megajolt problems - how to change the crank position sensor and not seeing max load??
Turbo Mini Forums

i am trying to check the timing on my megajolt

i have used a turbo base map from this site. i also am using a machined pulley and sensor bracked purchased from someone on here a little while ago.

when checking the timing with a timing light it differs by around 7 degrees from the megajolt map. i need to correct the trigger wheel to make the actual timing to match the timing figures on the megajolt software.

is there a way to calibrate the trigger wheel through megajolt to make the actual timing match that shown on megajolt?

i have tried various things on the megajolt but im not that familiar with it and none of it seems to make a difference.

also on actual full load ie throttle to the floor on the rollers nowherre near max load is achieved - does anyone know why? and how can i correct this?

cheers, dan

in the mj software you can do trigger offset.

you may have to change your load bins. it's possible that your load bins are more than the boost you run.

If something is worth doing, it's worth doing half of.

thanks for the reply. i have tried this and it doesnt seem to work. if you enter the 'global configure options' on the main menu you can advance or retard the trigger offset by 5 degrees either way. so if i retard it by 5 degrees, there are then two options - either 'ok' or 'write options', and then 'ok'. i have tried both of these buttons after changinf the advance but it doesnt make a difference - the 'green' (upload map to ecu) button on the top menu stays dark and cant be pressed. also when checked again with the timing light the timing remains the same.

cheers, dan

ok, i have just had another play with it. i have adjust the trigger offset by retarding it 5 degrees - to the maximum adjustment.

i have also had a look at the advance correction values. i have changed these to -59 (max allowable), the timing seems to be better on idle, but its still 2-3 degrees out from what megajolt is saying that it is.

after adjusting these values to the maximum i am still a little way off. should this amount of adjustment have sorted my problems as it hasnt?

the other thing i can think of is that the pulley wheel or sensor bracket could have a fault?

i think that my next step would be to try to add some adjustment to the sensor bracket. does anyone else have any ideas or tips? it seems very wrong to me that the 5 degree trigger retard plus 59 (i presume degrees )on the advance correction would only give me 5-6 degrees of adjustment? cheers, dan

The advance correction is something you use when utilising the aux input (such as temperature corrected advance so set them back to 0)

I suggest sorting your trigger wheel out if it is so far out. Alternatively you could just leave it retarded by 5 degrees and knock 2-3 degrees off the entire map (this is a bodge though)

If something is worth doing, it's worth doing half of.

cheers john. im going to see if i can move the bracket slightly to give me those 2 degrees...

regarding the map that i have not reaching max load - im running 6ish psi but have a bleed valve and may open this up to around 10 psi. though it didnt make max load today on the rollers is it advisable to leave the map as it is for now so that i can use this as a potential for when upping the boost? cheers, dan

You can leave it if you like. It won't hurt.

If something is worth doing, it's worth doing half of.

cheers john. by changing the timing to the max of 5 degrees im 2 out. thats fairly easy to correct mentally on the computer so will adjust the map and do it that way for now, until i next pull the engine. can you get offset keys to fit the crank pulley?as you can to adjust cam timing? or might the camshaft offset keys fit? cheers, dan

Rather than trying to correct one bodge with another you are better fixing the root problem properly by sorting out the position of your CPS.

If something is worth doing, it's worth doing half of.

the cps bracket came with the machined pulley. it attatches to 3 of the timing chain cover bolts. i could consider some sort of adjustable bracket. however as i know that im a total of 7 degrees out, (5 have been removed via the programme), it seems to me that the way to go would to offset the wheel by a known number of degrees, eg, maybe by using a 4 degree offset key (if they are available), which would then only make the timing out by 3 degrees, which could be delt with by the programme. with the rad/ic/ oil cooler as well as the alternator in the way it is going to be diffitult to test things by trial and error to any great extent. i though that if i could offset the pulley wheel by a few degrees then it would be sorted.

just an update on this - my timing light arrived today. checked the timing, it was still 2-3 degrees out as before. i changed the megajolt map, uploaded it to the ecu and ran it. the advance 'gauge' in the bottom corner of the map was reading different to what the map actually said. i think this may be because i didnt save the changes to the map prior to uploading them to the ecu. so i disconnected the ecu. i checked the timing using just the edis, i found this to be bang on at ten degrees. i then reset the original map, plugged the ecu in, uploaded the original map, took off the 5 degrees retard that i had put on it. started it up, checked timing, its spot on. i am slightly confused with what has gone on here. i have checked this a few times, all i can think is that i didnt press 'save' before adding the changes to the ecu, or that by disconnesting it i may have reset it some how? all i know is that it definately was 7 degrees out before, its now smack on. bloody computers...


i should be good to go, (third time lucky) when i take it to be set up at the rollers in just over a week

Edited by welshdan on 22nd Jun, 2012.

I found my megajolt would not adjust at all, in the end I just left all the values 4 degrees higher to make it right.

i had that on mine when i tried to change some figures in the map today. it wouldnt have it - the map changed but the 'advance 'gauge' was saying different. it seems to be resolved now after unplugging it for a few mins, whilst checking the CPS location using the edis module. this timing is spot on, so i think im happy with things. just slightly confused. im going to check it all over again tomorrow.dan

When I tried to check mine with a light it told me it was 60 degrees out.

The exact reasons why I still don't understand but apparently the one we had didn't like 'wasted spark' (I think) ignition system.

http://www.turbominis.co.uk/forums/index.p...tid=469104&fr=0

The thing is there is no point in having it if you dont know that whats on the computer screen is whats actually happening. With a wasted spark you have to half the number to get the actual timing with lots of timing lights...