Newbie question

hendrik6073 · Post by **hendrik6073** » Mon Sep 12, 2011 7:39 pm

Hi,

A while ago i was reading about the Megajolt system. Because i have a oldtimer Talbot Murena that i want to equip with it.
Only read about it, never bought or installed it.
Now i have a little trouble with another car and i was wondering if Megajolt might be an option to solve the problem.
If so i might equip both cars.

I have a 1992 VW Corrado VR6 (ABV) with a rotor ignition. Years ago i swapped the engine with a 1995 model that came with a DIS ignition. When i swapped the engine i choose the easy way and removed the DIS and turned it into rotor. I sold the DIS ECU, cables etc.

Now i have a problem with my rotor ignition, it leaks oil and a new one is expensive.

I was wondering if it would be possible to use Megajolt on my VR6 ABV engine. Is there somebody who has experience with this ?

Thanks

Hendrik
the Netherlands

hendrik6073 · Post by **hendrik6073** » Wed Sep 14, 2011 9:30 am

maybe i have to aks it a little different. Would it be possible be an option to use a megajolt system on a 6 cylinder injection engine to replace it's original rotor ignition ?
Or is there a possebility that i get trouble because of its original motor management and the fact that Megajolt would operate on its own ?

thanks

Post by **brentp** » Wed Sep 14, 2011 6:14 pm

Hello,

Sorry for the late reply.

The Megajolt+EDIS would fire the plugs independently of any system. When integrating with an existing ECU, a TACH_OUT signal might be used to feed an RPM signal into the ECU. This usually works if the ECU uses a simple RPM detection circuit off of the (-) connection of the original coil. After conversion to Megajolt the signal to the ECU is either connected to the TACH_OUT of the megajolt, or by using a flyback adapter circuit to sense the signal off of the multiple coil packs. 80's to early 90's engine management systems often use this approach.

For more modern systems, the distributor might need to be left in to provide the appropriate signal to the factory ECU, with the spark plug wires disconnected and the Megajolt would operate independently of the ECU.

hendrik6073 · Post by **hendrik6073** » Wed Sep 14, 2011 7:31 pm

okay, thanks for the reply. Problem i have with my current ignition is that it is leaking oil trough it, change engine to DIS would be expensive replace ignition for original VW also. So if i would use Megajolt it would only be a option if i can remove the original rotor.
Is there a way to find out how i would integrate Megajolt on my VR6 engine or is it trail by error ?

thanks

luxseven · Post by **luxseven** » Thu Sep 15, 2011 6:31 am

Hi Hendrik,

Without knowledge of the ECU and what it needs to operate, it might be trial and error. There is no reason why it shouldn't work with megajolt, the question is: how to make them work together. After all, the ECU manages ignition and injection accordingly and the map might not be accessible. As Brent wrote, you should be able to feed the Megajolt tach_out-signal to your existing ECU as a first step and see then what else you have to tweak and make it work. Anyway, you might be the first to do this conversion, so try to get as much information (web, manuals a.s.o.) and knowledge to proceed. Don't forget to post your success, others may need your input.
Cheers.
Jos

hendrik6073 · Post by **hendrik6073** » Sat Sep 17, 2011 10:57 am

Anyway, you might be the first to do this conversion, so try to get as much information (web, manuals a.s.o.) and knowledge to proceed. Don't forget to post your success, others may need your input.

I hope there are more people who build a megajolt on a engine with injection system ?
do you know people on this or other forums who buils it on a injection engine (maybe an other VW or Audi)

thanks

luxseven · Post by **luxseven** » Sat Sep 17, 2011 9:16 pm

Hi Hendrik,

No, I don't know any people doing so.
On an existing installation, the ECU more than certainly manage ignition and injection. Somebody converting to injection will also, IMHO, install an ECU capable of both. I am currently converting to injection and I was tempted to keep Megajolt for ignition and Emerald only for injection. The conversion is quite easy and you don't need the EDIS stuff when switching to Emerald because it has it's own ignition drivers. The idea was to feed the tach-out signal from Megajolt to the Emerald. But what if you want to switch between different maps? You would have to switch on two different places, whereas with one system, you only switch the ECU controlling both ignition and injection.
The way to go for you is, as mentioned above, to find out where to feed the Megajolt tach-out signal to your existing system. It makes only sense if you are able to 'look' inside of your ECU. Megajolt (and Emerald) are open systems and you can do your own mapping. That's why they are on the market. But you should try this! It's a different way of doing things and well worth to experiment. Keep us posted.
Cheers.

