measurement of intake manifold pressure. There will be very little at idle.

Cracked exhaust manifold and resulting leak will effect boost. The exhaust pressure, and flow, are what turns the hot side turbo wheel. As the hot side spins, it turns the other side, pumping air into the engine.



I believe you need to change the fuel filter to get your power back. Although a leak in the exhaust can cause a loss of power, it won't be as extreme as you discribe.

Restricted fuel delivery is the #1 cause of power loss in diesel engines. If you have 400 hours or more on your filters, change them.
__________________

twinboat is online now   Reply With Quote
Old 02-18-2019, 06:26 AM   #3
Senior Member
 
funjnt's Avatar
 
Join Date: Jul 2015
Location: Unionville, pa and Ocala, Fl
Posts: 517
Yes cracked manifold would decrease boost pressure. Fuel filters very important. I would change all filters for a good start. Also visually inspect all air intake and pressure piping to check for leaks. Filters are cheap and easy to change but,,, very important.

On any of my diesel machines or trucks when power is down, fuel filter gets changed.
__________________
2000 Country Coach Allure #30476
2007 Subaru Outback
Winters in Ocala, summers in Pa and North East US.
funjnt is offline   Reply With Quote
Old 02-19-2019, 12:15 AM   #4
Junior Member
 
RV_rob's Avatar
 
Join Date: Feb 2019
Location: Dallas, TX
Posts: 14
Thanks guys for the replies. I should have mentioned it in my first post, but I have recently changed both fuel filters and did oil change with new oil filter. After new fuel filters, I did not notice any change in power, it remained poor.

I did partially rebuild the CAPS pump with new pressure sensor (upgraded 3wire) and a new ICV about a year ago due to a no start condition. We got stuck at an RV park on I 40 for two months while I slowly wrenched on it in the evenings trying to find the problem and eventually found blown seals on top and bottom of the ICV. I also put in a brand new lift pump at that time just to ensure that I had good fuel flow, . Today I was poking around and found that my intake hose after my air filter but before the turbo has a pretty massive tear. I’m not sure if that would cause some sort of vacuum sensor to tell the ECM to slow fuel delivery or something, is that a possibility on this engine? i dont see any sensors on the pre-turbo intake. I’ve ordered a new air filter and will replace that torn hose ASAP.

Based on your answers I will see about testing fuel flow from the CAPS pump if you guys think that is the problem for low power and ZERO boost. Not sure how to do that, does anybody have advice or a troubleshooting steps for testing fuel flow restrictions from the CAPS pump?
RV_rob is offline   Reply With Quote
Old 02-19-2019, 12:20 AM   #5
Junior Member
 
RV_rob's Avatar
 
Join Date: Feb 2019
Location: Dallas, TX
Posts: 14
Actually, that last question is something I can probably find in previous threads or elsewhere online, I don’t mean to ask questions that have probably already been answered plenty of times. I guess my main question was how this thing measures boost, and if the exhaust leak is likely the cause of my zero boost condition.
RV_rob is offline   Reply With Quote
Old 02-19-2019, 05:45 AM   #6
Senior Member
 
funjnt's Avatar
 
Join Date: Jul 2015
Location: Unionville, pa and Ocala, Fl
Posts: 517
I er we have a coach with isc 330. We also have the silverleaf installed and I don't remember seeing it read boost. I don't think the isc varies fuel rate based on boost so there may be no stock boost sensor? The easiest thing would be to get one from an auto parts store or online, order 300' of extra tubing and just run it from under bed to driver station. Take rig for a ride around the block or park for that matter. That will show you actual boost.

The tear in the intake is worrisome. Hopefully that didn't cause any issues but, that wouldn't be related to this. Let us know.


