Hey guys, got my LT1 swap underway. The L98 is pulled out and the LT1 is in the car.

The LT1 is a 93 with a 4L60.

I have a couple questions though that I noticed when installing:
-there is a single wire weatherpack connector on the harness going to the transmission, its kind of around the bellhousing area... Is this the connector for the drivers 02?
-the 93 lower radiator hose seems to be the right shape but obviously the hose ID is too small for the thirdgen radiator. Everyone recommends a 92-94 vette lower hose... Does this hose have a larger ID on the radiator end?

Ill get pics up tomorrow.

 

The 93 4L60 is the same as the 90-92 4L60's in 3rd gens. A few internal updates were done to the 700R4 and the name changed to the more common function identification. The connector near the bellhousing on the drivers side is either a front O2 or the TCC connector. Is it flat, square or round?

 

Pocket, its a single wire round connector like the EST wire on a TPI, I have concluded its the o2 wire.

In other news there are 5 wires in the "starter group" that Im looking at. One knock sensor, one o2 wire, one thick purple wire for the starter and two small black wires with white stripes. Where do the black wires go?

 

IIRC there is a ground point near the starter on the block for Fbody harnesses

Do a continuity test to find out

 

Well, here's how it sits:


These connectors are located near the PCM, right where the harness branches and goes down to the starter. I've identified the second from the left as being the A/C pressure switch, the big one is the C100 (see here). The single wire on the far right is the fuel pump prime lead.


Those pictures are from my 'Berry, forgot the cable for my actual camera so I will get better pictures when I go home Monday night.

 

I found the chassis harness from under the hood of the 93. I think I will use the wiring and the other end of the C100 to make a sort of plug'n'play adapter for the LT1 harness to the GTA's bulkhead in the firewall, which just leaves me with the white and blue plugs that go into the passenger compartment. Then I have to tear apart the TPI harness and get back my fan circuits, windshield wipers, etc...

 

I wish it were that simple. The body connectors in a LT1 harness get redistributed all over the car. Some to the fuseblock, relay center, C100, C207, HVAC connector etc

Read over my LT1 harness thread along with the LS1 wiring threads in the swap sticky. The process is the same and seeing it adapted to multiple ventures shows what to look for more

 

Pocket, I have read over your thread on prepping a thirdgen harness. Am I correct that I will end up with a pigtail coming off of the C100 that needs to be connected as well as a pigtail where the old TPI ecm used to be (the C207). Im sort of unclear what happens to the C207... does it get run out the fender like the original ecm wiring?

 

It needs to reach under the dash somehow, either behind the fender or cut a hole under the HVAC box and run the harness through

 

Okay, itll probably just end up like the TPI harness, connecting at both sides of the firewall.

I think I have gathered all the schematics and pinouts I need to attack it this weekend, I have been searching for alternator wiring issues... I remember reading a thread where it was mentioned you had to use the TPI alternator plug? Maybe I'm mistaken.

 

Was able to start the motor today! I have the C100 down to what it needs to be and most of the wiring laid out, but it runs and it sounds goooood.

Pocket, in your LT1 wiring thread you mentioned that neither of the fuel injector ign feeds that come from the C207 can be used, why is that?

 

I reread over the LT1 thread and cant find where it says the INJ fuse wires from the C207 cant be used. I actually prefer to use them and spend a great deal of time researching the older 3rd gens that change around frequently so I can reuse as much of the stock fuseblock as possible, fed by the stock pickups

In my prep thread I mentioned you 'could' delete those functions and stick to the gauges, but they'd have to be moved elsewhere to a new fuseblock. Carb guys need this, EFI guys dont, they've got enough fuses already. No need to over complicate the job

 

Under the C207 diagram: https://www.thirdgen.org/forums/post...937-post3.html

I see now how you meant it, that if its cut down to the minimum three wires the INJ and PCM fuses would have to be moved. I thought it was a separate statement.

For my application Ill probably use 2 INJ leads, ECM lead, Speedo, TCC, ALDL stuff and P/N switch.

 

Pocket, of the 3 relays mounted by the C100 on my 88 GTA Ive identified one as Fuel Pump, one goes to the MAF... whats the third? It shares the same blue wire as the MAF relay. Then the two by the radiator seem to be the cooling fans

 

Hey Matt...good luck with your swap....nice to see you still are keeping the 3rd gen flame alive...lol.

 

MAF and burnoff relays. Neither are retained for the swap. You need a fuel pump relay and one for each fan. Thats it

They can either be mounted near the booster or relocated elsewhere under the hood. I generally move them under the pass battery tray

 

Yeah, barely. I've been busy finishing school and now starting graduate school plus work, I haven't driven the car in at least a couple years. It just sits in the barn.

