I have these three error codes and now my tach doesn't work. What do I do?
I have a 1991 305 tpi z28.

 

It is either a broken wire between the ECM and the distributor, or a bad distributor module or pickup coil. The ECM code is for a bad distributor in general. No tach is due to module or pickup coil or wiring.

Check the wires from the distributor to the ECM. It is highly likely they are fine or maybe broke at the plastic connector. My guess is the module or pick-up coil inside the distributor is bad. You can test the pickup coil by connecting a voltmeter on AC to the pick-up coil wires (NOT THE IGNITION COIL WIRES) and spin the distributor shaft and see if a few volts is generated when you spin the shaft.

Or just get a reman. distributor for $100 and drop it in.

 

Alright I'll try that but any ideas for the other codes?

 

The code 15 and 25 are probably due to a bad ground or the sensors are bad. Sometimes the ECM gives strange codes due one code being set. I would fix the distributor, re-set the ECM by disconnecting the battery and then see if the 15 and 25 code is still there.

 

Thanks I'll chek that out.

 

Something I forgot to mention was that the baseplate has been switched to an Edelbrock. I did not personally do it. So could of something of been screwed up when switched out?

 

My favorite kind of post..........I forgot to mention what caused the problem........

Since all three errors are related to the intake. The MAT and CTS have the same plug and swapping them with throw a code for each.........

Not plugging in properly or breaking the plug for the distributor will throw a code and give no tach signal.