Alternator problem???

[pszemia]

Hi, since i've been working a lot on my car and still going through CMA, i have found a problem in the oil pressure and temp reading gauge.

As i was heating up the engine to reach 180ºF to do all the tests, i found that the gauge was at 180ºF so i turned out the engine. After that i start the engine again instantly and the temperature was at 120ºF. Trying to check if the sender cable was well connected, i found that after pressing a little bit the accel the temp climbed again to 180ºF showing the actual temperature.

The thermostat is working fine i think, because some weeks ago i was driving hard and the temperature climb up to 230ºF and then when i slow down it came back to 180ºF or so.

The pressure gauge climbs ok, and goes back ok but when i depress the accel.

The oil level gauge is kind of dead (it's under the minimum) but after doing some checks and reading posts, i found that maybe the problem is at the tank level sender because if i dissconect one of the leads in back of the gauge it will climb to full position (so the gauge is working fine).

The problem came here: when i am driving little fast (60mph) and i drove across a little rough segment of the hihgway, the pressure and temp gauges go down and then up like moving with the car movement.

The other symptom i found is the G letter on when the car is at idle, and then it goes completely off when driving above 1000/1100 RPM. When caming back to idle (at a traffic light for example) it cames on dimm and then came brighter until i rev the engine up and then off again.

I though it could be an alternator problem, but the batteries are chargin ok, i checked this after a long without starting the car (15 days) and it started fine. I checked with a multimeter and both batteries are at 12.20v +o-. I haven't checked the batteries with the car running.

Is there a way to check if the alternator is working right or ther is a problem that is causing all this??

Thanks!!!

Ariel

[dshepp806]

Be sure any circuit related fuses are checked for good connection within the fuse block ..connections good at rear of instrument gauge (s) ????

What is the battery voltage while running (and revving)?

Sure "sounds" like a connectivity issue,...having things change when going over bumpy roads.....

Best,

[pszemia]

Battery voltages:

car off: 12.40v
car running at idle: 12.30v-12.50v (mostly at 12.40)
car revving: climbs from 12.40v to 13.90v at aprox 3500 RPM. if rev higher it will increase.

The oil tank level i found the problem the previous owner removed both cables from the tank sender and he cut them. I have to reopen the cables going to the rear lights and take from there the green/white and brown cable.. is that ok??

thanks!

ariel

[pszemia]

anybody?

[304065]

search for "blue wire" and "pickling" - you have high resistance in the charging circuit.

[pszemia]

john, i've search for it.

i measured the blue cable at the oil gauge and it has 1.44 ohm (at 2k measure) and 0.9v with engine on and after getting the engine a little hot it went to 1.36ohm (at 2k) everything with the cables all connected.

I don't know how to measure the complete cable ressistance with both spades disconnected my multimeter wont reach both ends.

by the way, the 14 pin connector is that one marked with a red line???

What are those 3 places for?? (blue lines)

and finally, what are those 3 fuses used for?



thanks!!

[pszemia]

bump

[pszemia]

one more try

[304065]

Ariel,

Yes, the 14-pin connector is circled in red. It's supposed to be wrapped up to the shell in black electrical tape, yours looks like it has been opened. You are also missing the defroster relay and the speed switch, this is what is supposed to go on the rectangular connector.

The rear fuse box

This thread may help:

Retrofitting a 69-73 MFI engine to a 1966 carb'd 911?

As far as your charging voltage goes, it sounds OK, you may want to check belt tension. Ideally you want at least 12.5v with the engine off and 13.5 or so to charge, up to about 14.5 volts is fine (but you probably won't see that high with a stock regulator)

[pszemia]

so my speed switch has been removed..

should i look for one to put there, or it isn't very important for the general car use??

the defroster relay i have to get one..

thanksss

ariel