Feels like I am making more like 170 hp instead of 270+.

I am suspicious of a low voltage problem. If charging system is low would a severe power loss be a system.

Elsewise what are some steps I can take to trouble shoot a power loss problem. I expect it to be a fuel problem. The MAF sensor seems to be responsive. New fuel pump and filter.

Any ideas are greatly appreciated.

Thank You,
Gus

 

Did you replace the optispark? This is a know issue in these engines. All sorts of bad things happen when it goes south. Are you storing codes?

BILL

 

It is very possible that this is a Opti Spark problem. The motor has just over 500 miles on it so I hestitate to replace any sensors and such. However, it has been sitting for ~6years so the Opti Spark maybe corroded...

I am not able to read any codes. I have not been able to wire up the data link for trouble codes. I will give the charging system another chance then investigate other possible problems. Just not sure where to start as of now.

My next step is to check the injector resistances... Is there a way to test or inspect the Opti Spark?

Thank You,
Gus

 

What year is the LT1 out of? I have read that there is a wire you have to put a resistor in or something when swaping the LT1 into a thirdgen otherwise the alternator will keep going bad. I dont know specifics, but I would check into it so you dont kill a few of them figuring out. Also what kind of conditions was the motor sitting in for all these years. I know that anything like dirt, dust, oil antifreeze, water or pretty much anything else you can think of an ruin an optispark. Also dont buy the stuff from a parts store if this turns out to be your problem because they will only give you the "cap and rotor". It is nothing like what you see on a distributer, but serves somewhat of the same purpose. If you are having problems with an opti it is not usually these parts that cause it. It is usually something wrong with the optical part of it that detects where the motor is at. I would get a new genuine gm piece, but look around because the list value is like $660, but you can find places that sell them for about 200. If you end up needing one go to the LT1 forum over at camaroz28.com and ask where you can get a good deal on one.

Ben

 

The resistor thing is interesting, if you step apon that one again I need details. I have not found information regarding a change to the altenator. Seems like it is pretty self contained?

My understanding is that a little rust inside of the optispark is the beginning of the failure. This is quick likely after sitting for 6 years in a standard garage. I won't rule that one out. I'll probably try to get it to a dealer and see what they think. I must hook up the data sync first, however.
The motor was pulled in a salvage yard and stored indoors from day one. It was in very clean condition since the first day I saw it.

Gus

 

I wont guarantee the alternator thing but I read something like that somewhere. If I find it I will let you know.

Ben

 

There is a guy in this thread that mentions it.(the resistor) https://www.thirdgen.org/techbb2/sho...hreadid=157553

Ben

 

The "resistor" is also the volt gauge. If you have the ALT sense wire from the square plug on the ALT connected to the stock gauge sense wire... or to an aftermarket gauge like I do. Then all is fine.

Also without that connected you would be running of battery voltage nothing more.. Use a volt meter while its running connected across the Pos and Neg post should be around 14-14.5v

 

Here is what I did to fix my voltage problem.

1 You must use your stock 3rd gen alternator plug, it has 2 wires where the LT1 only has 1.

2. Connect one of the wires to a 12volt switched power source. Connect the other to an auxilary power point, like the battery power distribution block. Right now I have a 15 amp inline fuse on the switched power source.

I will look tomorrow to see what color wires to hook where (it matters). One is brown and the other is red, I know that for sure but my memory fails me on which one to hook where.

Without doing this I burned up 2 alternators, both AC Delcos, since doing this I have a constant 14.6 volts all the time.

 

Does the thirdgen plug fit the LT1 alternator? Could you give an example of a swithched 12 volt power source?

Thanks

Ben

 

I have not done this yet.

However, I believe "switched power" is being used to describe power when then ignition is in run position.
I think the 4th gen altenator has some terminals that are not used. It sounds like the third gen plug will work with this altenator. Makes sense that the altenator would be somewhat of a standard part across the board.

My wiring diagram is a bit incomplete with this issue.

RickyzZ28 please let us know when you have time to check out the proper wiring specs.

Thanks Alot Everyone,
Gus

 

1) is not needed.

2) is not needed

If you are using a stock LT1 harness and retaining stock gauges.

Take the one wire from the(square plug) LT1 alt. connect to the brown wire going into the firewall bulkhead connector that has the group of wires for the gauges. ( brown wire is for the 12v "run" feed, goes to the I/P fuse panel( on some modles is the fan fuse) , the fuse completes the it then runs to the volt gauge")

The brown wire is not hard to find since it ran from the firewall bulkhead connector to the original alt.

 

Thanks for all of the help. This will be easy to do. I found the brown wire tonight before I checked the forum. However, I wanted to verify before I hooked it up. No need to fry some wires.

What is the likely hood that the altenator is not burnt up? Currently I don't think the red wire is running to anything... Which I think controls the internal regulator. Electrical Theory(it's been a few years).

Anyway, I'll give it a shot tomorrow.

 

No actually this will not work. I know I had mine hooked up like this when I first got my swap done. Burned out the voltage regulator on 2 New alternators. If you dont believe me ask mat89rs, he had the exact same problem and fixed it just as I did. Since then no problems, sooner or later if you do not have this done the regulator will die in your alternator. Trust me I know and mat89rs knows...

here are some threads:
https://www.thirdgen.org/techbb2/sho...hreadid=134368

https://www.thirdgen.org/techbb2/sho...threadid=82056

https://www.thirdgen.org/techbb2/sho...threadid=13127

 

Rickyzz28,

I followed those three links... the message forum was in troubleshooting mode at those times and I could not find a final conclusion. The link to http://www.alternatorparts.com/ is where I found the most concise information.

Please see if this is the proper way to hook up the altenator.

This weekend I hooked the LT1 altenator up to the battery via the LT-1 stock harness, to the battery. I took the one lead out of the back of the alt and ran it to "ignition on" with a 470ohm resistor. This seems to work. Could you verify that I this is correct or if I will run into problems.

Thank You,
Gus

 

Rickyz28 , True

Here's my defenition of your problem.

1. It could be the charging wire (big red). It has to be plugged in a way that it will be connected trough your wiring harness, not to the battery. so I suggest to plug it onto the ceramic power distribution center.

2. The red wire off the 3rd gen alternator connector has to be hooked to a ignition feed, if this is not done or if you use a feed that is smaller then the gauge of the red one, it will short out and you will loose all charges or it will overheat, melt, caught on fire !at that point you will fall on your nees and start crying.


3. The small brown wire off the 3rdgen connector has to be hooked to a power feed, this also has to be on the wiring harness, if you hook it to the battery it will not work properly, I suggest plugging it into the underdash.

4. Also something that you guys may have noticed, if you hook the brown wire to the battery, it will charges, but it will slowly stop charging, I mean , going form 14.6, 14.5, 14.3 down to 0


That's my advices. It worked for me after burning a few alternators.

 

Odd mine still has the same alt on it that came from the donor motor car.

Only been a year, and only 180miles on the speedo since then.
But if it was wrong it would have shown a problem by now.

Of course i'm using the ceramic block from the '94 Z for the big wire and now running off a autometer volt gauge.

Go figure it works.