94 Cavi tach install without B11 ECU pin?

[doberman_52]

I have a 94 Cavalier 5 speed that I want to intall a tach since it doesnt have one stock. The directions on the Sunpro Autometer Supertach II that I have says to hook the green wire to the white B11 pin on my ECU. My ECU does not have the B11 pin. Is there another wire that I can hook it up to to get the tach to work correctly? I dont have a DMM that has a RPM reader on it either.

[J-Ri]

Originally Posted by doberman_52

Is there another wire that I can hook it up to to get the tack to work correctly?

You had it spelled right in the title...

Anyway, you should have that wire, that's where the PCM gets the RPM from (or maybe output to a factory tach, don't have a wiring diagram
here)... Depending on the settings on the tach, you may be able to splice into one of the wires to the coils.

I saw one where a guy wrapped a regular primary wire around a spark plug wire (probably about 10 wraps) and ran it to the tach with no ground on the other side. The induced voltage was enough to trigger the tach. Looked pretty bad, but hey, it worked.

[doberman_52]

Tack was just a typo.

The wiring schematics say that there are 2 white wires coming odd the ECU. B11 and B3. B11 is the stock tach wire and B3 goes to the ICM for the plugs. There is only one white wire coming off the ECU and I would assume that that is B3 for the ICM. In the 2nd gen RS Cavi's there were no tachs in them stock from what I have seen or owned. So I can see why there is no B11 wire. I did try and plug it into the B3 wire, but the tach said I was redlining (rev limiter) at about 3 grand so I knew that wasnt right. I talked to a mechanic at a place I sometimes bring my cars to, and he told me best way is to take a DMM around the ICM or ECU
and find a wire that gives RPM signal, but I dont have a DMM that reads RPM's, nor do I have the money to get one like that.

[doberman_52]

There is also another black wire that is for the ICM too, I dont remember the pin for it though.

[doberman_52]

Anyone? I have tried to put it in the B11 pin slot and got nothing on it that way either.

[doberman_52]

Did they make any RS models that had a tach in them? Or would it be possible to use a Z24 ECU or would the connectors for the harness be different? There is no signal coming off the B11 pin at all.

[J-Ri]

Check the stickies at the top of this forum, one sounds like it's exactly what you need.

[doberman_52]

I had emailed sunpro last week about this. They told me that I should be able to splice it into a white wire coming off the ICM. I am assuming though that that is the same wire that I tried to use already. I have looked into the sticky before I posted this, but was hoping that I wouldnt need to do that.