installing megajolt - no spark!
Turbo Mini Forums

Evening all

I have been slowly rebuilding my car over the last few year from a spi spec to a carb’d turbo running megajolt. Recently I have wired the megajolt circuit in and amended the spi loom sufficiently. I am now at the stage where the engine turns over and I should have a spark from the coil pack

I have wired the coil pack, EDIS, crank sensor in as directed on the manual that came with this. I am sure of my wiring. There is a live the toe EDIS and the coil pack. The earth is good. However the engine turns but there is not a spark. Tomorrow I am going to recheck all of my wiring. What should I be doing next? Im thinking try changing the crank sensor, and then the rest of the hardware? Has anyone else come across this problem before or am I overlooking anything?

Cheers, dan

make sure the crank sensor is close enough to the trigger wheel, unplug megajolt and try see if it fires on the edis alone

Yes i moved to the darkside

Instagram @jdm_brett

i have yet to attatch the megajolt so only the edis is in the car at the moment. the sensor is around 1mm from the pulley. the live feed to the edis and coil pack are live when cranking also.

Could be the VR sensor wires around the wrong way and not sending a signal. The is some checks at the bottom of the MJ page

http://www.autosportlabs.net/MJLJ_V4_vehic...tallation_guide

Text from the above link

Verifying Signals

The following table identifies the proper voltages for the various electrical signals used by the system.
Expected Voltages What Where to measure Expected Voltage Symptoms Cause/Resolution
VR Sensor * Measure across VR Sensor terminal
* Measure across EDIS pins 5 and 6 * 0 volts when not running;
* Approx. 2.5V AC when cranking No Spark EDIS must receive signal from sensor for proper operation.

Check gap between sensor and trigger wheel (Max 1 mm);
No reading when measuring from sensor may indicate defective sensor;
Special Note: Sensor is polarized; reverse connections to sensor if a signal is measured but no spark occurs.
PIP Signal * Measure between EDIS pin 1 and ground
* Measure at PIP input on MJLJ and ground * Approx. 12V when engine not running;
* Approx. 5.5V with engine cranking/running No RPM reading on configuration software / No control of Ignition Advance; engine running in "limp home mode" PIP Signal from EDIS must reach MJLJ in order to measure RPM and command Ignition Advance via SAW pulse. Check wiring between EDIS and MJLJ; ensure appropriate pins are wired.
SAW Signal * Measure between EDIS pin 3 and ground
* Measure at SAW output on MJLJ and ground * 0V when engine not running;
* Less than 0.2V AC when cranking RPM Reading in configuration software, but no control of Ignition Advance; engine running in "limp home mode" SAW Pulse emitted from MJLJ must reach EDIS module in order to command desired Ignition Advance at run-time. Check wiring between MJLJ and EDIS; ensure appropriate pins are wired.
TACH output Measure at TACH_OUT output on MJLJ and ground * Approx. 5.5V when engine cranking/running Tachometer does not see TACH_OUT signal; external electronics not reacting to TACH_OUT signal MJLJ outputs a pulse on TACH_OUT when PIP pulses are received. Ensure MJLJ is powered and properly receiving PIP pulse.

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

cheers, we will look into this tomorrow. we managed to test the vr sensor and it showed 0 at standstill but only 0.2 when cranking so this may be the problem? i have looked on ebay and it looks like you can get the whole ford hardware for under £40 so this may also be a good idea - it would be handy to have a spare. i will definately check the vr wires, it seems this is a very common error when wiring this setup in. cheers

the vr sensor will send a +/-ve spike every time the raised section on the trigger wheel passed
to test it, with the voltmeter wired up to it place the vr sensor on to some steel ( it will stick obviously) and pull the steel away sharply you will get a voltage spike, either +ve or -ve ( have a search on this subject by me as im sure its on here witch way the spike should go)

Yes i moved to the darkside

Instagram @jdm_brett

We spent ages fooking about with benny's car trying to get a spark. It turned out he had metal swarf on the face of the sensor which was confusing it. Cleaned that of and got a spark straight away.

cheers for the input. i will check these and let you know how i get on. i checked the wiring to the crank sensor, all is well so i can rule that out. cheers, dan

cheers for the input. i will check these and let you know how i get on. i checked the wiring to the crank sensor, all is well so i can rule that out. cheers, dan

thanks for the input - this problem is now solved - the sensor had swarf on it and i now have a good spark - many thanks again. maybe this is a sign for me to get my arse in gear and not leaving it hanging around any longer! going to get the ic etc back on, sort the rest of the electrics and fit the fuel tanks, i should be good to attept to start it on my next free day!

bloody hell. I've been useful.

yea very useful! its one of those things that you could end up chasing for a long time to finmd the fault - i thought the ford hardware was duff so you saved me a couple of quid too! we have sorted most of the electrics now so just the fuel tanks to fit and refit the intercooler and we should finally be ready to attempt to fire it up! cheers