odd problem need some help

[A2TURBO]

I have installed uS to my 85 Ninja 900 and had it running pretty good alittle on the rich side but still good. I was cleaning my plugs away from home and the 10k resistor I had on the opt in+ to - side of the 1-4 coil broke! I didnt have any with me so I put the wire together and taped them up so I could get home and replace the resistor. well the bike ran for about three min and quite! now I put the computer on it and it reads the tach sig eraddicly just here and there I ran a datalog and noticed that when it reads the tach sig as soon as the engine starts it reads 13,000 to 20+k rpms (and it wont read the tach with the resistor put back in place) I removed uS and opened it up in fear that I had fried something but all "looks" good and doesnt smell burnt. should I reflash the ecu with the latest code (im already running it V2.889)? has this happened to anyone else?
heres a datalog

[A2TURBO]

I reflashed the 2.89 code version but it still would not read tach signal with the 10k resistor inline with opin+ from the - side of the coil. I simply twisted the wire ends together with the resistor still in place and uS started to read tach signal and the bike started. with a little tweaking of the new ve table the bike seems to run better than before heres another datalog

running again.xls

additonally, the actual engine speed is approximatly twice what is shown in the datalog for some reason uS only reads about half the actual engine speed Idle is at 1000 to 1200 rpm not 500 to 600 rpm.

[A2TURBO]

Well that was short lived! I did some tuning to the ase and wue and had it idling nicely shut it off and retapped the opin+ wire and now nothing. Ive checked my connections and everything seems ok but uS is not reading anytach signal at all. looking thru the last running datalog uS suffered several resets (10 of them) so I started looking for signs of noise in the system but I didnt see any im posting two more datalogs so maybe someone can see what I dont. the one titled new sunday is the running one the no run is a data log of starting attempt after it wont read a tach signal

[grippo]

The good news is that there isn't any noise on your tach line. In your "Running Again" datalog, every time the rpm goes to 0, it is because the processor resets (reboots itself). You can tell because secL goes to 0 on a reset. The most likely cause of a reset is a very short dropout in voltage, either from the battery (which is most likely during cranking) or the alternator. You can try putting a large audio cap across the battery and see if this helps or even run the processor from a separate battery that is not attached to the engine.

The rpm being half the value is probably due to something wrong in your configuration. If this was giving correct rpm before, then you need to really check all the variables in you msq and make sure they are correct.

[A2TURBO]

thanks for the reply grippo, but I dont think thats the problem as it was running fine before I tried to run it without the resistor. However I did try it off the battery (Iused the 15 volt power supply I first setup the ecu in march) still no tach signal Ive checked the wiring for that circuit (opin+/-) it was good my resistor is good (it reads 10k) heres a datalog and a msq

The attachment dataloghuge tach spikes.xls is no longer available

notice the huge tach spikes it gets when it does read (56k rpm) uS has never read the right rpm it has always been about half of actual I just thought it was bacause it was only hooked up to one coil out of two (the engine is a four cylinder running two coils with four wires in a wasted spark in situ

no run 05042009msq.msq

(25.06 KiB) Downloaded 37 times

I m starting to get a little frusrated, are ther some values I could check with my multimeter? just to ensure its not a hardware problem? ive reloaded the 2.89 code so I dont think is a software problem

[A2TURBO]

Al, do you think my problem could be related to this? http://www.microsquirt.com/viewtopic.ph ... t=tach+sig I looked at my board and it has not been modded Ill try to post a pic

[Matt Cramer]

Al, do you think my problem could be related to this? http://www.microsquirt.com/viewtopic.ph ... t=tach+sig I looked at my board and it has not been modded Ill try to post a pic

That link only applies to the VR input; if you are using OPTOIN, it does not apply to your board.

It may be a case of damage to the optical input circuit. R20 seems to be the easiest part to break there. Try measuring its resistance and confirm that it is 680 ohms. Note that resistance measurements are a bit tricky because the board is coated; you have to push the probes firmly against the resistor ends.

[A2TURBO]

Thanks matt, Ill check that tonight. but if its so easy to break that should I be using the vr inputs instead? The bike uses dual vr sensors for ignition and I have got values over 100 volst from the neg side of the coil just cranking it over. remember this is fuel only at this point and I just get my trigger from the 1/4 coil, so we can prevent it from happening again.
Thanks Matt

[A2TURBO]

Is this R20? if so its a1 750 ohms if not could you mark where its at? theres not a pic of microsquirt board showing the location of numbered parts and some of the numbers on the board its self are cut off or under parts and unreadable
(edit) I just checked it again and it is reading 1592 ohms! weird! it seems if I revers my leads I get different readings is that right? and looking at the pic I think I circled the wrong one I ment to circle the one between c28 and R29

[Bruce Bowling]

The R20 resistor is right next to the white 8-lead opto-coupler. If you hold the board so that the connector is on the left side (and board text is right-side up readable) then it is right above the opto-coupler on the extreme right side. Look at the mask image below, its located on the lower right side:



You say you were running this with a 10K series resistor? This is kinda high, I am not sure if the opto will even read this reliably.

You can check the opto circuit very easily - ground the opto- wire, take the opto+ wire and just tap it on the battery +12V repeatedly - this will simulate cranking RPM. You need to be in distributor mode when doing this (no wheel decode mode).

- Bruce