Rev counter with ECU?

[tony g]

Hi I'm in the early stages of converting to EFI on my Sprint and apart from the wiring I was wondering if the standard rev counter can still be used? As I wont have a standard coil set up which normally feeds the rev counter, will the rev counter accept a feed from the ecu? How have you engine conversion guys managed?

Cheers

Tony

[James467]

Haven't been able to do it on my Frontline K Midget, had to get a new rev counter.

There may be someone on the web who has designed a circuit board that you can put in a standard rev counter.

[Mad Mart]

I used the Ford Edis 4 with my Megajolt system. I can't remember how I wired it but I did use the standard Dolly rev counter.

[new to this]

I used the Ford Edis 4 with my Megajolt system. I can't remember how I wired it but I did use the standard Dolly rev counter.

Theres a couple of guys on the stag forum that have fitted EFI to the stag v8,one of them had the ford Edis system don't think they had problems with the rev counter

Dave

[Galileo]

If you're using a Megajolt, then the tacho output works just fine, you want to connect the normal -ve input of the tacho (white/slate trace) directly to the Megajolt tach output. I see you say EFI, so at a guess you might be using a Megasquirt instead, but I doubt that would be any different.

[tony g]

Im possibly going ford edis but maybe coil on plug or coil near plug ie with leads from coils. My mate that does ecu stuff says because the coil receives a "high" signal as standard there may be a resistor behind the tacho that may need to be bypassed. my ecu is a standalone most wont have heard of called ecu master or "emu" so Im not sure if its the same deal as megasquirt. Thanks for the input so far though

Tony

[Carledo]

When I built the Carledo I used a Vauxhall tach, though from a different model. This time with the Dolomega, I'm hoping to use the original dash including the tach, the engine loom has provided me with a tach signal wire but I am several months from finding out if it works!
I also need to source a 4" electronic speedo, the gearbox has a sensor and I have identified the signal lead to the dash, so SHOULD be straightforward! (famous last words!)

Steve

[Galileo]

The tacho is just looking for a -12v pulse per engine revolution. Can't think what adding a resistor would do, unless the tacho required a lower input voltage or the EMU requires a pull-up resistor. Mind you if you also added a capacitor then you have a basic low pass filter for smoothing out noise but there is no need to remove noise from an ECU output which will be a clean saw wave.

I couldn't afford (or justify) one of the more expensive high-end systems like the EMU or Emerald (Nodiz pricing has recently become very competitive), but as I'm competent around electronics, and have used the Ford EDIS before, then it was an obvious choice for me to chose the Megajolt. The beauty of Megajolt/EDIS system is if the ECU fails then the EDIS part just carries on with a fixed 10° BTDC setting by itself for a limp home mode, great bit of bulletproof engineering design by Ford on that one.

[new to this]

When I built the Carledo I used a Vauxhall tach, though from a different model. This time with the Dolomega, I'm hoping to use the original dash including the tach, the engine loom has provided me with a tach signal wire but I am several months from finding out if it works!
I also need to source a 4" electronic speedo, the gearbox has a sensor and I have identified the signal lead to the dash, so SHOULD be straightforward! (famous last words!)

Steve

i bought a electronic speedo for the stag for used on the zf gearbox,it matches other gauges

Dave

[Carledo]

Thanks Dave, I know they are out there, also they are not exactly cheap! But something will turn up!

On the tach issue, it occurs to me that i could easily test a Dolomite tach on the Carledo's Bosch Motronic system. It would be no more than a few minutes work to connect up an ignition live and an earth to the tach and connect the cars signal wire to it. At worst I can blow up the tach and that's no huge loss, I have several spare 1500 tachs lying around!

In fact, if it DOES work, It might be just the motivation I need to reinstall a more stock-ish instrument display in the Carledo, the Nova one I am currently using has a very poorly printed circuit and I can't get a replacement, its obsolete! And the speedo under reads by 40%! HMMMMM, got me thinking now! A very dangerous state of affairs!

Steve

[tony g]

Do it Steve , saves me blowing my only one up lol

Are you about this coming Saturday mate? Thinking of driving up for the bits

Cheers

Tony

[sprint95m]

Hi I'm in the early stages of converting to EFI on my Sprint and apart from the wiring I was wondering if the standard rev counter can still be used

Yes.
You may need a separate tachometer driver (depends on the ECU).

There is much info on EFI on the Sideways Technologies forum Tony.
Well worth spending some time on there .



Ian.

[tony g]

Hi Ian , the ecu has a connection for tacho that comes from speed sensors (i guess) im just a bit worried about simply connecting the wire to the tacho and frying the tacho or worse the ecu. I'll have a peek at sideways and see if i can glean any info cheers

Tony

[Carledo]

Do it Steve , saves me blowing my only one up lol

Are you about this coming Saturday mate? Thinking of driving up for the bits

Cheers

Tony

I'm sorting one out to try this morning, life being a tad quiet! I'm here all day Saturday but may not be compos mentis till about noon!
I'll PM you my address.

Steve

[tony g]