Microsquirt Newb

linuxman51 said:

Occasionally folks have introduced noise on signal wires coming in to the ms with proximity to outputs (esp high voltage outputs like coils), so I'd suggest you try and separate the outputs from the inputs as best possible in the loom.

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Makes complete sense. Do you favor one type of shielding technique over another? I'm reading people using everything from foil, foil tape, gutted coax, etc to add shielding. I'm not sure I can keep them completely separate as I'm likely having them come through the same spot in the firewall at the passenger side...although I may consider going to driver side for the input sensors since I also have the kjet harness split over there and thats where most of those sensors reside in the engine bay anyways.

bobxyz said:

What Wideband O2 sensor are you using? Does it provide separate sensor and power (heater) ground wires? If not, you probably [?] want to wire WB02 ground to a MicroSquirt power ground at the MicroSquirt.

I'm not sure what's the best setup for +12v injector power and +12v MS power. I'd think that connecting these together near the injectors would be best?

The CAS uses hall sensor outputs, not VR, and thus has better noise immunity.

Going back to adding a factory 60-2 flywheel/flexplate vs. CAS, the issue you'll run into with a B21 block is the mounting of the CPS bracket. The B230 blocks have 2 drilled and tapped bump-outs in the bellhousing for the CPS bracket. The early B21 blocks do not have the bump-outs, but my 84.5 GLT B21FT block did have un-drilled bump-outs. Without the bump-outs, you'll need to make a custom CPS bracket -- it took me way too may hours to do this for a rebuilt '82 block (drill press, hacksaw, and metal file).

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I'm planning on the Spartan 2 since I really don't need/want a display that goes with most the other ones. It also seems to get good feedback from users here as a no frills reliable WB that isn't a ton of money.

My plan for the 12V source for all is pretty much following the MS manual by getting it from the stock fuel pump relay harness. I'll of course make sure I'm getting proper voltage there, but I don't forsee it being an issue as that seems to be the popular source for the kjet to MS folks here. I'll have the 12v and 12v key on go to a terminal block where they will split to the two relays (main and FP). Pursuant to the MS schematic, everything that needs a 12v source for the install coming off a fused lead from the FP relay aside from the CAS which, from what I understand, needs to be triggered with a key on 12v source but not the FP relay since the MS won't trigger the FP until it gets a CAS signal. CAS would get its 12v from the main relay via fuse.


Yikes...I think I would have ended up the CAS route anyways even if I was aware of the flywheel swap with CPS option. Guess one could argue the end result is simpler/cleaner than the CAS, but the road to get there is more than I'd want to mess with for sure.

For shielded cable, DIY Autotune has both single wire (plus shield) and dual-wire (plus shield) cable in 10' increments. I'm assuming it's automotive temperature rated, and cut off a big spool. It's much easier to get it from them instead of trying to find someone else who will sell short lengths of the proper temp. rating. (I know 240turbo.com has lots of good connector parts, but I don't remember seeing any shielded cable.)

Traditionally, shielded cable is needed for sensitive, or low voltage, sensor signals when there is a lot of radiated electrical noise from the ignition coil, distributor, and plug wires. With your Truck coils, assuming the plug wires are short and away from the harness wires, you should be fine without needing to shield anything. The CAS, since it uses Hall sensors and 0-to-5volt signal levels, is already pretty noise immune compared to the low voltages from a VR sensor during cranking and idle.

If it were me and I was wiring a MicroSquirt from scratch, I'd find a waterproof fuse block and mount it in the engine bay near the battery. I'd run +12v power from the Volvo Junction Block (next to the battery) to the fuses and relays. From the relays+fuses, I'd run +12v power to the engine components (injectors, IAC, coils), with another fused wire going to the MicroSquirt in the cabin. This should keep it clean and easy to work on, plus you get to upgrade to modern blade fuses.

You'll still need to run fuel pump power from the add-on relay/fuse to the wire(s) on the original K-Jet relay harness, and run a wire for the WB02 power.

Does anyone know a good source for quality sealed fuse blocks? Something you could hose down without worry.

