VR Sensor not close enough?

electro_gyrocator · Post by **electro_gyrocator** » Sun Nov 29, 2009 1:22 am

Hi, I just love this site, and just got my MegaJolt unit and have been having a blast wiring it up in my Honda! But I'm having a small (noob) problem.

I got all the EDIS system wired in for basic (limp home) operation, to make sure everything is good before I go too far hooking things up. The problem I seem to be having right now is that I'm only getting 0.9v AC between pins 5 and 6 (from VR sensor) when cranking. I know I'm supposed to have 2.5v according to the manual... Does that mean that my VR sensor is not quite close enough to the trigger wheel? Should I also have 1.5v DC when going from pin 5 or 6 to ground?

I've been taking lots of pics along the way and will post them up when I've got it all operational! Thanks in advance for the help!

Post by **brentp** » Sun Nov 29, 2009 1:28 am

Hello, and welcome!

Cranking speed can affect the voltage generated, yes, but also the gap as you suspected. How big is the actual gap?

electro_gyrocator · Post by **electro_gyrocator** » Sun Nov 29, 2009 1:41 am

Wow thanks for the fast reply!

I used a piece of thin cardboard as a "feeler gauge." I measured the cardboard with a digital caliper and it was 0.8mm thick and was just a snug fit between the sensor and wheel. But I'm not 100% certain that I'm at a perfect 90 degree angle to the wheel. So maybe the bottom part of the sensor is that close, and the top part of the sensor is further away. It's in a tight, awkward place to really be able to tell for certain. I will go make some adjustments and see if I can't get a better signal.

Thanks for the help. I'll let you know what I find out...

electro_gyrocator · Post by **electro_gyrocator** » Sun Nov 29, 2009 4:12 am

Well, I managed to get the sensor a little closer. Now I'm reading 1.2volts AC across those pins. I don't think it's possible to get it any closer than that. Should that be sufficient signal to get spark? Or am I going to need an oscilloscope to check the signal? Could a steel mounting bracket possibly be causing the sensor to not be picking up the wheel as much?

NITROPIXIE · Post by **NITROPIXIE** » Sun Nov 29, 2009 12:16 pm

That all sounds good to me. Best thing to do now is test it by taking the spark plugs out of the block and check you are getting a spark with everything except the mjlj connected up. This way your putting less strain on the starter motor and battery.

I normally put my sensor as close as i can by eyeball. If it just touches the triggerwheel then it will only shave a little bit of the plastic on the end and wont cause any serious damage.

Don't worry about getting the exact voltage required, as long as there is one there then it should be fine. Steel mounting brackets are perfectly fine.

electro_gyrocator · Post by **electro_gyrocator** » Sun Nov 29, 2009 9:51 pm

Well, turns out I am getting spark. I was using my timing light to see if it was sparking or not, and the timing light wasn't picking anything up. So I pulled the plug and it's definitely firing! Man, I'm an idiot, should have done that in the first place! Well at least I know EDIS is working.

Now to trick my fuel pump relay into seeing a distributor signal. Maybe just bypass the relay and wire it to key on... Thanks for your help guys! More to come when it's up and running!

NITROPIXIE · Post by **NITROPIXIE** » Sun Nov 29, 2009 10:39 pm

You could use pin 11 on the EDIS in place of the signal from the distributor. Pin 11 is the CTO Clear/Clean Tacho Output signal and produces a signal very close to that of your distributor. The tachyometric relay only needs to see a signal within x amount of time before it switches off.

This should do the trick.

electro_gyrocator · Post by **electro_gyrocator** » Mon Nov 30, 2009 4:08 am

Thanks again for the reply. I used pin 11, and it drives the tach just fine, but for some reason won't trigger the relay. I'm not the only person who has had to do the diode trick to make the fuel pump activate on an 80's Honda. So I bypassed the relay for now and just put in a switch. Pump still only fires when the ignition is on, but now I can switch it off if need be. I fired it up after getting fuel and it ran!!! Yay!!! I'm pretty excited, going to wire in the rest of the stuff tonight and clean up my loom. For now, here's video of it running! Running a little rough but it seems to smooth out after it warms up. Probably will get some new HT leads for it and play with the timing in MJLJ after it's all wired in! w00t! Here's a video of it running:

http://www.youtube.com/watch?v=wQdK--uMrY4

alexander · Post by **alexander** » Mon Nov 30, 2009 7:15 pm

i connected a fuel shut off relay (ie same as your fuel pump relay) to one of the coil driver wires, so you might try that instead of the CTO pin.