Hi All,

I'm not terribly familiar with Water Injection, but the car I own came with one.
While I was pulling off parts, I noticed a huge amount of build-up and wasn't sure:

• Is this normal?
• Due to the prior owner not using Distilled water (I've only used distilled since ownership)
• Water Injection unit is faulty?

Cleaning this is looking like a pain...
Please help me diagnose this, thank you!

 

No advice about your issue but if you get a bucket of clr and let the throttle body sit in it for a few days or so, it will look new again. Suspend it in the bucket if you can so everything falls off

 

Looks to me like the oxidation you get when ally corrodes.
Methanol is very corrosive. Im going to go have a look at mine now!

 

I don’t know, maybe a combination of methanol and tap water...with occasional washer fluid thrown in? But that’s NOT normal.
I’ve been running pretty much distilled water only for over a dozen years and have nothing like that. Looked completely normal last I looked.
If you haven’t already, you might want to pull the IAC and IAT sensor as well.

 

what was the previous owner injecting sea water? I wonder how it looks in the UIM, LIM and motor!

 

Yea the UIM is the last picture.
It tapers off in the UIM, dissipating in the bottom port.

No idea what caused this.
My first impression was calcification or mineral buildup since it was chalky/powdery when I rub it off.

 

Looks like a combination of mineral deposits from tap water and some corrosion/pitting of the alloy.

 

That looks like the PO was using some very hard tap water, and/or too much methanol in his mix.

Not to thread hijack, but for those of you running a water/meth injection system, do you see any corrosion issues running just pure distilled H2O? Been thinking of WI, mainly just to bring the intake air temps down quicker after a heat soak condition.

 

6 months of watwer and meth with no corrosion so far. Definitely was used some bad tap water on those pictures above. I had always use boost juice though.
Get some WI and you will be more confident and happy about heat soak. You can't eliminate heat soak, but the engine will recover rather quicker.

 

^Short answer, no. See post #4.

OP, in addition to checking/replacing the IAT sensor and cleaning things up, be sure to follow the WI line back toward the reservoir. You’re looking for what SHOULD BE a filter and check-valve in the line. Along with the nozzle, they should replaced. Easy to do and not expensive.
WI is a great thing to have but the PO obviously was derelict. Don’t judge the value of WI by this.

 

Yeah the PO was running something weird through his system. I've been running plain windshield washer fluid (cheap blue stuff) for years with zero problems or anything, everything looks great in the throttle body.

Dale

 

Thanks all for the help and advise.
You guys definitely read my mind in how I was perceiving water injection!

I'm really fearing the disassembly of the TB.
Last time I tried dissemble of the TB on my prior RX7, I had a hell of a time getting the settings back right.

 

You may not have to fully dissemble it - just remove the TPS, and marinate the whole TB in a bath of CLR ("Calcium/Lime/Rust" - it's a cleaning product available just about anywhere) as described by cr-rex in the 2nd post. Read the CLR label first to verify what materials it's compatible with, but I don't think there should be any problems with the metals & plastic bits on a TB.

 

I might try something a little less aggressive first. Maybe a mix of two parts white vinegar/one part distilled water and a stiff toothbrush on the TB and butterflies. It’s probably going to discolor it regardless.
Figure a new TB gasket and O ring.

 

Im going to get flamed for this but the dishwasher works pretty good. I actually dishwashed my throttle body once. Got rid of all the scale that the pot-metal aluminium it's made of is prone to, and all the gold electro plated bits came out gold again.

 

Methanol is corrosive to aluminum. Water alone wont cause buildup like that. I normally just run water in my kit and have never seen anything like that in my throttle body.