Megajolt Setup
Turbo Mini Forums

Hi,

After 3 weeks in America I can finally get my megajolt installation finished.

Connected all up this morning only to find a dead battery so that is on charge. The question I have is that how should the TPS gauge function on the software. I have calibrated it so that it is always at 100% and when you depress the throttle is goes down to 0% is this correct?

If i try to do it the other way so that when the throttle is up it reads 0% but it comes up with an error saying my wiring may be the wrong way round.

Which is correct?

Thanks in advance.
Jon

It should go from closed throttle 0% to WOT 100%. Which wires are you swapping?

http://www.twin-turbo.co.uk
http://www.hillclimbandsprint.co.uk/default.asp

A man without a project is like a like a woman without a shopping list.

how have you wired it up, have you a 5v feed from the mj. re check your wiring from the mj to the tps. do you have a gauge to check the connections and what does what on the tps

Hi

I have three wires going to the megajolt, the 5v VREF from the megajolt unit, the TPS wire, and another which i cant remember what it does.

Does this mean i need to swap the TPS and other wire around to make it work the right way round?

Thanks

Jon

there will be 5vreff the tps wire from the jolt, and a gnd to the gegajolt sensor ground.

with a meter set to ohms measure the 3 pins on the tps, there will be a resistance from one to the other two, move the throttle and see which of the other 2 changes, that will be the tps signal to the megajolt.

once you have that one you can connect the other two, try it and just swap it if the throttle works the wrong way in megatune.

Ok, so basically I have the VREF (5 volts) in the right place - just need to swap the ground and TPS wires around?

Just to check, when it is set up correctly, when the throttle peddle is up, the TPS reading should be 0%, and when the throttle is depressed it should read 100%.

At the moment it is the opposite?

Thanks

Jon

yep up should be 0% down should be 100.%

what i'm getting at is the tps one needs to be in the right place, ie on the slider ( the one that moves between the other two) of the throttle pot, if not you could end up grounding the 5v reff which the megajolt may not like.

also read the throttle position sensor section on this link.

http://www.megamanual.com/v22manual/mwire.htm#tps

Surely I must have the 5 volts in the right place or the TPS sensor would just not work.

That means I can just swap the other to wires around?

Thanks

Jon

the sensor is just a potentiometer, a resistor with an extra movable contact. the TPS signal must be connected to the movable contact.

what happens is on end of the pot is conected to 5v the other to 0v as the throttle opens the 3rd (movable contact) changes voltage.

Ok.

So when i use a multimeter and connect terminals 1-3 both on open and closed it reads 3.6 ohms.

So terminal 2 must be the TPS signal.

I can then attach the other two, and then switch if the throttle position works backwards??

Cheers

Jon

exactly! :)

O.k

Got the megajolt working this morning and the car starts fine.

I am using a map which i received from a guy on here, but not sure if i have got the settings right. It starts after a few turns of the key but runs rough with a backfire under light acceleration, (just in my drive).

I wanted to be able to drive it to slark engineering to get it rolling roaded, is there anything i can do maybe to get it running a little better to be able to drive it there?

Thanks

Jon

what is your engine spec? someone may have a map they can send you that is similar.
also have you flashed it to your MJ? as running on the ecu at 10 degrees runs a little rough.
if nothing else you can run it on the ecu for a short distance depnding how far you need to go.

Is running on 10 degrees the basic setting??

What do you mean flash, i have loaded the map and it seems to be stored in the megajolt, do i have to then tell it to use that particular map?

The engine spec is 1330, kent 296 cam, hiff44 carb.

Also at present my cranking advance is set to 0, what should this be?

Thanks for your help,

Jon

Edited by jonb_5 on 19th Apr, 2009.

yes you have to tell it to use that map. i can't remember without looking but it is on the tool bar, there is an arrow up, and an arrow down, next to that is the icon to flash to the mj. Try that and see if it runs better

if you have a timing light whack that on there and check that it reads what megatune does,

if not then then you will need to trim it until it does (i assume there is a trim function in the jolt sortware? i have only messed with meagsquirt)

also 10 deg at idle is quoted in the manual, but that is with the vac advance disconected.

in the real world at idle advance is likly to be aroud 20 deg.

yep, mine is 22deg

O.k, my first mistake is the flashing to memory but i dont seem to be able to. Here is a screen shot when my megajolt is connected to my PC. The flash button is greyed out, does anyone know why this might be?

As you can see the map is there, etc.



Thanks

Jon

once you have swithed off the ignition, then switched back, then opened the MJ, is the MAP their

Yeah the map is still there. Even if i disconnect the laptop etc is stores it.

Does this mean that it is already flashed?

Thanks

Jon

forget what is on the laptop as this is saved, you need to open what is on the MJ.

Just connected the laptop to the megajolt and pressed the "get igntion configuration" button.

The screen shot i posted it what came up on the screen.

Cheers

Jon

Edited by jonb_5 on 19th Apr, 2009.

this would suggested the map is saved on the mj. you now need to check your timing with a timing light.
just a thought, change the pip and saw around and see if that runs any better

Hi,

How do I check the timing?

Also what will checking the pip and saw around do??

I rang up slarks today and they said I should be able to bring it up in a couple of weeks. Try and get it running better by then else I will have to trailer it up.

Cheers

Jon

timing with a timing light, if you have not got one you will need one to check this.

if i remember correctly changing the pip and saw around will ensure that you have them the right way around, i have done this a few times. If they are not the right way round you will not get the correct signal from the vr sensor. I think that is right