I would put money on the crack being the culprit of low boost.
__________________
2000 Country Coach Allure #30476
2007 Subaru Outback
Winters in Ocala, summers in Pa and North East US.
funjnt is offline   Reply With Quote
Old 02-19-2019, 10:12 AM   #7
Junior Member
 
RV_rob's Avatar
 
Join Date: Feb 2019
Location: Dallas, TX
Posts: 14
funjnt, thanks. I didn't think about running my own gauge, I will absolutely do that! I would really like to see actual boost PSI, because I'm having a hard time finding any info about what value the ScanGaugeD uses. Some say for this particular motor that it's an actual value provided by the ecm so I should call cummins to find out how the ECM calculates the value, others say it's straight Intake Manifold Pressure in PSI. I'm waiting for call back from cummins tech, I'll report what they say so you'll know for future reference. I wonder if silverleaf has "programmable" gauges like the scangauge so you can add the boost reading, regardless if it's "calculated" or actual psi from intake sensor.

Regarding the crack, I spoke with a local diesel truck mechanic yesterday and he suggested I go to Tractor Supply and get the 2000degF repair putty and a box of FiberFix HeatWrap Pro to temporarily seal the crack to help diagnose the problem. He said if it's "solves the problem" and I start creating boost again, then I know I only need a new manifold, but if not, I know that I might need to order more than just the manifold, like a new turbo kit, ect, since I'll have it apart. I agree that taking it all apart just to replace the manifold, the putting it back together to find it didn't solve much of the problem, then find out I need a new turbo or something would be a headache. The good news is however, I found our Turbo kit for this motor is EXTREMELY cheap. It's the HX40W, and can be had from Amazon Prime for $218! That's nuts to me. So forget wondering IF I need to replace it with the manifold, I'm just going to do it for that price. I expect others might do the same once they realize how cheap it is for this ISC 330.
RV_rob is offline   Reply With Quote
Old 02-19-2019, 02:26 PM   #8
Senior Member
 
Join Date: Sep 2010
Posts: 2,739
We found on both our 500 ISM and 605 X15 the computer read out is limited to a reading of 32 PSI. On both motors we put a add on Turbo Boost gauge and EGT . Both motors on step grades had over 40 psi taken from the intake manifold with tubing going all the way to the gauge on the dash.
tom chelbana is offline   Reply With Quote
Old 02-19-2019, 03:55 PM   #9
Senior Member
 
mackwrench's Avatar
 
American Coach Owners Club
Join Date: Apr 2016
Location: North Florida
Posts: 1,424
The split air intake hose before turbo won't cause the power issue you describe. It will however allow unfiltered air into engine and wear piston rings out rapidly.... called "dusting" the engine.
Does engine have any excessive blow by or use oil? Maybe you've dodged that bullet.

The low power can be the exhaust manifold split, but I'd also take a very close look at the charge air cooler hoses/clamps. Start at turbo and follow the CAC piping all the way through the CAC to intake manifold. Sounds like you have a large boost pressure leak. Look at the charge air cooler as well for any signs of damage or where something may have rubbed a hole in it....
__________________
1999 American Eagle
ASE med/heavy certified technician
ASE advanced diesel certified
mackwrench is online now   Reply With Quote
Old 02-19-2019, 07:40 PM   #10
Senior Member
 
Jon_C's Avatar
 
Join Date: Jul 2018
Location: Southeast Texas
Posts: 350
Id also check the scangauge for any ecm codes. Mine was derating on occasion due to bad crank sensor and id clear the code and it would reappear after low power every time. New sensor and runs fine.

My banks system fools the ecm into thinking there is less boost than actual. But sounds like you would know if u had a banks tuner
__________________
1998 HR Endeavor Cummins ISB 275 / Banks Allison 3060
2008 Jeep Wrangler with M&G air brake with breakaway
2015 Haulmark Edge Race Trailer 4 wheel electric brakes
Jon_C is offline   Reply With Quote
Old 02-19-2019, 10:21 PM   #11
Junior Member
 
RV_rob's Avatar
 
Join Date: Feb 2019
Location: Dallas, TX
Posts: 14
I fixed the intake hose today, I sure hope I "dodged that bullet"! I don't see any excessive blow by, but the only way I really know how to gauge that is we toad tow a white small SUV and I don't have much if any "gunk" on it. I definitely do not burn oil now make oil, I'm able to change it on schedule and I any see a very slight lowering on the dipstick from new to change time. I also tested lift pump pressure again today, as well as pulled the fuel return line to a bucket and it had good flow.

