no sync loss at idle but on rpm

[sheek]

car in question is a diahatsu charade gtti with a 4efte engine swap with all stock sensors

i wired up the car using NE for the crank and g1 for the cam input

running the latest alpa 5 firmware as well as trying the 1.4.1 released firmware.

tried with noise filtering both off and on on the crank and cam with no help, played with both pots on both ms3.0 and ms3.57 board.


the issue is the car will idle perfect but as soon as i give throttle it will report massive sync loss which increments from 0 to 255 and repeat as long as i am on throttle. this causes the car to not rev out. also when i lock the timing it is stable at idle but as soon as i touch the trouble it advances off the scale. (not good for a turbo car)

now here's the kicker. plugged in a friend's ms2 on which he was tuned on and with a slight adjustment of fuel car runs fine. 0 sync loss and revs right out.


configured the car for VR as the manual states and using the ms3x board for cam input and spark A for ignition


attached some logs with car at idle for first 5 secs then throttle for both composite and tooth logger

[sheek]

other things i have tried

move ms grounding from chassis to intake manifold

played with rising and falling settings on both cam and crank

moved cam input from g1 to g2

[sheek]

https://spaces.hightail.com/receive/Uou ... FpbC5jb20=

video

[billr]

Post a run log (MSL file).

[sheek]

RUNNING LOG.msl

attached a running log
idle and then revving

[sheek]

anything jump out at anyone?

[Matt Cramer]

I'm seeing noise on the cam trigger. If this is an MS3X, try adjusting the MS3X card's VR trim pots.

[billr]

The "req_fuel" is pretty far off, and I get a bunch of errors listed when I load the MSQ, but I don't think those are causing the poor cam signal problem.

I am unfamiliar with the "NE", "g1", and "g2" input designations. Are those unique to the Diahatsu, or is that something about MS V3.0/3.57 that I need to learn?

[Matt Cramer]

I am unfamiliar with the "NE", "g1", and "g2" input designations. Are those unique to the Diahatsu, or is that something about MS V3.0/3.57 that I need to learn?

This terminology is pretty common with Toyota and related ignitions.

NE = primary RPM signal. Usually a 24 tooth cam wheel or 12 tooth crank wheel. Later engines used the same designation for a 36-2 crank wheel (NOT 34-2 or 32-2; for some reason its tooth count causes more confusion than any other OEM trigger wheel). Some early implementations used this for a four tooth wheel.

G or G1 = what the MS generally calls a cam sensor. This usually triggers once per cam rotation, but there are other variations, including one tooth per cylinder on some batch fire designs or three unequally spaced teeth on VVTi motors.

G2 = secondary cam sensor, 180 cam degrees away from G1. Not used on all installations.

[sheek]

I'm seeing noise on the cam trigger. If this is an MS3X, try adjusting the MS3X card's VR trim pots.

i have adjusted both pots in both directions and the problems still persist
should i try adjusting cw or ccw?

i did both

[sheek]

hi there.. me again

i have modified the distributor by grinding off the teeth turning it into a 12-1 wheel. while i no longer get sync loss, im still getting severly retarded ignition while in fixed timing mode. im also finding it difficult to sync the ecu to the actual timing.


swapped over from my board to a friend's mainboard and the issue is exactly the same.

any ideas?

[sheek]

attached the new msq and new composite and tooth logs

thank you

[grom_e30]

see the double tooth for the missing area looks like the wrong capture edge to me

[sheek]

i tried both edges for capture and get the same issues

[sheek]

added different logs with same name

[grom_e30]

this second tooth log looks much better no more double long tooth, but there is some noise where the signal picks up extra teeth on page 15 may need to adjust the pots on the mainboard for that one

[sheek]

i adjusted the pots but the symptoms remain. what would cause a tooth wheeled pickup to not be able to synch timing withe the strobe and retard the timing on rev when in fixed mode?

[jsmcortina]

i adjusted the pots but the symptoms remain. what would cause a tooth wheeled pickup to not be able to synch timing withe the strobe and retard the timing on rev when in fixed mode?

Ignition capture backwards.

James

[sheek]

first let me apologise to the group, when i read over my update i noticed i said retarded but infact the timing is advancing on its own when revving with fixed timing. i set the fixed timing to minus 10 and the car revs better which identifies that somehow the timing is becoming terribly advanced and causing my severe misfires on rpm.

i have tried both capture modes and have the same result. is it possible that the coil is randomly releasing the spark before the ignitor fires it off and causing this phenomenon?

[Matt Cramer]

i have tried both capture modes and have the same result. is it possible that the coil is randomly releasing the spark before the ignitor fires it off and causing this phenomenon?

If you're using the Delco D585 / GM "truck coils", they're notorious for doing exactly that. Not aware of other coils with this "feature" but they may be out there.