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L28ET Megasquirt (MS2-3.0) ignition issue


240zdreamin

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Hello Hybridzers,

I've finally got to the fun part and am so close to starting my car after almost five years of build from the ground up. Mind you, I have to do body work and paint once she starts. Anyway, I've got the computer wired into the car thanks to Fric Frac for providing his amazing wiring kit. I've got the laptop connected and I'm seeing gauges. TPS and temperature work but I got no rpm which has led me to no fuel and finally led me to the trigger wheel in the distributor (82-83).Research tells me that MS2 isn't powerful enough to read the 360 increments on the wheel but can read the 6 slots. Further research suggests that replacing the wheel with the DIY wheel (36 slots) is best for MS2? Can anyone confirm this? I'm happy to outlay the $30 but would like to have some feedback from those that are more experienced than me.

Thanks everyone!

Aaron

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People seem to be able to get the stock turbo distributor to work.  So the trigger wheel is probably not your problem.  Not uncommon for the CAS trigger modules to go bad.  That seems more likely or the wiring isn't right.  Wiring is shown in the link below.  You need the pullup resistor to get it right. 

 

http://forums.hybridz.org/topic/23244-megasquirtnspark-mssmsns-installation-guide/

 

 It's hard to test the CAS's because they need power (or maybe the harness has its own pullup circuit) from the ECU to work.  The CAS module inside is fairly common, people use a later module from cars like Pthfinders if they don't want to buy the whole distributor.

 

https://z31performance.com/forum/z31-basics/how-to-guides-basic/20433-rsb-07-cam-sensor

 

Here's a link about the trigger wheel, although it still won't work if the CAS module is bad or wired wrong.

 

https://www.diyautotune.com/support/tech/hardware/nissan-trigger-disc/

 

 

Full disclosure - I'm just writing about stuff I've picked up here and there, although I did swap a CAS module after I destroyed one trying to figure out if it was bad.  The swapped one worked fine when I plugged it in to a functional harness and spun the shaft.

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Hmm, I know DIY has a wheel specific for the turbo for the MS2. Those VR sensors are pretty finicky, so I would be tempted to just buy their wheel as they have experience with it working at that resolution. The theory if I'm not mistaken is that the fewer teeth there are the lower resolution you get, but the peaks are much greater. With more teeth I think the system more or less sees a blur/ curved wave instead of a square wave. VR sensors are more peaky in nature. I think with enough tuning with the gain and threshold on the pots you can get the system to register, but not worth the effort and I'm not sure if the hardware is sensitive enough to pick up on that.

 

Granted as NewZed says the wheel won't matter if the wiring is bad. Are you getting no signal at all? Intermittent? You can "make" a test wheel and log it with a thin piece of metal with a few holes punched in it. 

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Here's the link to the sale page, just to round out the thread.

 

https://www.diyautotune.com/product/54-mm-optical-trigger-wheel-for-nissan-l28et-or-vg30e/

 

If he wired it up to use the six slots and it didn't work, then he probably has a CAS module, or wiring, or MS setup, problem.  The DIY wheel just gives better resolution, and a cam trigger for sequential.

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Thanks guys, I'm not getting any signal whatsoever. I had the computer and wiring built for an L28ET but suspect it was built for a toothed wheel on the crank rather than the distributor version and the software was programmed and tested on another L28ET and confirmed to work. The "spark mode" is setup as "toothed wheel" which may confirm my suspicions. In your opinion, will I need to make some changes to the motherboard or is the software customizable? I see different setups on the DIY website for both the VR and Hall triggers for MS2. I think i may just purchase the DIY wheel to obtain the fidelity.

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First off wire the distributor if you havent or check your wiring,

3 wires 12v , ground, pin 24 ( tach in )splicing into it 1/4k resistor from 12v . look at this diagram

post-4858-0-05188100-1493619978_thumb.jpg

 

Here is wiring depending if you are wiring from round plug or after if you happen to have.

post-4858-0-42596700-1493620027_thumb.jpg

 

YES the board hardware jumpers also has to be setup for what type of CAS

AND YES you have to put the setting in the software part.

