Someone who knows car wiring-Rev counter & Temperature gauge

[moondustka]

Hi, I'm in need of some electrical help for the rev counter and water temp gauge..

Firstly the car was/is a 2000, 1.7 that I've swapped with a Focus RS engine running on Omex 600 management.

The rev counter signal is taken from one side of the coil pack. This is enough to make an off the shelf, 2 cylinder tacho, work. When I hook it up the puma clocks it doesn't work too well and the needle flickers on idle, and flickers badly when you rev the car and drive it. Put my foot down the needle just goes straight to 7,000!

What I need to know is what electrical component do I need to stick in line to smooth the signal?? Do I need a voltage reducer? I've tried a transient voltage suppressor, which only made it a little worse if anything.

As for the coolant temp gauge, I can't seem to get this to do anything.. I know that one side of the sensor must earth? the other goes to the ECU, then 1 wire from that to the clocks. The Puma ECU has been removed completely... (to tidy it all up)

If anyone can shed some light, I'd really appreciate it!

Thanks,

Ben

 

[yippeekiay]

I'm not up to speed on rev counters hooked up to coils on the latest generation of cars or how the signal is sourced and where from - guessing most are via the ECU nowadays. Last time I did one was on one on a car with a dizzy cap and rotor arm iirc....yeah, a while back!!. But going by info I've read on other devices that need to pick up rpm have you tried just taking the signal from one cylinder?.

 

[martinthrapston]

Temp and revs will come from the ecu so you need to find what pin/wire you need to connnect to

 

[moondustka]

I have the wires to the instrument cluster - The rev signal is there, it's just not smooth..

As the temp gauge, I just have that wire from the instrument cluster to where the ECU used to sit too..

There is no Puma ECU

Thanks!

 

[oilburner]

It sounds like its getting too many pulses from the coil pack for the rev counter

 

[yippeekiay]

That was my thoughts too that's why I think it may work if he can get a feed off just one cylinder on the coil.

 

[moondustka]

It's not getting too many cos it reads pretty much right. It's just not a smooth enough signal. A 2 cylinder after market tacho works straight off one side of the coil pack (3 wire: 1 feed, 2 earths to ecu- ecu switches the earths to make spark) It needs some sort of suppressor I think, but I don't know what..

 

[warrenpenalver]

as you suspect, you need a cleaner signal. Is omex not capable of supplying a tacho feed?? seems a bit shit for a so called top dollar motorsport ECU.

the coolant temp sensor works by the resistance varying as the temperature changes. What you need to find out is if the original ECU to guage output works in the same way. It may well be a voltage based signal or a digital signal but until you find out you cant solve the problem.

worst case, hack out the guts of an early puma temp guage and fit it to your dash then run a standard puma coolant sensor to drive the guage.

 

[Voa]

who spliced the loom for the omex install ? I am guessing this has been spliced into an existing loom ?

try this

http://www.omextechnology.co.uk/page11.html

 

[moondustka]

Solved the tacho situation.. simple case of getting a pin from omex and hooking the rev counter up the variable tacho output of the ECU. Works perfectly..

Still none the wiser on the temperature gauge - Have been using my oil temp to monitor temperatures :lol:

So, are earlier puma temperature gauges different? How early a puma does it need to be? Would have thought the gauge was just resistance based, i.e. the sensor being the resistor?

 

[Dave2302]

Hi,

I'm having this exact same problem at the moment with temperature gauge, and have tried all sorts.................

Digital dash Temp gauge is fed a signal from the ECU on the white wire (pin 75 on Puma ECU) to pin 19 on instrument plug, but then it goes through a processor or 2 before going to the gauge itself which is a motor type gauge and has 4 pins.................

A simple earth or live signal via a temp sensor just won't work...................

No one has come up with a solution yet, so I'll probably be doing what Warren suggests and putting an early temp gauge in the later clock set, but that looks like aggro to me, so if anyone can tell us how to replicate / what the original signal is I too would be grateful :wink:

I think the clock set we need for the early gauge has to be pre 1998, certainly without digital mleage :wink:

Cheers Dave

 

[Dave2302]

I stripped a Scorpio Clock Set last night, cos my V6 Engine has a "Normal" Gauge sender, but the Scorpio is a digital dash too..................

It is the processor that is different and interprets the input signal differently, and puts a varying combination of live and earths around the 4 pins on the gauge to give the readings...................

This means unless you have the technology to change and / or re flash chips and alter the circuit board (way beyond me) then it can't be done.....................except...........................

There are 2 convenient screw pads moulded in the plastic inside the clock set, so I reckon the answer is get an analogue gauge from a non digital Ford dash or an aftermarket gauge, and then graft it's guts into the Puma clock set, with a couple of wires poking out by the multiplug to solder onto +ve and gauge sender wires

What I'm going to do is wait until it's running and probe the ECU for a gauge output, and then if there isn't one I'll do the above

Cheers for now,

Dave

 

[moondustka]

Fair enough!

I have sort of given up as I need to know accurate water temps so will be going with external stack gauge. Would be good to have the original working as well though!

If you do progress I would be grateful if could share some pics

Cheers!

 

[Dave2302]

Hi Buddy,

Temp Gauge all sorted, cost me under a tenner, (s/h Fiesta Clock Set off EBay) !!

Will Post up a how to with pics when I get a minute, but you wouldn't beleive how easy this is to fit the early gauge guts in the late clock set.................Screw holes are in exactly the same place

If you can Solder and have basic hand tools, it's an absolute doddle, just keep fingers nice and clean around the white dials :lol:

I am testing the calibration with hot water and an industrial standard thermometer later today, and fitting it all back together, but a single test last night showed just under half scale reading @ 160 F so sems about right :wink:

Cheers for now,

Dave

 

[Dave2302]

All done tested dusted and sorted

Here :-http://www.projectpuma.com/viewtopic.php?f=21&t=14395&p=183792#p183792

Cheers Dave