[lucas.bree]

I have a 1991 tb42 efi and the tacho is going crazy with the key on reds no engine running it bounces from 0rpm to 6000rpm and back and stops in the middle somtimes.The motor runs fine once you have started it but still the tacho crazys.How do you test the tacho where is the feed coming from is there a general problem these have any help would be good thanx:headwall:

 

[create]

Tacho feed comes from the coil. I had this problem and found it was a dirty/loose connection from my pertronix to the coil.
Unplug all the ignition connectors and give them a clean. Check the bolts on the back of the coil are all tight.

 

[marin]

Can also be dry joints in the dash itself on the circuit boards. Happens to solder after this many years.

 

[lucas.bree]

And whats the best way to wet the joints if this is the problem?

 

[OSH]

And whats the best way to wet the joints if this is the problem?

if your refering to the connections that have dried out on the cluster,
they will need to be re soldered.


just for a bit of refference,
i just had my GQ cluster 'refurbished' and new senders put in and it cost me $400.

 

[lucas.bree]

Can you tell me how to test the wires [plugs] that are on the back of the cluster to make shore its geting the right volts to the cluster so i can eliminate the cars loom etc thanx