Thanks pocket, thats how its set up now. I have the fuel pump relay by the C100 and both the coolant fan relays on the pass side radiator support.

Good news is its all pretty much done just need to clean up the wiring from the C100 and the C207 and then hook up the exhaust. Shame though, open headers sound so good.

 

Ive got ALDL B and ALDL M coming from the C207, and just "Serial Data Signal" from the LT1 harness.... what do I do with these?

 

IIRC its the TAN wire. the 93's used an older ECM that likely wont have the output field service wire (WHT/BLK)

TAN wire goes to the C207 pin for ALDL M. J IIRC. Im not near my wiring notebook so I cant give for certain

 

Okay, i connected the two tan's and left the white/black for later.

All of the wires are connected - I have only a couple remaining things:

Ive got the red LT1 ALT wire connected to the BRN C100 alt wire... some posts seem to mention a 470Ohm resister or some other stuff. My voltmeter seems to be functioning correctly this way however.

Second, I'll need to bypass the starter interlock. I thought I wouldn't need to since I'm still using my VATS key, but apparently the VATS module wont engage the interlock without being connected to the ECM (or maybe some other reason.) Anyways I pulled the drivers kick panel and didnt see the interlock relay, but I saw the PPL starter wire running in a loom towards the back seats.

 

Your alt needs the 470ohm resistor or a small light bulb to know the 12v down some. It will burn up after a month or so with a full 12v charge on the exciter

Dont trust the large purple wiring to immediately ID the starter solenoid wire. The large rear defroster is also ppl. Hunt for the starter relay behind the drivers kick panel. Sometimes they're behind that black goopy stuff and others they may be under the hush panel behind the fuseblock. Its wherever the assembly worker felt like shoving it that day

 

Pocket, how did the original thirdgen alternator work?

I'll poke around again for the relay... the only thing i saw immediately was an aluminum relay behind some rubber, but it looked like two conjoined relays and had none of the wire colors I was looking for.

So the VATS module just wont work without the ECM present? Seems like I shouldnt even have to do this if the VATS module just enabled the relay and gave the ecm the green light.

 

Well I found the starter interlock relay.

The problem was that the wiring color references I found on this forum were wrong (at least for my car). It was mounted up on the side above the kick panel and had 4 wires, 2 green and 2 yellow. There was one heavy and one small gauge of each color.

References I found on here said it should have been two yellows, a blk/yel and a tan/wht, might be a camaro-firebird difference?

With that bypassed the car started right up. The car runs really good, with the exception of the alternator not working. Voltage is around 12 and motor dies when battery is undone. Would not having the 470 Ohm resistor cause the alt to not function?

 

Update.... 470 ohm resistor installed, still wouldn't charge. Don't seem to be getting any voltage from the brown C100 wire, checked with key on and even running.

I suspect this has to do with the fact that my dash lights went out before the swap... never figured out what's wrong - no fuses are blown.

Pocket, do you have a relevant dash schematic or any idea what to check?

 

Check the fan/alt fuse

http://www.austinthirdgen.org/index.php?pid=19
http://www.lt1swap.com/pictures/100_1594.jpg

 

hey matt,,, i've been stalking you hey do you still have your turbo car? I got the bbs i'm starting to instal and would love to see and talk about your car or buy any parts you have left from it... check your private messages, i remembered your car from about 4 years ago

i did an lt1 swap in my 84 years ago,,, but i carb'd it... even before they made a carb manifold for it.. that was interesting

 

Looks like its coming along great. Boy these later model engines look right at home in our third-gen bays don't they? Good work!

 

Pocket,

I didn't see any bad fuses. The schematics you linked show the alt wire going to the c/h fan fuse which is not blown and has 12v with key on.

I solved the dash lights problem... the firebird only divorced dimmer module is bad.

I was able to make the alt work by connecting the red alt wire to the battery with a 470 ohm resistor. The resistor was only knocking the voltage down from 14.08v to about 13.something. what is the correct voltage that the alternator should see?

Any more ideas or schematics about the brn alt wire are appreciated.

 

Pocket,

I didn't see any bad fuses. The schematics you linked show the alt wire going to the c/h fan fuse which is not blown and has 12v with key on.

I solved the dash lights problem... the firebird only divorced dimmer module is bad.

I was able to make the alt work by connecting the red alt wire to the battery with a 470 ohm resistor. The resistor was only knocking the voltage down from 14.08v to about 13.something. what is the correct voltage that the alternator should see?

Any more ideas or schematics about the brn alt wire are appreciated.