I had a heck of a time finding a fuse and relay box that was what I wanted for a reasonable amount of money. Plan is something similar to this mounted in the factory ECU location. Found a nicer hella fuse block that has a clear cover on it which would be nicer for labels.

linuxman51 said:

it's alright, people fight with the vr sensor for the 60-2 almost incessantly, almost no one has issues getting the CAS to work. (fwiw I don't know 100% why folks have such a hard time with the 60-2 stuff, but VR signals in general can be difficult to get working cleanly)

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I fought with mine until I put a 10k shunt resistor in parallel with the VR sensor. Before that I would lose RPM signal over ~4000 RPM.

Alan29 said:

I had a heck of a time finding a fuse and relay box that was what I wanted for a reasonable amount of money. Plan is something similar to this mounted in the factory ECU location. Found a nicer hella fuse block that has a clear cover on it which would be nicer for labels.

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Looks fine, nice and compact with everything labelled. For main battery power, you can either splice a wire into the original fuel pump battery wire (assuming that your original wires are not rotting away), or you could go direct to the junction block by the battery. If you have a proper greenbook, you might be able to pull the original fuel pump wire off the junction block to clean it up some.

Excellent info on the FP wiring... thanks!

My engine wire harness under the hood is complete crap for the most part (a significant reason as to why I'm doing this MS install). Wouldn't be surprised if the fuel pump wire to the junction is garbage as well. I replaced the positive battery wire a few months ago and don't recall seeing anything trashed into the junction. Doesn't meant it isn't trashed further downstream, but maybe I'll luck out. Wish I had the time to really dig into all the under hood wiring at once. The headlamp wiring has seen better days as well.

Well...it's about to begin. Been spending some time this week yanking all the kjet and ac components. Trying to clean things up the best I can as I move along. Hind sight I should have gone all out with some degreaser and a pressure washer before hand. But also probably would have trashed my driveway. Going to do the best I can with cheap dish brushes and whatnot.

Tomorrow I'm going to start labelling and pulling the old harness. Few things I need to try to salvage from it if they are still in good order (exciter, alt, oil pressure, temp). My grey connectors at the firewall are complete trash so I may just pick up a weatherpack connector or something for the temp and oil leads I guess.

As with any project I'm running into more crap. Need to replace the radiator, get the stuff to move my ps pump down where the AC was, etc. Hardest part at this point is keeping all this organized in my tiny garage.

Anywho...thanks again for all the info. I'll post updates as it progresses.

Going much slower than anticipated. Pending an IPD order that is tied up from a Volvo heater hose from Canada to finish up the hardware installation side of things. Did finish up mounting the IC, rad, and efan (woohoo progress). Everything else is ripped out. Right now I'm working on replacing the existing wiring to the oil pressure, alternator, temp sensor, and start.

I'm taking advice here and doing the fuses and relays in the engine compartment as opposed to under the dash like I had originally planned. I couldn't find a fuse/relay box that fit my needs and budget so I'm using the fuse block I already have and placing that with my two MS relays and fan relay into a waterproof project box I found. Wires will pass through with waterproof cable glands. Going to mount it up where the ignition module and coil were mounted to keep it looking (hopefully) clean and stockish. Should have that box in my hands today so I can get all that complete.

Once I have my IPD order in hand its really just a matter of finding the time to do everything.

Dirty Rick said:

amazon.com/MICTUNING-Fuse-Relay-Switch-w/Harness

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I bought those a few weeks ago, they're not terrible.

I just realized, If mounted underhood, They need a cover as they are not water tight.

I use those relays without a cover, OP you'll need whatever pull up resistors, heat shrink tubing, heat shrink electrical connectors, and a nice heat gun, I think I got a porter cable from home Depot for fairly cheap

Hmmm, interesting thread. Ima do a bit of hijacking but that's better than creating a different thread on the same topic right..?
I'm going to follow this thread as I plan on doing the same thing - Microsquirt an 88 na K Jet, wasted cop, Yoshifab CAS, only difference is I'm using different coils (Delphi D514A) and that I'll be running E85 on it - with a flex fuel sensor ofc - oh and it being an Euro spec car its a B200, K cast, got my hands on 13mm H rods.

My biggest issue right now is sourcing the parts, euro - dollar exchange rate is low, import fees and shipping is high. Figure out 900 usd for the MS, CAS and coil bracket from Yoshifab...

Looks like OP is going with fuses under the hood, I'd like to make a separate fuse box in the car for the various MS - fuel pump stuff ect...
Any drawbacks in removing the glovebox to make an ECU - fusebox compartment, appart from the fact that I'll lose the storage space..?

