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Old 08-11-2008, 08:18 AM   #1
Spinman
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Question '90 Alternator upgrade from CS130 to CS144 = Need to add Resistor?

Some advise please -

I'm replacing the CS-130 alternator in my 1990 Coupe with a CS-144 unit (using a unit listed for a 1996 Olds Aurora Northstar Engine).

Everything I've read indicates that the two style alternators are plug and play - no conversion rewiring is required.

Everything seems to fit mechanically w/o any problems. Even has the same pulley. As expected, I needed to mill the upper flange fitting - removing 4mm so that it is narrow enough to fit into the existing bracket.

However, I'm still confused / concerned about the need to add a 35 ohm 1/2 watt resistor to the existing wiring harness or not...


Is the CS144 truly plug and play when replacing a CS130 - or do I need to add a resistor?

I measured the resistance from the disconnected positive battery cable (with the ignition on) to the "L" treminal on the disconnected alternator wiring harness - and measured 14 ohms. So there is some resistance, but less than half of the "recommended" (min) 35 ohms and nowhere close to the (max) of 350 ohms.

I'm not sure if the "battery icon" on the DIC is technically considered an idiot light - but I keep getting hung up on the fact that if I already had a CS130 installed in the vehicle, the CS144 should not require any additional wiring...


What have others that made the change experienced? Did you add a resistor?



****************************
From various web pages:

L-Terminal: This terminal is connected to the “Low” side of the warning lamp, with the lamp’s “High” side being fed by the ignition circuit. Some regulators require a 35-ohm resistance inline with this circuit if no lamp is used otherwise alternator damage may ensue. Some applications have a resistor connected in parallel to the lamp in case the lamp bulb opens up and burns out. The resistor will be there to provide a path for current and voltage. Some vehicles supply a 5Vdc reference to this terminal from their ECU or Computer; other vehicles don’t, so be aware of the various models of regulators. Other regulators may be tested by application of a 50-Ohm pull-up resistor to connect the L-Terminal to the 12Vdc source, I believe that any resistance between 35 Ohms (5-Watt resistor) and 500 Ohms (1/2 Watt resistor) can be used safely.



"The resistors provide a "tickle" for the charging sensor. The alternator was designed for a car that has a "dummy" light, which provides resistance for that sensor. So, if your car has no dummy light, there is no resistance, so there has to be a resistor somewhere in the system to provide a load."

"The switched 'light' (terminal 'L' on CS), must have 12V switched power with between 35 and 350 ohm resistance (typically the light itself). If below 35 ohm, the CS units will fail."

"On the CS-series there are variations on this. Some CS-130's simply require a battery voltage to the regulator. Other CS-series need a minimum of a 50-Ohm resistor in series with the "L-Terminal" on the units."

***************

So if the above is true - I don't know what the resistance requirements are for the CS-144 designed for an Olds Aurora - Maybe I should add a resistor to the circuit just to be sure that I'm over 50 ohms...
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Old 08-11-2008, 12:07 PM   #2
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I have an 89 with a 1991 dash and electronics.. here is what I did

I removed the CS-130, put it in a box on the shelf

I bolted the CS-144 in place and installed the belt.

I connected the main wire to the lug and connector the connector on the back of the unit.

Connected the Battery and have been enjoying the worry-free alt since..

this was in 2003.. I did not add any type of resistor
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Old 08-11-2008, 07:48 PM   #3
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I'm stumped...

Everything I've read to date has suggested that any late model CS144 alternator should work - just match the same frame style, clock position and mounting flange positions. So I didn't give any thought to searching for CS144 from a specific vehicle.

I installed the CS144 (140 amps / for a '96 Olds Aurora) and my battery warning light never went out. Quickly turned it off, not wanting to damage anything.

Reinstalled the CS130 - and naturally, the light went out when the engine was running.

Out of curosity, I took the CS144 to the local parts store and had it tested - everything is A-OK.

While they were preparing to run the test, I noted that they employed different wiring harnesses to connect alternators to the test equiptment. The cable for a '96 Olds Aurora Alternator is different than the cable for a '90 Corvette. I have no idea what's different between the cables (resistance perhaps?).

I suppose I need an alternator expert or a Delco-Remy engineer, but I wonder if there is something different internally between the 2 units I have. Perhaps the Corvette CS130 has a different resistance internally than the Aurora CS144 - thus the "L" circuit is not turning off the charging idiot light and telling the alternator that it is ok to proceed...

As I mentioned earlier - various web pages indicate that the "L" circuit requires resistance in the range of 35 - 350 ohms - yet I'm only measuring 14 ohms.

I hate to install a resistor in the line until I know what's really happening (and don't know if I install it in series or parallel with the existing idiot light).

More research..Yuk!
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Old 08-11-2008, 07:53 PM   #4
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why did you not buy a CS-144 for a LT1 like I told you to???

like I said.. I have NO issues.. going on 6 years
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Old 08-11-2008, 08:32 PM   #5
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Quote:
Originally Posted by -=Jeff=- View Post
why did you not buy a CS-144 for a LT1 like I told you to???

like I said.. I have NO issues.. going on 6 years

1) Because all the listings I saw only specified a 124 amp alternator for the '92/'93 LT1 - wanted to get a 2nd generation 140 amp alternator.

2) Had easy access to a spare Aurora Northstar Alternator.

3) Have been unable to find any definitive information as to any differences between the internal workings of the various CS144 alternators that would have mandated the use of a specific vehicle alternator.
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Old 08-12-2008, 05:35 AM   #6
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Quote:
Originally Posted by Spinman View Post
1) Because all the listings I saw only specified a 124 amp alternator for the '92/'93 LT1 - wanted to get a 2nd generation 140 amp alternator.

2) Had easy access to a spare Aurora Northstar Alternator.

3) Have been unable to find any definitive information as to any differences between the internal workings of the various CS144 alternators that would have mandated the use of a specific vehicle alternator.
so then use the 140 CS-144 from a 94..

is the PN of the Alt you got different from any of those found on the 92-96 vette?
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Old 08-12-2008, 05:38 AM   #7
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94-96 LT1 Alt.. GM PN 19135994
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Old 08-12-2008, 09:32 AM   #8
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Question. Does that 14 amp extra really help pr do much of anything to justify it all?
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Old 08-12-2008, 03:50 PM   #9
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Amps

Quote:
Originally Posted by aklim View Post
Question. Does that 14 amp extra really help pr do much of anything to justify it all?
When installing a alternator which is better 120 amp,140 amps ,or 540 amps ? Here is the answer. You actually only need and use a certain amount of amps to get 2 things accomplished. 1. to run the load and 2. to charge the battery. The way to tell what you actually need is to run a amp test with the engine off. Install a battery load tester amp clamp to the positive cable.turn on all the accessories...lights , w/s wipers radio etc. Read the amp total draw that you have. Now lets say it was 100 amps,and you had 120 amp alternator,then you would have 20 amps to charge you battery after usint the rest to run your load.Plenty..so when chosing the right alternator you must know how much the load is going to be. Remember we have volts amp and ohms..amps get the job done.
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