Contour Enthusiasts Group Archives Forums Modifications Forced Induction Digital tachometer

Hello everyone , been sitting in the garage the whole saturday looking like a freak trying to figure this out.

dont know if this is the right section to post in but i'll give it a try.

The problem is this:

I've decided to buy a NX Maximizer so make more use of the spray and to add some safety (save some of the clutch also \o)

The whole setup and installation was fairly easy, I got it all hookedup with the o2 sensor and throttle position.

The last thing in the install was to make a wire go to the one of the 3 wires comming from the coils. No problem i thought just put the wire in anyone of the 3 wires.

I turned on the maximizer and everything but the built in digital tachometer was working like it should.

The first thing that hit me was that the rpm multiplier was set wrong , after searching on various forums I found out that it was one of two settings that you could use depending if you used the tachometer output or a coil signal.

When I used the coilsignal setting the device said that my idle rpm was around 9500 so i put it on tachometer settings and voila i got the 750 idle rpm followed the indash revmeter fairly good.

I turned off the car and went in for some food , came back out after an hour, i decided to check everything again , so i booted up the system and had the car on idle, i noticed then that the rpm wasnt stable on the digitalmeter in the softwere it was running from 500ish to sometimes 900 but always comming back to around 750 +- some. I couldnt hear the car change the idle rpm and i'm sure it never did.

I guess it's the wiring since it's plugged in to take the readings from the coil and not the tachometer outlet.

Anyone had any problems related to this before? , i searched some here on ceg but since i'm a novice machanic i could use some extra help.

I'm including a screenshot to you know what this digital tachometer thing is.



Any help is very appriciated!

wow dont post 4 in the morning , bad english

I just thought i'd clear it up abit

The maximizer is controlled by a laptop , the softwere that is used for tuning has a builtin rpm meter , according to the install manual the wire used to read the rpm should be connected to one of the coils.

I did a search here on ceg and found out that others had some problems setting up a tachometer.

my problem is that I get very bumpy readings but I guess thats how the actuall rpm looks like when you meassure it in numbers instead of a regular analouge gauge.

I also searched for the maximizer but it looks like none has been using it.

Is there a problem with taking rpm signal from the coils on a Contour SVT?

That is because the circuit is too noisy from all the voltage spikes at the coils.

Look in a wiring diagram and you'll find a tachometer output wire from the PCM harness that will give you the signal that you are looking for. It can be tapped under the hood or in the dash going to the dash tachometer.

Sounds like a plan , thanks for that Warmonger.

and zetecChris, I guess you are now the new international super genious of the millenium, congrats

i wouldnt go that far, but thanks

No problem.