Megajolt E - Debug no spark at initial start

EDIS and Megajolt installation related topics. Be sure to review the <a href="http://www.autosportlabs.net/MJLJ_V4_vehicle_installation_guide">Vehicle installation guide</a>

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Elevenssc
Posts: 5
Joined: Wed Apr 05, 2017 1:39 am

Megajolt E - Debug no spark at initial start

Post by Elevenssc »

I hope this is the right forum for this question. I'm new to the Megajolt world so bear with me as I get up to speed. I want to thank you all in advance for your help with getting me back on the road.

Some background info...
1970 340 ran fine with distributor and MSD6AL
EDIS-8 is new-old stock
Coils and mag pick up are from a 1997 Ford Crown Vic
Trigger wheel is a custom 36-1 design to fit the Mopar crank pulley bolt pattern

After installing the components, and wiring the system over the winter, I tried to start it today and I have no spark. The light on the MJ unit comes on when turning the key to "on". The MJ and EDIS are powered from the same source, and grounded at the same location.

I went through the signal verification protocol and here's a summary...
VR sensor...0 volts in run and 0 volts in crank. Switched the leads on the sensor and got the same result. I have a 0.027" gap between the VR sensor and the trigger wheel.
PIP Signal...11.5 volts in "run" before crank, about 9 volts during crank (should be 5.5V at crank...is this a problem?) Voltages measured between EDIS pin 1 and ground.
SAW signal...11.5 volts in "run" before crank (should be 0...is this possible?...this is likely the source of my problem), about 9 volts during crank (should be less than 0.2v) Voltages measured between EDIS pin 3 and ground.
Tach out...about 9 volts at run (should be 5.5...again, is this a problem?) Voltage measured between MJ tach out and ground.

Diagnosing and debugging electrical issues in real time is challenging at times. Adding forum questions in the mix adds to the challenge. Please let me know if any other information is needed to help diagnose this no spark issue

Thanks again in advance for your help.

Tom

brentp
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Post by brentp »

Hi,

If you're getting no spark and you've verified power and ground connections to the EDIS module, then I would recommend swapping the following in the following order:

VR sensor - since you're getting 0 volts - that seems to be the smoking gun.
EDIS module
Coil pack

Let us know what you find out!
Brent Picasso
CEO and Founder, Autosport Labs
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Alex B
Posts: 163
Joined: Sat Aug 09, 2008 10:32 am
Location: Hegra, Norway

Post by Alex B »

I have written it before on this forum and I am writing it again: never swap without having tested with parallel operation! Install the whole MJ circus and use a set of extra spark plugs (preferably screwed into a bar of metal that is earthed to the car). Then run your engine. Much easier to see if you have a spark and to start fault searching if you don't.

Alex

Elevenssc
Posts: 5
Joined: Wed Apr 05, 2017 1:39 am

Post by Elevenssc »

Update...

Pulled another mag pick-up, EDIS-8, and coil from donor cars. Replaced the mag pickup with no success. Next step was to verify voltage and continuity at the EDIS.

In the process, I noticed that the wiring diagram on the website may be wrong (which I find hard to believe, but possible). Pin 1 on both EDIS modules is ID'd on the connector end with location tooth centered (closest to the mounting bolt on the same side as the connector). The wiring diagram from the website shows pin 1 on the connector end with the location tooth off center (which is furthest from the same mounting bolt). I wired the connector per the diagram from the website. Which one is correct?

Going to reverse the connector wiring and try it again...

Elevenssc
Posts: 5
Joined: Wed Apr 05, 2017 1:39 am

Post by Elevenssc »

Here's a pic...
Attachments
EDIS.pdf
(185.13 KiB) Downloaded 348 times

brentp
Site Admin
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Post by brentp »

any luck after reversing?
Brent Picasso
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Elevenssc
Posts: 5
Joined: Wed Apr 05, 2017 1:39 am

Post by Elevenssc »

Yes...Got spark, but still no start. Debugging coil integrity now.

Oh the joy of bone yard roulette :-)

Elevenssc
Posts: 5
Joined: Wed Apr 05, 2017 1:39 am

Post by Elevenssc »

Finally got some garage time :-)

Ive got good spark at the coils. Spark at the plug is weak to non existent. I'd planned to replace the donor wires once I got the car started, but it looks like I need to do it sooner.

Does anyone know if I can get the clip-on style coil connector in a "make your own length" plug wire set?

Thanks

Tom

brentp
Site Admin
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Joined: Wed Jan 24, 2007 6:36 am

Post by brentp »

Best way to make EDIS compatible cables is to get a generic set with the connectors you want that match the coil pack, then adapt them to the plug ends you need.

Glad you got further along!
Brent Picasso
CEO and Founder, Autosport Labs
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55f100460
Posts: 2
Joined: Sat Apr 28, 2018 4:45 pm

clip on coil pack boots

Post by 55f100460 »

hello new to the forum,
I found these Standard motor products part numbers TN25 boots TN26 Clips ST28 terminals. I ordered these parts from www.carid.com the only problem is you have to order in box quantity

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