MS1 - hard/NO starts

http://www.diyautotune.com
User avatar
Matt Cramer
KA-T.org Sponsor
KA-T.org Sponsor
Posts: 934
Joined: Mon Sep 15, 2008 5:34 am
Contact:

Post by Matt Cramer »

It looks like you're getting a bunch of noise pulses. I would check the condition of the wiring, and maybe trying the false trigger protection.
Matt at DIYAutoTune.com - Megasquirt ECUs, fuel injectors, wideband O2 sensor systems, and more
Nissan plug and play engine management now in stock!
Spoolin6er
Dreams of owning a 240!
Posts: 95
Joined: Tue Jul 03, 2012 2:30 pm

Post by Spoolin6er »

Matt Cramer wrote:It looks like you're getting a bunch of noise pulses. I would check the condition of the wiring, and maybe trying the false trigger protection.
Is there reason why I would be getting extra noise with the new wiring configuration? Do you mind explaining the reasoning behind having me switch from the "high to low" circuit to the "low to high"?

The false trigger protection can only b set to on or off in MS1 right? Or are there settings I'm missing some where?

The wiring in this car is pretty decent (much better than my older mx6), and I'm using the stock, shielded wiring. I checked the the resistance between MS BD connector and the wiring into the distributor and its < .4 omhs. Not really sure how else to check it.

I found a scope to borrow - hopefully I can figure out how to use it...
User avatar
schmauster920
Belongs To The TOP CONTRIBUTING MEMBERS!
Posts: 2612
Joined: Tue Feb 20, 2007 5:25 pm
Location: CA

Post by schmauster920 »

Check the continuity of both wires, the shielded wire and the sensor wire. The sensor wire cracks with age and contacts the sensor wire. Thats what happens to our knock sensor sub harnesses over the years
D21, Built KA24DE, 740cc, T4, WeatherGuard Tool Box, Tial 40mm, Megasquirt 3 in progress
Spoolin6er
Dreams of owning a 240!
Posts: 95
Joined: Tue Jul 03, 2012 2:30 pm

Post by Spoolin6er »

*EDIT* - I see what you mean, I'll check when I get home..

Thanks
Spoolin6er
Dreams of owning a 240!
Posts: 95
Joined: Tue Jul 03, 2012 2:30 pm

Post by Spoolin6er »

Checked to make sure the ground and signal wires had no continuity, and they don't. Should there have been anything showing up? Like some very high resistance that is internal to the CAS? I always hate checking for "no continuity" b/c its easy to not have a good connection to the wires you are checking and you would never know.

Anyway, decided to mod it back to a high to low circuit. Its back to the way it was, but maybe a little worse as far as miss fires under load. I originally thought they were caused by issues in my tune, but after looking at the tooth logger, the CAS signal is definitely my issue. Its much cleaner than the above screen captures, but its not right either. Its like its bad, but good enough for the false trigger prevention to figure it out (most of the time).

I wasn't able to get the scope today, but hopefully tomorrow... Do I tap into the optoIn and XG2 locations?

*EDIT* - was looking closer at the schematics for the hi-lo and lo-hi mods, and I realized when I switched to the lo-hi mod I didn't re-install c12. Although, the hi-lo mod shows using c12 and c30, and DiyAT suggests removing both here:
http://www.diyautotune.com/tech_article ... _240sx.htm

Got me thinking - should I mess with R12 or maybe add those caps? I've heard of people changing R12 to 1k for EDIS... but I don't know what they do, just a thought.
User avatar
Matt Cramer
KA-T.org Sponsor
KA-T.org Sponsor
Posts: 934
Joined: Mon Sep 15, 2008 5:34 am
Contact:

Post by Matt Cramer »

It wouldn't hurt to try putting the cap back in; it's there for noise filtering.

