GRM $2008 Feisty Festy MS Thread

[dok33]

Been lurking here for a while gleaning all of the excellent MegaSquirt info and decided to post up some info on our GRM $2008 Challenge project in hopes of getting some help




The car is an '89 Festy we picked up for $525 with a botched BP swap. The PO completed the swap but never got it running, I think mainly because of the hacked wiring (yes it's all butt splice connectors ):


More info can be found here: http://www.feoa.net/modules.php?name...wtopic&t=52156

We are currently trying to figure out how to wire up the MegaSquirt we picked up for $150 (MS-1 v2.2, will run MSnS-e). The harness is a mess and they unplugged everything for some reason but we were able to find all of the sensor clips (Disty, TPS, 3xtemp) with the exception of the coil.

The plan is to wire them into the DIY Autotune harness we have and we're currently trying to figure out what we need off the body harness for power/ground as well as relays for lights and other stuff. The team is 4 MEs and 1 EE so if he doesn't know what to do we'll be relying heavily on forums to figure this stuff out

Any pointers/tips would be greatly appreciated, I'll be sure to post plenty of questions once we get there

I'll leave you with a few pics of how the car currently looks:

[matt_fulghum]

looks good

nice to see another fellow GRMer on the board too!

if you need any help with setting anything up, we'd be happy to help out.

[dok33]

Thanks! My only questions at this point are:
-For those who wired a separate MS harness (like the DIY Autotune one), what did you keep in the way of factory power circuits/relays?
-For the BP coil, we don't have the pigtail from the harness so can anyone tell me the wire colors for each pin, 2 bump side and 1 bump side will work:


I've got the BP diagram so I can decode it from there, I've also read that the + terminal is a thicker gauge so that would help too.

[therieldeal]

the + wire is a thick gauge blue wire from the dash to a few inches before the coil. then it becomes blue with a stripe, and thinner gauge.

[dok33]

Try to condense the questions:
1. Any ideas which side of the coil itself is +? I need to take some pics of the engine harness in this thing (LOL), the coil wiring seems to be MIA..

2. Also, anyone running the stock CLT and IAT (does the BP have an IAT or just in the VAF?) sensors and have easytherm values for them?

3. Using the stock BP disty, here's what I'm thinking on hooking it up to the MS:
White wire (trigger) to CKP (Pin 24) on Miata diagram
Blk/lt Green (Grnd) to sensor ground
White/Red (13.8V) to ?? on MS (or is this just a 12V power signal?)
Yellow/Dk Blue (home) not connected
Coil (-) to Pin 36 on MS (Spark Output A on Miata diagram)
Coil (+) to 12V switched power

Do we need an igniter? I know the V3 PCB has an ignition driver but Im pretty sure the 2.2 doesn't (which is what we have).

4. TPS
Lt Grn/White (signal) to Pin 22 (signal) on MS
Lt Grn/Red (5V) to Pin 26 (5V) on MS
Blk/Brn (Grnd) to sensor ground

5. CLT
Blue/White (signal) to Pin 21 (signal) on MS
Blk/Brn (Grnd) to signal ground

6. Can all sensors go to the thick black wire on the DIY Autotune harness?

[ryan1]

lex or russell could help.

[dok33]

Cool, I was hoping Lex would chime in, I think he's running the same setup ignition-wise and always seems to be helpful

[gorgonheimer]

power to all who have a festiva and bp. im in houston so if you need some parts(i have a donor car and extra motor) let me know

[dok33]

Little update, wired everything but the injectors and IAT sensor up last night like this:
1. Stock BP disty:
White wire (trigger) to CKP (Pin 24) on Miata diagram
Blk/lt Green (Grnd) to sensor ground
White/Red (13.8V) to 12V ign power
Yellow/Dk Blue (home) not connected (verified with other MS users that it's not used)

2. Ignitor/Coil:
Dk Grn/White (SpOut) to Pin 36 on MS (Spark Output A on Miata diagram)
Blk/Orange to Sensor grnd
Yel/Dk Blue to Coil (-)
Coil (+) to 12V ign power

**still need to know which pin on the coil itself is + and which is - as we don't have the factory harness connector to decode...

3. TPS: not used (will use MapDot for Accel enrichment)

4. CLT: **need EasyTherm settings
Blue/White (signal) to Pin 21 (signal) on MS
Blk/Brn (Grnd) to signal ground

5. Injectors: Tieing 1&4 and 2&3 together (http://www.wihandyman.com/forum/show...=31479&page=10)
All wht/red wires to 12V ign power
Yel on #1 and Yel/Blk #4 tied to Pin 32/33 on MS
Yel on #2 and Yel/Blk #3 tied to Pin 34/35 on MS

6. IAT: using stock 1.9L Escort IAT sensor, need to figure out polarity and easyTherm settings if anyone has 'em

[dok33]

Finished the wiring last night but couldn't get it to fire. Looks like the MS isn't seeing a tach signal, RPM, pulse width, and duty cycle gauges in megatune are pinked out. Also was showing "Fuel Pump Off" in the lower left corner and wasn't kicking the FP on. Pretty sure it's hooked up right, if we ground the wire we're tapping into the FP kicks on...

I also noticed that we don't get any LEDs on the MS when it's hooked to the car. With the Stim the one closest to the serial connector is lit but not when plugged into the harness. Gonna do some more troubleshooting in a few days when we meet again. In the time being, if anyone has any suggestions they'd be much appreciated!!

[matt_fulghum]

When you turn the car on, do you hear the fuel pump run for a few seconds and then stop? If not, you probably don't have the fuel pump wired up right.

As for the tach reading... did you put in the 5V pullup? If you don't have the pullup resistor in there, it won't work.

[dok33]

FP doesn't kick on when it's wired to the purple wire on the MS harness (Pin 37), only if we ground the the wire at the FP relay.

For the 5V pullup, is it this one you're talking about: http://www.msextra.com/manuals/MS_Ex...al.htm#hallV22

[matt_fulghum]

yep, that's the pullup resistor you need.

For the fuel pump, have you got it wired up like the stock ECU, with the MS grounding a relay for the fuel pump?

[dok33]

Is it the high-low (first one on the linked page) or low-high setup (2nd one if you scroll down)?

On the pump-the MS wire is run to the wire at the relay that will kick the pump on if it's grounded. The pump runs if we don't connect the MS wire and just ground the wire at the relay, but if it's connected to the MS wire nothing happens.

[matt_fulghum]

I have forgotten exactly how it goes... I think it's a High to Low, but it shouldn't matter for getting an RPM signal, just for timing.

The important thing is having a 1k or 2k resistor from 5V to the distributor output wire, also make sure you're using the 4 vane output, not the 1 vane output.

As far as the fuel pump goes, I'm not sure what to say... I'll think about it when I'm off of work.