My notes for 83zxt to MSnS-e on v3 PCB (Hall and VB921)

[Guest 1seymour]

I had entirely stock EFI prior to this setup. Here's my notes on the install. I followed the MSnS setup link and the MSnS-e website to get things going.

 

I just started installing MS last Friday night.. so my experience is somewhat limited.. if you see anything that is incorrect, let me know. I got the car to fire up and idle this evening. still have to install the TPS before i can do much else.

 

I'm using MS I v3 PCB. The setup link in this forum seems to be for setting up v2.2 so I thought I'd share my notes.

 

I'm using the internal VB921 to drive the coil and the stock optical to detect tach.

 

To start with, I had to research some specs so that I could tell MS what I had.. took me a little while to find it all so I thought I'd list them here.

 

Component Specs.

 

Injector resistance (coil) : 2.35 ohm

Injector flow rate : 265cc/min or 25.2lbs/hr

 

IAT (intake air temp.) AND

CHT (cylinder head temp.):

10c/14F=9K ohms

20c/68F=2.5K ohms

50c/122F=.84K ohms

 

I used the CHT as my "coolant temperature sensor" for MS.

 

 

***wiring notes - some important power lines and relays***

 

To get the fuel pump and relay setup for MS:

 

Stock fuel pump relay information:

 

white w/black stripe is +12v (power in from EFI relay)

green is power out (to fuel pump and air regulator)

black is ground for the relay trigger (through neutral switch to ground)

blue w/red stripe is +12v for relay trigger (to ECCS)

 

Changes necessary for megasquirt:

 

blue w/red hooked to EFI relay power out +12v

black hooked to MegaSquirt pin #37

 

fuel pump ground (black) goes to Fuel Pump Control Modulator (F.P.C.M.).

wire this directly to ground.

 

 

Crank Angle Sensor (MegaSquirt tach. input):

 

(this wiring is from the harness side of the distributor wiring per the MS install notes mentioned in this forum)

 

+12v from EFI relay output to black w/white stripe

green w/black stripe to MegaSquirt pin #24

install "pullup" 1k 1/4w resistor between black w/white stripe and green w/black stripe. this can be done on the MS itself but I don't understand it's wiring well enough to pick out the correct place for this.

 

 

 

Coil:

 

coil uses direct fire via the VB921.

 

coil negative - MegaSquirt pin #36

coil positive - +12v line from Air Regulator is from fuel pump relay and conveniently nearby.

 

You want to use the fuel pump relay so the coil doesn't constantly charge. It will shorten the life of, or damage the coil, and could possibly damage the vb921. I had it setup for testing via the EFI +12v for several minutes on end while tuning without a problem. Your results may vary - I saw several posts related to this happening on the MS forums.

 

here's how you have to have your MS v3 wired for vb921 when using MSnS-e.

 

http://megasquirt.sourceforge.net/extra/pix/vb921-driver-single.gif

 

i used a spare CHT as my intake air temp sensor (3" tube with a hole in it for the temp sensor, about 6 inches long). the stock air temp sensor produces an identical signal.

 

(removed "(flyback)" from sentence at the top about the vb921.. vb921 and flyback most commonly used in association with megasquirt are not the same thing - flyback is generally associated with the injector driving circuit. i blame lack of sleep for this typo)

[Brad-ManQ45]

Thanks 1seymour!

 

I will be eventually installing MS in my '83ZXT, allthough I am thinking about EDIS for ignition...

 

Please keep us informed about your experience and especially tuning.

 

You might want to post what other mods you have done to your ZXT...

 

Brad

[Guest 1seymour]

3.1 stroker, cold air intake, flowmaster turbo muffler, 11lb fidanza flywheel. that's about all to report on the engine at this point besides megasquirt.

[FoundSoul]

Good Job 1seymour--- I've actually been working to document this process at the request of a customer. I ran it past Moby as I may borrow some info from his original (and excellent) article for the v2.2 install and he was glad to hear it would be updated for the v3.0 and welcomed my borrowing from his article if I needed to. I just updated my article earlier this week and posted it-- I've got more work to do but it's a great start. The temp sensor readings will be handy and I can add those to the article as well if that's cool with you.

 

I'll also update the article for the MS-II, which is VERY similar, just doesn't require the internal mod to grab the ignition signal from the LED and route it through the IGBT circuit to pin37. Otherwise it's pretty much identical.

 

Here's a link to what I've got so far-- more to come including pics of the mods and such:

 

http://www.diyautotune.com/tech_articles/how_to_megasquirt_your_280zx_turbo.htm

[Guest 1seymour]

just hooked up a 240sx tps to my 280zx tb. had to chop off the old one's arms, drill some holes in the arms and bolt them onto the new tps's arms. with the help of a couple washers, it lines up perfectly and will stay where i put it. now to wire it. im going to use moby's info for that. stock tps is just a switch, the 1990 automatic transmission 240sx TPS is full sensing and mates with the 280zxt tb shaft perfectly. the arms aren't as long as the 280zxt ones so the minor modifiction mentioned above is necessary.

 

on another note, i got the wiring harness with my ms. no relay box because i knew where the stock relays were and they are already wired to the fuel pump and everything else. i ran the new harness through the engine bay wall in the passenger side wire hole. i left the stock harness in there for the dash displays. only thing that doesnt work at this point is the tach. i'll post my solution to that once i get that far.

