Assembly guide – megasquirt(r) v3.0 main board electricity use


Note that on current production boards, there is no jumper to connect/not-connect +5V to pin #9 on the serial connector. It has 5 Volts all the time. This is normally okay, however with MegaView there is a problem. Pin #9 goes into a dead short on the MegaView board. The quickest solution is to cut pin 9 off on the connector or cut the wire for pin 9 on the cable – its not needed for anything. z gas guatemala In future revisions we will put a jumper on the supply to pin #9 for bluetooth wireless devices. If your main board has that jumper, you do not need to do anything other than remove the jumper to use MegaView.

corresponding to the PCB silk screen. The socket must be installed from the top of the board, and soldered from the bottom side. To prevent the socket from falling out while you turn the board upside down and solder, you can use a bit of scotch tape across the socket to hold it in place (this works for many of the ICs and some other components). Carefully solder the socket, and inspect each solder joint for shorts (to adjacent pins) or cold joints (solder applied to a joint the isn’t hot enough to flow properly, typically they won’t have a

41. Plug the stimulator into the ECU. On the PC using TunerStudioMS, right click on any of the gauges on the opening screen, and select the ‘Clock’ gauge. This brings up a new gauge in place of the previous one. (Note that if you have MS-II 2.8+ code, you may have to set the ‘ECU Type’ under ‘Fuel Set-Up/General’ otherwise all other menu items may be ‘greyed out’.) The clock should be counting up, incrementing every second (it will roll over at the value of 255 for MS-I or 65535 for MS-II™ controllers, then go back to zero). If the seconds count is there, you are running! If not, check the cable, make sure there is power, and check the COM port. The only other value on

Note: R11 and R10 form part of the EGO input circuit (with C10). It is very important that you do NOT install a capacitor across the sensor input before R11 (C10 comes after R10 and R11 and is fine). Some people have recommended adding such a capacitor to ‘smooth’ the sensor input. This will cause problems, especially with wide band analog outputs such as you find on Innovate’s LC-1.

This input circuit is also used – with the modifications below – if you want to trigger off the negative side of the coil, since the points control the negative side of the coil’s primary circuit. However, you can only trigger off the coil’s negative terminal if you are NOT trying to control ignition timing. Do either 50a or 50b, not both.

• In the place of D2, install a 22V or 24V Zener diode { 1N4748A-ND}, in the reverse of the indicted orientation (i.e., put the band at the other end rather than that indicated on the silk screen). Note that the stim will not be able to send a signal through this diode. If you have installed it, jumper it for operating on the stim. Later, when MegaSquirt ® is installed in the vehicle, you should remove the jumper. If you find that the tach signal sometimes jumps too high (20000 rpm or more) you can either replace the D2 Zener with one having a higher voltage rating (28, 32 or 36 Volts), or add one or more 5.6 Volt or higher Zener diodes in series into the tach input wire to DB37 pin #24 (the banded end of the diode(s) should be closest to the negative coil terminal).

These are the trimmer potentiometers used to ‘tune’ the VR circuit. gas x tablets himalaya The longest lead (and/or the one nearest the "1" imprinted on the case, depending on where you got your components) on each pot should go in the square pad closest to the heat sink. R52 is used to adjust the hysteresis, R56 is used to adjust the zero-crossing point. For VR sensor operation, the pot on

Note: A 399-4202-ND 0.001 µF capacitor should be substituted if MegaSquirt will be receiving higher frequency tach inputs. The smaller capacitor helps to maintain the signal integrity and timing. This 0.001 µF capacitor is especially useful for high tooth count wheels including all crank wheels that have more than one pulse per ignition event such as the popular 36-1 or 60-2 missing tooth crank wheels.• Install and solder C32 { 399-4326-ND, 0.01µF, 103 marking}. This is below C31, further from the heat sink. (Note that in some cases, if you experience tach related issues, you can try removing this capacitor.)

located beside D24 (which you just installed), closer to the heat sink. The side of Q22 & Q23 with the rounded edges (i.e., the shorter of the two flat sides) is referred to as the ’rounded side’, and it goes away from the CPU for both Q22 and Q23. If you imagined the side that had rounded corners was completely round, then it would match the PCB silkscreen. Be VERY careful when soldering these, the pin

before attempting this. gas in back symptoms If you do accidentally bridge the leads with solder, you can use a piece of solder wick (which is a fine braided copper ribbon) and a hot soldering iron to remove the excess solder. Note: if you got your kit from a distributor, be sure to follow any instruction they have supplied for these parts!• Install and solder U7 { LM2904NFS-ND}. This is located

You may also need to do this if the Hall sensor input is noisy in the vehicle. To reduce noise, run the ground from the Hall sensor to one of the jumper slots on the DB-37 connector (like DB37 pin #6 for SPR4), then connect SPR4 to XG1. Remove the jumper to XG2. (Note that you will have to ground XG1 with a jumper wire to run on the stim.) Twist the signal wire (DB37 pin #24) and ground wire (DB37 pin #6) together all the way to the ignition module, this will further reduce noise in the signal.

To avoid changing the tables in the MegaSquirt ® code with EasyTherm, the bias resistors at R4 and R7 should have a value equal to that of the thermistor sensor you will be using when it is at 81° Fahrenheit, 27° Celsius. However, the preferred method is to use EasyTherm (with MS-I) or ‘Calibrate Thermistor Tables’ in the tuning software (with MS-II) whenever possible.

