problems with FAV solenoid - no work, but getting very hot! ::fixed::

[softic]

oooh... Richard, I am very sorry - I was typing my replies from Blackberry mobile and mistyped the voltage!
The voltage on PIN 1 is 0.1V on idle and from 0.5V to 1.4V on throttle after threshold is reached (I lowered down the threshold for more easy testing).

So there is NO 12V, but 1.4V maximum... sorry for this misleading typo
What to do in this case?

Do I get it right, that you use PIN 1 as transistor opening control voltage?
Or it is something else?

[Richard L]

OK, delete the other tests on my last email. Pin 1 is the PWM switch to ground by the transistor.

So pin 1 is 1.4V maximum after threshold.

Can you check the rest of the unsoldered pads on the circuit board where the blown transistor was. Voltage of pad 1, 2 and 3. 2= test pin1

[softic]

Duplicate message from mobile (((

[softic]

Ok, if all harnesses connected and solenoid is connected as well - I see 13.8V on trnsistor pin #2, 0V on tr. Pin #1 and some small (looks like transistor control PWM voltage) 0.2-1.8V on trnsistor's pin #3 (right one on your PCB picture)
What if I will just connect transistor's pins 1 and 2?
I assume this will power the solenoid and open the valve constantly, right? Should I check this?

[Richard L]

If you connect transistor pin 1 (power ground) and pin 2 together, the FAV will switch on. You can check this.

Can you check the black wire of the molex is connected to chassis ground securely.

[softic]

Richard,

When I connect pins 1 and 2 - I got system fully functioning, with maximum flow.
Also I have checked both black and white wires on molex - there is 0.1Ohm impedance between them and chassis ground.

I can try to solder one more transistor and check results.
Also, when I shortcut pins 1 and 2 the system works on full load for few seconds and then the 'water level' warning appears - why?

Regards,
Alexey

[Richard L]

The system ground is wired very well.

As far as the signal tests of the controller is concerned, there is no reason why the transistor should blow.

If you bridge 1 and 2, it produces full flow. But if this flow is outside the WL and WH, it will trigger the fail safe, hence the yellow led comes on. For the time being, just bridge the DFS jumper (disable failsafe) until we have sorted out the transistor.

What is the gauge bar reading when you bridge 1 & 2?

[softic]

Richard,

Gauge bar shows all 8 bars when pins 1 and 2 connected and threshold is exceeded.
Also sometimes it shows 1 bar on idle, but most likely this is because of vacuum pulling methanol from the opened FAV.

Any other checks before soldering (and probably burning) a new transistor? :-)

[Richard L]

If you see 8 bars across, you would have tripped the WH failsafe. I thought you would know that already over seven months of use.

When you do the test, you must put a nozzle or two and calibrate the SC to suit.

I still do not know why the transistor failed. Let me have an update. I suggest putting a new transistor in. Before careful. Mos transistors are very sensitive to static electricity. Make sure the soldering iron is grounded.

[softic]

good note about grounding - will do it this time.
actually I have checked resistance between pins 1 and 2 last time after soldering a new transistor - it was okay... can it be because of too big current?
I estimate the current through the transistor should be no more than 1A (assuming we have 14V on it and 16Ohm load on solenoid).

so I will solder a new transistor this evening and will check the result.