Can the EDIS harm the megajolt unit?

[Nick B.]

I have a megajoltbox that I had put together four years ago.

It is a Megajolt Lite Jr V4 (MAP Kit) (V4). It was tested when built, but don't know if testet on pc as I was not the one building it. Due to me being a slow git it was not put on the car till yesterday. Connected to the car I ran into the "timeout readinding cylinder count" problem.

Since I was using a computer and a cable that is working well on another car, this was not the problem.

Then I tried connecting the MJLJ to another car running MJLJ. No luck

Next step was to power the unit with a 9V batery. Still no connection.

Went through all soldered joint, and I have tested voltages at the following locations:U1, U2, IC1, QG1 and PS1 as per assembly guide and all within spec. No obvious problems.


Could the EDIS in some way have damaged the MJLJ? The car does work fine in limp mode.?


Cheers
Nick

[Nick B.]

EDIT:

Could anything have ruined the firmware and give the cylinder count error?

And I have tried connecting he unit powered by a 9V battery to a PC using serial RS232 - same error


Cheers
Nick

[Swedge]

tried another pc?

[Nick B.]

tried another pc?

Yes, tried one laptop using a new USB cable. Did not work

Then tried another laptop with a known working install and cable (my mates car with a good MJ install). No luck

Finally took the unit out, and tested it with a 9V battery using the PCs RS232 serial port. No luck.

Cheers
Nick

[Swedge]

youve done the exact same ive done by testing the voltages etc, mine wont connect either i had a problem before where the oscillator and proccessor fried so had to get it repaired

my voltage checks were fine as well

mines has just done it again so its been sent off to nitropixie on here to check it over for me

[brentp]

Hi Nick,

We don't know of any cases where the EDIS module could damage the Megajolt. If it was possible at all, it would probably be via the PIP line input to the Megajolt. Overall, things that damage electronics in general are things that input into devices: power, ground, and any inbound signals.

Also, it's also possible that a bad connection or a short with other wires could inject a signal into the megajolt; say, a short with another signal back-driving noise into the SAW output of the Megajolt.

There is one mysterious failure mode we know of, and that's something we've seen with Swedge's unit as well as a very few other units where the oscillator and processor get damaged. The current theory is that power spikes / noise injected into the Megajolt's power supply is causing the problem.

In general,noise could come from:
- an old alternator generating excessive noise - either from regulator or alternator itself
- a battery with a bad connections (causing high voltage spikes from the alternator)
- sensitive signals being routed near high voltage lines - e.g. wires running too close to ignition wires
- sensitive signal wires with intermittent shorts to other signals, injecting signals into these wires
- etc.

[Swedge]

Check your alternator on idle and with some revs

Test it again with your blowers heated window etc on

It shouldn't really go above 14.7ish definitely not 15

I've tested mine and it seems fine but it could be yours

[Nick B.]

@ Brent: The MJLite v4 unit has been wired up to a friends car (with same MJlite) and his EDIS as a test, but same error.

If any shorted wires/noise etc it must have damaged my unit when mounted in my own car/EDIS.

Generator is new, same is wiring, do you have any advice trying to secure the MJ-unit? A capacitor of 1000uF? across power supply could take most of spikes / noise injected?

But then - I don't know if it's an assembly error - though power supply is working and all joints have been re-soldered.

Is the transceiver known to be easy to destroy? I am not familiar with this one.

And could this course the "timeout readinding cylinder count" error from the software?

If I am correct, the Darlington Transistor Array should be nearly impossible to kill?


I have no access to a oscilloscope, unfortunately. But measuring the voltage output from oscilator with an analogue multimeter, it gives a huge reply.

Left is the processor unit - can you supply a new one with firmware?

Thanks a lot for your patience.

@ Swedge. The generator is new. I am unable to start the car right now as I have removed the old ignition. Will try and test with the edis at a later time though. Thanks for the advise. BTW car is a Triumph Spitfire from 1970, so there really isn't a lot of eletrical equipment to turn on

Cheers
Nick

[Swedge]

Sound exactly the same problem I'm having

Even if the alternator is new it could still overcharge if it's not earthed right it probably will be fine though

[brentp]

Nick, how confident are you the Megajolt unit was working correctly after it was built? Was it originally built from a kit? Was it tested on a different engine than yours? It would be interesting to know the history of if it worked, and how long it worked since it was built. You touched on this in your first post but wasn't really specific.

[Nick B.]

Hi Brent

The unit was build from a kit. I was not doing the build - it was done by a fellow forum member (on another forum) who was soldering for a living, and had previously build 3 MJ.

He did test it, and confirmed the operation. I am unsure of what kind of testing he did, if he just measured the components or connected it to a computer. This was four years ago, and the unit has been resting on a shelf since, dry stored.

In any case - the testing would have been done on another car than mine, I will investigate this.

I suspect the processor is gone, and would like to replace it. Is it possible to buy a new processor unit with firmware from you?

Cheers

Nick

[NITROPIXIE]

Email sent. Hopefully we can resolve this issue.

Cheers

Ryan

[Nick B.]

Excellent - thanks

Cheers
Nick

[brentp]

Thanks Ryan, for picking this up.

We will be working with Ryan to see what the problem might be and go forward from there.

[Nick B.]

The MJ unit is being posted to Ryan today.

I just tried replacing the ULN2003A, but had same result. Also tried installing new firmware,but it doesn't get any further than count. I aborted after reaching 300.


Cheers
Nick