1979 Chrysler 300 tach wiring

[bonshee1971]

I have a 79 300 that I pulled the motor and rebuilt. Going back together with it, I decided to try an HEI swap to clean up the engine compartment. Works great and the firewall looks much better uncluttered. I simplified the factory harness and eliminated the wires that ran to the lean burn, distributor, and coil. Im trying to figure out which wire goes to the factory tach so I can hook it back up but Im having a hard time finding a wiring diagram for a 79. Latest diagram I can find is for a 76 Charger. Im sure these are probably pretty similar but Im not sure. Does anyone have any ideas or know what color wire goes to the tach? The diagram I found just shows the printed circuit but doesnt say what pin goes to what. Im stuck.

 

[396 Signet]

No way would I ever use an HEI ignition on a mopar but to each his own. By coincidence I worked on a buddy's '79 300 several months ago & too some pics. To best of my recollection the gray wire in the pics is the tach wire.

 

[bonshee1971]

Thats a perfect pic. That'll help alot. I appreciate the help.

 

[Crizila]

Hei - way!!!

 

[A383Wing]

yup, I'm going HEI module as well...

http://www.designed2drive.com/

 

[droptop]

Gray wire is correct for tach.

 

[Dobalovr]

Sorry to bring back a necro thread but my 79 300 tach only registers rpms up to 500 will not go past 500 regardless of engine speed any ideas?

 

[DeltaV]

Plastic lens is warped and the needle is dragging on it?

Check with Ray @HALIFAXHOPS for electrical suggestions?

 

[HALIFAXHOPS]

FSM is your best friend here aftermarket it is usually green.

 

[Dobalovr]

Good call on the plastic lens interfering DeltaV ill pull the dash apart and confirm that. Unfortunately the FSM was no help on this topic. Now just need to work on getting the fuel guage to read correct and stop the speedo from bouncing all over…. Troubles never cease

At least the wheels turned out ok

 

[XCELLR8]

Good call on the plastic lens interfering DeltaV ill pull the dash apart and confirm that. Unfortunately the FSM was no help on this topic. Now just need to work on getting the fuel guage to read correct and stop the speedo from bouncing all over…. Troubles never cease

At least the wheels turned out okView attachment 1356292

Like the wheels. On the speedo bouncing around, check to make sure the speedo cable is tight on both ends. My 77 Cordoba was doing this and it was loose in the engine compartment, tightened it up and no more bounce.

 

[Remy-Z]

Speedo cable could also benefit from lubrication. Does fuel gauge work at all or is it just really off?

 

[XCELLR8]

Speedo cable could also benefit from lubrication. Does fuel gauge work at all or is it just really off?

X2 on the fuel gauge. Mine quit working all together, as I watched it slowly go from full to empty. I ended up getting a pin hole in the float, replaced the float with another brass one and the gauge is working correctly. One thing I will add in my research is that the solid plastic floats do not like the new type of gas (ethanol) and start to be eaten away over time.

 

[Dobalovr]

Speedo cable could also benefit from lubrication. Does fuel gauge work at all or is it just really off?

The gauge does not work at all. Low fiel light is on needle bottomed out on E

The speedo cable goes to the cruuse contol might the cruise module be the problem?

 

[XCELLR8]

The gauge does not work at all. Low fiel light is on needle bottomed out on E

The speedo cable goes to the cruuse contol might the cruise module be the problem?

Your gas gauge is doing the same as mine did with the bad float. My speedo cable was loose at the cruse control as well.

 

[Remy-Z]

The gauge does not work at all. Low fiel light is on needle bottomed out on E

The speedo cable goes to the cruuse contol might the cruise module be the problem?

The float could do that. I'd also suspect a grounding issue...the little metal strap between the sending unit and the fuel line does not fill me full of confidence. As far as the speedometer cables, IDK if the module could be the problem, but I'd lube both cables up and make sure their connectors are nice and secure.