hello, i have a strange problem. with my megajolt version 4
if i run my engine (a-series) with edis only, it will run on 10 degrees of advance as checked with a strobe light, no problems.
if i run a map on megajolt (version 4; MAP version) with a set 10 degrees advance throughout it will also be exactly right.
if i run a map with any values above 10 degrees advance, the timing advance readout on the strobe will be double the amount above 10 degrees, plus the original 10, ie. if the advance is reading 20 on mj, the strobe will read 30 ( 10 + 10x2)
if the advance is 15 on mj, the strobe tells me the actual advance is 20 ( 10 + 5x2)
if the advance is 30 on mj, the strobe tells me the actual advance is 50 ( 10 + 20x2)
so the net result is the advance curve increases by double what it should!
please help!
ignition advance increasing beyond mapped values (by double)
Moderators: JeffC, rdoherty, stieg, brentp
What sort of strobe - is it a clever snap-on type digital one where you adjust the read out to give you a flash at TDC?
That type of strobe can give that sort of doubling effect, but they usually double the whole advance, not just on the MJLJ advance ...basically they're not designed for wasted spark ignition systems
That type of strobe can give that sort of doubling effect, but they usually double the whole advance, not just on the MJLJ advance ...basically they're not designed for wasted spark ignition systems
What brand/model timing light are you using?
You may want to test and compare with a different unit- perhaps one with a more simple design, without the digital adjust / zeroing feature.
What does your light report if the MJLJ idle advance is set to 35 and then 40 (providing your engine will run that way) ?
How about below 10 degrees?
You may want to test and compare with a different unit- perhaps one with a more simple design, without the digital adjust / zeroing feature.
What does your light report if the MJLJ idle advance is set to 35 and then 40 (providing your engine will run that way) ?
How about below 10 degrees?
i think ive solved it!
if i set the advance on the strobe to zero so it flashes on the spark (instead of using the buttons to make it flash at TDC) and then read off the value from the guage on the timing chain cover on the car, it seems to be working fine, all the values match.
it now reads 5 where before it read 10 degrees, because of course, i set the initial 10 degrees using the +/- buttons on the timing light.
thanks for your help!
now to find the real reason it was overheating....
if i set the advance on the strobe to zero so it flashes on the spark (instead of using the buttons to make it flash at TDC) and then read off the value from the guage on the timing chain cover on the car, it seems to be working fine, all the values match.
it now reads 5 where before it read 10 degrees, because of course, i set the initial 10 degrees using the +/- buttons on the timing light.
thanks for your help!
now to find the real reason it was overheating....
. sometimes.