To use an oscilloscope, you'd check TachSelect for the input and TSEL for the output signal.
Matt at DIYAutoTune.com - Megasquirt ECUs, fuel injectors, wideband O2 sensor systems, and more
Nissan plug and play engine management now in stock!
Spoolin6er
Dreams of owning a 240!
Posts: 95
Joined: Tue Jul 03, 2012 2:30 pm

Post by Spoolin6er »

Ah, well I'm no longer near my car, but I took a look at the input signal and the tooth log. The tooth log looked the same as usual, with what looks to me to be missed teeth more than false teeth. (constantly incorrect/varying positions of "long" pulses, and every once in a while a few shorter than normal pulses)

Here are some pics from the scope: (TachSelect to XG1)
https://lh4.googleusercontent.com/-Uz83 ... .39.26.jpg
https://lh4.googleusercontent.com/-tRYH ... .34.42.jpg
https://lh3.googleusercontent.com/-Gqcj ... .32.56.jpg

I think that last picture has some screen ghosting. The signal looks pretty clean at idle and constant rpm except for what seems like a consistent tooth with some noise while its high. When I rev the engine it goes pretty crazy (voltages seem to jump) I tried some type of auto mode, and it seemed to look better - but I don't know anything really about scopes...

I'll post a video shortly.
Spoolin6er
Dreams of owning a 240!
Posts: 95
Joined: Tue Jul 03, 2012 2:30 pm

Post by Spoolin6er »

Spoolin6er
Dreams of owning a 240!
Posts: 95
Joined: Tue Jul 03, 2012 2:30 pm

Post by Spoolin6er »

comments? I don't really know what i'm looking at/for here.
User avatar
nismoautoxr
Encyclopedia-Nissan
Posts: 1153
Joined: Mon Jun 23, 2008 8:16 am
Location: Leeds,Alabama
Contact:

Post by nismoautoxr »

thats not anything I recognize . If you have the time and voltage parameters on the scope adjusted correctly you should be getting a 0-5v square wave form which Idont see there .
Ricky Ragan,
95 SE ,LS1 N/A and T56, 230/232 @.050 cam, MS3 with MS3X,GC coilovers,17x8.5 Enkei RPF1 on 255 40 17 RS3 Hankooks, 377HP/351TQ , megasquirt3 fully sequential
User avatar
Matt Cramer
KA-T.org Sponsor
KA-T.org Sponsor
Posts: 934
Joined: Mon Sep 15, 2008 5:34 am
Contact:

Post by Matt Cramer »

The signal actually looks pretty good to me. I'd investigate where the MS is grounded at this point.
Matt at DIYAutoTune.com - Megasquirt ECUs, fuel injectors, wideband O2 sensor systems, and more
Nissan plug and play engine management now in stock!
Spoolin6er
Dreams of owning a 240!
Posts: 95
Joined: Tue Jul 03, 2012 2:30 pm

Post by Spoolin6er »

That's what I thought. I'm using the stock ECU grounds, so I don't know exactly where they're going. But there is a huge ground lug (to the body) next where the stock ECU was that I assume is where some of the ECU grounds go. Here is how I have it wired:

https://docs.google.com/file/d/0B1cQUbx ... sp=sharing
Spoolin6er
Dreams of owning a 240!
Posts: 95
Joined: Tue Jul 03, 2012 2:30 pm

Post by Spoolin6er »

is there a way to check for noise on the MS grounds while I have this scope?
User avatar
Matt Cramer
KA-T.org Sponsor
KA-T.org Sponsor
Posts: 934
Joined: Mon Sep 15, 2008 5:34 am
Contact:

Post by Matt Cramer »

You can run the scope from a ground point on the MS to the negative terminal of the battery, and see what the voltage looks like.
Matt at DIYAutoTune.com - Megasquirt ECUs, fuel injectors, wideband O2 sensor systems, and more
Nissan plug and play engine management now in stock!
maik21
Driving Mom's Station Wagon
Posts: 32
Joined: Tue Oct 16, 2012 8:59 pm

Post by maik21 »

i used to see some sr20de distributors get dirty with oil inside it. when that happens with stock ecu, sometimes car revs gets erratic and hard to start. when car start , it dont work as supposed to be working.

i install one of this 24-2 disks from diyautotune but i dont use wasted spark. i only use 24 slits to have ignition in coil. car starts better than with oem ecm every time you turn key. car friend is only for drag so it is used 1 or 2 times per month. so it have a long time sitting in garage.

when i installed this little disk, distributor has some oil inside. so i cleaned it very well. maybe you have this problem to. ka distributors are similar to sr20de b13 sentra.

