Strange but when I start the Regency from cold the tach doesn't work and the voltmeter reads about 11.5 volts.
Kick up the revs after letting it buid pressure even if warmed up, both guages read like that. Take it out on the hwy for a good run and after 5 or 6 miles all of a sudden the tach kicks in and the voltmeter jumps to 13.5 volts and stays there for a 50 mile drive. Shut it down and restart afew minutes later (after fueling up in this case) and everything works normal. Let it sit overnite and no tach and 11.5 volts on start up again!
Any ideas??
Oh and when hot after a drive it idles @1000 rpms. Used to idle at 750 approx.
Thanks in advance.
Don

It sounds like your alternator may have sticky brushes and/or dirty slip rings. I had the same type of problem with my airplane and a Ford Pinto years ago. After startup, the alt would not charge until the engine ran a few minutes or revved fairly high.

Regular use may improve it. You may have to intervene if it gets worse. You may get by with spraying some cleaner in the brush holder (if the alt has vent holes for access) Otherwise it may be slip rings. They can be shined up if you disassemble the alt to get to them. On the other hand, depending on the age you may want to just swap it out if the problem gets worse.

Hi Don, this may sound nuts, do you happen to have a continues duty solenoid in your electrical compartment? jump it to check it or in my case I replaced it and all was well, including the turn signals, radio etc
HI Steve

quote:

Originally posted by Steve VW:
I had the same type of problem with my airplane and a Ford Pinto years ago.

How interesting to have owned an airplane (upscale) and a Pinto (not upscale).

quote:

Originally posted by Steve VW:
It sounds like your alternator may have sticky brushes and/or dirty slip rings.

In addition, a good cleaning and tightening of all connections might help. Metal expands with heat, and a marginal connection could get tight as it expands when warmer. I have seen connections that tightened up when hot.

Chevy owners will know this works the opposite way on a long stud on the solenoid. It expands when hot and loosens things up. Chevy introduce an SB which added a Belleville washer to keep the connection tight.

The Pinto was along time ago..(80-83) I was doing field "computer" (IBM punch card stuff!) service at that time, I was putting about 500 mi a week on the car. I had 3 of them in all, bought them used and cheap and used them as disposable cars. I got 200k mi on the '72, 160k on the '74 and 150k on the '76. Given the company mileage allowance at the time, I made money on them!

Plane comes many years later (97) I have put about 800 hrs on it since. (Actually for a plane it's not really upscale, the Cessna 172 is the Chevrolet of the sky; there are over 31,000 of them flying in the US alone)

To save the thread:

(Hi Tom!) As he points out there may be an intermittent 12v source that powers the tach and provides alt input. In my gasser I'd be looking at ignition/distributor wiring, but I don't know the layout for the diesel rig wiring, since the engine doesn't care about no steenking electrons to run!

I to had the plesure of working on many a 1442's (reader/punch). Miss working on that old iron. The quality of machining in that stuff was somthing else.

Back to the thread. Don't overlook a battery cell starting to short out. I don't know how the tach works on the Cummins I know on my Dad Cat 3208 it was a gen/motor set up. His speedometer was set up the same way.

Doorman

On my diesel Regency the system uses Hall Effect speedo and tach. (for more info see Hall Effect in Wikipedia)If the transducer is going bad or the 12v to it is defective the instruments will not work. You can measure the voltage at the sensor or determine if it is bad. I replaced mine when the speedo and tach started moving erratically. Are you sure the engime is running at 1000 rpm or could it just be the instrument?