I am trying to do an LS1 style engine swap in my 71 Firebird and am in need of an engine harness on a budget. I have heard that you can make the truck harness work but it is hard to do. Any suggestions?

 

I got a truck harness from a 5.3 for $150

 

the injector connectors are different between the truck motors and ls1's

 

Is that something that is easily changed, or is it a huge pain in the butt?

 

you could change the connectors, or just pick up a set of truck injectors. I like using the truck harnesses better, the wires seem to be longer and you can route them how you want.

 

they make adapters to go from one connector style to the other. i think fic has 'em.

edit: in fact, i believe this is what you need. little spendy though.

 

If the truck harness has the electronic throttle, and you are running the cable style, you will have to re-pin the PCM connector to have discrete connectors for the IAC, IAT, and TPS (did I forget any?)

The LS1 uses a different connector than the truck for the fuel injectors. The LS1 is a Minitimer and the truck is an USCAR.

I think the GM product line used the Minitimer connectors since about 1985, so there should be plenty in the local junkyard that you can solder on to your leads - but you can pay big-bucks for an adapter if you want to.

If you are running the LS1 style manifold, you are going to have a hard time fitting the truck injectors in it without some sort of custom fuel rail - the truck injectors are much shorter than the cars.

 

Be advised also if you are going to use a truck ECM, 04 and later will not have IAC controls onboard, so it will not work.

 

Wow...seems like maybe the truck harness may not be the way to go.

 

You will only have the add 7 wires total to make the TPS and IAC work.

If you find an earlier truck harness you wont have to add these.



The injector connectors are less than 2$ each and easy enough to solder on.


Also remember you may need to change around a few other pins on the C1 and C2 connectors to match the camaro PCM pinouts.

 

Vans do!

 

What years are the best to get (truck harness)?

 

I'd try to find a 99 to 02, because 03 and up are dbw, except for vans as stated earlier. Not sure when they went to dbw.

 

Actually its all in the programming for the PCM. He would have to get it tuned anyway to get VATS turned off, so thats just something else he could have his tuner do.

FWIW I'm running an 04 Yukon PCM with a modified 04 GTO programming. (04 GTOs were the only ones to have DBC. O5-06 were DBW) Just something to think about.

 

You could just take apart the Fuel Injector Connectors and re-pin them with some LS1 Injector Connectors
I have a set of 8 LS1 Injector Connectors that I snipped off of my Harness when I put my LS2 ones on. I can take what's left of the wiring out of them, label them and send them your way if you are interested.

 

If he doesn't I'll take em Merv

 

No prob..they are just sitting around collecting dust.

 

You are correct that is the exception, along with 4.3 S-10 ECM's

03 and later truck serv# ECM's do not have IAC drivers on board, I have verified this by actually looking at the board. It was a cost savings thing by Delphi when the majority of the GM line went BDW in 03, who would guess saving $.50 on a driver semiconductor in each ECM would add up. They still built limited IAC compatible ECM's for vans and S-10s though

I am running an 04 Express Van ECM 12586243 on my 03 BDW motor converted to cable TB with an 02 cal

*Also he cannot just swap the plug body over from harness to harness. The pins utilized in the two plugs are different.

 

I'd have to disagree with 2 of your points (Unless I mis-interpeded, what you're trying to say), first up until and including 2004 4.3 V6's needed IAC drivers in their PCM's, since they didn't have DBW availiable, so truck service numbered PCM's did have to have the IAC drivers installed in them. Since you could also get a full size with a 4.3 in it. By the way it also used the 12586243 service number PCM, which does have IAC drivers in it

As far as the differrances in the PCM harness plugs, the major issue is the Blue / Green plugged harnesses for drive by cable had the grounds for the O2 heaters returned through the PCM, so they could shut them off, so it wouldn't be hard to repin a harness from a Blue / Red plugged PCM to work with a Blue/ Green PCM

 

Since I bought a 5.3L engine with the 03 truck intake on it, can I just use the injectors off of the truck intake for the LS1 intake? The only thing is, I am pretty sure it is a Flex-Fuel engine. Can I use these injectors...or do I have to change the connectors for the LS1 style injectors and use LS1 injectors? Thank's for the help guy's!! Tim.