44-2-2 flywheel and bosch 139, engine running.

JTbo · Post by **JTbo** » Sat Mar 18, 2006 11:13 am

I thought to let others know how this works out as I have read lot of maybe and perhaps from many places.

Car has this 'weird' 44-2-2 flywheel (2 sections with both missing 2 holes, that are 180-degrees apart each other 1st at 90BTDC) and VR-sensor reads those holes in it. It had stock Renix ignition system.
4 Cylinder engine Volvo B200K that is converted to Megasquirt Fuel Injection from carb setup.

I'm running MS-I v2.2 board and extra code version 29j

I have made now lm1815 based circuit as described in MSnS-E site and installed it to car and got car running too.

Here is settings I did use to make car start:
Wheel decoder base teeth = 22
2nd trigger = off
Trig pos A = 3
Trig Return Pos A = 11

Spark Settings:
Trigger Angle = 65
Cranking timing = Trigger Return
Hold Ignition = 0
Spark output inverted = No
EXPERIMENTAL Oddfire = No
Fixed Angle = -10
Trim Angle = 0

Constants page set as you would without ignition control, rpm is NOT doubled and does not need to divide by 2.

Car started and I let it idle until fully warmed, car's rpm gauge and gauge in megatune shows same rpm, car's gauge connected to coil (-).

Maybe this helps someone that has Renix ignition, Jeep, Renault and Volvo are at least known to have this kind of ignition, jeep just has different flywheel (6 cyl engine, principle should be same), some Renault 5 models had this wheel too.

I tried to write this so that search would find this post better, sorry if it makes it bit odd to read ;)

M_US_E30 · Post by **M_US_E30** » Sat Mar 18, 2006 1:57 pm

What about a motronic with 113 teeth and three dowels 120deg apart? Could it work on this?

Tony

Post by **jsmcortina** » Sat Mar 18, 2006 2:40 pm

113 teeth on the crank is too many for the wheel decoders in MS1/Extra or MS2.

James

JTbo · Post by **JTbo** » Sun Mar 19, 2006 6:27 am

Little update, need to use 24s9 style wheel decoder as 25 style wheel decoder goes crazy around 2300-2500rpm, with 24s9 style wheel decoder it goes crazy around 5000rpm, I'm not sure what causes this, but must search solution.

Revs start jump to 32000rpm after 5000rpm, other that that there is not even small jumps, rpm signal looks very nice.

GeorgeGt · Post by **GeorgeGt** » Mon Mar 20, 2006 7:10 am

if u get some funny revs reading , then try to load ur vr sensor with resistor , i cured mine with 330 ohm resistor.

JTbo · Post by **JTbo** » Mon Mar 20, 2006 9:18 am

GeorgeGt wrote:if u get some funny revs reading , then try to load ur vr sensor with resistor , i cured mine with 330 ohm resistor.

I installed today 390 ohm resistor between VR-input and ground as described in extra code's page.

Now I have got few rpm spikes to my datalog, but not 32000rpm or so. However now there is more of these spikes, here is url where you can see those:

http://www.janiervast.com/gallery/v/alb ... _problems/

I did put whole datalog there too, there is perhaps few other funny things, but rpm and spark are those that are important.
I'm currently running without accel enrich and fuel map is not right, also I need to replace bias resistors, minor things.

I'm now not sure what these two RPM readings are, I believe that one of them is wheel decoder (ie. what megasquirt takes in) and other is what megasquirt sends out, but which one is what?

Anyway, usually it is RPM that is graphed that spikes, but when revs go over 5000 you can see that it is other rpm that spikes.

For example, position 3102.711 seconds, suddenly rpm goes from 51 to 60 and immediately back to 51, other rpm goes from 5127 to 5172 and then returns to 5133.

But position 3092.838 seconds only one rpm changes, from 1516 it jumps to 4113 and then returns to 1482. Other rpm is 15 and goes to 14 and stays there as it should.

Looks like that these two rpm are not related to each other when spikes occur as usually only one spikes at time.

I have set soft limiter to 6000 and hard limiter to 6200 so that is where it cuts spark.

I'm going to test shielded wires, but now I'm thinking that perhaps I should test other resistor value?
However I'm not very good in electronics so I have no idea what value I should try, I don't even understand what this resistor does?
Does it make Vr-signal weaker or just shape it somehow?

I have those 390 ohm resistors, next is 4700 ohm, that may be bit too much? Of course I could try to put two 390 ohm resistors, that would be only 780 ohms, but maybe that is too much too?

Here is no electronics shops near so I need to order all parts by mail, so I think I will order resistors at same time as shielded wires etc. stuff, just need to find out those resistor values first

JTbo · Post by **JTbo** » Wed Mar 22, 2006 4:17 pm

Well, at least 4700ohm resistor did not change a lot, maybe bit more spikes, but that is all.

I don't know if I'm even connecting resitor properly as it seem not to do much, one end of resistor is in vr-input of lm1815 circuit and another end is put to ground, same point where lm1815 circuit ground is.

But maybe I should put this resistor between two wires of VR-sensor? Is there difference as other wire is connected to ground and other to lm1815 circuit, only difference is 15cm in location as how I understand it?

Now I'm waiting for new wires that are shielded to arrive, maybe answer is in there.