Fixing tachometer on 1983 Cutlass Supreme

[Ranger1]

Hello all...

I am trying to help a friend fix a tachometer on a 1983 Cutlass Supreme (which is in excellent shape otherwise). He recently had to replace an intake gasket, which required removal of the distributor. After reassembly, he found that the Tachometer would not return to 0 RPM correctly, depending on what state the ignition key was in. But, if the engine is running the tachometer seems OK.

As I am not an expert on this stuff, I was hoping someone may be able to offer some ideas on things to check out.

Thanks.

 

[Ranger1]

FYI.... This '83 Cutlass has the gas-powered V8 engine.

 

[Propflux01]

Are you saying that when he turns OFF the key, the tach needle just goes randomly somewhere on the dial, and when he turns ignition key ON, then needle goes to zero and operates normally when engine is started?
If so, I believe that is actually normal operation. I have seen many of those early eighties GM cars' tachometers do this. I know it looks funny but as long as it records proper operation when engine is running, then press on with pride. however, if this all started after his removal of distributor (now are you really Sure of this)then maybe he pulled or disconnected a wire or ground.

 

[Ranger1]

Yes. This only occurred after he finished working on the engine. He bought this car brand new in '83 and is very observant of these types of issues.

When he turns the key ON, but the engine is not running, the gauge goes up to about 1000, and when the key is OFF...it's about 500. But, when the engine is running, the gauge seems to be at the normal running RPM.

He believes he reconnected the grounds correctly (and had cleaned the connections too). But, he did say the distributor was very difficult to pry loose.

Is there something else that could had been misaligned or damaged during removal or the re-install that would show similar issues?

 

[Hokiefyd]

This is indeed simply the way they work. My '84 Cutlass was the same way. Key-out, it would usually sit at about 900 rpm. Key-on, and it would return to 0.

 

[Hokiefyd]

If key-on, it jumps to 1,000 rpm, then that is not normal, and there has to be something disconnected somewhere. He didn't remove the gauge cluster, did he? There's a jumper on the back of the tach that needs to be set for 6 or 8 cylinder operation. Could that have gotten dislocated?

 

[Ranger1]

No. He did not touch the gauge cluster.

Right now, he trying to decide how to fix this. Buying a new distributor or such. But, if all else fails, I believe he will go to a dealer to get it fixed, as he is certain it is not working like it had been before the other engine work.

 

[sasilverbullet]

Originally Posted By: Ranger1
No. He did not touch the gauge cluster.

Right now, he trying to decide how to fix this. Buying a new distributor or such. But, if all else fails, I believe he will go to a dealer to get it fixed, as he is certain it is not working like it had been before the other engine work.


I don't think the problem is in the distributor. Look elsewhere. Old cars are famous for "you work on one thing, and something totally removed from it breaks". When you move old wires, they can break or change impedance and look fine on the outside. It's a wiring issue, going to be hard to find.

Good luck!