LS1Pariah

So after months wasted, and more money and frustration than I can count chasing this F#%*ing charging issue, I'm wondering if there is an old school alternator that is clocked the same, and will bolt up to the ls1. I have replaced the alternator with a delco, Fail. Then the truck 145 amp, still having problems. So then I replaced the excite wire with a brand new dedicated wire, and that worked for about two weeks. Well after driving home last night with no lights in the pitch black, I've had it. We did some testing today and when I bypass the excite wire I get a perfect 14.1v. So the alt works, but the PCM intermittently decides to not send the signal via the excite wire, so it's either replace an ecu and get the tune loaded, or buy an oldschool alt and run an ignition turn on wire and be done with it. Hoping someone has an answer to this.

wssix99

iTrader: (5)

Did you actually test this at the PCM? Any chance that there could be a problem with the exciter wire you installed? How did you crimp it in?

If you want to switch to a single wire, these guys can give you good suggestions: http://www.alternatorparts.com/

LS1Pariah

I have access to factory connections, so it was done just like it was new. I'll give them a call Tuesday and see if they can help. If anyone knows off the top of their head that would be great too.

1 FMF

iTrader: (1)

how many wires do you have in the connector plugging into the alternator, and what year?
i thought, depending on year, that the alternator got either a 12v or a 5v turn on signal which is referred to as the exciter wire. if this output from your pcm is bad, you might be able to find a 5v reference from some other pin and feed that to the alternator rather than buying a new pcm. the other wire is the battery reference signal to know what battery voltage is. i forget what the other 1 or 2 wires are, one might be the idiot/warning light.

http://oljeep.com/gw/alt/edge_Altern...html#Section_3

wssix99

iTrader: (5)

No matter which way you go - fixing your exciter problem is the easiest fix. Its not rocket science and I doubt that your PCM is screwed up.

If you go to a new alternator, you could have bracket/pulley issues and lots of other fun. My understanding is that a single wire alternator is less efficient and will cost you a lot more $$$ in gas.

LS1Pariah

There is only one wire in the connector plug. It's the exciter wire. my understanding is that the PCM raises and lowers voltage it outputs through that wire, so it's not a constant voltage source. And the old school alt has an internal regulator so once it sees the battery voltage come up, it starts charging less which would lessen the drag on the engine so I can't see how mileage would be affected.
How further can I address the issue? I've replaced the alt twice, as ran a new dedicated excite wire with factory terminals... And the other day during testing it worked intermittently.

1 FMF

iTrader: (1)

what year and make car is this?
i find it hard to believe that besides the big output wire on the back of the alternator there is only one wire going to it. this is oem?
on late model vehicles the internal regulator inside the alternator is actually a microprocessor, and if it senses something abnormal it stops the alternator from outputting. without knowing more my guess is some other problem is causing the alternator to shut off.

http://www.motor.com/article.asp?article_ID=1203

LS1Pariah

It's a complete 2001 drive train from an Fbody in an RX7. All systems including traction control, ABS, BCM, Fuel Tank and evap system, and gauge cluster are all installed and working in the car, and have been for 5 years now.

wssix99

iTrader: (5)

Ohh...

If you are sure that the exciter wire splice you made is good and the wire is in the correct terminal position on the plug, you might check for corrosion in the PCM connector. There is a TSB requiring new seals every time that plug is removed. If the plug was removed for the RX7 conversion, water might have gotten in there. Such a thing could cause really odd results and lead to other gremlins.

wrencher

iTrader: (2)

Yes this is a 2 wire alternator system. 1 large output wire & 1 "L" control input terminal.

