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New MS3 install for my L28ET


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I've got my engine repaired, and I am now setting it up for a MegaSquirt 3 install to control fuel and spark. I will use this post as my "build thread", and will update with questions and pictures as I progress. But for now I just want to make sure I am getting the right stuff as I need to control costs as much as possible.

 

The engine: L28ET with cam, new damper, turbo distributor, 7MGTE injectors (low Z), stock ignition. Plan to run batch fuel injection and distributed spark (for now). I am also planning on speed density control using Zmanco's baseline tune ported from MS 2, I think the fuel and ignition maps will copy in, we'll see.

 

I will be using GM air and coolant temperature sensors. I have adapted and installed a Hyundai TPS on my Weber 60mm throttle body. My boost controller will not change, it's a Greddy ProfecB that works with the stock wastegate. I also plan to get a wideband O2 controller, probably the LC-1.

 

Initial questions:

 

I am looking to get just this MS 3 kit from DIY. I am good with electrical assembly and soldering.

http://www.diyautotune.com/catalog/megasquirtiii-wpcb-v30-unassembled-kit-with-black-case-p-419.html

 

Will it do what I need? I don't plan to go distributorless or sequential injection, but I do want it to control my electric radiator fan, fuel pump, and LC-1 wideband. I also do not plan to do anything with active startup and idle control other than factory equipment (it's a track car). I am having trouble finding out the details on exactly what the kit includes.

 

Is there any advantage to getting the trigger wheel for the turbo distributor? I do have a Z31 wheel in it right now.

 

I plan to build my own relay board where the old factory relays lived, in front of the battery, so I think I can run a single harness from the MS 3, and split it out in the engine compartment.

 

Any input is appreciated, please let me know what your experiences and mistakes have been.

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You don't really need anything else. You should get your WB02 for when you install the MS3. You don't need the new optical wheel if you are not doing sequential injecton or distributorless ignition.

  As an Electronics Eng let me tell you NOT to buy the DIY wiring harness. You really should run shielded wiring in a electronicly noisy engine bay. I suppose you could buy the DIY but r

The TPS isn't as critical but if you are shielding the other sensors why wouldn't you shield the TPS as well. The WB02 should be shielded as well - it's pre packaged but will you run it's harness dir

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You don't really need anything else. You should get your WB02 for when you install the MS3. You don't need the new optical wheel if you are not doing sequential injecton or distributorless ignition. MS3 will controll your fuel pump relay directly. You'll have to check but I believe you can controll the fan relay without any additional hardware with the MS3 (haven't installed my electric fans yet). For idle control a mechanically adjustable idle air feedback is a good idea - get rid of all the stock IAC and associated vacuum and heated water lines. You can change the stop on your throttle body for idle air but I believe a bypass system is a better way to do it.

 

Your engine harness only needs to be split in a couple of places - you can see the custom one I built here - it's in a 280ZX but it will be a similar configuration for the S30.

 

 

 

 

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My throttle body has a bypass for setting the idle speed, and I have no engine accessories. For cold starting I have a factory fast idle air bypass that uses an electric element instead of coolant to close the bypass when warm. It works ok, and for the track it's all I need.

 

I've heard the innovate LC-1 needs to be powered after the engine starts, so I thought it would be a good thing to have the MS control the power for it, maybe just a timer, or with coolant temperature, not sure... Has anyone implemented that yet? As long as I don't need to de-multiplex anything off the main 37 pin connector, I'm ok with wiring a power relay just for the LC-1.

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As an electrician and part time electronics guy, let me tell you from experience-Spend the $65 and buy the DIY wiring harness. I built mine and I spent sooo much time building it and troubleshooting it, that it is not worth the effort. I built my relay board also, but once again-time vs money. Fortunately mine worked the first time and I didn't have to troubleshoot anything.

 

A small detail I put into my relay box was an auxillary switch to bypass the ignition switch.

 

I made a relay with some alligator clips and a radio shack horn button to make a remote start switch, and now I have complete control of the engine without climbing in-n-out of the car repeatedly.

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I have my LC-1 powered from a relay that is turned on by the ignition relay - signal taken from the stock ignition box. It is on while cranking, which is technically not a good idea, but usually the sensor is not hot yet (except in the case of starting after a stall). I have had it like this for over a year with no issues.

 

I also recommend getting the wire harness from DIY. It will save you hours of work.

 

I use the MS3X for ignition, so take the following with a grain of salt...

You should be able to use the fidle output to control a fan relay.

Be sure you have a way to control ignition - it requires a high current driver.

 

I recommend you email the guys at DIY with your questions. They are extremely helpful and will make sure you get what you need.

 

Sam

 

 

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I definitely appreciate the comments, especially with regard to the connector wiring. And nice trick with the ignition bypass - I might do that.

 

I am fairly solid with the ignition, at least for now to get it running. The ZXT stock coil and transistor driver can be driven directly by MS-III. On the off chance it doesn't have enough drive current, I can add the transistor to the MS PCB.

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As an electrician and part time electronics guy, let me tell you from experience-Spend the $65 and buy the DIY wiring harness. I built mine and I spent sooo much time building it and troubleshooting it, that it is not worth the effort. I built my relay board also, but once again-time vs money. Fortunately mine worked the first time and I didn't have to troubleshoot anything.

 

A small detail I put into my relay box was an auxillary switch to bypass the ignition switch.

 

I made a relay with some alligator clips and a radio shack horn button to make a remote start switch, and now I have complete control of the engine without climbing in-n-out of the car repeatedly.

