TD New Guy
Join Date: Jul 2009
Location: Edgewood WA.
My Ride: 87 Datoyna Shelby Z
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Re: Running rich. Need a new O2 Sensor?
Yep, done that V reading several times. With external voltage regulator the alternator outputs at 15.1 V, switched F1 was 14.8 V. Converting back to the stock Power Module (no external VR) it takes a little time to run the battery down to the alternator's discharge voltage of 11.2 V then switched F1 was 10.8 V.
FYI: Did a full field test with just the Power Module and then again after converting back to the external regulator. On both, after grounding, the voltage climbed quickly to 17 V then I just as quickly removed the ground. It might have climbed higher but I didn't want to risk damaging anything so stopped the test. This test only took maybe 3 seconds to hit 17 V.
I've repeatedly tested (1) Logic Module Red connector Cavity 5 (LMRC5 that goes to Power Module 12 pin Cavity 11, PM 12-11) and (2) alternator Field 2 (PM 10-8, Alternator Field Control). Been instructed that both are supposed to pulse but neither do.
(1) LMRC5 (Connected to PM 12-11) with key off there's 135 mV and with key on or engine running only 165 mV. This is the Voltage regulation signal / Alternator Field Control wire, a dedicated wire between the 2. Previously I confirmed it was a good wire with the meter and it wasn't open or shorting with other wires. Now I'm paranoid and tomorrow with check the connectors on both the LM wire loom and inside the LM. Don't think it's the LM as the back up did the same thing.
(2) Alternator Field 2 is a dedicated wire to PM 10-8 (Alternator Field Control). This is the wire that's cut and replaced by the new external voltage regulator's Field wire.
*From studying the manuals my understanding of the Daytona's voltage regulation is this: The battery temperature is determined by either or both
(1) PM 12-3 Voltage Regulation Sense sending a signal to LMBC20 (that tested at 4.6 V, don't know what it's supposed to be) or
(2) PM 12-6 sending Direct Battery Voltage to LMBC2 & LMBC22 that tested at battery voltage 15.1 V, the LM calculates a temperature / voltage ratio and has LMRC5 send a output pulsed signal to PM 12-11, finally PM 10-8 sends a pulsed signal to Alternator Field 2 that increases or decreases voltage depending on battery temperature. It seems as there are no pulses coming from LMRC5 then PM 10-8 wouldn't send them either. Going further back it seems everything is based on the PM sending that 4.6 V signal to LMBC20. I'm thinking as the battery temperature goes up & down this voltage would also but haven't come across that information. As the PM's voltage regulator didn't completely fail (still puts out about 11.2 V) it could be interfering with PM internal calculations resulting in 15.1 V when the external VR is installed. Didn't think to test PM 12-3 / LMBC20 with the external VR removed, will do that tomorrow.