dingusboy

I tuned the the 65 Cutlass to the factory indicated 500 rpm which seems pretty low. Now, when I put the car in reverse, the GEN light comes on. I think this is a function of the low rpm's, but I haven't had the time to tune it back up. Any suggestions on the what I should be dialing rpm's in at?

frankr442

If it's designed to idle at 500 RPM (is your tach accurate?) and its running smoothly, rather than mess with the idle speed I'd check the alternator and regulator. What's it putting out at say 1200 RPM?

MDchanic

Yeah - what's your voltage when it does that?

- Eric

TripDeuces

Is that 500 rpm in gear?

dingusboy

In gear. I will check voltage tonight...hopefully.

dingusboy

Checked the volts at the battery. I have 12.87v off. 15.00v ignition on. 14.91v engine rev'ed. 14.7v with load (lights, radio, fan). 14.7v no load in reverse. Wha'cha thinkin'?

TripDeuces

I think those values are high. Each cell on a battery provides 2.1v. So 2.1v x 6 = 12.6 That is what a fully charged battery should read. Sounds like the voltage regulator is gone because 15v, 14.91v and 14.7v are high. Voltage should be between 13.5-14.5v. I would check your grounds to the lights including engine to body and body to frame. I would also get a new voltage regulator. Are you sure the voltage meter is accurate?

dingusboy

I believe the voltage meter is good. Does it matter that I keep the battery on a tender?

Highwayman

My memory thinks the external voltage regulators are adjustable for voltage.

MDchanic

Those numbers sound a little high to me, but we were worrying about your output being LOW, and it clearly isn't.
If you are not boiling your battery or blowing out light bulbs, then I wouldn't worry about it.

That being said, we still don't have a good answer as to why your GEN light is coming on in reverse.

I wonder whether you don't have some sort of a crossed wire between the backup lights and the GEN light.

- Eric

dingusboy

Kinda what I thought. If I put pressure on the shifter so that It stays in reverse (but off of the reverse light contact) the gen light goes out. But, where would the circuits cross over?

MDchanic

Ah HA!

I would unplug the backup lights from the neutral safety switch and jump the plug with a paper clip to see if it makes the GEN light go on.

If so, then you've just got to follow the wire that is supposed to go to the backup lights and see what some previous idiot has done with it.

Not much fun.

- Eric

foulpalamont

Just curious if you ever fully troubleshot this. The exact thing is happening with my 64 Jetstar 1. Up until this morning, the Generator light was always on, but I've replaced the voltage regulator and it's cleared up a bunch of problems. However, when in reverse, my Generator light does come on as well. Was it the neutral safety switch or wiring?

MDchanic

Another possibility: You could have a bad engine-to-body (firewall) ground.

Does the light go on as soon as the selector is in R, or does it wait a fraction of a second until the engine "clunks" into gear?

If there is no ground strap between the head and the firewall (or a jumper somewhere serving the same purpose), then ground will be completed wherever there happens to be continuity, which is likely to be the throttle linkage. When the engine shifts as you go into R, it may interrupt the connection slightly, and affect charging or the regulator.

Easy enough to check.

- Eric

foulpalamont

Actually, I'm embarrassed to admit this, but it happened to be the reverse light fuse. It had blown. Thanks! Replaced fuse/no light.