 

As an Electronics Eng let me tell you NOT to buy the DIY wiring harness. You really should run shielded wiring in a electronicly noisy engine bay. I suppose you could buy the DIY but replace all the sensor wires with shielded ones. All modern vehicles have shielded signal wires. Even the stock 280ZXT harness has shielded O2 and optical dizzy wiring. It's true you will save some time installing but if you have any noise issues in your harness it's a major nightmare.

 

Use the MS output for your spark - the IGBT on the MS board is uh more optimal (haha I almost said better but that would be against the rules ;) It's designed to protect itself whereas the driver transistor on the turbo coil won't. Just bypass it.

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We've shielded the tach input wiring; the other sensor signals don't move nearly as fast and can be dealt with using a combination of hardware and software filtering. I haven't seen an OEM harness with all the sensors shielded - at most, the RPM signal, O2, and TPS may be sheilded, and it's pretty common for the O2 and TPS shields to be omitted.

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Shielded cabling is hardware filtering and one of the best solutions for noise in an engine bay....

Check the schematics on a KADE, etc the vast majority of the signals are shielded....

even the old stock L28ET has the O2 shielded....

RPM, O2 and TPS are the vast majority of the minimal signals required for MS to run...

 

Sure lots of OLD EFI systems that weren't that complicated may not have used much in the way of shielding but newer systems which rely on more accuracy use shielded cables. Shielded cables prevent noise from even getting to the system. The additional cost of shielded cables is marginal but the benifits are very significant. Some of the most difficult issues to track down are noise related and if you are trying to patch it after the fact it can be very difficult. Start with a good base and you'll elimiate a lot of strife.

 

 

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  • 3 weeks later...

I got my MS-III kit on order. I've modified my exhaust so the LC-1 sensor will come up through the shifter. It seems like the best mounting location for the MS-III is under the passenger seat, so the O2 wiring should be all there.

 

I understand the body is not suitable for grounding the unit. I am thinking the best place to ground it is on the engine where the battery negative connects. Is that typical? I am not sure the LC-1 should be grounded there, but rather close to the MS itself, so the O2 signal ground does not get the injector and ignition noise.

 

I plan on taking some photos prior to wiring the harness. I've already started with mounting and wiring the relays in the stock location on the right fender. I have pigtails on all my sensors and injectors, just getting ready to run wiring to the relays and the MS.

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You don't need the new optical wheel if you are not doing sequential injecton or distributorless ignition.

I have been searching this forum and the Megasquirt forums, and I still don't understand the distributor (camshaft) input to the MS. If I still had the ZXT distributor wheel, I would re-install it, since it has the 6 equal slots. But I have the Z31 wheel in it, and it has one slot wider than the rest.

 

Will this cause timing issues for the MS? If the slot leading edge is the same angle as the rest it might not be a problem, but does anyone have this trigger setup working and can verify there aren't ignition timing issues? Perhaps I could flip the wheel over if the MS tach input uses the falling edge. Any other suggestions?

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Will this cause timing issues for the MS? If the slot leading edge is the same angle as the rest it might not be a problem, but does anyone have this trigger setup working and can verify there aren't ignition timing issues? Perhaps I could flip the wheel over if the MS tach input uses the falling edge. Any other suggestions?

 

I've worked with other customers using this.

 

MS2 and MS3 allow you to flip which edge it uses in software; if it is set right, it works. Getting it backwards produces exactly the effect you think it would.

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Thanks Matt, I'm finding out the answers to my questions, and I'm glad the firmware seems to be extremely flexible to input types.

 

And I finally found the schematic suggestions and other informational pages, and I'm glad to see my grounding ideas are the recommended ones. I'm looking forward to receiving, building and wiring the kit to get this frankenstein monster back alive.

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The best way to run the ground would be a crimped and soldered lug from the battery to a point on the chasis near where you have the MS mounted. At that point the ground wire from the battery and all your other grounds from signal wires, shields, etc should come into the same lug crimped and soldered all together. That gives you a solid ground that is referenced to the ECU ground and limits noise. Soldering will emiminate any noise from mechanical connection movement, oxidization, etc.

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I'll second FricFrac's comments about crimping and soldering. When I did my install I soldered all the small signal wires, but only crimped the large gauge wires. I knew better, but wanted to get it back on the road. The other day I redid the connectors where power is pulled from the alternator. There are several connections including the inline fuse. Just doing that resulted in the typical system voltage as reported by megasquirt increasing by nearly 3/4 volt. I was surprised it was that much since all the old connections were in otherwise good condition.

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Received my MS-III kit on Saturday, it's completely assembled now, I will be testing it this week. I decided to install the ignition driver and drive the coil directly. I have the main relays wired and operating. Still have tons of wiring to do. Here are some pictures of the current state of affairs.

 

IMG_20120422_213716.jpg

MS-III kit built.

 

IMG_20120422_215831.jpg

Injectors, sensors in pigtail state.

 

IMG_20120422_215941.jpg

Relays installed in factory location.

 

IMG_20120422_215811.jpg

New intercooler plumbing.

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  • 3 weeks later...

A bit of progress, all the engine wiring is done, all the plumbing including a new intake, cold side pipe, BOV, 440cc Supra injectors, pallnet O-ring fuel rail and turbo oil line.

 

IMG_20120507_231907.jpg

IMG_20120507_231927.jpg

IMG_20120507_231940.jpg

 

I still have the gauge panel, the LC-1 wiring, and the MS-III end of the harness to complete, then hopefully it will be a smooth transition to tuning.

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