66belvkm

Had to replace my ecu on 66 belv 440,autozone also regulator spiked to 16 volts so replaced also. got 12 with key on and 14.50-15 running is this normal?

moe7404

be sure that the ECU and the voltage reg, box is grounded to the frame. a good diagram of the ECU can be found at ALLPAR.

66belvkm

Thanks for the reply. Its about 14.8, with lights and radio on.I noticed when car warms up it drops to about14-14,3.ckd. and redid all grounds also cleaned and greased bulk head connector.

440roadrunner

Getting up around 14.5 and more is too high. Check both the "sense" line, which is same as the line powering the regulator, and the ground path

To do this, do the following.

1--You need to check for voltage drop in the supply path from the battery to the regulator IGN terminal. Turn the key to "run" with engine off. Stick one probe onto the battery positive post. Stick the other probe onto the "key" side of the ballast, or if inconvenient-----

you can also use the blue field wire on 70/ later systems, or directly to the regulator IGN terminal on 69/ earlier system.s

What you are measuring here is the direct voltage drop in the path----

battery --- fuse link -- bulkhead connector -- ammeter -- harness splice -- ignition switch connector -- through the switch -- back out the connector (on the ignition run dark blue) -- back out the bulkhead connector -- and to the ignition, regulator, etc

ANY point(s) in the above path can have bad connections and cause a drop

You are HOPING for a very low reading, the lower the better. If you read more than .3V (three tenths of one volt) you need to find out where you are losing voltage. The more voltage that your read, is ADDED to an otherwise proper regulator, IE if you have .5 (1/2) volt drop, and the regulator is at 14, then you will regulate at 14.5V

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2-- Now check the ground path. This time, make two measurements, both with engine running, battery "normalized" Make the first test with all accessories off, and once again with lights, heater, etc turned on

Run the engine at a good fast idle to simulate "low" cruise, and put one probe of your meter on the battery negative post. Stab the other probe directly onto the regulator mount flange, and be sure to stab through any rust, paint, etc. As earlier, you are hoping for a very low reading, the lower the better. More than about .2V (two tenths of a volt) means you need to improve grounding. The regulator MUST "see" the same point as the battery negative terminal.

66belvkm

Thanks for the info going to get into it tomorrow.

66belvkm

Just want to thank you all for your response on my trouble shooting.Found lots of bad wires,replace and back cruising if it ever stops raining out.

440roadrunner

Very good