 

if anyone wants to clean up this info and post it somewhere or copy/use it wherever, go for it. im all about helping out other Z owners and now that i've joined the megasquirt community, they might as well benefit, too

 

another great point that's different between v2.2 and v3.0 that isn't mentioned on the diyautotune site is the internal flyback being beefed up to handle the injectors without the external flyback board (ms site recommends external flyback board for more than 4 low imp. injectors with v2.2 if i recall properly).

[Guest 1seymour]

oh yeah.. and im going to use PWM with the internal flyback instead of the resistors for driving the injectors. if i have any issues with it, i'll go with the resistors later.

[DAT240Z]

Hi

Jerry, it was I that asked you to please do a wite up for me and the rest of z guys. Thanks for what you have done so far and look forward to seeing the compleletd project.

[mobythevan]

The notes are good, the more people that add a writeup like this, the more unique installs we can cover.

 

 

I just had one question in relation to this sentence:

 

I'm using the internal VB921 to drive the coil and Hall to detect tach.

 

If you are using the 83zxt distributor it will be using an optical sensor. At first that led me to believe you had set up your own crank sensor with a hall sensor (magnet glued on flywheel or damper). Just curious what you are doing for the trigger input.

[Guest 1seymour]

i wired it up per your instructions with the 1k pullup resistor and followed the "Hall" wiring from the ms page:

 

http://www.megasquirt.info/ms2/V3assemble.htm

 

(search for "optoin")

[Guest 1seymour]

im using the stock optical. not sure if that actually utilizes the hall circuit or not. i just associated the two because they are mentioned everywhere and is the same for wiring that im using.

 

"For the Hall sensor, optical sensor, or points:"

[Guest 1seymour]

i mentioned that i did the tps the other day. after wiring it up, i tested it out last night and it works like it should. i should finally get a chance to do some tuning tonight.

[Guest 1seymour]

i've been busy and so has the wife.. which means when im home, she's not.. and unfortunately, she has the laptop

 

so far i've got the car to fire up and idle and that's about all i've had time for. everything i used for settings is what the ms website said to use for the setup i've got.

 

i think it's pretty safe to say that the way i've set everything up is working and should work well for a straightforward stock 83zxt to ms v3 msns-e conversion.

 

only real issue left is how to get the dash tach display to work. i'm pretty sure it triggers off of the - side of the coil but i haven't tried it yet.

[mobythevan]

I changed the sticky format and updated the must read thread links. That includes a link to this thread, so even though it isn't sticky, the link will always be around and easy to find. Let me know if that doesn't work for someone.

[HB280ZT]

1Seymour,

 

So anymore information on your install? People want to know.

 

HB280ZT

MS&S-E V3 board in work!

[Guest 1seymour]

sorry for the delay.. busy times.. wife's using the laptop waaay too much.. going to have to get my own

 

anyhow, i'm pretty sure i figured out the tach signal today while waiting for her to get home.

 

i have 2 wires going to my coil prior to this change. - from megasquirt and + from air regulator power line. for the stock 280zxt, the condenser is connected to ecu and power and the other - line goes to the tach display. old coil wires had 2 wires coming from coil - terminal. snip the one that goes to the condenser and hook the other (goes straight into harness) up to the - on the coil.

[Guest 1seymour]

my tach shows rpm now and i have the car idling correctly.

 

i setup the timing via moby's notes to get it started and then tuned in the timing via the trigger angle. i ended up using about 63 for my trigger angle instead of what moby mentioned. from his post, it seemed like everyone should use 78 but my timing just didn't line up on that mark. i suspect my oil pump shaft may be a tooth off but am not certain and dont feel like messing with it if i can just change the trigger angle to achieve correct timing. i think it's safe to say that whatever trigger angle gets you to where the timing mark lines up with a timing light and ms reads the same, you're set. someone please correct me if im wrong on this.

 

on another note, im reconsidering using the CHT as the coolant temp in megasquirt. the CHT goes up pretty quick and ends up off the top of the chart in megatune rather quickly. i think this may cause problems when tuning since the coolant is generally at a lower temperature range.

 

wife should be home in a little while with the laptop... then tuning can continue.

[Guest 1seymour]

noticed on another thread that moby wondered which distributor i was using.. im using the stock 83 opto.

[goodoldjam]

Seymour, any thing new, do you have it all up and runnin?

[Guest 1seymour]

having some issues with the vb921, i believe. after running for a few minutes, my spark deteriorates and eventually stops. lights on ms keep firing away but for whatever reason, the spark cuts to distributor above idle. if i turn off the car, wait 10 seconds, it fires right up and revs fine but after just a few moments of reving, the spark cuts whenever i rev. if i leave it running like this, eventually it won't idle.

 

seems like somethings overheating but i haven't been able to figure it out yet.

 

i'm currently trying to get it running via the hei module just to verify if it's something to do with using the vb921 that's causing the problem.

 

i've seen a number of complaints about the vb921 not working for people.

[DAT240Z]

I have the same problem, the coil only fire a few times and than stops, the tries to run but dies. I send the ECU back to DYIAUTOTUNE, twice. The first time he found the the unit have gotten hot and fried the vb921, also lost one bank of injectors which he fixed.The second time he found nothing wrong, I got the unit back friday and the skark still does not work, I have replaced my coil,check all my wires, grounds, still nothing.I have been fighting this problem for a month now. I have serched the megsaquirt forum and have not found anything that could help.I'm seriously thing of buyng SDS. When I think of all the money I have spent on megasquirt I could have had SDS. Lets hope someone here can help us.