Jos

hendrik6073 · Post by **hendrik6073** » Sun Sep 18, 2011 12:15 pm

hmmmmmmmm thanks for youre response........

i will keep posting information i collect so other people can look into it. The car i want to place megajolt into is my day to day car and a car i need.

i think as long as i do not blow my ECU i can switch back. So if megajolt would not work at all or not good enough i can always hook up my rotor ignition again.

i am collection electrical scheme's of my car at this time, when i have them i'll post them i hope it is input for others to give their opinion about it.

thanks again

luxseven · Post by **luxseven** » Mon Sep 19, 2011 7:56 am

Hi Hendrik,

I like your approach! You might be on the edge of building something unique.
People did it, but maybe not that exact configuration you have.
Have a look on this guy having kept injection on his Rover V8 and converting to Megajolt:
http://www.pirate4x4.com/forum/showthread.php?t=690068
And in case you haven't found the pin layout yet, look here:
http://diggipdf.com/documents/vr6_crank_sensor/
Cheers. Tot ziens.

Jos

hendrik6073 · Post by **hendrik6073** » Wed Sep 21, 2011 10:18 am

thanks.

i gonna contact somebody at the 4x4 forum to find out more about that installation.

In the attachement there is a electrical diagram from the ignition system on my VR6.

(i am not so familiar with these type of ignition systems so if i ask a stupid question please forgive me)

What i have to find out (i think) is what signals are coming in and out of my ECU, 3 signal in/or out
is what i see on the diagram, i do not know what signals these are. If i look at my tacho i also cannot find out if
it gets his signal from the ECU or somewhere else.

i was reading information on the Megajolt, i understand that i choose between a vacuum or a throttle position sensor ?
and if that's the case, are these both the same megajolt ecu ? or are there different devices for each situation ?
I think i have a vacuum that i could use. VR6 has an throttle position sensor, i think i cannot add another.

I read there is a kind of 'limp mode' that would help checking the installation without Megajolt. Do i have to programm something for that ? because it seems to me that very 6 cylinder engine has his particular specs, like firering order and moment.

i read something about the risk blowing up the engine and that you always should put the car on a professional power test bench
is that correct ?

thats it for now........ thanks again.

luxseven · Post by **luxseven** » Wed Sep 21, 2011 12:12 pm

Hi Hendrik,

Carefully read the Megajolt manual. What you intend to do (I think) is replacing the whole ignition part of your engine without touching the injection part (?). Therefore, you will also have to install the Ford EDIS 6 module which will fire the separate coils. The limp home mode is internal to the EDIS module and gives you a fixed advance of 10° before TDC (top dead center) if the Megajolt fails (or other problems with the installation). To make Megajolt work, you need the VR sensor signal and the TPS or MAP signal.
TPS and MAP are two different kinds of the same Megajolt, one fitted with a map-sensor on-board.
After your last post, I get the feeling you haven't read the whole manual. There is a lot of complimentary info to be found on the internet as well, but you have to understand how everything works prior to change your ignition-system. Further on, you want to keep the injection part of your engine, which makes it difficult. The EDIS and the Megajolt modules have tach_out signals which might be compatible for use with your injection-ECU, but you have to find that out for yourself.
The risk of blowing your engine? Isn't this why we all doing that stuff?

)
Cheers.

Jos

hendrik6073 · Post by **hendrik6073** » Wed Sep 21, 2011 12:20 pm

get youre point about reading more. because all information is in English language sometimes i have to ask some questions to check if i understand everything right, because engine electronics are not my day to day bussiness understanding takes some time.

luxseven · Post by **luxseven** » Wed Sep 21, 2011 12:33 pm

Hi Hendrik,

If you have specific translation questions, you can PM me and I see what I can do for you. I even have some dutch buddies around who may help. The graphs in the manual are for the most self explanatory and they give about all the information you need for cabling and to know what signal comes from where and has to go where. As your project is very specific, you will most certainly not find any complete instructions. The easiest way would be to change to Megasquirt which is a complete ignition/injection-system, or to some other ECU like Emerald (that's what I currently do to convert to injection).
Cheers.

Jos

hendrik6073 · Post by **hendrik6073** » Wed Sep 21, 2011 12:37 pm

okay, i come back on it.

thanks

hendrik6073 · Post by **hendrik6073** » Wed Mar 06, 2013 12:28 pm

a while ago i got all the parts to build Megajolt on my Matra Murena. I also want to use it on my VW later on, now i start with the 'easy' one just to get familiar with it.

The project start to get somewhere and today i wanted to position the trigger wheel. Now by reading i got confused so to be sure i ask this question.

When cyl 1 is on TDC the valves are ready to open ? right ?
or do i need the TDC on combustion ?

thanks.