Community Forums

mrbap · 06-28-2013, 12:41 PM

Hi Snappy,

Yes, there is air coming directly from the air compressor at the "air exit" fitting. It Puffs out air in bursts, which I'm guessing is normal. My little portable compressor, when hooked up at the very beginning/front of the air discharge line only pumps gauges on DP to about 50 psi. When I hook up the air line back to the compressor fitting, bypassing the air dryer, it also took a while to get psi to 50.

I wondered if air dryer somehow helps normally in increasing pressure ? Still guessing here - like everybody else. Does anyone know where the second line coming off the GOVERNOR goes? I know one line goes to dryer, but what about the other line? Could where ever that leads to be a cause? Any electrically issues involving these air systems?

I'm lost here! Back to troubleshooting for now!

Fkrel · 06-28-2013, 03:49 PM

The second line at the gov goes to the air tank its the signal line that shifts the gov when it reaches the prefered pressure

mrbap · 06-29-2013, 06:25 PM

Alright....STILL NO LUCK!!!

I think my LAST troubleshooting attempt will be to take a peek at the unloader in the air compressor. In trying to educate myself on these "systems" it still seems to me this COULD be a cause of my issues.

Has anyone actually done the unloader repair using the available repair kits? How much work is involved?

Does anyone agree/disagree (in my situation with "0" psi) a defective/stuck unloader might be the issue?

Thinking of taking it apart just to see if it's "gunked/stucked"

Please keep the thoughts coming!

Chow5656 · 06-29-2013, 06:33 PM

It VERY well could be the unloader.. IF it is the air will be coming out of the bottom of the dryer.

mrbap · 06-29-2013, 08:39 PM

Thanks Chow!

I tried so many things, I've forgotten some of them. But I'm pretty sure while the DP was running once, I did try and feel for air all around the dryer. Is it possible if the compressor was pumping out less than full capacity, due to partially stuck unloader, I might not feel any air pressure around the dryer? I guess I'm asking if you/anyone believe(s) a defective unloader might still be cause, because I felt no air leaks at the dryer.

Thanks to all....I'll keep you posted and checking back.

BFlinn181 · 06-29-2013, 08:46 PM

I'm not familiar with the fittings on the hose you've replaced, but could you remove it from the dryer and temporarily put a gauge on the hose to measure air pressure? If you get good pressure there, you'll know the compressor is O.K. and then can work on dryer and governor.

Chow5656 · 06-30-2013, 04:42 AM

You can get a fitting to by pass the dryer to see if that's it... But, don't leave it that way!!! Also the compressor still could be bad.. It might not build pressure... It could pump air until there is some kind of pressure and then blow by the rings in the compressor.

J Walker · 06-30-2013, 08:53 AM

mrbap Sorry for your troubles. For troubleshooting, did the air pressure go to zero before or after you replaced the dryer filters? If after then suspect the new filters or the installation. It seems clear now after your investigation that the air is not getting past the air dryer so it should be fairly easy to find the cause. Maybe you could take it apart again and look at the instructions and see if anything is wrong.

mrbap · 06-30-2013, 10:28 AM

Thanks JW & Chow!

I did bypass the dryer at one point and still could not get tanks to fill. I agree issue is prior to the dryer. I wish I could just hook up and auxiliary air compressor somehow and call it a day!

I am heading to Home depot for more fittings and will actually attempt to test the unloader.

Frankly I am surprised with so many people following this post, no one seems to have knowledge about the unloader valve. Sure we all comment and can read how it works. But NO ONE has had an unloader issue? If you did, what were the symptoms?

Thanks to all reading and SHARING their knowledge.

Dr4Film · 06-30-2013, 10:51 AM

Here are two PDF files that may help you understand the air system and possibly solved your problem.

Dr4Film ----- Richard

Chow5656 · 06-30-2013, 11:01 AM

If you have bypassed the. Dryer and you still didn't build air.. I would have to lead toward the fact that it IS the compressor!!

J Walker · 06-30-2013, 11:29 AM

Since most everything has been checked so far, I will add the obvious. Maybe you do have air pressure and the gauges are not indicating it. For example without pressure the MH will not move. The rear brakes will lock. You can crawl under the MH and pull the air release lanyards on the two tanks and see if there is pressure. Also, you can find an air port and make a pressure measurement there. On the gauges, they are probably digital like mine driven by a unit such as my VDU. They do have failures although it is usually one of the two pressure sensors at a time not both. On of my sensors went out. I suspected the gauge because of the way it was fluctuating, much faster than the pressure could change. I pulled the lanyards and found pressure. I eventually replaced my VDU.

EngineerMike · 06-30-2013, 11:52 AM

I doubt it is the compressor or you would likely have had black oil in the air dryer & a lot of it. Unloader could be the problem. You are actually in good shape w/your finding that it is within the compressor to air dryer circuit. Outside of limited working room, that isolated the problem greatly.

The battery tech should be made to sit on the batteries he attempts to charge until he learns to check to see if there is water in the cells. That way he has some "skin in the game". Duh.

A well made ground system consists of two positive paths to battery ground. On my rig there is secondary ground circuit using a welded stud on the frame; path goes engine block/strap/stud on frame/stud on frame@batt compartment/strap/battery. Starter circuit goes starter ground stud/strap/battery. The starter circuit is easy to check; the secondary has more parts.
The Cummins engine has several open threaded bolt holes on the lower block that can accept a ground stud.

mrbap · 06-30-2013, 12:44 PM

Thanks again to all for helping me sort through this issue! hello to EngineerMike!!

Mike, you made feel a little better with your comment about a failed compressor should show "oil" and plenty of it in the dryer. That was not the case here. But I understand, perhaps a bad seal, will cause less than full compression pressure and I could still have compressor issues.

Got back from home depot. Made my "unloader" tester. My understanding is to pump air with my portable unit into the "unloader port" on the compressor. Then shut off air and watch gauge for pressure drop. Any drop in psi means the unloader spring needs replacing as air is being released (fully or partially into atmosphere) and not compressed. If pressure holds steady it is NOT an unloader issue.

MIKE, I noticed you winter in Havasu!! That's where I live YEAR ROUND. It was 120° yesterday. Troubleshooting on days like this is no fun. Today, im staying inside and taking the day off!

Thanks to all again!