I am about 2 weeks from finally getting my Lt1 project under way. I am however undecided on the wiring harness. I know most people have used FIS and let them "marry" theirs together, but I found out that Painless makes one and it is only $350 from Jegs. I know you have to have a 93 Ecm for it(with vats removed), but it looks like it will be alot cheaper to go that route(and suposedly just like FIS its a direct drop in). Has anyone here used the Painless LT1 wiring harness and if so what are your thoughts on it?
Thanks,
MM

Wait about a week or so and i'll let ya know cause im ordering it this friday.

I didnt get the one for the LT1, but for the L98. It was anything but Painless. I call them Painful Wiring.

Theres a reason its cheaper.

Was yours really that bad madmax??
What was so bad about it?

Z28racer: I wish I could wait a week to order one, but I have got to get one soon. Man, I hate to spend any more money that I have to, and the one from FIS is like 625, then there is the computer swapping and reprograming, another $200 or so. It quickly hits a grand or so just in the wires and computer junk!!
What made you decide to go with the Painless LT1 harness?

Thanks,
MM

Well...

It doesnt have the connector for the underdash harness. You WILL need this. Using the old one is a real PITA, you cant buy the connectors, so its either carefully take them apart (like I did) or cut+splice. It also (for me) relocated the relays to about 6" from the ECM. This sucked. I wish they would have let me decide where I wanted them, rather than forcing me to try and find a spot so close to the ECM to put them. As it turned out, I had to lengthen those wires too. There was also tape missing from the wires that didnt have connectors, so I had no idea what they were for until I read through the manual (which sucks btw) and found out what they were. I suggested to them in a phone call to make a diagram of their harness and label it, rather than trying to put it into text, which resulted in some stuff being here, and some there, and one there, and it was just all over the place in the manual.

Next time, I will spend the extra cash, it wasnt worth my time to sort out the harness.

Thanks madmax... After all that, I think I'll be going the FIS route...Man I sure don't want to be cutting on my harness and having to worry with adapting junk. FIS said that their 625 is pretty much a direct drop in. I haven't heard of any complaints about them, so I guess I part with the extra money....Thanks again..MM

I talked to FIS today and they said that they can take my 89 305TBI harness and cut off the things I won't need and add the new LT1 junk to it...It will also be converted to a 94/95 computer system so I will need a 94/95 chip with the Vats removed from it.

My question is, are the talking about the engine harness only or is it the inside harness(underdash)or both, and can I use the 96 LT1 fuel pump in my car or do I need a aftermarket one?

Also (one more question) have you guys every heard of www.carputing.com . They were recommended by FIS and susposedly you can reprogram your PCM with a laptop just like the ricers do...This ofcourse would be cool because you can customize it anytime you want.

Thanks,
MM

Hey guys thanks for your help.
I was going to get Howell Eng. to do my wire harness for $1,120, but I didn't. He was going to covert the 95' LT1 to run speed density, thats not worth a #%@%. The 95' LT1 ran off of a mass air and the injectors fired in a seq. order. They were not speed density which was batch fire. I got in contact with this guy from LT1.com who specializes in the wiring of an LT1 and the LS1 and told him of the guys from Howell and he helped me out. LT1.com can rewire the stock LT1 harness to fit into my 91' and still keep all of the gauges in the can functional, like:
speedometer
tach
oil pressure
oil level
diognostic prong
temp. gauge
They would also delete all the wires that the 95' harness didn't need to work in the 91' and still keep the computer from running in any type of limp mode. The check engine light will be running properly and the wiring which is to be deleted would be completly deleted which the computer would not turn on the check engine light.

So basiclly everything will still work. There price was only $175 for the wiring.

They could do the programing of the computer but it would be like a hypertech programer. For the mods that I was doing they told me to get in contact with a guy by the name of Ed Wright from Fast Chips and he could do the programing of the computer.
The mods are:
Lunati 383 stroker kit
Comp cam Dur.@50 230/244 Lobe sep. 112 Lift .510/.549
AFR 195's
SLP headers
3' exhaust flowmaster
MSD coil MSD 6A
ported intake
52mm throttle body
30# injectors
3.73 gears
NX wet kit 150 shot

The price for the programing would be about $350.

Does anyone know anything about either one:
www.LT1.com
&
Ed Wright for Fast Chips
If so, let me know somthing.
THANKS. Leathal_Injection

BTT

read my last post.........thanks

Got it today, sweeeeeet harness, all connections labeled and most pre terminated, even has wire for the fuel pump, aldl port and check engine soon light, definetly worth it.

Ack !
its too short to run the wires like the factory tuned port so you either gotta drill a new hole in firewall or do what im doing, lengthen 41 wires...... but still a very nice harness.

Think we could get the correct url for that LT1 place?

I was told it is http://www.lt1350.com
I think I am still going with FIS though.....Sounds to good to be true if you know what I mean.
MM

has anyone else used LT1350.com s wiring setup for a 3rd gen LT1 swap? i wanna know what i should do,thanks.

Is that fls a website it not what is it ?

04-25-2001

may no longer be in business 12 years down the track
And times have changed ; for a LT1 swap you want a 94/95 computer ; not the troublesome '93 type

I have a 97 lt1 383 comp n wires thats y I am asking . Do u have any idea what I can do its my first swap I am a old carburetor man but I like to go with the fuel injection

Have you read the LT1 write ups?
https://www.thirdgen.org/forums/ltx-...questions.html

So you use the earlier 94/95 setup because it is a easier and simpler install
( can use your 96 computer with mods )
What trans do you plan to run

I am thinking my 700r4 but later going to the t56