Yesterday i managed to finish up the assembly and installation on my 96. MSI, V3.0 board. this is a stand alone wired up directly to the stock harness. After the hardware installation i unplugged the coil packs, flashed the 029V firmware, downloaded the MSPNP 9697 msq to get me going, replugged the coil pack and cranked the key. Car has 550 injectors installed.

As soon as i cranked the car fired up right away and ran very rough then rougher and rougher until it stumbled and stalled. this was all over the span of 5 seconds. tried to crank again, no good. then had an oh **** moment, the mspnp is setup for the stock 250 injectors. so i went in and rescaled the req fuel and cranking PWs. still no luck. then i unplugged the fuel rail and cranked to clear it out if its flodded and plugged back. no good. reflashed the firmware, double checked the wiring, and spent about 2 hours debugging before i had to quite to for now.

Here are some things that i noticed.

CLT temp is always pegged at -40F, i need to figure out why that is.

IAT is also always at -40F.

the fuel pump does turn on and off, i can hear the relay when i crank and at power on.

TPS always reads 253-255 regardless of the actual throttle position. i also noticed that the flood clear box at the bottom right of megatune is illuminated red. does that mean it's active? maybe the jacked up TPS reading is telling MS that i'm trying to clear the engine and it keeps the injectors off? i tried unplugging the TPS connector and that did not help.

i will probe around with a DMM and figure out why the MS isn't getting those signal when i get home tonight.

Im wondering if there is something i did that was obviously wrong. and why did the car start at all in the first place. i dont know why but i also have a fishy feeling that the coil packs may have fried. What do guys think?

 

#1 too much fuel. you didnt scale anything for 550s.

CLT and AIT, it's missing the signals.

TPS, it's seeing a full 5v.

 

Definately fix your intake and coolant temps as these are critical for warmup and after start enrichment.

Another thing you might check is your fuel pump. I was having similar issues where the car would start, idle for a moment, then die. Turns out the fuel pump wasn't turned on.

 

Seconded. Solve all this first.

Make sure you got the TPS wiring correct at the harness, and make sure you kept both R4 and R7. For 550's, be sure to scale back warmup and cranking settings as well. I vote starting with 2.0 in the 160F bin and working ur way up .2 - .4 per bin.

 

Are you sure you don't have the coil's reversed as well? Remember the outputs should be COILA-COIL2 and COILB-COIL1

You must have the TPS signal and 5vref wires wrong. You'll never get it running without a functional clt reading let alone no iat. You did leave R4 and R7 installed correct?

 

i've spent another 2 hours of hair pulling today. here is some more information and answers

1. the image braineack has for installing the IAT to the stock 94+ MAF plug is wrong!. You need to connect the sensor between pins 1 & 3, not 2 & 3. pin1 is the ground connection. after correcting it the IAT now reads correctly.

this is the wrong image


2. The clt pin is pegged at 5V, i verified that all the wiring is correct down to the actual sensor behind the head. for some reason MS is sending 5V to the sensor all the time. im being suspicious of the grounding of the sensor, i'll track that and see where it goes to the harness.

3. This is how i have the coils wired up, DB31 goes to coil1&4, DB36 goes to coil2&3. Is that correct?

4. i have the TPS wires done per the write up, but i'll swap the wires and see what that does.

 

i've resolved another problem. the TPS ground was floating. acording to the factory diagram it goes into a junction box located at "right side of WP" and i don't know where the hell that is.

 

You are having the same exact problem I had. The junction box goes back to the factory computer. You need to ground the wire coming from the junction box on your boomslang harness.

https://www.miataturbo.net/forum/sho...t=18080&page=2

 

Then brain's picture or the maf connector will work for you, because it works for me.

 

Jsisco, thanks. i was just figuring that out as you were posting. now i get readings from everything except the stock narrow band O2 (not using a wideband yet) and the CLT. I have verified that the CLT reading isn't 5V anymore, more like 2ishV which makes sense and i've traced it all the way to pin25 per the MSI V3.0 schematics. but Megatune is still showing -40F and the O2 reading is still all the way to the right. does this sound like a firmware issue?

Also, if someone can verify i have coils wired up per my reply earlier i would really appreciate it.

Plus, what's verbosity and what should the setting be in the MS uploader?

 

Image is straight off DIYAUTOTUNE's installation manual....check the host of the picture....

http://www.megasquirtpnp.com/models/...e/IMG_7222.jpg

 

It couldn't hurt to try reflashing the firmware. Did you tell the megasquirt you are using the narrowband? I don't know this for sure, but it may not show anything until its warm. I would just try starting once you have a CLT and IAT reading.

That is how mine is wired.

I had trouble burning with the MSII downloader. Just burn straight from Easytherm. Just make sure you still put the .inc files from easytherm in to your MS folder. Just click "download to MS" in easytherm with all the right settings.

Just trying to point out that they were correct and work for me. Since you are a badass and they are in the howto I figured they were your work.

 

Did you unplug the igniter when you flashed the firmware? I see you only mentioned the coils...

For ***** n giggles try new plugs, you can render plugs pretty much useless pretty quick running that rich. Especially if you are trying to get an EMS started for the second time with a tune that probably has crap cold start settings and an AF that is less than ideal.

 

No I unplugged this here as it says on the DIY site. what are the symptoms of a fried coil? would that start at all? what if one is fried, would it start and lump on two cylinders?

 

When I did my install the car started and ran long enough to satisfy me so I could leave the project alone for a few hours, when I came back it wouldn't start. I ended up fixing it with a new igniter. I had unplugged the coils but not the igniter.

This is from DIY's site:

Things to be careful of:

IF USING THE STOCK IGNITORS:

"When the MS is powered off, it's spark triggers are grounded. So you MUST make sure the MS is powered on if the coilpacks/ignitors are also powered on! During installation, it's common to have the MS attached to the ignitors, and have the ignition key "on," but not have the MS powered up yet. So I make sure I do power and grounds first to the MS, and attach the spark outputs LAST before I am ready to start the car.

You'll know you're doing it right if the "power transistor" (a.k.a. the ignitor) is not too hot to the touch."

I have a 1.6 so maybe things are different or maybe my igniter frying was caused by something else and unplugging the cols is enough... but after that I probably flashed my firmware 2 or 3 more times, unplugging both the coils and the igniter, and I had no further issues.

 

1.8s have no ignitor, they are on the coilpacks....

 

D'oh!

 

I got all sensors working now. i actually got the car to catch a couple of times but it was extremely lumpy and ran at around 300rpm. checked spark and i'm only sparking on 1 and 4. the weird thing is that i also heard the fan relay click on and off at fairly high frequency and the fans spinning slow. to me this means 3 things.

1. i have Fan mod circuit output wire and coil 2 wires switched so the MS is actually sending the spark signal to my fan relay.

2. i have a burnt coil2 :(

3. or ???

 

****, i blew one of the coil packs. anyone have a spare 1.8 coil pack?

 

Forget the 1.8 coil packs they are far too expensive and fragile for a MSer. Go for a COP setup. I see it as an upgrade for cheaper than the OEM replacement.

Im not entirely sure why they blew if you disconnected them when flashing.

Possibilities:

1. You were right about cocking up the fan and spark output. More likely the settings in Megatune than the wires mixed up.

2 Somewhere in your harness the trigger signal is being "lost" and the coil was energised for ages cooking it.

Check the Megatune settings and get back to us