Hello everyone, As my subject states, I have an '89 IROC-Z with a 1995 LT1. The engine has been in the car for about 3 years now, but I've only been able to drive the car a total of probably 1 year during that 3 years due to gremlins. I paid a buddy of mine to perform the swap, which included all of the wiring to make my factory gauges work. Right off of the bat, I had alternator issues. I'd buy an autozone alternator, and it would last a day, or even a week if I was lucky. After dealing with this issue through probably 10 autozone / advance auto alternators, I decided to bite the bullet and buy a Powermaster. After I put the powermaster on there, things seemed to work absolutely great. Well, this past summer, I noticed some weird things happening... The door locks, windows, and radio would intermitingly work. After a week of driving the car with these issues, my buddy locked the keys in the car with the keys in the ignition. The car was not running, but the ignition was turned to the "on" position. The keys were locked in the car for about an hour. The next day, I go to drive the car, and the voltmeter read 0. Again, I was out an alternator, but instead of $100, I pissed away $400. So, back to square one. The car has been sitting since September. First and foremost, I know NOTHING about wiring, and have no real mechanical experience working on cars. So, I'm kinda feeling myself blindly through this ordeal. About 2 months ago, I started trying to investigate the situation on my own. I called both Painless and Howell, and they both said very similar things -- They mentioned a charging light helps to lower the current running into the alternator. BTW - Both guys were super helpful and nice... highly recommended. So, here's the deal... I checked the wires running into the alternator. There are two plugs. PLUG #1 - Round / Oval plug with 4 pins (1 is bigger than the other 3). It is labeled SFLP /PED 2 . It is connected to 1 red wire. This red wire has been cut, and reconnected with a "butt connector," why, I don't know. I don't know if this plug mentioned below even goes to the alternator... I can't remember (the alternator has been off the car since August...) PLUG #2 - Smaller plug with 2 pins. Connected to 1 Black wire, and 1 Green wire. It is labeled PED 14. Please, for the love of g0d, tell me what I have to do to make this thing work. I tried to give you guys enough background info to shed light on the situation. If I need to buy some parts, please tell where to get them.... In other words, explain everything to me like I'm a two year old because I'm clueless about this stuff. Thanks for the help! Peace. BTW, my car ran a 13.12 @ 107.5 on street tires only... with just exhaust, K&N's, and programming. I want to break into 12's real bad on street tires!! So, lets GET 'ER DONE!

The wire two over from the big red one on the plastic connector, run a 12v wire to it but with a 480 ohm 1 watt resistor inline.

I think we've all had troubles with this, but I think some of it was covered in the "LT1 wiring for dummies" post, you might try that one first and see if you can come up with a solution. I think the main reason we keep frying alternators is it overcharges and blows the regulators out. I went through 6 O'Reilly Ultima alternators. So far this one has lasted for quite a while. I thought I was going to have to replace it over Christmas as it started acting funny again, but then it quit and has been working fine since.

Like I said.

When your ready for the troubles to stop, run the resistor.

yeah I was making my post as you made yours. resistor is the easiest way.

Okay... sorry for being a total dunce. I seriously am infantile in my knowledge. Could you, or someone else expand on this reply? I don't understand how to go about this, or what exactly to do. I don't know what the "wire two" is. I'm literally not trying to be a smart ***.... I honestly don't know.

What I have, is one connector (SFLP), and one red wire attached to it. You are saying, take the red wire, splice it in two spots, run another 12 volt wire with the resister inline, from the first splice to the second splice of the main red wire?? In other words, it would look like this:

o <-- PLUG
| <-- red wire
D <-- new wire spliced in (but with a resistor inline)
| <-- red wire

Or, are you saying something completely different? If this is the case, why couldn't I just run a resistor inline on the red wire and be done with it? Or would that cause way too much resistence?

Does that makes sense?? Again, I seriously apologize!! I feel like a total jackass... and I'm a programmer for chr1st sakes!!!

TexasLT1 - BTW, I did check that post, but it's greek to me...

The plastic connector that plugs in has 4 pins, the first being a large red wire, loop that back to the stud on the back of the alt, the next one do nothing with, the third you want a 12v wire going to it but with a 480 ohm 1 watt resistor inline.

If you are using the stock LT1 alternator connector you should only have one red wire in the little plastic connector, 12v through the 480 resistor just the same, problem solved.

-- LT1 ALTERNATOR SWAP --

Okay, after gathering all the info from painless, howell, and your replies, I went and consulted the manuals that I purchased for the swap (1 Helm 1995 Fbody, 1 Helm 1989 Fbody). On the 1995 charging system schematics, it shows a 470 OHM resister in the Instrument Cluster (circuit running through the voltmeter). On the 1989 side, there doesn't appear to be any kind of resister anywhere in the instrument cluster relating to the charging system.

Conclusion: as Z28Racer already stated, there has to be a resistor inline, otherwise the alternator will always be "excited" and the regulator will always be on, thus burning it out prematurely. If you think about it, it makes sense because most people doing LT1 swaps usually wire most of the harness into the bulkhead connector, and rarely touch the instrument cluster wiring... at least, that's what I've seen....

