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Topic: Can't build air, not the D2 governor (Read 1757 times) previous topic - next topic

Can't build air, not the D2 governor

I could use some forum wisdom here... I was coming down the mountain from Idyllwild and got the air loe air pressure alarm. After pulling over and checking things over, I used the aux compressor to raise the coach (which adds air to the front and rear tanks and got further down the mountain where I pulled over once again. Checking things over, I tapped the D2 with small hammer and didn't notice any difference, but after using the aux compressor to add air, I started down the road again, lo and behold it once again behaved normally building pressure to cut out and and cutting back in as usual. This continued until I got to our home base (about 60 some miles) until I was pulling into our site whereupon it stope building air. Since the only thing I did at the second stop that might of affected the air system was to tap on the D2 governor, I had high hopes that changing the D2 would fix it. Sadly, it did not. I need to move it from our site down to the storage lot (less than a quarter of a mile from our site) and so will try bypassing the air dryer tomorrow. Before when I was stuck by the side of the road in Canada, the air dryer had failed and the air was continuously puking out of the p-urge valve on the bottom of the air dryer, that is not happening now... I would appreciate some speculation or better yet, likely approaches to a solution before I tackle the issue again tomorrow.
Don
Don & Tys
1999 U270 3602 WTFE #5402
Xtreme Stage 1 w/Headlight, Step Conversion, etc.
2009 Honda Fit Sport with Navi
“Ignorance more frequently begets confidence than does knowledge” (Charles Darwin)


Re: Can't build air, not the D2 governor

Reply #1
The D2 governor does two things.  It signals the air dyer to purge and it lifts the valves in the air compressor to stop the pumping action.  If the valves won't return to service, you won't have air.  Think stuck.
1992 Foretravel Grand Villa
U225 SBID Build No. 4134
1986 Rockwood Driftwood
1968 S.I.A.T.A. Spring
1962 Studebaker Lark
1986 Honda VF700C
1983 Honda VF750C
Duke, the Dog
N1RPN

Re: Can't build air, not the D2 governor

Reply #2
I'm thinking along the same direction as Old Toolmaker.

There's really only 3 components involved in the air pressure "generation" process:  the engine air compressor, the D2, and the air dryer.  Since your malfunction is intermittent (randomly comes and goes) it is obviously not a blocked or blown out air hose.  You changed out the D2 so we may assume it is OK.  You are only too familiar with air dryer failure symptoms, and have ruled that out.  Only thing left is the air compressor.

I thought you installed the ARB 12V air compressor so you could pressure up the air system with it?  Use it to make the drive to storage lot?
Chuck, Jeannie & Bella the MalChi
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Kia on a Kar Kaddy SS
I may suffer from the Dunning-Kruger effect, but I seriously doubt it...

Re: Can't build air, not the D2 governor

Reply #3
Bypassing the air dryer (my next step as well as hopefully aiding my move down to storage) should tell me if the compressor is doing its thing or not... likely a stuck valve in the air compressor if it doesn’t. I did spray a bit of WD40 in the unloader port of the D2 mount, maybe it will free up something. R&R of the air compressor is not something I look forward to...
Don
Don & Tys
1999 U270 3602 WTFE #5402
Xtreme Stage 1 w/Headlight, Step Conversion, etc.
2009 Honda Fit Sport with Navi
“Ignorance more frequently begets confidence than does knowledge” (Charles Darwin)


Re: Can't build air, not the D2 governor

Reply #4
As it is right now, the aux is only triggered by the leveling system. I have yet to wire in the switch to control it directly. It will work to get me down to storage if I raise it up as high as I can and then let it settle to ride height.
Don
 
I thought you installed the ARB 12V air compressor so you could pressure up the air system with it?  Use it to make the to storage lot?
Don & Tys
1999 U270 3602 WTFE #5402
Xtreme Stage 1 w/Headlight, Step Conversion, etc.
2009 Honda Fit Sport with Navi
“Ignorance more frequently begets confidence than does knowledge” (Charles Darwin)


Re: Can't build air, not the D2 governor

Reply #5
Don I’m unfamiliar with our air compressors but on other compressors reed valves are used. I have seen them have one of the mount screws back out and rotate so as not to seal. Also seen them fatigue crack. I’m very curious to your findings. I’m sure some type of unloading valve is used, but have no clue. Suspect a affordable repair if the compressor is not damaged. Your bypass fitting will give good indications
Scott
Scott and Kim Davidson
If your going to be dumb, you got to be tough.
June 30, 2020
2001 U320 3610 Barn find
Build 5834

Re: Can't build air, not the D2 governor

Reply #6
I have had the unloader valves stick on my crane. It uses a Bendix compressor. I was able to spray Corrosion X into the head assy. by removing 2 bolts and fixing the problem. The valves on it are like an automobile engine and the valve stems were sticking. I don't knows how the one on my Cummings engine works but if it has a similar configuration the same thing could happen and maybe the same cure would work.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Can't build air, not the D2 governor

Reply #7
R&R of the air compressor is not something I look forward to...

