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Dammed Rev Counter, I just dont get it :(
The Baron - 18/5/11 at 07:35 PM

I recently did a pinto to zetec conversion, and am using ESC ignition module, which works a treat.

the rev counter has me foxed!!!!

I am using a AST electronic rev conter, but it is reading really low.

ha ha, i hear you say you need to take a feed from both sides of the coil pack.

when i try this the engine nearly stalls.

ideas.....

Cheers,

B


HowardB - 18/5/11 at 07:41 PM

er diodes?

not sure how the particular piece of kit works, but if you short both sides of the coil pack together then the engine will struggle. Perhaps there are some diodes required,.....

hth


big_wasa - 18/5/11 at 07:44 PM

if you take from both coils you will need some electronics. Have a look on the mega jolt site,

Is your tacho not adjustable for multi cylinders ? just set it to two. Job done.


The Baron - 18/5/11 at 07:46 PM

The penny has just dropped.... 'diodes' .

Cheers all


BenB - 18/5/11 at 08:18 PM

On my AST tachometer it had a rotary dial on the back, you could make it read anything you wanted. Great for SVA and the dB test


The Baron - 19/5/11 at 04:59 PM

mmmm, it still doesnt work

I tried 2 different diodes:-

1n4007 and 1n5352

2 off of each connected to the green/yellow & the green/red on the coil pack to the pulse pick up on the rev counter (the rev counter will only do 4/6/8 cylinders)

with the same effect of the engine trying to cut out.

when holding onto the ends (whilst they were the wrong way around) i noticed that i still get a electric shock from them?

do i also need a resistor to knock the voltage down?

so i am no further forward ....

any more ideas?

Cheers,

B


Werner Van Loock - 19/5/11 at 05:18 PM

have you tried this:

megajolt site


MikeRJ - 19/5/11 at 05:50 PM

Getting a shock from coil primary is to be expected - it will have around 300v here when the ECU fires the coils.

You need three diodes, two blocking diodes (at least 1N4004, no lower or you risk them breaking down) and a zener diode to block the DC 12v level. Something around a 15-18v zener will be fine (e.g. 1N5248).

Have a look here

Note that some tachos also require a pull-down resistor from the anode of the zener diode (i.e. the side that connects to the tacho) to ground, 4k7 has been used with success.

[Edited on 19/5/11 by MikeRJ]


JAMSTER - 19/5/11 at 06:02 PM

trigger wheels do a tacho driver £10 i bought one last week works a treat

http://trigger-wheels.com/store/


The Baron - 20/5/11 at 04:50 PM

Top idea Jamster.

I have just ordered one.

Thanks to all