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

[Richard L]

The FAV draws about 1A at 100% DC.

The transistor will take 3A quite easily. After soldering the new transistor, power the system up without the FAV connected. If it doesn't blow, then plug in the FAV.

[softic]

new transistor soldered with soldering iron and my hands grounded.
test pin 1 vs. ground pin resistance is around 16MOhm now, which seems to be correct.

tomorrow will do the test - in which sequence should I plug harnesses to find the problem?
first DI (user) and then FAV, right? or just FAV right after molex? anything to test after just molex connected?

sorry for soooo many questions - I have another track day on Thursday and want to fix my HFS-3 kit before I go there

[Richard L]

Connect the FAV last. Keep checking the pin1 and ground.

We are very close to get it to its original state. If everything works, not sure why the transistor failed.

I am here to help. I am very glad you are able to do all the electronic work.

[Richard L]

One thing you might like to check, the FAV cable is not damaged along the length.

[softic]

ok, checked with new transistor.
all worked fine for some period of time, but after few minutes the system started behaving in very strange way:
- the flow sensor showed some flow in accordance with current fuel IDC
- the pump motor in the trunk worked only for 1 second every minute
- the actual temperature on the intake was not reducing so I assume there was no actual flow (((

this all is very strange because right after installation of newly soldered the FAV worked perfect and there was a REAL methanol flow causing the real intake temperature decrease (from 40 deg down to 3-5 deg) and motor of the pump was working constantly during flow (I hear its noise which is quite loud)

now I took my mainboard back to home, disconnected it and measured impedance of some reference points:
- resistance between mainboard test pin #1 and ground is around 12MOhm
- resistance between transistor pins 2 and 1 is around 12MOhm
- resistance between transistor pins 2 and 3 is around 10-12MOhm
- resistance between transistor pins 1 and 3 is around 4.6kOhm (which I assume is very bad)

I'm getting a bit crazy of all this, especially when the system shows high methanol flow (up to 8 bars) while actual flow is not as big (if there is any).
Should I try buying and using electronic oscilloscope to check for some more diagrams?

[Richard L]

4.6Kohm between 1 and 3 is normal. It appears everything is looking good. You might have some air in the system or the FAV seal is playing up

I suggest purging the system, manual testing the system on the windshield. Please go one step at a time.

[softic]

good point, I will do both checks!

[Richard L]

I am staying with you as long as you need me.

The system has been off for a while with other works in the car. So good a good system check is advisable (mechanically). May be all you need to do is Purging the system and do a windshield spray test.

[softic]

Richard,

I am very glad and thankful for all your support during these days!
Finally the system seems to be functioning and I really see the water flow / temperature drop!

Today I have a very long circuit race event (3 hours track-day), so I will have all chances to test the fix.
After that is all is fine - we close this issue.

Thanks!
Alexey

[softic]

OMG, the result of properly working FAV is just amazing!
last week the lap time without WMI was 1:21.8, but yesterday it was 1:16.0 - very good achievement!

Richard, I would like to thank you for all your help!
the result I have achieved is worth of all the pain with diagnostics - you are the best!