Don,

If the dryer checks out OK then here are some thoughts on the compressor and D2.

If the compressor pumped any at all that leads me to believe that it (the compressor) is just fine.  Now that don't mean that you don't have trouble with the unloader which is a bolt on part.  Depending on which compressor you have will depend on what type valves and unloader you have.  So crawl up in there and get a picture of the model Hoslet (WAG here) compressor you have. There are unloader rebuild kits out there and most are ~$50.  You can use Kroil also and do like Cman suggest by spraying into the compressor inlet/unloader and see if it can loosen up some gunk that can build up in there. If you do have to pull the unloader it can be done on the coach which will save you some extra work.  One word of caution is if you do pull the compressor some have to be timed with the engine (here in lies the extra work from above) so read up on timing before you start.

Now I know this may seem like a remark from an over educated burro (smart azz) but when you replaced the D2 did you make sure that you had the plugs in the right ports? Or it could be a bad rebuilt D2 so try another one before you tear into the compressor.

Mike
Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."

Re: Can't build air, not the D2 governor

Reply #8
Can't help with fixing the problem but could you use your generator and an air compressor plugged into the external connection to keep it aired up to move it?
Forest & Cindy Olivier
1999 36' U320 build #5522
2013 Rzr 570
2006 Lexus GX470
2011 Tahoe LT 4x4
Previous 1998 45' 2 slide Newell, 1993 39' Newell

Re: Can't build air, not the D2 governor

Reply #9
Can't help with fixing the problem but could you use your generator and an air compressor plugged into the external connection to keep it aired up to move it?
An electric compressor will not have the CFM to operate the brakes safely.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Can't build air, not the D2 governor

Reply #10
The generator will be able to drive a big enough air compressor to do the job.
1999 36ft. U320 Foretravel
Build # 5436
1998 Suzuki Sidekick Sport

Re: Can't build air, not the D2 governor

Reply #11
I was slammed with sticker shock when I looked for an air compressor for my 8.3.. If I had been home I would have tackled rebuilding my on in my shop. Your lucky your home Don and not in El Paso Tx.
Dub McBride 1996 270

Re: Can't build air, not the D2 governor

Reply #12
Don I’m unfamiliar with our air compressors but on other compressors reed valves are used.
Scott

Scott sit back and think for a moment.  The compressor is gear driven and turns anytime the engine turns, and it has poppet valves.  All you need to do is lift the exhaust valve to stop the useful pumping of air.  That's what the unloader mechanism does.  It holds the valve open and the compressor goes wiffle wiffle wiffle.

If the unloader is coming and going a spritz of your favorite penetrating oil will buy you a little more time.  Prudence dictates purchasing the kit, cleaning the unloader and replacing the wear parts.

For industrial air compressors 5HP is the dividing line.  If your compressor doesn't cycle all that often you can start and stop the compressor.  When you get into the other 50% of pumping capacity you change the compressor over to run all the time and use the unloader.  The electric motor will thank you.

And yes some compressors use reed valves.  It's just that these don't.
1992 Foretravel Grand Villa
U225 SBID Build No. 4134
1986 Rockwood Driftwood
1968 S.I.A.T.A. Spring
1962 Studebaker Lark
1986 Honda VF700C
1983 Honda VF750C
Duke, the Dog
N1RPN

Re: Can't build air, not the D2 governor

Reply #13
Thanks for the thoughts Mike... Our coach has a Holset compressor (which is bthe reason it has to have the external isolation valve on the air dryer). I see that find it parts may have a rebuilt unloader assy for about $75. I will have to remove items like the air dryer and my Davco primary fuel filter, but it may be changeable without removing the compressor... I will order one jsut to have if I can figure out the right part number. They also have unloader rebuild kits but the for less than a $100, it is a no brainer to to get the who;e assembly. I will remove the unloader plug from the D2 and try spraying some Corrosion X in the port. BTW, should the motor be running when I do this? Would it get drawn in or blown out? ::)
The compressor model is a Holset QE296EC
Don
Don,

If the dryer checks out OK then here are some thoughts on the compressor and D2.