Mackwrench.... thanks for the advice, I googled how to check that and I've already filled a big spray bottle with soapy water and am ready to head over to storage tomorrow and check for leaks thru the entire CAC plumbing to where it enters the engine. I tried to "patch" the manifold crack today, but getting the clamps off the intake hoses/turbo ended up being a real headache as the bolts were cakes with grime and the nuts strips, so I had to just use my dremel to cut the bands/clamps. I ordered new ones from amazon. So tomorrow I will patch the crack and see if I get better results.

Jon_C.....I don't have any codes, that's one of the most frustrating things about this. I did throw a code when I was testing the turbo actuator, 102 fm4, which I believe is Intake Manifold Sensor Low Voltage, and I cleared it and no more codes, so I know it's reporting codes.
RV_rob is offline   Reply With Quote
Old 02-20-2019, 06:41 AM   #12
Senior Member
 
Jon_C's Avatar
 
Join Date: Jul 2018
Location: Southeast Texas
Posts: 350
You can pressure test cac with 2 short 4” pvc pipes glue cap on ends drill hole on end of one and install a metal tire valve core then pressure up to 30 psig IIRC cummins recommends no more than 5 psi loss over 45 min thankfully mine had no leaks. One bit of advice on those big clamps is make sure u get them lined up straight when their tight. I had one a little off and it was leaking during the test, straightened and then good they are holding back up to possibly 25-30 psig pressure on regular basis and they need to be straight and tight. A little never sieze on the threads wont hurt either
__________________
1998 HR Endeavor Cummins ISB 275 / Banks Allison 3060
2008 Jeep Wrangler with M&G air brake with breakaway
2015 Haulmark Edge Race Trailer 4 wheel electric brakes
Jon_C is offline   Reply With Quote
Old 02-20-2019, 06:49 AM   #13
Senior Member
 
Jon_C's Avatar
 
Join Date: Jul 2018
Location: Southeast Texas
Posts: 350
And theres almost 0 maybe 1 or 2 boost pressure until you put the motor under a load. I can get about 10 psig pulling against my parking brake but thats it, otherwise u have to drive it to get boost.
__________________
1998 HR Endeavor Cummins ISB 275 / Banks Allison 3060
2008 Jeep Wrangler with M&G air brake with breakaway
2015 Haulmark Edge Race Trailer 4 wheel electric brakes
Jon_C is offline   Reply With Quote
Old 02-20-2019, 07:02 AM   #14
Senior Member
 
Jon_C's Avatar
 
Join Date: Jul 2018
Location: Southeast Texas
Posts: 350
Last thing my exhaust manifold was cracked when i bought it and it ran great, did not have boost gauge like i do now but without sufficient boost it barely runs, im sure your crack is causing some boost loss but unless its really bad itís probably not the main cause of your issue. I went back with a steed speed ceramic coated steel manifold guaranteed to never crack , so far so good. And they claim up to 40hp gain. And yes boost readout is from the map sensor ( manifold absolute pressure)

Heres a post of some before after pics of motor with the new manifold and sone cleaning.
http://www.irv2.com/forums/f61/thanks-to-all-on-forum-402819.html
__________________

Jon_C is offline   Reply With Quote
Reply



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Boost pressure on 350 hp 8.3L ISC jacwjames Cummins Engines 26 08-15-2015 02:29 PM
ISM450 intake manifold pressure sensor morninghill Cummins Engines 12 07-18-2014 11:34 AM
What is max turbo boost supposed to be..& min. oil pressure at idle, ISC 350 Cummins StansCustoms Alpine Coach Owner's Forum 10 12-02-2011 01:06 PM
ISC Boost Pressure Spec? F&D ABQ Alpine Coach Owner's Forum 1 07-05-2010 12:11 AM
1999 isc 330 hp no boost pressure diceman1530 Cummins Engines 16 10-29-2009 07:47 AM

» Featured Campgrounds

Reviews provided by


Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 04:12 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2019, vBulletin Solutions, Inc.