A simple Megajolt "diag light" indicator

alhbln · Post by **alhbln** » Wed Mar 31, 2010 7:25 am

I wanted to have some kind of unobstrusive diag light for my 240Z installation to check if the Megajolt is still working or if am running in limp home mode. What i did was to install a retro style bulb signal light indicator, wired to user out 1, in the 240Z's air condition switch housing (the air condition is long gone, but the "cool" and "hot" switch now selects the profiles) and then configured the user output to activate when RPM is below 700.

Now when i switch the ignition on, the signal light will glow in a friendly green, telling me that the Megajolt has woken up and is running. As soon as the engine has started, the light switches off, indicating that the Megajolt is functional and receives PIP

Post by **brentp** » Wed Mar 31, 2010 3:19 pm

Very nice! Let us know if you ever see a fault condition.

Funky Diver · Post by **Funky Diver** » Wed Jun 09, 2010 11:07 pm

A nice solutions *sticks it on the project list*

Dean924s · Post by **Dean924s** » Thu Jun 10, 2010 12:18 am

That is a cool Idea!!!! If my car goes in to limp mode it is slower than a Yugo. .. or an 1983 diesel rabbit. It would be nice to know before I pull out of the driveway!!! I like it.

Post by **brentp** » Thu Jun 10, 2010 12:20 am

As before, please report back if *it ever* comes on

alhbln · Post by **alhbln** » Thu Jun 10, 2010 5:43 am

My Megajolt installation has been finished last week, and the 240Z started at once on the very first test - nice product, thanks Brent!

I had no time to post an installation report yet but will do as soon as i have visited the rolling road.

When running the car with the Megajolt disconnected to force limp mode it works as expected, the diag light stays on. I'll get back should i ever have a real failure

This is not really a must have mod but then again i like having a diag light.

Diag light on while ignition is on: MJ ok and ready to rock
Diag light off while ignition is on: MJ defunct or no power to the MJ
Diag light on while driving: MJ does not receive a signal from the EDIS controller
Diag light off while driving: MJ running as intended

capri_turbo · Post by **capri_turbo** » Sun Jun 13, 2010 4:59 pm

nice idea... but if you use the "tach out" on the MJLJ, the tell tale that the unit isn't working is that the rev counter simply stops working... if engine still running then it's in limp home mode on the EDIS.

alhbln · Post by **alhbln** » Sun Jun 13, 2010 5:19 pm

Correct, if you wire the tach via the MJ tach output, no tach activity is a good indicator that you are probably in limp mode.