i use instructions for configuration from diyautotune. theres a install guide for nissan b13s, so maybe you need to take a look.
maik21
Driving Mom's Station Wagon
Posts: 32
Joined: Tue Oct 16, 2012 8:59 pm

Post by maik21 »

you need to be sure optic sensor inside distributor is clean. if not, you need to try cleaning it.

tacho spikes too when i first put megasquirt in the car but it was because i take signal from -coil ant sent do tacho. i only put a resistor between tacho and -coil. this tacho is driven from oem ecu so i only put a variable resistor and find the right resistor for this configuration and it worked very fine from idle to 7800rpm.

i have other problem where tacho spikes and was from a bad coil dwell configuration. it spines at 5000 rpm and misfires to, but i get the good dwell configuration and the it work fine all the way without spikes in tacho and without misfires.
Spoolin6er
Dreams of owning a 240!
Posts: 95
Joined: Tue Jul 03, 2012 2:30 pm

Post by Spoolin6er »

Sorry it took so long, ground scope video is up:
http://www.youtube.com/watch?v=-yL-2Zvj ... tube_gdata

It looks very similar to the CAS signal logs in that there is noise while accelerating the engine, but not while holding a constant rpm.

Thanks maik21 - the CAS is very clean inside. However, I haven't messed with the dwell settings much. Any idea how that could causes tach spikes? It sounds like your first problem was the actual tach in the dash, when I was referring to tach spikes, I meant rpm spikes seen in the MS logs. Looking at the tooth logger shows there is definitely something going on with the CAS signal or the decoder...

What are you guys using for dwell settings with the stock s14 KA24 coil?
User avatar
nismoautoxr
Encyclopedia-Nissan
Posts: 1153
Joined: Mon Jun 23, 2008 8:16 am
Location: Leeds,Alabama
Contact:

Post by nismoautoxr »

3.5ms max and 6ms cranking and around 1ms spark duration was what I was running with no problem but I did not run single coil for long . 3 months on single and I switched to LS2 coils and the 12-1-12-1 wheel from DIY but with the same optical sensor and dizzy. I always had problems with starter kickback with the 4 slit wheel. That was eliminated by the 12-1 wheel from DIY. HIghly recomended.

Have you tried a known good dizzy for giggles?
Ricky Ragan,
95 SE ,LS1 N/A and T56, 230/232 @.050 cam, MS3 with MS3X,GC coilovers,17x8.5 Enkei RPF1 on 255 40 17 RS3 Hankooks, 377HP/351TQ , megasquirt3 fully sequential
Spoolin6er
Dreams of owning a 240!
Posts: 95
Joined: Tue Jul 03, 2012 2:30 pm

Post by Spoolin6er »

3.5ms max and 6ms cranking and around 1ms spark duration was what I was running with no problem but I did not run single coil for long.
I'm 3.5ms running, 6.0ms cranking, and .2ms min discharge period (not even sure what that means)

No i haven't tried a known working dizzy (besides mine, since it was working before I installed MS). I don't know anyone that will let me take their dizzy and open it up to install my wheel. There's always the junk yard, but that doesn't really count for known working...
Spoolin6er
Dreams of owning a 240!
Posts: 95
Joined: Tue Jul 03, 2012 2:30 pm

Post by Spoolin6er »

Hey Matt, have you had a chance to look at the scope of the MS ground that you asked for?
User avatar
Matt Cramer
KA-T.org Sponsor
KA-T.org Sponsor
Posts: 934
Joined: Mon Sep 15, 2008 5:34 am
Contact:

Post by Matt Cramer »

Took a look at it and that looks like a fair amount of ground offset. Where exactly is the MS grounded? In our experience, "good chassis ground" is often a contradiction in terms.
Matt at DIYAutoTune.com - Megasquirt ECUs, fuel injectors, wideband O2 sensor systems, and more
Nissan plug and play engine management now in stock!
Spoolin6er
Dreams of owning a 240!
Posts: 95
Joined: Tue Jul 03, 2012 2:30 pm

Post by Spoolin6er »

