Ark1

I am having trouble obtaining a spark on my leading coil. I have tried 2 different leading coils. I have read that the leading trigger signal should be between 3 and 5 volts. Is that Correct?

I have 2.46 volts and a pulse of 4 mil seconds.

Here is a You Tube video.

I will post this on the MegaSquirt form, but need to know the parameters of what the stock coil requires to fire.

Thanks,

Ark1

Ark1

Here is an update. This has taken me 6 weeks to get past several problems with the MS2.

As I stated the new board I purchased had a bad R20 resistor.

https://www.rx7club.com/attachment.p...1&d=1366335102


This caused the Q 5 transistor to burn closed and I lost the secondary injectors. The board was returned to DIY Autotune and a new resistor was installed. When the board came back I used a Noid light to check that the secondary injectors were not firing. Wrong, Q5 was still shorted. I emailed DIY Auto tune and requested a replacement board. A 3.57 board was shipped to me, but judging by the dust on it, it had been sitting somewhere for a bit of time. I transferred my Zeal Daughter card from the original board to the replacement board. I could not get the Crank out put from the CAS to fire the board injectors. I was assured that the replacement board had been tested. Using and Oscilloscope I proved the CAS to be working correctly. I transferred the Zeal daughter card back to the original board and obtained flashing LED lights. At this time I had trailing spark but no leading spark.

I salvaged the Q5 driver from the replacement board and resolved the secondary injector problem.

When I start a project like this I make a manual with all of the information so that I can read it, make notes and check off my progress. The manual is part of the car.

https://www.rx7club.com/attachment.p...1&d=1366335522


I proved output of the Leading spark at D14 but the output was low. It should be 4 volts but was only 2.46 volts. The scope showed a pulse signal. Open circuit without the leading coil connected it was 4 volts. I spent weeks testing and trying to come up with a solution. Several emails went back and forth with Matt at DIY Auto tune.

Q6 inverting transistor was found to be bad and was changed from the spare board. It too did not resolve the leading spark issue. Matt suggested that I by pass the inverting circuit on the board and go directly from Pins 7,8 & 9 from the CPU to the out put pins that drive the leading and trailing coils. A change in the spark from normal to inverted signal was done to the CPU flash, no change in leading spark coil status

Then I found the following. This the email I sent to DIY Auto Tune with what I found to be the problem.

Matt as I laboured over this issue of no Leading spark I found an error in the DIY Auto tune wright up.
https://www.rx7club.com/attachment.p...1&d=1366336005

The Leading coil has 3 wires coming out of the Ignitor.

Tan +12 volts.

Red Signal Pulse

Black Ground.

Black is not a ground for this coil. It is a signal wire on the Primary winding ( -) of the coil after the ignitor. See Leading Coil.jpg

So if the black wire is grounded as in the instructions the output of the ignitor is loaded down and fails. Also the coil sees a continuous 12 volts from the car battery and burns up.

In the write up it should mention that the coils require a sound case ground to operate, there is no mention in DIY Auto tune write up or the Haynes manual.


Totally lost and before I realized what was happening I decided to install a spare trailing coil to be fired by the leading coil signal lead from the MS-2 as I knew the trailing coil worked. In researching how the trailing coil fired I soon realized that the trailing coil does not have a ground connection. Which led me to the leading coil also on the Factory wiring diagram and it does not have a ground connection either. The ground connection for both coils comes from the case of the coil to the body of the car, Period.

See Factory wiring diagram.


https://www.rx7club.com/attachment.p...1&d=1366336081


Now if you would look at the picture of the leading coil ignitor.

https://www.rx7club.com/attachment.p...1&d=1366336205


The Tan wire goes to the Module and through a ballast resistor then directly to the Primary coil lug.
The Black wire starts from a bullet connector then goes to the module and then directly to the Primary coil lug.

So following the instructions will no matter what is s set in the ECU memory, Normal or inverted will toast the ignitor and Leading coil. I have 3 failed units that will support this written direction.

From an electrician's view point a print would certainly be a better way of showing what the connections are and should be made. The bullet connector on the black wire is an output possibly for a tach signal.

Just to let you know a good functioning ignitor viewed on the scope will show open circuit, not connected to the coil about 50 volts at the primary lugs.( Once again not connected to the coil). The pulse is very profound


I will do a post on the RX7 owners club with my findings. I must conclude that not very many people could have followed the directions as closely as I have, or if they have the car is running only on the trailing spark plugs.