I assume it's possible to keep the mechanical fan and then switch to E fan later on ? France's climate isn't harsh and I plan on running a nice 16 row Mocal oil cooler + E85 runs cooler too, but I'm not sure how it affects it all.

Oh and something else that I don't quite understand is the crank position sensor - to drive the wasted spark - this https://yoshifab.com/store/billet-redblock-dsm-cas-adapter.html alone isn't enough to drive it ? Sourcing a 60 - 2 flywheel isn't that easy here... From what I understand, It is not enough alone. There are a few website that sells trigger wheel options, with VR sensor. https://shop.klracing.se/sv/artiklar/-remskiva-b230-8v-3-spar-.html this solution looks like it could mount either a 60 - 2 trigger wheel or a 36 - 1. The website also offers brackets, sensors and wiring. Would this single VR output be enough to drive my injectors (all at once, I don't plan on going sequential) AND a waster spark system ?

Last but not least, I don't really understand the whole wasted spark/wasted cop options with the 2 VS 4 output (I'm relating to this "There are 2 ways to do "wasted spark" with COP, use the wasted spark setting and pair up the coils, or use "wasted COP" and use all 4 outputs." from Dirty Rick)

Main drawback I can see to putting everything in the glove box is possible added complication of you need to remove the dash board. You would want to install it so there is minimal work to be done with the MS stuff should you need to yank the dash. That may not even really be a draw back. Really all user dependent and what you are comfy with.

The Yoshifab DSM CAS adapter plus a DSM CAS with the appropriate wheel installed in the CAS is all you need for crank position. No need for messing with a flywheel.

You can def keep the mechanical fan. Many do.

Alan29 said:

Main drawback I can see to putting everything in the glove box is possible added complication of you need to remove the dash board. You would want to install it so there is minimal work to be done with the MS stuff should you need to yank the dash. That may not even really be a draw back. Really all user dependent and what you are comfy with.

The Yoshifab DSM CAS adapter plus a DSM CAS with the appropriate wheel installed in the CAS is all you need for crank position. No need for messing with a flywheel.

You can def keep the mechanical fan. Many do.

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Hmmm, the wheel sold by Yoshifab isn't the appropriate one, right ?
I think I'll go with the modded pulley style solution, I can get the whole settup with brackets and sensor for cheaper than the Yoshifab CAS (thx shipping and customs...)
Any big drawbacks with this solution ? Brackets aren't an issue as the company sells them.
Any difference between a 36 - 1 teeth and 60 - 2 teeth wheel ?

Thanks for the help

A 36 tooth wheel is a better choice for a MS2/MicroSquirt as a 60 tooth wheel is pushing the processors capabilities.

60 teeth comes real close to "to much information" for a MS2 but a MS3 will not be bothered.

60 teeth "works" with MS2 but at high RPM it will slow down the code by updating faster than the MS2 can process.

Dirty Rick said:

A 36 tooth wheel is a better choice for a MS2/MicroSquirt as a 60 tooth wheel is pushing the processors capabilities.

60 teeth comes real close to "to much information" for a MS2 but a MS3 will not be bothered.

60 teeth "works" with MS2 but at high RPM it will slow down the code by updating faster than the MS2 can process.

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Thanks for the infos ! Then 36 is the way. Plus on the 60 tooth versions, the tooth looks damn small. It being mounted on the front of the engine I'd rather have the more rugged thicc teeth yeah.

OP, for the coil bracket, are you going homemade or aftermarket ?
Im tempted by aftermarket ones but damn, the cost. Yoshifab one + import fees is above a hundred eurossss...

The Yoshifab coil mount was one of the "luxury" items I went with on the build. It's a nice piece for sure, but you could be creative and put something together for sure.

Alan29 said:

The Yoshifab coil mount was one of the "luxury" items I went with on the build. It's a nice piece for sure, but you could be creative and put something together for sure.

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It's the cost that bother me...
And I'm not sure about the definition of the thing, the wheel inside it seems to have less pins + the dizzy turns quite slowly.

Also I'm tired of clocking dizzy, so that's out of the way.

I got my hands on an old old but nice O Scope, will be useful when dealing with VR sensors ^^

I haven't run across any other sort of LS coil mounting solutions for this car. Could always look at mounting them on the apron or something. There are a few universal type mounts on Amazon and the like that stack them together fairly well.