The CS130D (Charging System) generator has a high amperage output. The "130" designation is the outside diameter of the stator laminations, measured in millimeters. CS series generators include a delta stator, rectifier bridge, and rotor with slip rings and brushes. A built-in regulator incorporates fault detection circuitry. Dual Internal Fan (DIF) design is indicated by the "D".
The generator operates with 2 wire connections and a ground path through the mounting bracket. The first wire connection is the BAT (output) terminal. This terminal must be connected to the battery during operation. The second wire connection is connected from generator terminal "L" to PCM. This circuit monitors generator operation.
Regulated voltage varies with temperature. System limits voltage by controlling rotor field current while field current is on. Regulator switches rotor field current on and off at a fixed frequency of 400 cycles per second to help control radio noise. By varying overall on/off time, correct average field current for proper system voltage control is obtained. At high speeds, with lower electrical loads, on-time may be 10 percent. At low speeds, with higher electrical loads, on-time may be as much as 90 percent.

PCM applies ignition voltage to generator "L" terminal circuit. A small amount of current flows from this circuit through the generator windings to ground to create a magnetic field which starts the generator process. When generator is at operating speed and producing voltage, a solid state switch for the "L" terminal circuit in the generator opens and the PCM detects that the initial start-up current flow has stopped.
PCM expects to detect low voltage on "L" terminal circuit prior to the generator rotating at operating speed and conversely expects that circuit to be at ignition voltage potential when generator is operational. When PCM detects a fault (circuit shorted to ground or circuit shorted to voltage), the BATTERY light will illuminate.
DTC will set when PCM detects an improper voltage on generator "L" terminal circuit.

DTC P1637: GENERATOR "L" TERMINAL CIRCUIT ("F" BODY) diagostics;

Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK. After performing OBD system check, go to next step.
Start and operate engine at idle. Using scan tool, monitor generator "L" terminal parameter. If scan tool indicates that generator "L" is inactive, go to next step. If scan tool does not indicate that generator "L" is inactive, see DIAGNOSTIC AIDS.
Using a test light connected to ground, probe generator battery feed circuit. If test light illuminates, go to next step. If test light does not illuminate, diagnose charging system. See appropriate GENERATORS & REGULATORS article in STARTING & CHARGING SYSTEMS.
Turn ignition off. Disconnect generator harness connector. Start engine. Check voltage to ground at generator harness connector terminal "B". If voltage reading is 10 volts or greater, go to step 11. If voltage is not 10 volts or greater, go to next step.
Turn ignition off. Disconnect PCM harness connector. Check continuity between generator harness connector terminal "B" and PCM harness connector. If continuity exists, go to next step. If continuity does not exist, go to step 8.
Check continuity between battery ground and generator harness connector terminal "B". If continuity exists, go to next step. If continuity does not exist, go to step 9.
Repair short to ground in generator circuit. After repairs, go to step 13.
Repair open/high resistance in generator circuit. After repairs, go to step 13.
Check for poor connections at PCM harness connector. Repair as necessary. After repairs, go to step 13. If connections are okay, go to next step.
Replace PCM. Program replacement PCM using required equipment.
Check for poor connections at generator harness connector. Repair as necessary. After repairs, go to step 13. If connections are okay, go to next step.
Replace generator. After replacing generator, go to next step.
Using scan tool, read and record FAILURE RECORDS DATA, and clear DTCs. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, select SPECIFIC DTC INFO for this DTC. If scan tool indicates that this DTC FAILED THIS IGN, return to step 2. If scan tool does not indicate that this DTC FAILED THIS IGN, go to next step.
Using scan tool, select CAPTURE INFO and REVIEW INFO option. If any undiagnosed DTCs are set, diagnose affected DTCs.

I suggest basics be double checked.
Volatage drop tests from the output lug to battery positive while loaded.
The same for alternator case to battery ground terminal.
Both should be very low less than .10 volt< even that high I would be looking for a bad connection/ poor cable wiring etc.

LS1Pariah

Wired in a redundant circuit with a light bulb to create the proper resistance giving it the correct voltage and it still worked I intermittently. Swapped alternators again, and for now it seems to be working. Still using the other circuit instead of the PCM signal just to make sure.