Spark, but MJ won't control timing

General Topics for configuring, operating and tuning the Megajolt. Also see the <a href="http://www.autosportlabs.net/MJLJ_V4_Operation_Guide">Operation Guide</a>

Moderators: JeffC, rdoherty, stieg, brentp

Post Reply
TheBirdmanJD
Posts: 3
Joined: Thu Sep 03, 2015 11:07 pm

Spark, but MJ won't control timing

Post by TheBirdmanJD »

So i've just tried to start my car up for the first time, 1970 Toyota Crown running a 2JZ and triple webers. First off, I believe I may be one tooth off on the cranks sensor. I'm using a Toyota sensor in a factory location, with a modified factory trigger wheel. I was expecting to be about 5 degrees off as I can't move the sensor location, and it falls directly between teeth when at TDC. While cranking, my timing light shows #1 firing at 0 degrees. I can modify the trigger wheel, but I'm also having another issue. Changing the cranking advance has no affect on what I'm seeing with my timing light.

I have verified the wiring for PIP/SAW and verified that I am getting 12vDC not running, and 5.5vAC when cranking on the PIP line. Then I'm getting 0v not running and .08vAC on the SAW line when cranking.

Anybody have any thoughts?

Thanks,
Bird

TheBirdmanJD
Posts: 3
Joined: Thu Sep 03, 2015 11:07 pm

Post by TheBirdmanJD »

Upon further testing, I've found I'm only getting .5 vAC from my VR sensor. I'm going to try to see if I can get a Ford sensor to fit in my application, but I'm not sure it will (I'm currently using a Toyota sensor). Since I am getting spark I assumed the VR sensor was working ok with the EDIS module. Would the low voltage allow the EDIS module to give spark, but not communicate correctly with the Megajolt?

brentp
Site Admin
Posts: 6274
Joined: Wed Jan 24, 2007 6:36 am

Post by brentp »

We have some handy verification steps here you can go through.

http://autosportlabs.net/MJLJ_V4_vehicl ... tion_Steps

First step is to get the EDIS running by itself at 10 degrees - then you can connect the Megajolt to control timing.
Brent Picasso
CEO and Founder, Autosport Labs
Facebook | Twitter

TheBirdmanJD
Posts: 3
Joined: Thu Sep 03, 2015 11:07 pm

Post by TheBirdmanJD »

I actually got it working with the Toyota sensor. My sensor is off 5 degrees, and it's a lot easier to just use the offset correction to solve that issue. That way I can leave my sensor in it's factory mount. My engine won't run at 5 degrees though...triple weber carb setup, and it really likes more timing to get started. I believe my problem was metal dust on the sensor. I'm now getting greater than 1 volt AC from the sensor and everything works great!

So for anyone reading this in the future, a Toyota sensor from a 2JZGE VVTI motor and a modified trigger wheel from the same work just fine with an EDIS module, you'll just be 5 degrees out. The trigger wheel was stock a 36-2 with the missing teeth in the wrong place. I welded the missing teeth back in, then cut off the correct tooth (which is still 5 degrees out)

Here's a photo of my trigger wheel and sensor (note photo is upside down).

Image

brentp
Site Admin
Posts: 6274
Joined: Wed Jan 24, 2007 6:36 am

Post by brentp »

Fantastic, thanks for the update!
Brent Picasso
CEO and Founder, Autosport Labs
Facebook | Twitter

Post Reply