Hardware setup for Hall sensor/LED17/Bosch Mod 139-PWM Idle
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Keithg
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Hardware setup for Hall sensor/LED17/Bosch Mod 139-PWM Idle
KeithG
Posted by email.
Bosch Mod 139
I just installed this combation in my car, only difference is Hall sensor mounted on the crank pulley with small 2 magnets.
I did my install as in schematics 2 ( outside wiring ), because I was afraid if I connected RHS of D9 with D8 (replaced with resistor) I would loose Stimulator funktion, when needed. I decided to connect pin 24 on the relay board to +12V inj2 through 1Kohm resistor (I use only INJ bank1). This way is everything outside the MSbox.
But maybe I am wrong on this one.
I have one question too. Keith, what dwell setting to use with "smart" Bosch module?
I use MsnS-extra 029q2 and I put Fixed duty cycle 75% for dwell, because there is not " no dwell control" option.
I have not tried to fire my car yet, but I am not sure about this.
Thanks for help,
Regards, Drazen
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Keithg
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Hardware setup for Hall sensor/LED17/Bosch Mod 139-PWM Idle
2) try both and see which is better. I did some measurements of the dizzy wheel and determined that the OE bosch dizzy produced a 60% DC pulsetrain. I also noted that my dwell control with 50% and 75% was not as consistent on the scope as I wished. Both should work. This is why a 124 module would be a better selection as MSnS-E 029 has very good dwell control. I got a hotter spark with the VB921 instead of the Bosch module, though that may have been a 'less than optimal' module. My experience... YMMV.
KeithG
Posted by email.
bosch module
I sort of chose 039 module because of simplicity (installation and dwell concerned), but I would definitely like to use direct coil drive with VB921 or dumb ignition modules ( eventually getting rid of distributer too).
I have pair of these Bosch modules together with coils that were used on Alfa Romeo Twin Spark engines. These cars had 60-2 wheel (not sure-lazy to count), and 2 distributers just for spark distribution to the appropriate cylinders. So these modules must be "dumb".
Do you reckon I could use one of these instead of Bosch 124 module?
Could you suggest some "safe" dwell settings to start with?
I really appreciate your help,
Regards, Drazen
Ignition Control Using LED17 as Spark Output (Hall Effect Distributor and a Bosch Mod 139 Ignitor)
Mod to Megasquirt controller/distributor/Bosch 139 Mod:
1) Run a wire from distributor signal to DB 37 pin 24
2) Remove R10 (resistor), D5 (diode), and D8 (diode or a jumper)
3) Replace D8 with a 1.3K to 2.0K ohm resistor
4) Jumper the RHS hole of D5 to XG1
5) Jumper the RHS of R9 to the bottom hole of R10
6) Jumper right-hand side of resistor R23 to negative leg of LED 17 using a 1K ohm resistor
7) Jumper negative leg of LED 17 (or the collector leg [3] of transistor Q9 [ZTX450]-> it shouldn’t matter) to X11.
9) Run a wire from Bosch Mod 139 pin 1 to negative side of coil
10) Run a wire from a switched power supply (powered when cranking also-like MS main relay) to Bosch Mod 139 pin 4
11) Run a wire from a switched power supply (powered when cranking also-like MS main relay) to the positive side of coil
12) Run a wire from Bosch Mod 139 pin 2 to ground
13) Run a wire from Bosch Mod 139 pin 3 to negative pin of the distributor
14) Run a wire from Bosch Mod 139 pin 5 to positive pin of the distributor
15) Deal with the setup values