So I got my car up and running on the COPs yesterday. With one issue... I have no Tach.

MS reads rpm fine, but the cluster gets nothing. From my understanding there are 2 wires coming from the ignitor... one for ecu rpm and the other for cluster rpm... those get tied together at the ignitor and being fed the signal from the Tach output of the COPs. I have all four Tach outputs tied together for this.

Thoughts on why I have no tach? I'd kind of prefer to not use the Tacho output on the MS... one less wire to run and one output saved for something else later.

 

Well that's the suck huh.

Plug in the stock computer with the COPs on. The car won't start (no AFM) but see if the tach reports anything. Cranking speed is like ~300RPM or so.

Then at least we'll know if there's a problem somewhere with the COPs, or if it's something with the MS

 

I get tach no problem with a stock ignitor in.

 

I had the tach working for the short time I had the car "running" on ms2 in stand alone. So its gotta be your wiring.

 

Yah, i just checked it all and it seems good. All of them ohm out to only the plugs they are supposed too.... its frustrating.

I'll give it another go monday night, visiting folks for the rest of the weekend.

 

soo... you're not going to plug in the stock ecu to see if you have a tach signal with the COPs and stock ecu? the results would be telling.

 

If I can find the stock ecu sure.

When using the stock Ignitor, I get tach signal at the Cluster. This is a 93 and the cluster is driven from the ignitor (if memory serves). With that said, I don't fully see the point of plugging the ecu in.

 

Because if you saw tach signal with the stock ecu & COPs, you'd know the COPs' tach out works and the problem is somehow related with the MS.
If the tach still didn't work, then you know it IS the COPs, human error in their harness, or error on Lazzer's pinouts.

 

But if it works with the MS and the stock ignitor.... then its not the MS.

 

http://megasquirt.sourceforge.net/extra/tachopin.html

try that last resort???

 

Yah, that'll be the last resort. I wanna have as little excess stuff from my PnP setup as possible... the more wires.. the less PnP :P

I'll be trying it all again tomorrow, working on full exhaust and the hood at my buddies.

 

Did you get your tach working?

Isn't yours a 1.6?

If so, the ignitor gives the tach signal to the cluster (it feeds the diag connector too).

I borrowed from the COP thread.


Maybe you can tie 2 of the tach outs from the coils to the ecu pin, while the 2 others to the tach pin. Or just bridge the wires.

 

I said that the two wires at the ignitor, for the tach, get tied together at the ignitor. That's how we did honeydesean's and it's working fine. Splitime you said you tied them together at the ecu? From the ignitor, doesn't one go to the ecu and the other to the dash? If so how did you tie them at the ecu?

Pin 4 and 5 in the above picture.

 

Corrected the first post, I have them tied together inside the Ignitor casing. 4/5 are being fed all 4 tach signals.

 

Ok I just had to make sure. I think I went over all that with you before. Time to find an ecu to try.

 

I'll be taking another stab at this today.

 

What if the tach signal is different to the ecu signal?
Maybe try to connect 2 cop wires directly to the tach (ie: 1 and 3) with the other 2 cope wires (2 and 4) to the ecu. That way there would be less drain of the signal.

I'm just thinking out loud here and could be way off.

 

+1

Good idea.

 

The tach signal for megasquirt comes from the CAS, it has nothing to do with the coils.

 

<-- currently eating a big fat crow.

With COP in. And Tach signal only coming from 1 and 2.
Ecu I get rpm in Cluster... MS I get no rpm in Cluster.

With COP OUT.
Ecu I get rpm. MS I get rpm in Cluster.

WTF