First, look at the RPM – it should change when you move the RPM pots on the stimulator. Note that if you have installed the VR input circuit jumpers in step #52, the stim is not currently designed to put out the sort of signal (AC) the VR circuit expects. However, by adjusting the pots at R52 and R56, you might be able to get a useable signal into MegaSquirt. The RPM may not be stable at each end of 1000-6500 range, but it should be workable over that range, at least. Then you’ll know that the rpm input circuit is functioning at it should.

62. Install and solder the transistors Q2 and Q4 { ZTX450-ND}. These are located to the left of the MOV1. The side of the transistor with the white label faces the DB37 connector. gas efficient cars If you got this transistor from a distributor (as part of a kit) then they likely have special instructions for it (search the packaging or contact the distributor). Distributors sometimes make substitutions for various reasons, and thus their notes are important. If your Q2/Q4 are the standard Digi-Key part { ZTX450-ND}, but don’t have a white label, then the side with the rounded edges is the ‘curved side’, which is oriented to be closest to the DB37 connector.

injector LEDs light up, tracking the RPM. ( Note that if you have installed the VR input circuit jumpers in step #52, the stim is not currently designed to put out the sort of signal (AC) the VR circuit expects. However, by adjusting the pots at R52 and R56, you might be able to get a useable signal into MegaSquirt. The RPM may not be stable at each end of 1000-6500 range, but it should be workable over that range, at least. Then you’ll know that the rpm input circuit is functioning at it should.) Also, the fuel pump light should be

Note: normal MAP readings in kPa for the MegaSquirt controller when the engine is not running (or is on the stimulator) should be somewhere around 85-103, depending on your elevation. You can check the tuning section of this manual for the details of how pressure varies with elevation. This is a good time to clean the excess flux from the board. A common problem with boards that were working and quit for no apparent reason is flux residue. Remove the processor. Wash your board with:

Lightly scrub both sides of the PCB with an old toothbrush. When cleaning flux, it is sometimes impossible to wash it all off, some of it has to be scraped lightly to remove it. Use a round toothpick broken in half for scraping the tough parts. This gives a small pointy end and large end to work with and reduces the chance of damaging the PCB. Be very careful not to damage the silk screen or traces. b games car Rinse the PCB in hot water, then allow the PCB to dry completely. There should be very little haze left once it dries.

If you want to seal the finished board, use a conformal coating. Wait until you have tested the board thoroughly though. If you do not think you will be doing much repair work on the board, you can not beat silicone conformal coating. electricity vampires It does require some digging to get it off for repair, however. Avoid the urethane coatings, as they are considered permanent and are a pain to try to work through.

You can also buy a spray can of acrylic lacquer conformal coating at most local electronics suppliers for around $10.00. If you are going to be working the board, "Krylon Krystal" clear spray works very well. Several coatings, preferably baked at 175-200 degrees in between. This should slow down or prevent "solder bloom" and other deterioration of the PCB. Condensation is a fact of life for an outdoor component undergoing temperature changes. You can solder right through the stuff and the residue cleans well with pure grain alcohol.

The recommended place to install the MegaSquirt ® box is in the passenger compartment (like under the seat, kick panel, etc), this is where many OEM boxes are located. In addition, you will need access to the RS-232 serial connector for tuning, which is hard to access under the engine hood. If you put the MegaSquirt box in the passenger compartment, you will not have heat-related problems (unless you mount it directly in the path of the air stream of the car heater).

Note that MegaSquirt ® is a bank fire injection system, you connect half the injectors to the driver for one bank (pins 32/33), the other half to the other driver (34/35) [4 are shown]. See: the FAQ. You can connect them in any order. For troubleshooting ease, having each bank on a separate driver might help. However, you might want to separate them into alternates in the firing order, which some people have claimed is theoretically slightly beneficial. As an example, on V8s with bank fire systems, manufacturers typically run one bank off one driver, regardless of the firing order. The advantage of doing it that way is it makes troubleshooting easier.

All MegaSquirt ® installations must have an input ( tach) signal to determine engine speed. This signal comes in on pin #24 of the DB37. A variable reluctor (VR) input ( tach) sensor is shown ( above) for the input. To use a Hall sensor, optical sensor, or points trigger, you connect the signal to the same input pin (DB37 #24) as the VR sensor. You must ground the VR other lead of the sensor as well, and pin #7 is shown for this (though pin #2 can also be used). However, pin 7 is not a ‘dedicated’ or specialized ground for the VR sensor, it just happens to be a ground (the next revision of the PCB will have a dedicated ground for the VR circuit on DB37 pin #2, so use pin #2 if you think you might upgrade at any point).

Pin #19 is the sensor ground. If you have two wire CLT and IAT sensors, their grounds (and the TPS ground) should run back to the DB37’s pin #19 to reduce the potential for noise in the sensor signals. There should be no continuity between the chassis ground and DB37 harness pin #19 when the controller is disconnected from the DB37. hp gas online registration This ensures that the sensors are grounded directly to the controller, reducing the chance of inducing electrical noise in the signals.

The DB37 pin #36 is an output, used to control an ignition module, or control a coil directly (if the high current ignition driver circuit is installed). It only needs to be connected if you are controlling ignition timing and dwell. The ignition control signal from MegaSquirt-II on DB37 pin#36 corresponds to the relay board pin S5 of the 20 position terminal strip.