H2O / Meth injection losing flow signal

Shift518 Automotive
1

My 04 STI has a SMH / Labonte hybrid h20/meth injection setup. Its an SMH injection system with a Labonte MAF based controller and an Aquamist failsafe and gauge. As of recently the Aquamist gauge’s “S” indicator has been randomly cutting out… which, if my research is correct, means that i am losing connection to my flow sensor. When the “S” indicator is off and I get on it just enough to where the meth would normally kick in (only tested it once very carefully as to not cause damage to the engine) the “B” indicator blinked and the water injection blue LED got brighter which I believe meant that the controller was telling the system to spray… but the flow “meter” did no illuminate. So from what I can tell it seems like the problem is with the flow sensor.

The system utilizes the washer spray reservoir with the pump mounted directly to the reservoir. From there the line goes through a small gauge directly off the pump (I’m assuming pressure, but I haven’t really looked closely) then to a stainless steel line that goes under the IC and I can’t follow it from there without taking the IC off. I’m currently trying to locate a install manual / wire diagram for the SMH system but my pump has 4 wires coming off it, 2 on each side of the pump. There is a white and black wire coming off one side in which the white wire goes to ground. And the other side has a black and a red wire coming off it. This black wire is cut and re-routed to the MAF sensor. From what I can tell it seems like the flow sensor is possibly a part of the pump itself or it is mounted under the IC… not sure which.

So I guess my question is, does anyone have an install manual for a SMH system so I can get an idea of where the flow sensor is located. Or can anyone who has a similar setup point me in somewhat of the right direction as to where to continue looking for the issue and how I can test the different components. The only time the system kicks in is while driving (not sitting and revving the engine) which makes it difficult to test out the flow and see if I am actually flowing at all or not. A wire diagram of the system would help that way I could disconnect the injector somehow, send a 12v signal to the pump, and see if I am even spraying out of the pump.

Any ideas are greatly appreciated.

2

Somewhere I have the instruction manual for this setup. The AM flow sensor is inline with the main feed line to the nozzles. It “should” be installed within about 2-3 feet from the nozzles, and before any type of anti syphon solenoid.

The sensor is a small rectangle with two 1/4" quick disconnects. They should be taken apart and cleaned out every 10K miles or so. They have a small mag-trip plastic impeller in them that can wear out.

By pass the connection at the main controller and see if it solves the issue. If not, you know it’s no the sensor. I can take a look at it for you beginning of next week.

3

I’m thinking the sensor may need to be cleaned. I talked to Gus about it and he said that it had done it to him once before but went away and never happened again. I guess the sensor is directly under the intercooler… so it’ll be fun to get to… lol. I guess I’m not sure what you want me to do with bypassing the main controller? Are you talking mechanically or electronically? If you mean electronically then I’ll have to find a wire diagram for it.

4

i have a light grounded and hooked up to the pump 12v+ lead so when the pump turns on so does the light. but i also dont have it maf referenced. i have a simple on/off setup with a holley n2o safety switch working backwards off a vac line. normally set up for 7psi of fuel, now works with any positive pressure in the manifold. simple.