cleaning any of these components is a risky proposition, they are not built for cleaning, therefore replacement is the only surefire way to guarantee a correctly working component. trim valves, o2 sensors, fuel sensors, map sensors, all of them are so sensitive that any cleaning solution that has effective ingredients enough to clean them generally damages the internals to some degree so cleaning is not recommended. Brakecleaner is so caustic it basically has a severe reaction with just about everything it comes in contact with, especially plastic parts. Carburetor cleaner is not as caustic but still will damage these sensitive parts. Contact cleaner may be a safer solution because it is not near as caustic and does evaporate quickly but it's cleaning capability is limited and requires a larger amount of it.

Now as for 1badgirl's question about open and closed loop systems? Actually these newer systems utilize both, open versus closed is relative to the operation of the 02 sensor.
If you want to learn the basic operaton of this try looking here, it explains it fairly well: enginebasics.com/EFI%20Tuning/Closed%20Loop%20o2.html

Just copy and paste that link above in your browser url bar and it should take you to the site, i left the prefix off so the forum would not censor it.

Just an idea: would deionized water damage the injector ? For the sake of cleaning.

We are having a similar issue with a Yale. How do we tell the difference between OPEN loop and CLOSED loop?

The only cleaner recommended for these trim injectors is carb cleaner, brake clean will destroy them. I have had limited success cleaning theses injectors. Replacement is the best option.

I was told from a mechanic that I trust that soaking an injector overnight in diesel fuel is the industry standard method for cleaning gas fuel injectors...not sure about LP gas injectors though...I am experiencing hard starts and weird idle issues on my Yale. I'm wondering if my trim injector is failing. This is my thread for my Aisan unit and fuel issues:

https://www.forkliftaction.com/forum/thread.asp?trid=23062

Friends
Read Gram Information EF001
Troubleshooting Procedure for Mazda LPG Fuel Mixture DTCs
522655-1 and 522660-1.
It's an old issue.
NOTE: Confirm that the fuel injector orifice size is correct. It should be 2.0mm (0.077") for all
Fortens models equipped with 2.0L/2.2L Mazda LPG engines. Note that there were some fuel
injectors shipped from the parts depot with the incorrect orifice size. The incorrect injectors
have an orifice size of 1.4mm (0.055"). Replace if necessary. The improper stock has been
corrected at the parts depot.
clarification and ID details.
FFSS-13-X92 is 1.4mm (0.055") (1619123) Gold colour
FFST-13-X92 is 2.0mm (0.077") (1620009) Silver colour with blue dot on inlet tube

Same code came up on a Hyster H2.5 FT with 343 hrs on the clock. No problems except the code. I have always drained the converter each service with the Aisin type converters. It seems that only the Hyster & Yales make the oily residue as Toyotas don't. Back to the code , it occurred both times while I was servicing & had the engine idling for a while. Holding engine at high idle for 30 seconds cleared the fault.

Well I did try to clean it with carb cleaner, and there was a tremendous amount of crud in the line and filter housing, despite the fact that the FPR was recently rebuilt. sounds like it needs an injector and filter ,and the only dip-stick engine compartment was me then. Lesson learned and I will never forget it if thats what it turns out to be.

You may want to drain the oil from the vaporizer, there is a drain plug on the side torward the radiator it is 13mm socket size. Also don't try to clean the trim injector with gumout as this destroys the injector and I haven't found any cleaner that doesn't destroy the injector.

The Trim injector is for idle conditions. The coil should read 3.5-4.5 ohms. Connect 12 volts to injector and you should here a click each time it is connected. The fuel system converter should have a drain located on the battom left side that needs to be pulled every om to remove contaminants. There is also a inline filter just before the injector that may be clogged. Need to replace as cleaning rarely helps. Ensure you get the kit as the o-ring will come with it. You can insert a wire, about.05 size into the end of the injector to clean out while applying 50 psi thru it. Good Luck.