Can't start ! No RPM reading and No spark

General Megajolt Questions and Answers

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ben25
Posts: 8
Joined: Wed Jan 25, 2012 1:55 pm
Location: France

Can't start ! No RPM reading and No spark

Post by ben25 »

Here is my problem.
First of all I verify 3 times my wiring and everything seam to be good.
(just a precision : my MJLJ and EDIS have a permanent +12v that I stop with my battery cut off)

So my configuration is with the EDIS4 and MJLJ V4 with MAP configuration and a good computer/MJLJ connection
When I try to start my car the starter motor is on , I see on my computer that the vaccum value have variation but I don't have nothing on the rev gauge.

And I don't have any spark !
I have verified +12V on MJLJ, EDIS and on the Coil Pack and everything receive the power.

So have you an idea of why I can't start and why I don't have any spark ? (tried 2 differents coil pack et EDIS4 and the problem is the same)
Last edited by ben25 on Wed May 09, 2012 7:05 am, edited 1 time in total.

brentp
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Post by brentp »

The common problem with no spark is a mis-wired VR sensor. The VR sensor will not work if it is wired backwards; try switching the wires connected to the VR sensor and try again.

Also, you can also go through the verification steps, here:
http://www.autosportlabs.net/MJLJ_V4_ve ... tion_Steps
Brent Picasso
CEO and Founder, Autosport Labs
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ben25
Posts: 8
Joined: Wed Jan 25, 2012 1:55 pm
Location: France

Post by ben25 »

Thanks for help Brent.
I've tried to inverse vr sensor wiring and it's the same.
I've make some vérification of signal.
Vr sensor seems to be ok
Saw signal seems ok.
Tach out also.
But pip signal is not normal:
Between edis pin1 and ground 0v when not running. But i should have 12v....
I've measured voltage on pip input on mjlj it's still the same : 0v.


I'have take a pics of my rev limiter wiring if it's help:

http://imageshack.us/photo/photo/692/im ... 53230.jpg/

Can someone tell me why i dont have a pip signal?

So whats wrong with my pip wiring?

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

Post by brentp »

Your hard rev limiter wiring looks good. What I would recommend you doing is remove the Megajolt from the system, set it aside, and jumper the coil power to +12v. This eliminates the Megajolt from the system for initial testing, since the EDIS can run the engine by itself at a fixed 10 degrees limp-home mode. Get the engine working on EDIS alone before plugging in the Megajolt.

Regarding the PIP signal: have you verified power to the EDIS when engine is turned to ON? and verified +12v and ground are connected to the correct pins on the EDIS module? Also, when the engine is 'ON' can you verify you're getting +12v to the megajolt power pin (on molex connector).

Keep us posted on what you find out!
Brent Picasso
CEO and Founder, Autosport Labs
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ben25
Posts: 8
Joined: Wed Jan 25, 2012 1:55 pm
Location: France

Post by ben25 »

I have remove the MJLT and and jump the coil power to +12v. The engine don't start.

I've check my wiring everything is good, I have +12V to MJLT and EDIS when contact is on.
When starter motor is ON, I have +9V to MJLT and EDIS.

I suspect a low battery so tomorow I'll recharge the battery and test it again.

I check also have a signal between coil (A/B) and +12V on coil pack. So it means that normaly spark must fire...
I have mesured resistance on the ignition cable I have around 15 Ohm on each cable.
So maybe a poor signal due to a low battery could be the reason of my problem.

Am I on the good way to find my problem ?

eds911915
Posts: 32
Joined: Wed Mar 14, 2012 1:51 am
Location: Costa Mesa CA. USA

Post by eds911915 »

you just described my EDIS instalation to a Tee except i get intermitant spark. did you ever figure it out?

ben25
Posts: 8
Joined: Wed Jan 25, 2012 1:55 pm
Location: France

Post by ben25 »

I've change my battery and it's still the same...
I dont have made all verification of voltage in different wire but I admit that I'm a bit fed'up with my carb installation...
I'm realy thinking about bodies setup now.. :(

brentp
Site Admin
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Post by brentp »

Would it be possible for you to find a person that can help you look over your wiring? Possibly someone with the proper test equipment: volt meter, oscilloscope to verify signals, etc. Perhaps someone who has already done the EDIS/Megajolt installation in your area? I'm thinking there must be a simple ground or power issue that can be easily identified.

Otherwise, if it is possible to take pictures of all your wires, clearly showing where they route and post them here, the community here can help identify the issue.

Also, some people have set up trigger wheels on a bench, spun with a drill or motor. this is rather extreme, but takes the engine out of the equation. Ultimately, the Ford EDIS module is a simple and reliable controller - wired up correctly it *will* work.

