Downstream Injector not working when machine is on

Hello all. I purchased a DXPW4240 (4gpm, 4200 PSI) pressure washer a few months ago. It was downstream injecting perfectly until about a week ago. I did some research & determined it was from the bleach corroding the spring inside of the injection port. I replaced the port, ball, and spring, but now it won’t pull any chems when the machine is on. I have tried everything from running it without any equipment on after the pump, to turning the spring around, to going back to my original black and pink (2nd story) tips, yet no pull of chems. Once again, it creates suction when the machine is off. I even dialed down my pressure, but still nothing. Help!!!

Injectors last anywhere from a day to a couple of months. Replace the injector. If it is a built in injector, replace your pressure washer


Out of curiosity, how much were you using it to DS?

Seems like since I’ve switched to the 3 way valve and my injector gets rinsed constantly they last forever with no maintenance. I still have 2 backups but we havent needed them in what seems like forever. I like it way better that way!


Ditto. I feel like the orifice is going to wear too large before the spring ever goes, lol.

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By replacing the injector,which piece are you talking about?

i use it to DS about 20-30% of the time. I mostly use bleach & soap to soft wash. Only use high pressure with a surface cleaner to do ground surfaces.

3 way valve? Got a photo or link?

I’ve replaced the part that houses the ball and spring. Is this what you are talking about?

Would this work? Can I just plug this in and plug the old one?

You would be much better off getting a better machine, or at least another pump.

Well I just bought the machine a few months ago. Still haven’t paid it completely off, so buying another one isn’t an option. What type of pump do you recommend I buy? And why?

A pump without a built in injector so you don’t have this problem again. I normally suggest Udor, but that would be overkill for what you have. Get a general. We don’t know what you are doing. If you are washing commercially, obviously get rid of what you have and get a good unit. If you are a homeowner, put a general pump on it and cross your fingers.


Yes get a bolt the same size to cap it off and then you can use the down stream injector then use the machine until you can save up for a better pump

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Ok, I’ll cap the old ads injector, & buy that quick connect one to use. This should work for now, correct? I’m just curious as to what the heck happened to my old injector. I replaced the spring, and even put the same injector and ball back on…

That’ll work, but you’d be better off ordering one without the adjustment from one of the regular wholesalers. The injector itself runs about $15, then get the QCDs you need.

Without the adjustment? QCD’s? I’m new to all this, man lol.

What type of general pump should I be looking at getting? They make hundreds of them lol

You want a fixed injector - not adjustable

QCD I assume is your quick connect/disconnect fittings.


One that matches the specs of your motor and your gpm/pressure needs

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