You'll have to let me know how this works out for you, my alternator isn't charging at all.

My issue seems to have been taken care of. You might want to give Dana a call over at www.lt1350.com.

What exactly did you do to solve your problem??? In June of 2005 I had a 95 lt1 swapped into my 84 camaro, and over the last few months I've had some serious electrical issues. I believe that it's my alternator, any info woiuld be greatly appreciated.

Use the stock LT1 plug with the one red wire. Take the red wire from the C220 connector, put a 470ohm 1 watt resistor inline and the splice that wire into a switched ignition 12v source, this will make the alternator work when needed, mine charges at 14.1v with no problems at all.

camarobeast84,

Do exactly what Klortho has prescribed. Splice the red wire, and solder in the 470 OHM resistor-- that's it. My red wire was already running from a 12 volt source.

I'm getting ready to take my car to my mechanic this weekend to have this and various other kinks worked out, and will definately go over the info in this post with him. I've got another question for you guys though. I read in one of these posts that there is an issue with swapping an lt1 into a 3rd gen in regard to the factory gauges. If I run say autometer electric gauges would I still need this resistor? Also, my speedo (145mph) and temp gauge don't work and my fuel gauge is completely inaccurate. Have you guys had similar issues or have any advice?

All my gauges work just fine, you still need the resistor, that's what keeps the regulator from being on all the time.

The resistor has nothing to do with your gauages. It is simply in regards to prematurely burning up your alternator. If you are having issues other than your alternator, your harness is probably wired incorrectly. My alternator was constantly "excited," which would burn up the regulator, so it would not turn on / off anymore.. since it was always "on."

89_LT1_IROC,

I read in a different thread that you started, that you were using a 33ohm 5 watt resistor inline on the wire running into the L lead of the regulator plug.

Which is it? Did you use the 33ohm or the 470ohm, or did you try the 33 first and then switch to the 470??

I'm in the process of upgrading to a Powermaster 140A or 200A alternator, Optima redtop, and the big 3 in 0 gauge, and I want to make sure and get everything just right.

THANKS!

Use the original LT1 plug, splice in a 470ohm 1w resistor inline and hook it to a 12v source, that's all that needs to be done.

I've only found a 470ohm 1/2 watt resistor, will that work? If not, then where can I find a 1w?

I also thought that I'd share something that I found on lt1tech.com's hybrid board:

"A problem that I have encountered is that the alt. a Camaro has two wires, One heavy one that is mounted with a ring terminal to a stud. The other is attatched to the "L" terminal. The heavy wire goes directly to Batt. positive. The other has a 470 ohm resistor in it and this goes to IGN on. I decied a little more research was needed . I discovered that the resistance needed is dependant on what else is in the circit. The final voltage is VERY critical.
The solution is to forget about "L" and the resistor altogether. Instead, feed full batt. power (from IGN) to the "F" terminal (Field). I have recommended several people use this method on differing applications and so far, not a single failure."

What do you guys think?

I had read the same thing on lt1tech.com but it was only after I installed the resistor. Feel free to try it, I found my resistor at www.mouser.com. I am going to test to see if I fixed my alternator tonite, so I'll let you know how it went.

You can try it, I personally don't want to fry a $130 alternator to test it.

Well, what about the resistor??

You can order resistors from where Camarokid89RS said at mouser.com they sell electronic pieces.

I installed the resistor in the circuit for my LT1 alternator, but am still having charging problems. I went to the parts store and they said that it's charging fine, but the voltage is low, like 11 volts. I also thought the voltage was low because the gauge reads about 10 in my cluster. When I have the lights on and the fan is running it reads less, but even over long trips (30 minutes of straight driving) it doesn't seem to drain the battery dead. How can I fix this, and how is it caused?

Which wire did you hook the resistor up to?

I soldered it into the wire that goes to the "L" terminal on the alternator. The car has not much power with low voltage and it's upsetting

That should come out on the C220 if I remember correctly (it's the only red wire in the blue/white/black connectors), that wire should be hooked to a 12v switched source.

I am dang near 100% sure it's wired correctly, I think that the parts store did the test wrong and that the alt itself is bad. I'm going to take it off today and take it in and test it and get a different one if needed. It's gotta be that, I don't know what else it could be.

Well, problem's fixed. I don't know how, but it's fixed. I took the resistor out, took the wire that would go to the "L" terminal and spliced it to the "F" terminal and she works fine. Strange.

Klortho, my car doesn't have a C220 connector!? It seems that the shop who performed my swap either bought a custom harness from Speartech, or had them adapt the harness that I already had. I'll have to give them a call to find out which, in the mean time do you have any suggestions?

What type of resistor is being referenced in the above posts?

I see a Ohmite Silicon Coated Power Resistor, Metal Film Resistor, Thick Film Resistor, Thick Film Chip Resistor, Flameproof Metal Film Resistor, Metal Oxide Resistor, etc. etc.