Afternoon,

When i started my car up for the first time the rev counter was reading double what the engine was actually doing (i.e, engine was running at 1000rpm and rev counter was reading 2000rpm.

Does anyone know how i can interupt the signal and half it??

I rung a company who can supply me with a device to do this but its £70 or i could buy a brand new, super accurate and smooth Stack Tacho. Its a bit more expensive but then it is brand new



My car is a Escort Turbo with DTA P8 management (its not possible to alter the tacho output from the ECU.

Thanks

Matt.

 

i got the same prob with mine m8!

I thinkk Simon @ SECS is sort of lookin in2 doin somethin for me! that or just take a feed of the coil pack!

 

its beause your using MFI clocks with an EFI managment

EFI= wasted spark system

 

No mate i'm using EFI clocks.

Its because the ECU gives out 2 signals per revolution and the clocks require 1 signal per revolution.

I do like the stack but my interior is becoming so odd ball with different guages etc, i'd like to keep the existing rev counter.

Matt.

 

i was usin the mfi clocks & just gettin random fookin spikes & not makin any sense! i changed to efi clocks & now it reads double!

 

http://www.thor-racing.co.uk/

They are the guys i spoke with about a signal convertor (reducer).

They can do it but they are so busy it would not be for about 2 weeks.

Plus he said theres about £5 worth of equipment and about £55 worth of labour putting it together + VAT + Delivery.
I'd hate to pay out £70 for something worh £5

 

fook that! lol

will c what simon comes up with!

 

I know a electronics engineer and i've emailed him to see if he can come up with something.

If possible i will produce a device and sell it as i know a few people with the same problem.

Matt.

 

Is this a problem with all management systems? Just wondering...

 

tony it depends what signal your tacho is expecting and what signal your ECU can output...

most modern aftermarket ECUs are switchable...

similar sort of thing to aftermarket tachos... theyre universal n you can flick them between normal spark/wasted spark/4cyl/6cyl etc. etc.

woulda thought that one of the ERST tachos woulda worked with DTA? ive seen a 2.0 ZT ERST using using normal clocks and DTA management

 

mine reads half it because i have now got a wasted spark system, i will design an interface, when i can be arsed

 

Not true,

Most modern ecus send 2 signals per rev as its a more accurate and smooth way of doing it.
However the old ford system only required 1 signal per rev.

From what i understand the easy remedy is to connect the Tacho signal wire to 1 of the coil outputs.

 

doesnt your pectel ECU have an output for the tacho you could use instead, surely with something as as T6 they covered all the bases

 

why dont you just do that then?

 

Jim Galbally,
it does, but im using that output for something else a little more important

 

I'm told the signal can peak (overpower) and damage the Tacho.

 

isnt that how its driven as standard? i havent got a wiring diagram here, but i think it is

 

no most modern (4cyl) engines send 2 signals per 2 rpm (as oposed to 1 every 2 rpm) because they all use shonky wasted spark coilpacks which knackeres your spark plugs out quicker but costs less to produce

but good ol ford used a PROPER distributor with proper spinny whirry bits which do things the 'ol fassioned way

 

Neons???

 

go on gazza, what does it do, i'm curious

 

fuck someone has rumbled me they do flash faster as the engine gets faster

 

Comes through ECU as standard.

Well my old EFI system was wired that way.

Distributor systems come direct from the coil.

I'm using distributorless ignition by the way.

 

EDITED, I got it wrong

 

i havent built the unit that the output will be driving yet

EGR als me hopes

the the outputs are user programable, so you can use then for many things, but you would be suprised at to how fast you can use up all the outputs

 

shit i was thinking wrong then

 

Take a feed off one side of the coilpack and run it through the Ford-standard suppressor.

Using dizzy-clocks will also fix it afaik.

/Munk

 

matt dont worry i know what you meant about the 1 per 1rpm thing, i made the same mistake the other day n it was pointed out to me :P

as for the MFi dash... sorted, surely you can pick up an MFi tacho for pennies? there r shitloads of XR3is in the scrapyards to rob clocks from...

 

Fooking totally confused my self with this now.
However just spoke with my electronics engineer mate and he confirmed what i originally said was true.
Can't get my head round it....it is a friday afternoon.

Luckily i have 2 spare sets of clocks sat at home so will swap them over and see. Will be interesting to see as B19-TRB had problems doing it that way.

 

i think people are getting confused here!

the coil on a four stroke, four cylinder engine fires twice every rev,
the difference on a coil pack driven four stroke, four cylinder engine it still fires twice per rev, but only one side of the coil pack is driving the rev counter! so the rev counter reads half

 

So basically my DTA is sending the signal from BOTH sides of the coil to the Tacho (hence double reading)
But the old ford system only sent the signal from ONE coil.

So all me and B19-TRB needs to do is use the signal from one side of the coil pack with an inline noise filter to run the Tacho

 

hoep i cleared something up at least

 

oh shit gareth i just realised i once again was talking bollocks

 

Not like you

 

@ Me


jon whilst youre here, do you have the original address of the old BSW motorsport please as the only addy i have written down is his new one

 

This little circuit works ok if you have converted from dizzy to wasted spark and are still using the stranded rev counter
It provides 2 pulses per engine revolution, the same as if you were using a dizzy


Cheers

Steve

 

Matt, if none of the above work let me know ill sort it for you