Megasquirt users thread to discuss all things Squirty

[nuk1ear]

i have the crank as falling and cam as raising. Maybe i should swap them around and see what happens. Is it a problem that i have both cam and crank wires in the same seethed cable? total 3 wires, 1 ground (its shared in the dizzy as im sure u know with the 20v) and 2 signal wires.

check out my latest logs of the composite logger showing the input signals.
http://www.msextra.com/forums/viewto...?f=131&t=46054

such a mess, not sure whats going on, maybe interference from the crank signal?

[oldcorollas]

i thought you'd want falling, as the zero crossing point happens at same time regardless of speed? (need to check the voltge goes +ve then -ve.. and if not, swap the wires around)
if one is rising and other is falling, they their relative timing (in degrees) will change with RPM... which could be giving the sync errors?

same cable should be ok.

"either way it doesn't explain how the car would start this morning and idle and run perfectly fine, then later on it won't idle and it won't start unless i crank it for a couple of seconds, then flood clear and it will start."
leaky injector??

also.. are you 200% sure you have the coils firing in the right order??

[nuk1ear]

yeh pretty sure coils are correct order. I checked them on a bench test before installing the wire harness to the car using TS ouput test mode. Checked injectors and coils (using spark plugs in the coil packs to ensure they fired too) and everything was as expected.

I had an injectors issue, injector was open 100% of the time. This was because of a dead transistor on the peak and hold driver. Fixed that. If you look at my cranking composite logs you will see a completely insane and wrong input signal lol. The cam and crank are basically giving the same signal. Ill be checking my wiring and ensuring that my MS3 and MSx are set correctly for VR sensors and not hall effect.

Any other tips welcome!!!! Im not sure about the raising and falling thing tho. If you look at this link:
http://www.diyautotune.com/tech_arti...t_vr_index.htm
you can see that they clearly say using opposite triggers for crank/cam is ok. Also, If you check all my composite logs, i tried with all possible combinations of triggers for crank and cam and they all presented basically the same log. Only time it changed was when using the noise filter

[oldcorollas]

hmm, if the VR conditioner output goes high at the zero crossing, then waits a bit and goes low... then you'd want it to trigger on the rising edge?
basically you want it to trigger at the zero crossing?

i think.... but i can't remember properly...

and give battery a charge... low voltage can do whacky things also..


is triggering voltage too low? ie crank and cam are triggering on the nboise from theother sensor, as well as their actual signal?
can get your hands on a dual trace O-scope?

[nuk1ear]

I dont think ill be able to get my hands on one, ill just start with the basics as i said:
-check wiring
-check correct jumper arrangements for VR setup and charge battery

then maybe ill turn the VR conditioners on the cam if nothing else works.

[knightrous]

Can you do a tooth log while cranking?

Looking at your logs, your sync 11 error seems to be the same as my issue. The second trigger (CAM) is triggering too early.
Googling up some pics of a 3SGTE distributor led me to this

This has the funky snail cam shape on the G wheel (second trigger / CAM) like my 20V distributor.
For this you will definitely need to run with these settings.


Check that you are using the correct pickup as well. If your using G1 instead of G2 (or vice versa) you'll end up with wierd results (or requiring large 360+ degree BTDC tooth degree). Also check that you have fueling setup for 1 squirt per cycle when you have sequential fuel enabled, it will run like a WRX if you have it set to 2 squirts

[nuk1ear]

Thanks for that, but ur only showing the cam wheel trigger setting, im on MS3+MSx, what edge do u have the crank triggering on?

Also, if you check my post on the megasquirt forums, u can see i posted composite logs of all 4 different trigger edge setups for both crank and cam combinations. No differences. Only when i added noise filtering did anything change.

ALSO, its possible i wired up the CAM trigger to G1 sensor (G2 i used for crank). This could messs SHIIIIT up and show those logs i think!

[knightrous]

G1 and G2 are both sensors for the 1 tooth G wheel, both are for detecting the CAM, you need to use NE (24 tooth) for the Crank.
There is more info on how the Nippon Denso dizzy's work here:
http://msextra.com/doc/ms3/trigger-wheel.html#nippon

[nuk1ear]

ah yeh sorry, it was a while ago when i did it. As i said, ill check my wiring first. If its fine, then maybe i should fiddle with the hysterisis resistors on the boards? It looks to me like im getting 1 good signal, but the other has so much noise.

[knightrous]

Do you have a 57K resistor on the CAM input?
I had to put that on my DIYPNP before the CAM sensor would detect properly.

[knightrous]

Do you have a 57K resistor on the CAM input?
I had to put that on my DIYPNP before the CAM sensor would detect properly.

[nuk1ear]

no i dont, i have it exactly as the manual says, JP7 on the MSx board should just be left unjumpered for VR sensors, only jumper for hall etc. Do you mean the hysteresis or input resistant variable resistor pots? I have both the crank ones and cam input ones set fully CCW as the manual says. I could add some resistance to the cam input and see what happens.

[knightrous]

http://www.diyautotune.com/diypnp/do..._assembly.html

Cam Adjust: This lets you change the trigger voltage on the VR2 input. R20 increases the threshold trigger voltage, R21 decreases the threshold trigger voltage, and R39 can be adjusted to move it either way. If you already have information on what works for your sensors, solder a fixed resistor to either R21 or R20 as documentation recommends. For example, most Nippondenso ignitions work best with a 51K resistor in the R21 slot and R20 empty. If you're having triggering problems and want to be able to adjust this yourself, leave R20 and R21 empty. Install R39 and adjust as needed to get a clean signal.

You might need to remove the adjusting pot that handles the trigger threshold and replace it with a 51K resistor. It might be worth asking on the MS Extra forums about this for further clarity.

[nuk1ear]

Well this is embarrassing, and ill take all the abuse i deserve lol.

Main Plug
Pin 1-> should be G- (nothing was wired here)
Pin 24-> should be NE (G- was wired to here)
Pin 8-> should be nothing (NE was wired here)

Cam signal was wired correctly on Plug 2.

Pin 8 is still a ground, hence the crank signal would work just opposite polarity right? But the cam signal has no effective ground correct, as it would want to ground to pin 24, which is not an internal ground in the MS unit....

Shame on me

[oldcorollas]

good work on finding it out before burning the car

and you've provided another bunch of data points for the MS fault finder gurus