Autosport Labs

Hi, my MJLJ worked pretty good for a year or so. Only problem was that the rev limiter was set to 5800, but it would not let me rev over 5300 no matter where I set the limit. Now it won't let me rev over 4000. This started on the way home from a drive and has continued. I checked all the connectors, ran it w/o the MJLJ, replaced the EDIS4 unit with no change. Any suggestions?

Check that your crank sensor/bracket hasn't moved out of alignment. It's one of the things we've seen in the past that has caused this sort of issue.

First thing I checked, I had that problem initially in the first 100 miles, but it hasn't moved in another 1500. Perhaps the two symptoms are unrelated, rev limiter problem vs not revving over 4000? I never had control over the rev limiter, that is it was not adjustable and was stuck on 5300, but the engine ran great otherwise. Now it sputters and misses and after fires at around 4000.

I have decided to start from first principles and check everything. First difficulty is that I cannot seem to find what the correct gap is between the VR sensor and the trigger wheel in any of the installation instructions here. Can someone show me where that information is to be found, please?

Hi Westfield 11,

about a 1mm gap between sensor and trigger wheel is optimal.

This is getting frustrating. The gap is spot on at 1mm, the bracket is of heavy welded steel and is securely attached. No loose wires or connectors, tugged and pulled on them all. The motor is an A-series from a Sprite, it starts right up and idles smoothly. No change if I pull the plug from the MJLJ. No change if I plug in another EDIS box either. It still will miss, pop and bang as I get up above 3800 or so. AFR is good at 12.5 to 13, plugs look good and have the correct gap, spark plug wires are nearly new and are snug at both ends. Coil is an Accel and is a year old.

If this persists, I am tempted to throw the MJLJ in the trash and just go back to the distributor......

interesting posting...we are facing a similar problem and have now idea how to cure it!!

on our car (super-seven type, ford x-flow engine) it beginns with lack of power and spluttering.

connecting the laptop to check the mapping results in a toally random mapping, orignal data´s are lost.

donwloading the original mapping cures the problem for several days, weeks or maybe only a few hours.

have you shielded the wiring to the ECU?

Yes, I am using shielded wire and I have the shielding grounded to the chassis. I am wracking my brain trying to think what might have failed in the system the day it went bad. All was well for about 45 miles and then it just began to miss and sputter at 4000 rpm and it has done so ever since. This, despite my checking everything I can think of. BTW this is an A-series in a Lotus 11 replica......

I will try to reload the map, but given that the problem persists with the MJLJ removed from the system, I don't hold out much hope of improvement.

this sounds similar to our problem....have you ever checked the mapping on the ECU, when the car begins to show those problems?


we even changed the megajolt ECU, the EDIS...but no success.

If this problem occurs with the Megajolt system disconnected from the system, it's very likely something with the installation - either electric or a mechanical issue.

A very common occurrence with misfires in the mid-rpm range is a vibrating sensor bracket - the bracket has a harmonic vibration around mid-RPM and causes an erratic signal which the EDIS module cannot understand. The solution is to make the bracket more rigid.

Can you post pictures of your sensor bracket setup?

@brentp:

is this also related to my problem here:

http://www.autosportlabs.org/viewtopic.php?t=3732

our bracket is very sturdy (we used the same bracket on another engine which is running trouble-free)...unfortunately no pic available right ow.

After pulling my hair out for weeks, I just removed the MJLJ and reinstalled the distributor. It now runs great, better than ever.....

good idea, on our cars we are still suffering from some cut-outs, even we could improve / solve that the ecu´s set themselves to a default / emergency mapping.

we bought another programmable ECU, brand NODIZ, lets see how this performs