turbo2SE

iTrader: (1)

hey guys im going to list what i did off the top of my head that we have trouble shooted and see if you can see if i missed anything i can try next.

i finished the duel vr build on my megasquirt ,however no luck getting the car to start... Peter Florance is helping with the car and tuning. he confirmed the MS is working perfectly with the jim stim. i am getting a rpm signal , i am getting spark and fuel. and the timing is correct. im using a somewhat N/A map that has gotten the car running in the past with the missing tooth setup . and we made the changes over for the 2nd signal pickup.

im using pins 25 27 29 for the spark leading and trailings... AND pin 31 for the 2nd VR signal input
im looking at the FAQ and noticed is says to put the 2nd VR signal to the (UI or pin 11)? isnt pin 11 a ground? i do have the 2nd vr signal soldered into the JS8 . " can someone explain this further on the UI pin 11 thing? or am i correct to use pin 31 for my 2nd vr pickup???"

i have a V3.0 with ms1
stock cas no missing
running a j-spec turbo2 motor .

Jobro

iTrader: (2)

As soon as you can afford it, its time to move to mega2!

I only briefly had dual wheel working with mega1, then I threw in my mega2 chip.JS8 for megasquirt1 2nd vr input does sounds familiar.

I am using a greatly simplified version of the megasquirt VR sensor circuit. There will be no problems using db37 pin#31 as if I remember correctly its just for SPR4?

I'm pretty sure I have a 300R and 10nF across the 2nd VR sensors wires. The positive goes to a spare pin, then onto the proto area. I have an 18k in series with the VR+ signal, and then a smaller pF size cap across the VR+ to ground.

The output pin on the LM1815N has a 4.7k pullup resistor, and a 1k series resistor back into the megasquirt cpu pin. All thats remaining then is a few de coupling caps, I use 3, one in uF region, one in nF region, and one in pF region, these are straight across the LM1815N power and ground pins.

Well I set the LM1815N into zero crossing mode, by grounding the selection pin. Then you need decide whether you are using mode1,2 or 3. I'm pretty sure I'm using the adaptive mode still, so thats another R and C of whatever values is in the schematic.

If you want I can probably copy mine back into a diagram if you need it.

turbo2SE

iTrader: (1)

jobro im going to take a few pictures of the board i didnt use the proto area at all . i used this add on board http://www.jbperf.com/dual_VR/index.html.

forgot to add that i combined both the CAS grounds to pin 7 . spun the CAS by hand and i can hear both working correctly on the jim stim and on the car also. im going to look over the motor a little more and see what i can come up with cause i know we had this thing going with the missing tooth setup.

thanks for the responce.

pmrobert

Peter is very knowledgeable - what's his opinion? Do you have logs of your start attempts? The jbperf board has been very reliable in my experience(s), shouldn't be a problem.

-Mike

turbo2SE

iTrader: (1)

how do i post my datalogs? and or if i cant post it what am i looking for? peter hasnt had the chance to see my datalog yet and the weather isnt helping us much also....
once i get a good weather day ill get you guys an update on this matter.

pmrobert

An option that would get a greater number of knowledgeable eyes on your issue would be to restart this thread on msextra.com. Peter is usually present, I'm there as mike_robert. A look at your .msq and log would be very helpful and it's easy to post them at msextra.com.

-Mike

muythaibxr

I wouldn't ground the Ne and G grounds together for starters... I always run the ground for G to the lm1815 board as close to the chip as I can get it.

Other than that, if you have compression, spark, fuel, and air, you should have a running engine.

The pin 11 thing... The output of the lm1815 circuit should go through a 1k resistor to pin 11 on the CPU. IF that's not connected, the engine also won't run.

What do you have your trigger settings set to?

Ken

turbo2SE

iTrader: (1)

11 ,1 ,5, 7
no missing
rising only

changed the G- to pin 8 and the Ne- to pin 7 .

update for you guys. well good news the grounding fixed the problem. thanks for the help. however i lost all compression to rotor 1 so that will set me back in tuning date.... im going to have to rebuild the motor . i tried to see if i can free up the apex seals but with no luck on that so . its time for a rebuild heh. well im happy the car started up atleast =) time to save up for a rebuild kit now bah....

jamespond24

iTrader: (13)

But does it still work when you put both the negative wire together. Right now I don't have a 5 volt reading out of the ne+ nor the G+ output on the daughter board. Could the grounding be the problem?

pmrobert

Depending on how you built the LM1815 circuit, you may only get very short +5 pulses on the outputs of the LM1815. Are you scoping this or trying to measure with a meter?

jamespond24

iTrader: (13)

Measure it with a digital meter. When I put the stock ecu back in I get around 5volts when cranking so does this apply to the MS too?

pmrobert

The LM1815 circuits condition the output from the VR sensor. The VR sensors output a signal that first rises to a positive value then decreases, going past the "zero" line and sweeping negatively. The point where the VR signal is crossing the zero point occurs exactly when the tip of a wheel tooth is precisely the sensor in the CAS. Very nice for determining when and where a tooth is on a moving wheel but useless for a digital processor which only understands "on" or "off". The LM1815 interprets the VR sensor output such that the output of the LM1815 circuit abruptly changes state when the input of the LM1815 aka the raw VR sensor G and Ne wires, passes zero. The processor CAN easily read this signal which is a 5 volt square wave signal. The LM1815 circuit can be assembled (and often is) to produce a short pulse at VR zero crossing. This you almost certainly will not be able to see or reliably detect without a scope. Attached is a scope shot for illustrative purposes.

jamespond24

iTrader: (13)

Can I turn the ignition to ON and turn the CAS to see if there's a pulse on the injectors and spark? I did this on the stock S5 T2 ecu and it is fine but when I did the same to the MS is didn't give me any spark. Also please take it easy on me I'm a noob

pmrobert

Yes, that's an excellent way to check and see if all is wired/set correctly. Personally, I wouldn't attempt a start without doing this or checking things on a proper stim. A mistimed spark can break apex seals, stuck injectors can wash oil off the housing walls, etc., etc. Please understand I'm not being hard on you or critical in any way and am willing to help you - I'm way too old to play the high school games so many people seem to enjoy. I'd be happy to look at your .msq and logs - PM me for contact info.

-Mike

jamespond24

iTrader: (13)

No you're not being critical at all I just very new at this stuff and still learn the words and terms. Pm'ed you.

Thanks

turbo2SE

iTrader: (1)

just wanted to see if this looks correct to everyone that has done the duel vr. this is how i have mine wired up right now but i cant try to start the car again since i have the motor torn apart now for the rebuild did you guys want pics of my board as well to double check that as well??
get back with me on this guys thanks again.