woldson Posted February 28, 2007 Share Posted February 28, 2007 yep that is where i found it, but you have to reference the left image to the writing on the right weird, must of been an engineer that wrote it:) Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted February 28, 2007 Author Share Posted February 28, 2007 Sorry guys. i've given up.. I have tried EVERYTHING I double checked.. and tripple checked and quadrople checked the wiring .. everything is correct.. just the damn thing is NOT working. I can only assume its a bad FET or a bad X4 output.. which is nearly impossible to measure due to the pulsewidth modulation. So maybe I will order a new FET.. but i've given up.. trust me when I say i have tried everything.. Quote Link to comment Share on other sites More sharing options...
z-ya Posted February 28, 2007 Share Posted February 28, 2007 Did you load the latest Extra code? At some point I plan on using the boost control feature, and I will probably try to test it on the bench first. When I have some results, I'll let people know. It is kind of low on the priority list at this point, but I may get inspired over the next few weeks. Quote Link to comment Share on other sites More sharing options...
Bernardd Posted March 1, 2007 Share Posted March 1, 2007 Damn I really hoped you'd get it. Did you contact the dude with the successful boost control on the volvo board? Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted March 1, 2007 Author Share Posted March 1, 2007 I did not.. I am still running 021u.. maybe upgrading the MS version might help.. any ideas on how to test the FET? Quote Link to comment Share on other sites More sharing options...
z-ya Posted March 1, 2007 Share Posted March 1, 2007 Yes, test the FET by first disconnecting the gate from the circuit. If you pullup the gate to +5V using a 10K or so Ohm resistor, the coil in the valve should energize. If you tie the gate to ground, the valve should turn off. The gate acts like a switch, allowing current to flow from the drain to source. In other words, when the gate is high (+5V), there will be a low reistance between the source and drain pins. When the gate is low (ground), the reistance between the source and drain pins should be extremely high (not enough current flow to turn on valve). Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted March 1, 2007 Author Share Posted March 1, 2007 Hmmm.. i was talking to Rboyd (loose screws) who used to be a member on here who actually had Megasquirt and a functional Boost control... he had a bad FET injector driver.. and it locked the injectors open (e.g. grounded them) Soo I could simply have a bad FET! I guess they fail often. Quote Link to comment Share on other sites More sharing options...
datman Posted March 1, 2007 Share Posted March 1, 2007 You could place a 12v lamp in place of the valve for testing just to see what's going on, as Z-ya mentioned try a pullup on the gate to control the lamp Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted March 1, 2007 Author Share Posted March 1, 2007 Datman what do you mean?! Ya mean I should apply a 12v source on the "gate" terminal which Megasquirt would normally apply out of the X4 output correct?! Quote Link to comment Share on other sites More sharing options...
datman Posted March 1, 2007 Share Posted March 1, 2007 If you look at post #46 Z-ya explains how to do it. You need to connect a 10k resistor or similar to the gate pin and the other end of the resistor to +12 this will allow currrent to flow across the drain and source, if you place a lamp where the valve would usually be you should see it light up...if you had the MS connected and controlling it you would see the lamp change brightness depending on the voltage applied to the gate pin. Make sure you disconnect the FET from the MS before you start connecting pullup resistors to the gate pin Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted March 2, 2007 Author Share Posted March 2, 2007 alright guys.. I will be testing the FET on saturday morning before I head off to work.. i appologize for the rediculously long wait!! School and work and snow storms combined = slow car progress Datman.. when you say "lamp" do you mean hook up a small LED or a light?! maybe it's the UK terminology lol Quote Link to comment Share on other sites More sharing options...
datman Posted March 2, 2007 Share Posted March 2, 2007 I was going to use the word bulb but thought you guys called them lamps a 12v bulb from a car brake light or indicator will do. Quote Link to comment Share on other sites More sharing options...
z-ya Posted March 2, 2007 Share Posted March 2, 2007 I'd pull it to +5V from the regulator in the MS, not +12v. Also, you just need a multimeter to measure the resistance between the source and drain. Quote Link to comment Share on other sites More sharing options...
mobythevan Posted March 2, 2007 Share Posted March 2, 2007 Dumb question here, but how did you physically connect the FET to X4? I don't remember X4 being connected to anything on the v2.2 pcb, so you have to solder onto the pcb pad to use it right?(it is not connected to the DB37) I could be wrong, and I haven't kept up on this thread too good, so maybe you mentioned the setup already. Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted March 2, 2007 Author Share Posted March 2, 2007 Gate (pin1) has a small wire soldered onto it, and it leads to the X4 output on the PCB2.0 board. It is soldered to only X4 and I made sure there was no other contact. The wire has a 100ohm resistor inline from the FET to the X4 output. The wire leading from the GATE on the FET also has a 10k resistor to the Source (ground) wire Basically identical to this Gate (pin1) is the yellow wire, it goes to X4. I connected it to the gray wire using a 10K resistor, then after that I installed a 100ohm resistor inline, it's under the heatshrink. Drain (pin2) is the white wire, it goes to X12 which goes to pin 27 on the DB37 connector. From there I have a wire going out the DB37 connector to the blue (or black) wire on the solenoid. Source (pin3) is the grey wire, it goes to the ground pad of the missing D1 diode. I've confirmed that this is a common board ground. Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted March 28, 2007 Author Share Posted March 28, 2007 I went ahead and updated post #24 with pictures. I still cant figure this out Quote Link to comment Share on other sites More sharing options...
mobythevan Posted April 5, 2007 Share Posted April 5, 2007 Did you get a chance to try using an LED to indicate when the FET switches on/off? I would do that and not even hook up the solenoid/valve. Put the LED in place of the solenoid with a resistor to limit current. So X12 to resistor, otherside resistor to band on LED, other side LED to 12 volts. Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted April 6, 2007 Author Share Posted April 6, 2007 thats a good idea Bryan!! that way I can keep the LED in the car and see if it turns on! great idea! what kind of resistor should I use?! would a 1/4watt 470ohm work?? i have several spares Quote Link to comment Share on other sites More sharing options...
mobythevan Posted April 6, 2007 Share Posted April 6, 2007 470 or 330 ohm woud be good Quote Link to comment Share on other sites More sharing options...
z-ya Posted April 6, 2007 Share Posted April 6, 2007 Depending on the frequency at which the FET switches, you may not see the LED blink. The human eye can not even see 60Hz! I'm sure the PWM rate on the boost controller FET is much higher than what the eye can see. The LED will most likely appear on, but slightly dim. Quote Link to comment Share on other sites More sharing options...
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