Factory tachometer and Painless wire harnes

[Jorns]

Hello. I have a Jeep cj7 1986 with 258cid. I have done frame off restoration on it and i have issue with the factory tachometer.
I bought the cj7 wire harnes set (#10110) from Painless. And i am done installing it and everything works just fine beside the factory tachometer.
The tach that i have is a Jeep stock tach from the factory setup.
Originaly it is connected in series of a red wire with white traces under the dash. But the painless wiresystem suggest that I should connect to the purple tach wire and the red wire on the fuel gauge. I know that the black and orange are for the bulp, and that works fine. Look at the attachement to see how Painless suggest connecting the tach.

When i connect it like that, the engine refuse to start.
It seems like this way of connection is for aftermarket tachs like omix ada and crown. But i want to keep my stock tach, because it looks bether and it´s stock like rest of my gauges.

How do i get the stock tach to work with the painless wire set? Do i have to connect it like it was originally. And if so, how and wich wire do i split and connect trough the tach?

 

[SteelHeadz]

I dont know the color codes of the painless wiring system however, you should trace the wiring where the painless instrucions tell you to hook up onto the factory tach. There should be a lead that goes to the ignition coil , positive terminal and another to the ignition key on. Verify that these wires are hooked up under the hood correctly.

 

[Jorns]

Hi, thanks a lot for your respons.

I dont know the color codes of the painless wiring system

Take a look at the Painless wire harnes manual at page 18-19. The schematic says that the purple wire marked #TACH should be connected to the negative side of the coil.

however, you should trace the wiring where the painless instrucions tell you to hook up onto the factory tach. There should be a lead that goes to the ignition coil , positive terminal and another to the ignition key on. Verify that these wires are hooked up under the hood correctly.

I have allready done that, i have checked my connection, and i have studied the schematics. My setup should be correct comapared to the Painless harness manual.
But as you are saying, the tach cable should be connected to he POSITIVE side and not the NEGATIVE. This is what confusing me, since the factory tach is connected at the POSITIVE red/white wire. I think with at an aftermarked tach this will work, but i want to use my stock one.

I have also a thread about this at Jeepunlimited. I am not allowed to link to pics or url´s here at jeepz, but at jeepsunlimited i am allowed. Take a look at that thread and you see what i mean. I have som pics there. It is in the cj forum with same topic as here.


Thanks in advance.
Jorns.

 

[SteelHeadz]

Hi, thanks a lot for your respons.


Take a look at the Painless wire harnes manual at page 18-19. The schematic says that the purple wire marked #TACH should be connected to the negative side of the coil.



, the tach cable should be connected to he POSITIVE side and not the NEGATIVE. This is what confusing me, since the factory tach is connected at the POSITIVE red/white wire. I think with at an aftermarked tach this will work, but i want to use my stock one.




The schematics i viewed was a factory setup and the tachometer reference circuit is on the positive terminal. Have you switched the purple wire from the negative to the positive terminal of the coil?, if it doesn't run, this could mean that there is another circuit spliced into the purple wire from painless wiring. I would suggest that you leave the Ignition and ground connection hooked up and run a separate line for the positive terminal coil to the tach gauge with the purple wire attached to where painless suggest it's connection. Test it for proper operation.

 

[Jorns]

The schematics i viewed was a factory setup and the tachometer reference circuit is on the positive terminal. Have you switched the purple wire from the negative to the positive terminal of the coil?

No, i haven´t. I´ve been thinking about it, but i have been afraid of shortcutting/fry a cuircuit/tachmeter.

, if it doesn't run, this could mean that there is another circuit spliced into the purple wire from painless wiring.

It doesnt run with the purple wire connected to the negative side of the coil. Never tried to connect to the positive side of coil, since the Painless wire manual says it´s should be going to the negative side.

I would suggest that you leave the Ignition and ground connection hooked up and run a separate line for the positive terminal coil to the tach gauge with the purple wire attached to where painless suggest it's connection. Test it for proper operation.

I could try that, But are we sure that nothing is going to fry?

Jorns

 

[SteelHeadz]

I could try that, But are we sure that nothing is going to fry?

Jorns

Do the bypass first. Connect a line from the tachometer to the coil without connecting to any of the painless wiring and see if the tachometer works properly. If it does, then leave the painless wiring system hooked up the way it is. Run a new strand of wire dedicated for the tachometer in the wire loom.

 

[Buck hour]

Hello. I have a Jeep cj7 1986 with 258cid. I have done frame off restoration on it and i have issue with the factory tachometer.
I bought the cj7 wire harnes set (#10110) from Painless. And i am done installing it and everything works just fine beside the factory tachometer.
The tach that i have is a Jeep stock tach from the factory setup.
Originaly it is connected in series of a red wire with white traces under the dash. But the painless wiresystem suggest that I should connect to the purple tach wire and the red wire on the fuel gauge. I know that the black and orange are for the bulp, and that works fine. Look at the attachement to see how Painless suggest connecting the tach.

When i connect it like that, the engine refuse to start.
It seems like this way of connection is for aftermarket tachs like omix ada and crown. But i want to keep my stock tach, because it looks bether and it´s stock like rest of my gauges.

How do i get the stock tach to work with the painless wire set? Do i have to connect it like it was originally. And if so, how and wich wire do i split and connect trough the tach?

Just call the techs. I have the exact same wiring kit from painless in my 77 7 and the purple wire should be from the engine. But either way just call tech support. Usually a guy named mike answers. I asked him the same question and he helped me out no worries

 

[Jorns]

The Bypass can damage my coil when i thinking about it. I have a ballastresistor on my setup to prevent the coil for getting +12V. If i do the bypass i will override that and the coil will get +12V.

Another guy at another Jeep forum told me to connect it in series with the red/white ignition wire . I will try that to see if it works.

Buck Hour: Hi, i know i can call the tech support, but since it is easter I have to wait to next week to talk to them.
And also, in the Painless wire Harness forum the topic has been discussed before, but the support guy concluded that the tach must have been defect.

How did you solve this? WHat did the Painless wire harness support guy told you?

 

[Jorns]

UPDATE: Never mind, i got it working. I connected it in series with the red/white wire on the ignition.
Thx a lot for respons.

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