# Megasquirt no spark/fuel, need help, wiring diagram inside.



## boxerdudejay (Jun 16, 2009)

Some brief history on my setup, my megasquirt was pulled from a running mk1 gti with JH turbo, it was wired up with a mk2 knock box and it had a MS relay board. The wiring job was so messy and poorly put together that i pulled it all apart and redid it, Now i am not getting spark or fuel, i have it wired up according to some users diagram's and according to the mega manual.

My car is a 78 GTI and it has a white/violet wire that originally was connected to the coil, i cant figure out which side it was connected to, it also had a black wire in the same connector but was cut off, is this for the (+) side? its not connected now.

Here is how it is currently wired up, can someone tell me if something isn't right or if i am missing something? (sorry its a little messy)









Some things i tried
- pin 32/33 to inj 1/2, pin 34/35 to inj 3/4
- removing the msd box
- swapped bosch ign modules and distributors with known working units


My setup:
Fresh PG block
Ported ABA head
T3 Turbo/manifold
mk4 2.0l AEG intake manifold
g60 injectors, 3.5bar fpr
other goodies


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## ps2375 (Aug 13, 2003)

Are you getting an RPM signal in megatune? Are you just running fuel only or are you doing fuel and spark with the MS? The diagram looks the be fuel only. Where are you taking the RPM signal for MS from? It needs it to provide both fuel and spark. And if you are using the MSD, you don't need the ICM, the MSD does that function for you.


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## boxerdudejay (Jun 16, 2009)

Pin 24 on the MS connector receives tach signal right? shouldnt the ign module send it from pin 7? I dont know if megatune is detecting rpm's, since the car doesn't start, when cranking the tach in megatune stays at 0rpm.

If i dont need the ICM then i just wire pin 24 to the signal wire at the hall sender correct? ground and positive are pretty straight forward, what wire would i connect the white (trigger wire) on the msd box too?


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## Prof315 (Jan 5, 2009)

boxerdudejay said:


> Pin 24 on the MS connector receives tach signal right? shouldnt the ign module send it from pin 7? I dont know if megatune is detecting rpm's, since the car doesn't start, when cranking the tach in megatune stays at 0rpm.
> 
> If i dont need the ICM then i just wire pin 24 to the signal wire at the hall sender correct? ground and positive are pretty straight forward, what wire would i connect the white (trigger wire) on the msd box too?


Tach at 0 while cranking = no RPMs.


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## ps2375 (Aug 13, 2003)

Again, fuel only or spark and fuel? And I would send hall signal directly to MS for tach signal. I am also using an MSD box and am running fuel and spark by the MS and do not use the ICM.


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## boxerdudejay (Jun 16, 2009)

Sorry yeah just using MS for fuel, i am 99% sure i have MS1 v2.2, which from what i read ms1 doesn't control spark. Ill try and switch some things around and report back.


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## Prof315 (Jan 5, 2009)

boxerdudejay said:


> Sorry yeah just using MS for fuel, i am 99% sure i have MS1 v2.2, which from what i read ms1 doesn't control spark. Ill try and switch some things around and report back.


The easiest thing to do if you are fuel only is to use the tach signal from the MSD as your Megasquirt tach in (pin 24). MS1 basic firmware does not support spark but MS1/Extra firmware does.


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## need_a_VR6 (May 19, 1999)

MS1 (with the right code and board mods) CAN control spark. 

Are you setting it up *exactly* the way the PO had it?

An unmodded ECU will want a 'coil' type signal (big voltage spike) and that's hard to get with the MSD in the mix. You can't trigger off the coil - from MSD, you'll have to use the MSD tach output with a relay coil pullup, or mod the ecu to read rpm right from your hall sender. 

If you post pics of your board top/bottom someone will be able to id if there are mods, no mods and what to try next.


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## boxerdudejay (Jun 16, 2009)

Thanks for the help, ill get some pics tonight of the board.

Its hard to say if i had it wired like the PO, he had a relay board, and a knockbox from mk2 gti wired up all together and it was a nightmare of a wiring job, i deleted the knockbox and relay board to clean things up a bit.


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## boxerdudejay (Jun 16, 2009)

Heres some pics of my MS board.


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## need_a_VR6 (May 19, 1999)

I can't see for crap on my phone, what are the color codes of the two resistors that are 'in the air' and where do the ends land?


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## boxerdudejay (Jun 16, 2009)

They are both connected to R10. They are light brown/tanish color with a gold, brown, purple and red stripe


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## boxerdudejay (Jun 16, 2009)

Did some searching and still cant seem to find any info on what these 2 resistors on R10 are for.


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## 1.8T16vhead (Aug 3, 2006)

here this is how i mod my V2.2 boards for fuel and spark 

remove d8 and instal a jumper 

run a 1K resistor RHS of r26 to - on the led you are using for spark and run it right into pin 36 on the db 37

xg1 to x14











and here is the wiring diagram









hope it helps 
and if you need a msq i got a few


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## boxerdudejay (Jun 16, 2009)

I may be wrong but i was told with my MS1 board that they dont support spark?


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## ps2375 (Aug 13, 2003)

The v2.2 board can, with the correct mods.Then all you need is the MSnS firmware.


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## 1.8T16vhead (Aug 3, 2006)

you can run fuel and spark with V2.2
ask to 
need a vr6 
t3bunny
valvecovergasket

and a few more people arround here 

i have done it over and over 

let me take some pictures and i will post them later


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## ps2375 (Aug 13, 2003)

It is obvious by the picture of your board that it is not modded to support spark. "1.8T16vhead" has posted a crude diagram of the mods needed to support spark on the v2.2 board. Unless you are very familiar with what you are doing, I wouldn't do it, send it off to Paul and have him mod it for you, then you know it will be done correctly and will work. Mine came modded by someone that is no longer around, and works fine, but if I had it to do again, and I did for another car, I would go with a v3 board, as it supports spark from the get go.


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## boxerdudejay (Jun 16, 2009)

Sorry i was just a little confused, after reading it doesn't support spark and then reading it does and back and forth its just a little contradicting but i will mod it like 1.8T16vhead says to and try one of his msq's.

Still curious on how i wire in my msd into the megasquirt.


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## ps2375 (Aug 13, 2003)

pin 36 to the input of the MSD. The MSD takes the place of the ICM.


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## need_a_VR6 (May 19, 1999)

I would follow the mods listed in the documentation section on msextra. If for no other reason then they are easily referenced. 

Spark output to the msd, make sure you use fixed dwell and inverted output in the software.


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## 1.8T16vhead (Aug 3, 2006)

here are the pictures 

i like spark out to pin 36 in DB37 in case you ever install a V3.0 there is no need to modify the 
harness 


































and if you need a MSQ i can E-mail it to you 

here a picture of the engine in my rabbit with megasquirt


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## need_a_VR6 (May 19, 1999)

You can always use a different spark pin on a V3 as well... I usually use 25,27,29,31 due to the coil cars to keep consistent across different setups.


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## 1.8T16vhead (Aug 3, 2006)

you are right


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