Socals14

Figured I would get the new sub forum kicked off with a new thread for tach setup. This should be a continuation of the brief discussion from the add-subforum thread.

******

Only issue I am having is my dash tach doesn't work. I have 94, so the ECU does not provide the signal. The Haltech has an adjustable tach output. I can specify a square wave up to 12v. Set to low or high with a 4k7 pullup. So, I am not sure how this should be setup. Any thoughts?

Timwrx responded with:

I've got an Elite 1500 and love it, for tach output I'm using DPO1 and I have mine set to Active State High and Pullup Voltage 12v and it works great, does a cool tach sweep on start up.



I started with a PnP adapter but ended up bying a basic loom and wired it in using a combination of existing harness and new connections.

So much you can do with this ECU and very easy to work with.

Socal responded with :

How did you setup the pulses?

timwrx

In the Tacho tab
Pulses per Cycle = 4
Tacho needle sweep RPM = 8000

Socals14

Well, shoot. You running stock coils?

Socals14

So that was a no go. I get a jump of the needle at High/12v with 1 or 2 pulse settings but otherwise nothing.

timwrx

No I'm running IGN-1A coils in sequential output rather than wasted spark, I'll check my old setup files from when it was stock and get back to you.

msmola2002

I see fuel level conditioner thingee in there, hiding behind can hub. What dash are you running?

timwrx

AIM MXS Strada

msmola2002

Nice!

Socals14

So I have tried like multiple combinations with the stock coils and nothing seems to work...I did find out two things:

Disconnecting the tach ouput altogether seems to prevent the car from starting.
I can observe the manipulation of pulses through the diagnostic port IG- output. (I have an AEM wideband failsafe gauge pulling RPM from this source).

So, I am at a loss. Unless there is something else I am missing? Grounds? I could go back through those and make sure they are all tip top.

timwrx

I'll check my original settings when I get home but you could try setting the pulses per cycle to 8 as there are twice as many ignition events with wasted spark.

timwrx

Just checked my original settings from when the ignition was stock,
Active State - Low
Pull-up Voltage 5v
Pulses per cycle - 4
Tach needle sweep RPM - 8000

My car was originally a 1.6 so may not be the same.

Socals14

UPDATE:

So I installed FF LS Coils. Car started and ran. Even took it for a drive around the 'hood in order to autotune it a bit. Again, I was able to pick up the tach signal from the ECU at the diagnostics port via my AEM Wideband Gauge software, but the tach itself still does not work. My tach output settings in the Elite were low, 12v pullup, and 4 pulses. The needle moves upon start, sweeping about half way, but does not register RPM. It is really weird, as the wiring diagram is clear, the signal to the diagnostics port and cluster come from the same wire...the yellow/blue wire originating from the "ignitor" in the wiring diagram....which itself is weird because the ignitor is in the coils on a 94.

Couple of other interesting notes; The ECU location 2I is an input, not an output on the 94 ECU. I am basically using it as an output now. Not sure what to do next except try to explicitly tap the black/white wire, which carries the Elite tach output, and connect directly to the cluster tach's yellow/blue wire.

Any other thoughts are welcome.

Barton

Check pin 1F. I've found some 94 cars have the tachout on the ECU on 1F instead of 2I. Should be able to tell from the wire colour.

Socals14

No wire at that position.

msmola2002

finally got my shtibox started, and having the same tach issues.

Out of the box, the base map setting is low, 5v pullup, 4 pulses and 8k sweep.

With that tach is dead. Set it to 12 pullup and then playing with high or low, I can get it to hold at 1k for idle, but as soon as ou touch the pedal it bounces all over the shop.

Socals14

I'm at the point where I might as well scope the signal. Gonna try to do it next week.

msmola2002

I have emailed haltech. I checked the parameters in tunerstudio and the only option is output pin, and number of pulses, which is defined as normal and half, with the popup box stating normal is for a 4 cyl, so there are no funky parameter options on the MS.

msmola2002

Ok. So driving around and dicking with long term trims. Tach bounce is between actual rpm and double. So will be idling at 1k rhen the needle bounces but it bounces to 2k. At 3k it bounces back and forth to 6.

Socals14

Seems erratic.

msmola2002

Tach is working!

for me the secret sauce is

Active State - High
Pull-up Voltage 12v
Pulses per cycle - 0
Tach needle sweep RPM - 8000

haltech tech was very helpful and offered to do a remote connect to have a play but my work hours has overlapped with their hours so far this week.

"Basically the ECU just needs to provide 12v power and the coil provides the negative signal to trigger." - I suspect that when the signal from the coils is in phase with the output from the haltech, I get correct RPM, then for some reason it ends up out of sync, and the haltech and the coils are both feeding a pulse out of phase with each other, and I get double rpm, or something wacky. Either way, working now and very happy. Now to get onto the AC. I think I can see a sticky thread coming at some stage with each topic holding settings for various things that once sorted can be shared.