I just made an adapter to the stock ECU wiring, so its grounded to the same place(s) as stock (there are quite a few ground wires). I assume most of them go to a ground lug with several wires that comes right off the engine harness and grounds to the body near the stock ECU location. It is on the side of the passenger foot well.
User avatar
Matt Cramer
KA-T.org Sponsor
KA-T.org Sponsor
Posts: 934
Joined: Mon Sep 15, 2008 5:34 am
Contact:

Post by Matt Cramer »

It would be better if you grounded the MS to the engine block or cylinder head.
Matt at DIYAutoTune.com - Megasquirt ECUs, fuel injectors, wideband O2 sensor systems, and more
Nissan plug and play engine management now in stock!
Spoolin6er
Dreams of owning a 240!
Posts: 95
Joined: Tue Jul 03, 2012 2:30 pm

Post by Spoolin6er »

I'm pretty sure it is grounded there as well. I have like 6+ ground wires leaving the MS, and I'm pretty sure one of them comes off the engine harness and grounds to the head. I will check to be sure...

Is it possible to have too many ground locations? Should I ground to the engine only?

Thanks
User avatar
Matt Cramer
KA-T.org Sponsor
KA-T.org Sponsor
Posts: 934
Joined: Mon Sep 15, 2008 5:34 am
Contact:

Post by Matt Cramer »

Using multiple separate ground locations can create ground loops. Use a single point.
Matt at DIYAutoTune.com - Megasquirt ECUs, fuel injectors, wideband O2 sensor systems, and more
Nissan plug and play engine management now in stock!
Spoolin6er
Dreams of owning a 240!
Posts: 95
Joined: Tue Jul 03, 2012 2:30 pm

Post by Spoolin6er »

Alright - this is really getting annoying!

I re-ran wires to the CAS with shielded wire and grounded the shield at the MS - no change.

[rant]I need to vent for a sec and say that I HATE Nissan for making all the wires in the distributor plug black, white, or b/w!! and the FSM is garbage, NO pinouts aside from the ECU![/rant]

I de-soldered all the grounds except the new CAS ground and shield, and the sensor ground. Then I ran two wires side by side to an OEM ground point on the head. - NO CHANGE.

The tooth log looks exactly the same. The missing tooth pulse seems to come at random intervals - some times only separated by a few teeth. :?

I'm about to give up and go with some other EMS
User avatar
Matt Cramer
KA-T.org Sponsor
KA-T.org Sponsor
Posts: 934
Joined: Mon Sep 15, 2008 5:34 am
Contact:

Post by Matt Cramer »

Can you try using the VR conditioner input? It is a bit more sensitive and less likely to miss pulses.
Matt at DIYAutoTune.com - Megasquirt ECUs, fuel injectors, wideband O2 sensor systems, and more
Nissan plug and play engine management now in stock!
Spoolin6er
Dreams of owning a 240!
Posts: 95
Joined: Tue Jul 03, 2012 2:30 pm

Post by Spoolin6er »

Interesting - is this going to effectively invert my square wave? ie trigger one tooth off?

Any specific instructions? Pots fully clockwise?
Spoolin6er
Dreams of owning a 240!
Posts: 95
Joined: Tue Jul 03, 2012 2:30 pm

Post by Spoolin6er »

So i never drove the car after removing the extra grounds and replacing the CAS wiring, I just looked at the logs and saw that it had the same issues and called it.

Well, went to drive it today, and its MUCH worse! I haven't taken any new logs yet, but its crazy because it feels kinda like it did when you told me to switch between low-high/high-low. The car never misses when the engine isn't under load, but as soon as i load it (>25% throttle), it starts missing. What could possibly be causing interference only under load??

I'm so lost :(
User avatar
Matt Cramer
KA-T.org Sponsor
KA-T.org Sponsor
Posts: 934
Joined: Mon Sep 15, 2008 5:34 am
Contact:

Post by Matt Cramer »

That's a good starting point, but you may need to adjust the trim pots, and you will definitely need to check the timing (the trigger angle may have changed). Can you get a data log of it breaking up?
Matt at DIYAutoTune.com - Megasquirt ECUs, fuel injectors, wideband O2 sensor systems, and more
Nissan plug and play engine management now in stock!
Post Reply