If the compressor pumped any at all that leads me to believe that it (the compressor) is just fine.  Now that don't mean that you don't have trouble with the unloader which is a bolt on part.  Depending on which compressor you have will depend on what type valves and unloader you have.  So crawl up in there and get a picture of the model Hoslet (WAG here) compressor you have. There are unloader rebuild kits out there and most are ~$50.  You can use Kroil also and do like Cman suggest by spraying into the compressor inlet/unloader and see if it can loosen up some gunk that can build up in there. If you do have to pull the unloader it can be done on the coach which will save you some extra work.  One word of caution is if you do pull the compressor some have to be timed with the engine (here in lies the extra work from above) so read up on timing before you start.

Now I know this may seem like a remark from an over educated burro (smart azz) but when you replaced the D2 did you make sure that you had the plugs in the right ports? Or it could be a bad rebuilt D2 so try another one before you tear into the compressor.

Mike
Don & Tys
1999 U270 3602 WTFE #5402
Xtreme Stage 1 w/Headlight, Step Conversion, etc.
2009 Honda Fit Sport with Navi
“Ignorance more frequently begets confidence than does knowledge” (Charles Darwin)


Re: Can't build air, not the D2 governor

Reply #14
Vet10 latest finditparts discount i have. May expire at 1158 pm today.
Mark
1999 U270 40 #5518
USN. USPS.

Re: Can't build air, not the D2 governor

Reply #15
Not sure whether or not these are direct replacements for the Holset model I have, but a search on "Holset QE296EC
" yields 3558072X by HALDEX - Remanufactured Cummins/Holset Style Compressor - QE296
Note that it lists just the QE296 without the suffix EC. I don't know what the letters "EC" refers to, but it may be significant, i.e., port orientation, the fact that it doesn't include the unloader assy, or?

In any case, the price for a rebuilt at less than $300 (plus a $312 core charge) plus a rebuilt unloader assy @ <$50? Speaking of the unloader assy, anyone know how I can tell if this is the right one for my compressor?
3559582X by HALDEX - Remanufactured Compressor Unloader Assembly

Sounds like a fairly reasonable price to me, but first I would by the unloader assy and try it if the compressor doesn't build air after I try  bypassing the dryer...
Don
I was slammed with sticker shock when I looked for an air compressor for my 8.3.. If I had been home I would have tackled rebuilding my on in my shop. Your lucky your home Don and not in El Paso Tx.
Don & Tys
1999 U270 3602 WTFE #5402
Xtreme Stage 1 w/Headlight, Step Conversion, etc.
2009 Honda Fit Sport with Navi
“Ignorance more frequently begets confidence than does knowledge” (Charles Darwin)


Re: Can't build air, not the D2 governor

Reply #16
Found one that has similar "assembly number" (plus the "X")  to the metal tag in your photo:

Cummins/Holset Compressor - 3558186X/QE296

If you look at the different QE296 compressors in the link below, you can see 3 different mounting flange configurations.  The "EC" suffix on your compressor's model number might refer to mounting flange type?

Holset / Cummins QE296 Compressors

Catalog link below, see page 1-38, top left diagram for Assembly Number 3558186:

http://precisionrebuilders.com/pdf_catalogs/AirCatalogPAB-0902.pdf
Chuck, Jeannie & Bella the MalChi
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Kia on a Kar Kaddy SS
I may suffer from the Dunning-Kruger effect, but I seriously doubt it...

Re: Can't build air, not the D2 governor

Reply #17
Not sure whether or not these are direct replacements for the Holset model I have, but a search on "Holset QE296EC
" yields 3558072X by HALDEX - Remanufactured Cummins/Holset Style Compressor - QE296
The compressor you linked (above) says it is for Cummins L10/N14 engines.  Not what you got (different mounting flange).

The one below says it is for Cummins C-Series.  Also note the correct Assembly Number.

3558186X by HALDEX - Remanufactured Cummins/Holset Style Compressor - C-Series
Chuck, Jeannie & Bella the MalChi
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Kia on a Kar Kaddy SS
I may suffer from the Dunning-Kruger effect, but I seriously doubt it...

Re: Can't build air, not the D2 governor

Reply #18
Thanks for the research Chuck!  ^.^d I want to get a rebuilt unloader assy but the one that is suggested at Find It Parts is shown as not available. This part looks like it should be used across many models. I wonder how universal they are... I would like to have one assembled in hand so I can drop~n~swap if possible, but as yet I find none for direct sale from a website. If I can find a rebuilt to buy, I plan to take the old one apart and maybe fix, so I would just eat the core charge.
Don
The compressor you linked (above) says it is for Cummins L10/N14 engines.  Not what you got (different mounting flange).

