Hi,
I'm in a world of hurt here, hopefully someone will have a suggestion that can save my bacon.
I am in the process of building a MS2DIY for my 1989 MX5 using this guide: http://miataturbo.wikidot.com/ms2-a
But when building I forgot one of the pull up resistors on the spark circuit, causing one of the transistors to blow:
After changing out the blown transistor and adding the missing resistor I did a spark test in the car and only spark B is firing. If I swap the trigger wires on the coils the other set fires, so I guess they are physically OK.
Next I replaced the other mod transistor, Q6 and Q8 even the D14 and D16 LEDs and checked resistances of R24-29 and mod resistors but no good.
With the daughter board removed comparing the outer legs of Q6 and Q8 I get different readings -Q8 open and Q6 shorted.
Both R24 and R28 show 5V when the MS is powered up, beyond that I don't know what to check.
I've also been over my soldering with a 10X loupe and there are no bridged traces on the top or bottom of the board anywhere.
What should I be trying next because I'm out of ideas?
Miata 'Joes better spark mod' mistake. No spark A output
Moderators: jsmcortina, muythaibxr
Re: Miata 'Joes better spark mod' mistake. No spark A output
The build instructions found in the manuals linked at the top of the page are what you should have used. Google and other search engines that lead you away from those are NOT your friend. The BEST way to do logic level spark outputs is the TC4427 FET method shown in the manual.
As far as your lack of spark A, the different readings on Q6 and Q8 suggests that one of them ( probably Q6) is bad
As far as your lack of spark A, the different readings on Q6 and Q8 suggests that one of them ( probably Q6) is bad
Linfert Performance/321 Motorsports
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SCCA 2023 FP National Champion Tuner/electrical engineer
100s of MS systems built installed and tuned
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SCCA 2019 SM National Champion Crew Chief
SCCA 2023 FP National Champion Tuner/electrical engineer
100s of MS systems built installed and tuned
Support the developers!
Re: Miata 'Joes better spark mod' mistake. No spark A output
OK, I've emptied the proto board and ordered a TC4427AEPA, resistors and fresh Q6,Q8 transistors. Hopefully they will solve the problem.prof315 wrote:The build instructions found in the manuals linked at the top of the page are what you should have used. Google and other search engines that lead you away from those are NOT your friend. The BEST way to do logic level spark outputs is the TC4427 FET method shown in the manual.
As far as your lack of spark A, the different readings on Q6 and Q8 suggests that one of them ( probably Q6) is bad
Re: Miata 'Joes better spark mod' mistake. No spark A output
I don't understand the build in the injection circuit flyback dampening has been left out but PWM current limiting is installed.
A different transistor has been installed in Q7, if this is an ignition out it should match the other channels
Something strange has been done to the serial connection. Is that bluetooth or USB?
Yet the clock parts for a MS1 processor ARE installed.
I don't think leaving out a pull up resistor would blow a transistor, I would suggest you have an external wiring issue.
Do you fully understand what you are trying to accomplish or are you blindly copying what someone else has done?
It might be best to describe your hardware setup.
Are you doing COP?
Do you have high or low impedance injectors.
Is this a V6 or a I4?
Are you aware that USB cables can make a serial connection on a running car almost impossible? <ignore if you have installed bluetooth
I can't see if there is an insulating spacer under the nut on your Fidle mod output.
A different transistor has been installed in Q7, if this is an ignition out it should match the other channels
Something strange has been done to the serial connection. Is that bluetooth or USB?
Yet the clock parts for a MS1 processor ARE installed.
I don't think leaving out a pull up resistor would blow a transistor, I would suggest you have an external wiring issue.
Do you fully understand what you are trying to accomplish or are you blindly copying what someone else has done?
It might be best to describe your hardware setup.
Are you doing COP?
Do you have high or low impedance injectors.
Is this a V6 or a I4?
Are you aware that USB cables can make a serial connection on a running car almost impossible? <ignore if you have installed bluetooth
I can't see if there is an insulating spacer under the nut on your Fidle mod output.
Correctly identify your MS ecu here
Read the Do's and Don'ts to avoid the common pitfalls before starting your install or asking for help
Use only these manuals other manuals may cause brain damage or worse.
Read the Do's and Don'ts to avoid the common pitfalls before starting your install or asking for help
Use only these manuals other manuals may cause brain damage or worse.
Re: Miata 'Joes better spark mod' mistake. No spark A output
Thanks for looking my build over Rick.
I'm running the stock Mazda coils, twin coil wasted spark setup. Both coils are working on the stock ECU and both can be triggered with spark B (off D16) in test mode if I swap the trigger wires at the coils to test.
The injectors are new Flow Force 640cc which are high inpedence. Product link: http://www.flowforceinjectors.com/produ ... -kit-miata
The parts are due to arrive today, so I will follow the '5.3.1.3 Logic spark outputs - FET driver method' from the official manual and see how we go.
The change of Q7 was part of the mod at http://miataturbo.wikidot.com/ms2-m to run the fan relay -this is working correctly if I force it on in Tunerstudio.A different transistor has been installed in Q7, if this is an ignition out it should match the other channels
That is a bluetooth adaptor, it has been switched off the whole time because I've been using the serial connection in the car to try and simplify things, until it's running properly.Something strange has been done to the serial connection. Is that bluetooth or USB?
I have checked over my harness quite a few times in the last week and I'm certain it's correct.I don't think leaving out a pull up resistor would blow a transistor, I would suggest you have an external wiring issue.
I have been following the miataturbo guide to the T, which has worked for many many others.Do you fully understand what you are trying to accomplish or are you blindly copying what someone else has done?
The Mica spacer and bolt insulator is under Q4. The multimeter shows an open circuit between the top of the TIP122 and the heatsink.I can't see if there is an insulating spacer under the nut on your Fidle mod output.
The car is a 1989 Mazda MX5/Miata with a 1.6L I4Are you doing COP?
Do you have high or low impedance injectors.
Is this a V6 or a I4?
I'm running the stock Mazda coils, twin coil wasted spark setup. Both coils are working on the stock ECU and both can be triggered with spark B (off D16) in test mode if I swap the trigger wires at the coils to test.
The injectors are new Flow Force 640cc which are high inpedence. Product link: http://www.flowforceinjectors.com/produ ... -kit-miata
The parts are due to arrive today, so I will follow the '5.3.1.3 Logic spark outputs - FET driver method' from the official manual and see how we go.
Re: Miata 'Joes better spark mod' mistake. No spark A output
Just an update:
I fully redid the ignition circuit as laid out in the manual with the TC4427 etc and we have spark!
Although I'm sure the design of the miataturbo mod works, I had done something wrong and just starting again with this even simpler design got me through.
Thanks again for the help guys.
And now onto the next thing -a sneaky vacuum leak. But that a question for another forum.
I fully redid the ignition circuit as laid out in the manual with the TC4427 etc and we have spark!
Although I'm sure the design of the miataturbo mod works, I had done something wrong and just starting again with this even simpler design got me through.
Thanks again for the help guys.
And now onto the next thing -a sneaky vacuum leak. But that a question for another forum.