Oil change resulted in power boost which resulted in DS injector malfunction?! Or hap

I know I should’ve stayed home all day today. But I didn’t. And as a result a weird thing happened to my pressure washer today.

It’s a 4GPM/4200PSI cold belt driven machine. I downstream.

I changed the oil in the engine and the pump. It’s my 3rd oil change as I have around 150 hours on this pressure washer.

Went to do a job. Applied house mix as usual. I noticed right away that the machine was a bit more powerful compared to the way it was before the oil change.

I was like “Alright! Awesome!”

Then I went ahead with rinsing… and realized the injector was still pulling soap!!

The injector itself is new. Not more than 15 hrs on it. I just replaced it. So I doubt it’s the injector. But then again anything is possible, right?

I kinda suspect it has something to do with the fact that the machine has become more powerful. I know it sounds lame but the heck! I don’t know how to explain this.

I ended up finishing the job running back and forth to the trailer and pulling the injector hose out of the bucket to rinse.

The results were great. The customer happy. But what’s next? I gotta fix it somehow.

And what’s weird is - let’s say it was due to oil change. And let’s say by changing the oil my pressure washer’s performance returned to its original level - like when it was brand new. But when it was brand new I had no problems with DS injector and soaping/rinsing.

I’m gonna check the PSI with the gauge tomorrow just out of curiosity. But idk, I’m lost.

Does anyone have any thoughts on this?

Alex @ Nothside Power Washing

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Are you over revving the engine? Or did you touch the unloader? What is your injector size? Get the 2-3 gpm injector, not the 3-5. It sounds counter intuitive but the smaller the orifice the better draw and less problems.

Also your nozzle might be getting worn out and that causes the injector to stay on.

i was just thinking the exact opposite thing ralph.

i was of the belief that opening the orifice is what creates the back pressure that basically triggers the DS injector to kick in. is that wrong?

my brain is telling me that if his machine is in fact performing better, a smaller soap orifice would simply turn into a large rinse orifice?

Over revving? I didnt even know it was possible to over rev it. So no on this one. And no, I haven’t touched the unloader.

The nozzle wear is a possibility though. I didn’t think of it.

I’m using 3-5 and it’s been working excellent up until today. So I think I’m gonna stick with it and order a new nozzle kit.

I’m out of Gutter Grenade anyways. So it’s time to call pressuretek again :slight_smile:

Alex @ Nothside Power Washing

Sent from my iPhone using Pressure Washing Resource

Your nozzle has to be a certain size to stop the injector from drawing soap. The back pressure does that. If the nozzle is worn the nozzle orifice is bigger and therefore keeps the soap coming. The injector size is the reason you are having this problem. Your nozzles have to be precise, because of it. Any deviation such as a worn nozzle will cause your problem. If you go one size smaller you can add hose length and not have to worry about injector problems. I used a 2-3 gpm injector with my 5.5 gpm machine and never had any problems.It also draws more soap. Most guys go with a smaller injector because we all use 200 feet or more of hose.

So should I order the 2-3 gpm injector and a 4gpm nozzle kit?

Alex @ Nothside Power Washing

Sent from my iPhone using Pressure Washing Resource

I would. The only problem is, you will lose some flow, unless you buy or make an injector bypass. You can ask Bob from ptek to set you up with that. The other alternative is to shut off the machine and remove the injector. You lose about a 1/2 gallon with the smaller injector. Do some searching on the forums. There is a lot of info on injectors and the problems that go along with them. I like every bit of flow I can get. Rinsing power is a an important part of efficient pressure cleaning.