Compatable tachometer

dan97019 · Post by **dan97019** » Wed Jul 28, 2010 10:42 pm

Does anyone know of a tachometer that you can buy off the shelf that will work from the tach out pin on MJLJ ver 4 without having to make a circuit board or perform some sort of witchcraft to make it work?

cng1 · Post by **cng1** » Fri Jul 30, 2010 8:04 am

Any modern electronic tacho will work just fine.

Humpty · Post by **Humpty** » Sat Nov 13, 2010 7:08 am

A couple of noob questions for you guys.... I have been fiddling with this set-up for a while now.... The car ran sweetly for ages, but I took the car off the road some months back (defect notice from the plod), at which time I pulled the turbo gear off the Dub.... No I'm back to fitting it all up and the car will not play ball....

Looking through the archives in search of an answer to one of my problems... I have revived an old thread in the hope of getting some clarity....

I have a Autometer Monster Tach hooked up to the tach out pin and the gauge is receiving a signal.... The issue seems to be the accuracy of it... The MJLJ program reads a different rpm when compared to the tach...

Any one have idea on this?

Could it be related to the possibility that the timing is a bit out?.... That's the other issue.... My trigger wheel is out by what looks to be 5º.... I have run the engine with the MJLJ disconnected and it ran fine in the "Limp Home" mode?.... I know it's possible, but how do I fine tune the timing?

I'm getting myself confused....

cng1 · Post by **cng1** » Sat Nov 13, 2010 8:46 am

Is the tacho reading a constant double/half/1.5/0.75 times what it should do?

Humpty · Post by **Humpty** » Sat Nov 13, 2010 10:17 am

I think it's around half.... Your thinking the wire pinouts in the back of the tach?.... That seems to be correct.... BUt will check them again tomorrow...

cng1 · Post by **cng1** » Sat Nov 13, 2010 12:05 pm

Check if it definitely is half. If so then you've probably got a switch on the back of the tacho labelled 4-6-8-12. If it is currently on 8 switch it to 4, if its on 12 switch it to 6

NITROPIXIE · Post by **NITROPIXIE** » Sat Nov 13, 2010 5:34 pm

Hey humpty.

What is the advance in limp home mode (mjlj disconnected.turned off)???

The MJLJ has a trigger offset in Global Controller Options. With this you can counter affect any error you get when physically setting the TDC with the triggerwheel and VR sensor, up to a max of +/-5 degrees.

When this has been setup correctly, the advance you get on the computer screen should be mirror the timing marks on the engine.

Hope this helps

Ryan

Humpty · Post by **Humpty** » Sun Nov 14, 2010 1:26 am

NITROPIXIE wrote:What is the advance in limp home mode (mjlj disconnected.turned off)???

Looks to be about 5º advanced.... Hard to tell accurately as there are exhaust pipes and sensor mounts in the line of sight... Going to add some marks to the mount and wheel to confirm TDC, then check once more.

NITROPIXIE wrote:The MJLJ has a trigger offset in Global Controller Options. With this you can counter affect any error you get when physically setting the TDC with the triggerwheel and VR sensor, up to a max of +/-5 degrees.

I did try that yesterday, but couldn't tell if it had taken effect.... Then I had another look at the Global Controller Options window and the offset value wasn't showing any longer?

Humpty · Post by **Humpty** » Sun Nov 14, 2010 11:08 am

Tacho sorted.... The PO (of the tach) told me it had been modded for a 4cyl engine.... Silly me assumed that that was the case.... But I pulled the heat shrink off the tagged link wires and they had been soldered back together... In 8cyl mode!!!!

Didn't get to checking on the timing issue.... Will do that tomorrow....