931a2 air pressure

[Desertshark]

So last week I was lucky enough for my fuel shut off solenoid to go out. Well new part cam in and kinda running. My new issue today is the air pressure... for some reason it is building crazy pressure close to 150 psi so shut it down and drained tanks. Anyone have idea what decided to go out now and won't let pressure regulate properly ?

 

[doghead]

If it's freezing there and you have not propperly maintained your air system(including the dryer)it may be your PPV, search it.

 

[Desertshark]

Desert southwest don't see a lot of freezing weather. It has warmed up a lot lately. I have replaced air dryer last year. Don't know if it will help but I do have horn and wipers . So thinking I may need a air dryer service kit.

 

[doghead]

Does your expello valve seem to be working? They do clog up.

 

[Desertshark]

Not gonna lie..... have no idea what or where that is... unless it the needle in the ppv

 

[Desertshark]

I did cycle or drain air of my tanks a few time.... to be hones the no. 1 valve kept pushing good amount of moisture once opened all the way.

 

[doghead]

It's under the bottom of the air drier, it's where the water comes out.

A search for expello should help.

 

[Jericho]

PPV is a good suggestion from Dog Head, fixed mine . if your getting water from the drains you need to get the system " dry" and drain daily, do a air drier service, check all your valves for operation and don't be surprised to find some inop, they will be clogged with exfoliated grunge, still working thru them on my M 931A2 Search hi and low before you buy parts , prices vary WIDELY , ppv valve from 24$ to 200plus$ Too check the air drier heating element simply hold your hand NEAR it after you start the truck it ,you will feel the heat. , filter change is straight forward as well as the element change

 

[Desertshark]

Well I found a ppv for 18 bux and ordered it will also order a dq6036 filter service kit... maybe next week when parts are in I will have better up date.

 

[74M35A2]

Doesn't the governor control air pressure? Maybe if I read the TM I would know better.....

They are cheap and easy to replace. Throw one of those at it too. NAPA sells 2 versions, one is better sealed than the other against external elements, but both same functionally. Control valve in compressor head could be lunched also, less common, but it has happened to a few here, in addition.

 

[silverstate55]

You'll notice that your air system will behave much better after the air dryer service. Be sure to follow the recommended service interval for it as well. Some members have swapped the stock air dryer for the upgraded MRAP style with good results; "SEARCH" is your friend.

 

[BenRoberts]

Search ppv pressure protection valve. I just had that issue a few months ago.