 

You could run the stock wheeled dizzy and coil then fire out with high ignition out from ms2 to drive the coil out lined here.

https://www.diyautotune.com/support/tech/install/nissan-datsun/megasquirt-your-280zx-turbo

 

SO

if your going to run the DIY wheel follow the hardware and software setttings in this page per your setup! They are many variations from ecu 3.0 vs 3.57 to how you will run your ignition out single / wasted / cop sequential

https://www.diyautot...n-trigger-disc/

 

Goodluck

 

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Unfortunately, I've had the computer and wiring built for almost two years now (I'm way ahead with all my purchases but my work kicks my ass). Anyway, I've contacted Kurk a couple of times and no response so I'm trying to do it myself based on deductive reasoning and a lot of research. So that's what has led me to this point. I'm not incapable, its just a time sink when you have limited amounts of it and I feel that I need to understand this better anyway. The distributor wiring is configured to plug into the square box connection. The coil is driven directly from the computer. I think i need to jump the wiring in the computer to match the 82-83 distributor and update the trigger wheel. Once that's done, I'll need to update the settings in the software. The difficult part will be tracing the wiring from the various locations under the hoodto the computer.

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I read somewhere that Kurk is no longer doing harnesses.   I'm curious what's up as he was always very helpful, even to those who didn't purchase a harness.  Hopefully he is ok.

 

 

I do know one thing, is that he always wanted to use the L28ET distributor for his setups.  Chances are your is set up like that too.  There is only one way to figure it out though.  Figure out what version of MS you have, which software and open it up.  Lots of reading and track it all down.  In the end you be better off as you will understand how it all works.

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I just read your last post in this message, and it seems strange to be using the matchbox on the distributor.  The whole point of MS is to make it tuneable using the MS for as much as you can.  You should be able to delete the matchbox completely.

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 The distributor wiring is configured to plug into the square box connection.

 

He implies that he had the CAS in his first post, talking about the 360 slots.  Maybe he's unsure of what he actually has.  The DIY wheel won't do him much good on a matchbox distributor.

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1. Open your ecu and see what ignition its setup too.

2. If your using the high current driver I linked all the diagrams pin 36 will go on - of coil, + positive side will get ignition 12v switched.

 

If this was a bolt on pretty much setup using his FricFrac harness and he already setup your ecu ( Ive seen his works looks great just follow his stickers on the wiring) its a no brainer hopefully.

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Thanks guys, the distributor has a matchbox plug in connector but this is after the round connector pigtail was removed. Kurk built the harness with a matchbox connector.

I'm going to go with the DIY wheel and follow the instructions on the DIY website. I'll let you know how I go. It is strange that Kurk hasnt responded.

Cheers,

Aaron

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  • 4 weeks later...

Hey guys, just received the DIY trigger wheel, bolted it in and presto, first turnover of the engine it starts. It runs pretty rough and after calibrating the CLT and TPS, rougher. Anyway, I've spent some time checking the following:

  • Spark plugs - black and smell like unburned fuel
  • Plug wires - resistance checks out
  • Injectors - resistance checks out, haven't checked to see if there are any blockages
  • Coil - resistance checks out

I have the SCG-1 hooked up and wired in (done by Kurk) and the AFR sits around 10-11 which is quite rich. I'm using the MAP that came with the SCG-1 and it uses a dedicated vacuum connection to the plenum. I get very little movement in the MS Fuel Load gauge which makes me think I have a vacuum leak or is this unrelated?

I tried to adjust the timing (rotate the distributor) but it did nothing then I read something about MS2 adjusts for timing based on the Cranking Advance. Mine is set to 10 deg. Kurk provided a base tune map and maybe it's time to make adjustments but before I do that, I'm hoping that the more experienced people out there may have some suggestions?

Thank you!

Aaron

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