ok when i first got my car the rpm or tach would not move at all sometimes it would sporastically move but it would never keep moving...ive tried taking it out and making sure all the connections were good but it did not help at all...ifd anyone could help me on this it would be greatly appreciated

 

I had the same problem. I found an gage cluster for $20 at a junk yard & now it is fixed.

 

Speed/Refrence sensors? Check those make sure they didn't come loose

 

In my '84 this occasionally happened. Turned out to be a ever-so-slightly loose connection on the ignition coil. The tach is connected to the coil ground to get the rpm signal.

 

My S2 had the same problem when I bought it. I took the tach out and could actually see one of the larger resistors had a fatigued solder joint. I reflowed the entire circuit board and the tach is rock solid now. Hope this helps.

 

Many many years ago, back when I had my 924, the tach didn't work. It was due to a faulty ground...... What car do you have?

 

I just went thru this with my project car (early '85). Tach wouldn't work at all. It turned out to be a broken wire at the 9 pin connector in engine compartment against the firewall. Theres two green wires in pin 1 of that connector. The larger green comes from the DME going to the coil. The smaller one in there is a back feed into the car to the tach. The small one was broken on mine. Check that connector/pins/wires there. Good luck

 

i have a 84 na 944

 

ok guys ill be sure to check all of those thnx for the input ill be back to tell you if anything helped

 

Put this in your signiture so you get the correct answers to your questions. There is a difference between the early and late 944's, 951's, 968's, 924S's and 944S's.

As to your question; the early tachs sometimes take the big one. You need to try one that works.

 

When I connect my tach it doesn't read but the 2nd rad fan comes on, and stays on... Any ideas?