The one below says it is for Cummins C-Series.  Also note the correct Assembly Number.

3558186X by HALDEX - Remanufactured Cummins/Holset Style Compressor - C-Series
Don & Tys
1999 U270 3602 WTFE #5402
Xtreme Stage 1 w/Headlight, Step Conversion, etc.
2009 Honda Fit Sport with Navi
“Ignorance more frequently begets confidence than does knowledge” (Charles Darwin)


Re: Can't build air, not the D2 governor

Reply #19
If I can find a rebuilt to buy, I plan to take the old one apart and maybe fix, so I would just eat the core charge.
Don
That would be my approach as well. 

Richard
Jan & Richard Witt
1999 U-320  36ft WTFE Build Number: 5478
2008 Roadtrek Adventurous RS Sprinter
2011 Jeep Wrangler Unlimited
Jan: NO5U, Richard:KA5RIW
”summer bridge”


Re: Can't build air, not the D2 governor

Reply #20
Update and some head scratching :o I got the coach down to our boondocking location safely. The head scratching is because bypassing the air dryer did not result in the compressor doing its thing. So... I add air with my trusty HF ultra quite compressor, and put (eventually ::) ) 120psi in. With the air dryer in the system, the wet tank would leak down while the brake tanks would stay at 120psi. But now with it bypassed, the wet tank stayed at 120! So, though it seem that the compressor is not compressing (I think it has to be a stuck unloader because of the fact that it started working normally long enough for me to about 65 miles of moderate elevation changes and winding roads and then failed again after stoping to unhook the towed here at home base. My reading on this is that the dryer has failed and the unloader valve has become stuck... maybe because of cr@p from the failed dryer??? What think you? I am going to pull the air dryer off and see just how hard it is going to be to get the unloader assy off. I have a brand new old stock one (along with a new isolation valve). I just have to fabricate a mount for it. I am going to see if I can work out a mount that will give me full access for servicing dryer from behind and better access to the compressor etc. The current mounting system is very inconvenient.
Don
Don & Tys
1999 U270 3602 WTFE #5402
Xtreme Stage 1 w/Headlight, Step Conversion, etc.
2009 Honda Fit Sport with Navi
“Ignorance more frequently begets confidence than does knowledge” (Charles Darwin)


Re: Can't build air, not the D2 governor

Reply #21
Don,

Here is the part numbers that should fit the QE296 unloader. PAI # 220038 or Cummins 3803766. Make sure that you don't get a kit for the SS models as they won't work on the QE compressor.  Here is a video of what you are up against. https://www.youtube.com/watch?v=9VM3m0dROV0

Mike
Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."

Re: Can't build air, not the D2 governor

Reply #22
Pamela & Mike, that is an excellent video! Another video that makes it clear what type of air dryer Is applicable to the QE compressors used mostly before the 2000 model year, apparently only on the ISC powered model coaches.
http://www.youtube.com/watch?v=LjWQStJxXf8

Don,

Here is the part numbers that should fit the QE296 unloader. PAI # 220038 or Cummins 3803766. Make sure that you don't get a kit for the SS models as they won't work on the QE compressor.  Here is a video of what you are up against. https://www.youtube.com/watch?v=9VM3m0dROV0

Mike
Don & Tys
1999 U270 3602 WTFE #5402
Xtreme Stage 1 w/Headlight, Step Conversion, etc.
2009 Honda Fit Sport with Navi
“Ignorance more frequently begets confidence than does knowledge” (Charles Darwin)


Re: Can't build air, not the D2 governor

Reply #23
Don,

What a lot of people don't understand is the need to use the correct air dryer that is mated to the compressor you have.  Very good explanation in that video.

Mike
Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."

Re: Can't build air, not the D2 governor

Reply #24
I have a new PURest air dryer that says it isn't compatible with Holset compressors. Without the isolation valve, I don't think the OEM "Pure Air Plus" is either. My thinking that the addition of an isolation valve See picture below)  would do the same thing for the PURest that I have on hand... Any thoughts? I would consider that Turbo 2000 with the QE compatible configuration mentioned at the end of the short video I posted, but sounds like it might be pricy considering I can't find out how much they are without calling a dealer...
Don
Don & Tys
1999 U270 3602 WTFE #5402
Xtreme Stage 1 w/Headlight, Step Conversion, etc.
2009 Honda Fit Sport with Navi
“Ignorance more frequently begets confidence than does knowledge” (Charles Darwin)