Let us know as you progress!
Brent Picasso
CEO and Founder, Autosport Labs
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ben25
Posts: 8
Joined: Wed Jan 25, 2012 1:55 pm
Location: France

Post by ben25 »

I'm going to test again with voltmeter and a friend... I also will try to take some pics of my wiring.
Find someone in France who have installed an EDIS is not easy.
Keep you informed...

ben25
Posts: 8
Joined: Wed Jan 25, 2012 1:55 pm
Location: France

Post by ben25 »

I've tried to make some pics of mt wiring but I doubt that someone who will see what go where ... lol

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Just a pricision my crank sensor is fixed on an aluminium mounting plate, can it be a problem for ground the sensor or not ?
Should I use a stell plate ?

Spockie-Tech
Posts: 152
Joined: Wed Jan 02, 2008 12:52 pm
Location: Melbourne, Australia

Post by Spockie-Tech »

General Troubleshooting proceedure for Megajolt Ignition Systems is start at the business-end (the Spark Plugs) and work backwards up the chain of components until you get to the Megajolt (which is the last component).

0, Remove the Megajolt and put it aside, you dont add it in until the engine can start and run on just the EDIS module

1. Remove spark plugs from engine, and lay them on the engine block (so they have a ground)
2. Manually connect 12v direct from the battery to the coilpack common pin
3. Briefly tap an earth wire on the coilpack signal pins and observe the spark plugs to make sure they are sparking
-- this verifies your plugs, leads, and coilpacks are ok. If you dont get sparks, then you start checking coilpack resistances, open plug leads etc. If OK, proceed to next step

4. Plug the coilpacks into your wiring harness, unplug the EDIS module and put it aside until step 10.
5. Do the same test again, but this time at the EDIS connector end. Using paperclips, bits of wire or clipleads etc, Connect 12v to the pin on the EDIS connector that goes to the coilpack +, and tap the pins that go to the coilpack -'s. Observe for spark. This tests the wiring from your EDIS connector to the coilpacks. If you spark in step3, but not here, then check connector and coilpack wiring.

6. Check the 12v input pin to the EDIS on the pin connector for power (I think you said youve already done this, but was it tested at the EDIS pin ?)
7. Check the EDIS pin earth/- lead connector to the battery negative with a multimeter to make sure it has a nice low resistance connection. Anything over 5 or 10 ohms is bad.
(Some of those crimp/bullet connectors near the edis connector in your photos look a little rough to me.)

8. Check the resistance between the VR+ and VR- (VR Sensor) *pins* on the EDIS connector with the sensor plugged in. You should see a relatively low resistance, but not 0 ohms (short circuit) or high/infinite (open circuit).. I forget the value right now and dont have a VR handy to test, but you are looking to see the resistance of the pickup coil in the VR Sensor thorough your wiring. If you read tens or hundreds of ohms, thats probably about right. If you need, I can verify the correct value when I get to my workshop and have a VR sensor handy.
9. Keep the meter connected to the VR pins on the EDIS connector and Unplug the VR sensor connector on the back of the sensor. You should see the resistance go to infinite/open as the sensor coil is removed. This verifies the connection from your sensor to the EDIS. If it doesnt go open and stays low, you have a short/miswire somewhere.

10, Plug the EDIS module back in. re-verify the 12v and ground connections, Check for 12v on the coilpack common, crank the engine and watch the plugs. (edit- you might want to keep the plugs away from the plug holes and only do a very brief crank test here, since if the engine is sucking fuel, it will probably blow it out the empty plug holes, and you dont want a spark nearby or you might have an *External combustion engine* ;) - If you get no sparks, or weak/intermittent sparks, reverse the VR sensor + and - wires. One polarity should show a clear and regular sparking.

If you get no sparks here, and have a spare EDIS module handy, try changing it. If you still get no sparks, change the VR sensor if you have a spare. If you dont, try to find someone with an oscilloscope nearby to verify there is a sine wave (with a blip from the missing tooth) coming from your VR sensor.

If you get sparks, put the plugs back in the engine and crank it over. If it stumbles, kicks, or backfires, you have the plug/coilpack leads in the wrong position. let us know if this is the case and I'll give you some tips on how to get them right.

Hopefully, at this point, you will have found and corrected the problem and your engine will kick into life with a fixed 10degrees timing (limp home EDIS only mode). If so, *then* then you start adding in the megajolt, and working on the rev limiter wiring and so on. Build it up one step at a time.

The EDIS system on its own is very simple, all it needs is a good 12v power feed and ground (2 wires), the correct wiring to the coilpack (3 wires), and the VR signal (2 wires) and it should run. Just *7* wires to get right (for an EDIS4 - not including the Sparkplug leads) and you should be running.

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