I bought a single-stage 60 ga. upright Ingersol Rand compressor from Habor Freight a couple years ago, painted one vehicle and now it won't shut itself off because it can't reach full boost anymore. Last time I tried it, it got up to about 60 lbs. or so, instead of 130-ish whihc is where it should reach. It could have gotten polluted sucking in paint-laden air, albeit through it's tiny air filter, which I have since run to the outside to gather fresh air (and did so before I completed the paint job and started having the problem.) I called a repair guy who wasn't much help, said it could be anything, and granted, it could, but somtimes they don't give you the whole story. Should I just rip into it, clean it and put it back together or is it more complex than I might think it is? Or simpler? Any ideas? I'd like to paint my new Fiero since no one seems to want it. Sorry for the rant and thanks for any input.

Make sure your check valve is not bad.

I WILL DO THAT. Any idea where it's located or what it looks like?

most compressors use a two seperate reed valves to let the air flow one way.
if they are dirty/rusty/got paint specks stuck to them then they wont make a seal

THANKS FOR the info guys, I will check it out! I may have a compressor again soon!! Wo Hooooooo!!

If it's never reaching shutoff, I will second Buddy's diagnosis of reed valve malfunction. There is definitely either a problem with the reed valves and/or an obstruction somewhere on the intake side of the compressor.

You have checked to be sure that it's not something obvious like the tank drain valve left open ... haven't you?

[This message has been edited by Marvin McInnis (edited 07-06-2005).]

quote Originally posted by Marvin McInnis: You have checked to be sure that it's not something obvious like the tank drain valve left open ... haven't you?

not saying I wouldn't do that.... but yes, I did be sure on that! ;-)

The check valve refered to is generally at the tank end of the air line that goes from the cyl to the tank.

Russ

My check valve is on top of the tank, right where the compressor out, enters the tank. DeVilbiss 80 gallon two stage, 175 psi max. Was having a problem with it taking longer to get to pressure, BUT when it did, I had air escaping from the pressure switch relief valve. Turned out to be my check valve. Put in a new one, problem gone. If you hear a leak after you have some pressure, and turn off the unit, then look at the check valve. If not, then yes, have the reeds checked out. Could also be the line connecting the the compressor to the tank, a leak after the tank, a gasket on the head, the piston, the rings, etc........

Kevin

quote Originally posted by Lambo nut: If you hear a leak after you have some pressure, and turn off the unit, Kevin

*whacks self in head*

that's so simple it just might work....

let it build up about 60psi or so and then shut it off, turn off the radio, and listen for a "hiss"

I'd sayt the rings on the pistons may not be sealing very well. How long did it sit unused after the one paint job? MAybe some oil through it's intake, Spray oil of course, may losen things up a bit and dislodge paint from the insides.

quote Originally posted by buddycraigg: does it lose pressure overnight or does it just have a hard time building up high pressure?

I didn't get a chance to look at it again tonight, I seem to remember hissing when it;s running, but not when it's shut off.
It won't build the proper pressure period. It's starting to sound like the reed check valves.

quote Originally posted by buddycraigg: does it lose pressure overnight or does it just have a hard time building up high pressure?

It did both. Would take longer and longer to get to pressure. The check valve would eventually seal after a while, if not, would cycle up all over again. Was running way too much for my liking.

And if you are hearing a hiss while it is running, might not be th reed valves, as they are in the head. Not sure you would hear them leaking. Get you a spray bottle of soapy water, and start her up. Spray all the fitting you can find, around the head, etc. At least make sure it is not an outside leak, before tearing her apart.

Kevin

My compressor did that a few weeks ago and it turned out to be that I had forgotten to close the drain valve at the bottom of the tank.

I'm betting on the reed valves in the head. I went through the same thing with my 80-gallon DeVilbiss Pro 4000. Three months old & it broke a valve in one cylinder. It would pump up on the other cylinder-FINALLY- in about 45 minutes if it wasn't being used.

Take off the heads & look. If you're competent to zip your own britches, you'll have no problem.

Solved! The obvious (seemingly) suggestion to research the hissing, led me instantly to a bad connection on the copper tubing coming out of the cylinder head to the tank. The flared end was 90% cracked and broke off when I disassembled it. I put on a compression fitting, the guy said it would hold twice the pressure I need it too, I sure hope so! Thanks for all your help and suggestions!

The compression fitting should be just fine. That is what mine has from the factory, on both ends, and reaches 175psi. I would double check with the soapy water, to see that it does not leak after installing. Had to tighten mine up pretty good to get a leak free seal. Would save some run time on the compressor.
Glad you got it going again.

Kevin

Kevin, thanks again for your help. Do you have a Lamborghini kit too, judging from your screen name? I am building a Countach

Sent you a PM.

Kevin