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Crazy Tacho
FastBarney - 15/12/08 at 08:48 PM

hey

my tacho is doing crazy things
when i am driving my car and accelerate to 4000 rev the tacho is going to end of the tacho 7000 revs then getting to 0. then it's go to the normal revs. When i am driving slowely and not accelerate hard the tacho worksfine.
When i rev teh engine when i am not driving , just stationairy the tacho works fine. It seems he has got it only when i am driving the car.
I am using diodes between the tacho and ignition to get it working.
It's not the tacho.because i used a mate's one and its the same.
somebody a clue what it is.
Components are ok , tacho ok.
i don't know there is nothng between.
maybe something is wrong on my ignition?
cheers melvin

paulf - 15/12/08 at 09:09 PM

What ignition system are you using? is it wasted spark with a coilpack such as Megajolt?.If you are using Megajolt then it is possible to use the pip signal from the Edis module , this usually works better than trying to get a good signal from the coilpack.
Paul.

mediabloke - 15/12/08 at 09:13 PM

^^^ What he said. My tacho was all over the place over about 2k, until I moved the input feed from the MJ tacho feed to the PIP.

Danozeman - 15/12/08 at 09:25 PM

Which wire is the pip on the edis? MInes crap too!

paulf - 15/12/08 at 09:36 PM

Pin one on the edis module.
Paul.

quote:
Originally posted by Danozeman
Which wire is the pip on the edis? MInes crap too!

FastBarney - 16/12/08 at 05:45 AM

i am using the original ford zetec ignition
original ecu and coilpack.

thepest - 16/12/08 at 07:00 AM

Wait guys why would a normal rev counter read a signal from the PIP? doesn't it need a high voltage kickback from the coil or similar?

P.S. My Tach does the same sometimes

FastBarney - 16/12/08 at 04:52 PM

but a time a go he didn't go crazy mine.
my tacho is ok; test it with a other one from a mate, same probem.
Diodes are ok ; replaced them to be sure.
so the only thing is that it could be is that the signale is wrong when i drive it.
Tomorrow i will try a other coilpack and sparkplugcabels. i have a spare set. maybe teh problem is somewhere there. i will let ypu know tomorrow.
cheers melvin

mediabloke - 16/12/08 at 11:01 PM

quote:
Originally posted by thepest
Wait guys why would a normal rev counter read a signal from the PIP? doesn't it need a high voltage kickback from the coil or similar?

Not necessarily. It seems to depend on the type of rev counter. Most aftermarket rev counters take a switched low-voltage input.
quote:
ETB (who made my gauges) say:
"4. Connect Pin 4 (signal input wire) in either of two ways:-
a) For conventional distributor based systems, the signal wire should be connected to the negative (-ve) side of the ignition coil.
b) Engines using electronic ignition modules that have their own output wire for a tachometer should be used to provide the input signal for the tachometer."

As the PIP provides a 1-pulse-per-revolution, I found it a more reliable trigger than either a diode bridge or pull-up resistors.

thepest - 16/12/08 at 11:29 PM

what the hell, I'll give it a go

FastBarney - 17/12/08 at 08:18 PM

changed the coil pack and sparkplugcabels
and didn't help
He already did it when i was driving from my driveway.
Anybody got a idea?
cheers melvin

paulf - 18/12/08 at 04:31 PM

Connect the rev counter to pin 1 on the Edis module , many people have had the same problem and this usually works no need for any diodes etc.
Paul.

quote:
Originally posted by FastBarney
changed the coil pack and sparkplugcabels
and didn't help
He already did it when i was driving from my driveway.
Anybody got a idea?
cheers melvin

FastBarney - 18/12/08 at 05:32 PM

hey
i don't have a edis module
i have a ecu. found that there is a tachometers signal that comes from the ecu.
but the signal is to small it is only 0,3 volts.
will try to get it up
and see what that will give
cheers melvin

Macbeast - 19/12/08 at 08:53 AM

Ummmm...

What is a PIP ?

Does a tacho work off the Greenwich time signal ?

( sorry )