DIY Auto Tune has confirmed on their test car that my findings are correct and have amended the on line instruction manual that the Black wire has no connection and that the coils are grounded to the car body.

I now have leading spark and am in the process of putting the engine back together. I have a few tests to do, secondary injector firing, fuel priming and pressure test for leaks and expect to test run the engine on the stand this weekend. I will post a video with it running.

I sure hope no one else has had this much trouble, I am almost there.

Ark1

https://www.rx7club.com/attachment.p...1&d=1366336515

Ark1

Here is the You Tube Video of the engine running on the stand.

The Mega Squirt manual should really have the installer ( Me) prior to starting lock the timing at Zero degrees in my opinion. Just one less thing to try and figure out why the engine is doing what it is doing.

Anyway, in the process I lost all 4 injectors but had spares. Lost 3 Leading coils as well.

What I learnt, never connect the coils or the injectors until you can prove that the MS2 is not sending a signal or power to the device when on and not cranking.

I am past that now.

Please take a moment and see this engine run.

Ark1

diabolical1

iTrader: (3)

well, this is my second go-round on this MS2 install and i'm finding out many things that I did wrong the first time. this is one of them. I grounded the coil per the DIYAutoTune and I think that explains a lot of the failure I had with my brother's car.

I was attaching my GM Weather Pack connectors to my coils tonight (my Gen II this time) and of course, I decided to pull the coils apart to map all the wires and make new diagrams for my personal future reference (much like your binder ) of the 8 wires coming out of the trail coil assembly, there is only 1 black wire and it is ground for the T2 coil, so i'm thinking it can't be the tach signal as the DIY writeup states.

I only found 2 wires that I was unable to figure out: the yellow one and a dark gray one.

1. DIYAutoTune listed the yellow one as IGF and states it's not needed for the MegaSquirt; however, the legend on the igniter itself lists it as TAC. i'm wondering if that's the tach signal. at this point it is just for my personal curiosity that I want to know what it does.

2. the dark gray one is CPU1 on the legend and is not mentioned on the DIYAutoTune chart at all. in all fairness, it "looks" black so maybe this is the tach signal they listed on their chart. anyone know?

I know you got your engine running already so you've already answered whatever questions you had. this thread has been helpful to me, so thank you. i'm really glad I ran into it and I will link it to the thread i'm about to create in the Megasquirt forum/section.

diabolical1

iTrader: (3)

well, it appears my skepticism was a bit misplaced. in this other thread of yours (https://www.rx7club.com/megasquirt-f.../#post11485261) you run the tach signal from the lead coil on the bullet connector black wire that connects indirectly to the negative post at the coil itself.

so I guess since the black wire on the trail coil runs to the negative post on the T1 coil (I misspoke in my earlier post, it is NOT T2), then it is indeed the black wire that gives the tach signal.

so I still have no idea exactly what the dark gray (CPU1) and yellow (TAC) do; but the DIYAutoTune chart, with regards to the tach signal, is very much correct. I just want to clarify that I was wrong in my earlier post.

Ark1

This whole set up is a bit tricky and the write up was not correct. I am sure others have just gave up. What I am finding is that the trailing plugs are firing on the wrong rotor and I cannot seem to change them other than by switching the High Tension leads at the coil. What you will notice if they are on the wrong rotor is that the engine when cranking miss-fires and just about stalls the starter.

To prove this I disconnected the low side leads and cranked the engine and started it, no stalling of the starter. I then reconnected the low side leads and again stalling of the starter. I swapped the High side leads and no stalling of the starter happened. I rotated the CAS 180 degrees changed the High side leads and again stalling of the starter. So for now I have the High side leads swapped.

I can live with this.

Ark1.

Snaple07

iTrader: (17)

I wired my trailing coil the incorrect way then...that is probably why my engine has been making this lobbing sound like a stroked out V8. Do you have any pictures of the trailing coil as it is supposed to be wired and hooked up correctly. I don't have the zeal daughter card and I did modify my CAS by grinding 2 teeth. The write up that I followed was this

http://stuff.pw.cx/Megasquirt%20MS2%...azda%20CAS.pdf

and good grief...that write up was last updated November 2nd of 2007...........

I am also looking for a good starting point or example for a spark advance map.