OldBBody

I have a question about setting up a wiring harness properly.

Since I have a 1993 OBD1 car I need to merge my EPROM ECM & wiring harness to my future LSx PCM and wiring harness.

Is there anyway to future proof the new harness?

Meaning... can I get it made to where ANY LSx engine & trans. can go in or will I have to always stick with what I started with? Say for instance I start with a 5.3L/4L60e and I end up wanting to swap in a 6.0/4L80e? Can I always use the same wiring harness and just re-tune or replace the PCM?

I am not doing this per-say but I am trying figure out how much flex-ability someone has when they start down this LSx swap path .

Thank you.

JB

Adam123

iTrader: (1)

You can set the harness up, but if you change transmissions you will have to get an adapter harness I think. I can't recall what is different on the two transmissions, I just know there is a difference. You should look into getting a harness kit from BP Automotive or PSI conversions. They sell a do it yourself kit. Also there are different reluctor wheels on newer engines 58x vs older engines 24x. So if you are set up for a 24 and go 58, you'll have to get a converter box. I think knock sensors are located on the side of the block on newer engines as well. For the most part if you set up the engine for lets say a 01 DBC 5.3 w/4l60e and decide to swap a 02 6.0 dbc 6.0 4l80e, you will have to get an adapter harness for the transmission and probably a different drive shaft. Everything else will swap over. But if you decide to go to a newer engine lets say a 08 6.0, you'd have to get the converter box and either a DBC throttle body or the electric gas pedal and wiring to put into your car.
Hope this helps

gofastwclass

iTrader: (2)

The 4L80E has two speed sensors (input and output) and uses the same controller plug with a different pin out.

The overall length of a 4L80E and a 4L60E are close enough that the driveshaft will work - if a different yoke is used (which may require a conversion u-joint). You WILL need a different transmission crossmember as the transmission mount is in a different spot. The 4L80E is also much larger, heavier, durable and requires more power to turn than it's counterpart, but has a better split between the gears.

If you stay Gen III or Gen IV things stay simpler and there are no conversion boxes necessary. Crossing that line gets really sticky if you don't know what you are looking at.

Decide now if you are going cable throttle or drive by wire. Cable is simpler from a swap stand point, but drive by wire has several advantages that may be nice.

OldBBody

Thanks guys. Just these two posts clarify a lot for me.

So as long as I am swapping within each Gen. everything should be fine but if I want to jump from Gen 3 to Gen 4 or vice versa I need adapters or change connectors but its possible and not a deal breaker. That is what I wanted to know.

OK and I got one more scenario I didn't think about before. Now what about going from a carb conversion 6.0 engine with a non-electronic trans like a 700r4.... then going to a fuel injection/4L80e upgrade later? Can I have the harness built for a 4L80e even though I am not running one and just have it there for later because I am running a non-E trans temporarily?

For that matter... what if I am not running FI at first either? How much modification does my stock wiring harness need if I don't do any FI or electronic trans at all by just going to a carb and the 700r4 for a while?

You are right gofast... I realized that I am going to need a different trans. mount... I was thinking of contacting bbody specialty company Clear Image and asking them what their advice is for the 1993. With the increased output of the LSx engine... I don't need something that's going to fold up like a wet noodle under there. Its gotta be stout.

In 91-93, the Caprice didn't come with a double hump trans cross member because those models only had single out exhaust. So when the earlier model guys needed dual humps for true dual exhaust...they would use the 94-96 B-Body trans cross member because it would work on a 91-93 B Body with no issues... but the frame needs to have new mounting points created that were a few inches lower. They also had to change the trans tail shaft adapter to the 94-96 one as well.

Unfortunately... with 4L80e... its not going to be that easy. My gut feeling on this is... I imagine I will have to get a trans mount for a 94-96 B Body with the tail shaft mount fabricated to take the 4L80e's mount pattern and then have the frame on the 93 Caprice mod'd to accept the later model trans mount. That mount is going to be more expensive then a normal conversion mount. It'll have to be done to a certain extent anyway though because the 4L80 is bigger.

Its either that or the other option I have is that I can temporarily use the 4L60 that is in the 1993 already and use a carb conversion and avoid the initial expense of that modification too. I have been looking for a good used carb intake kit lately because that is definitely and option I am seriously looking at. Here's the other thing.. the stock 4L60 I have has been rebuilt with an HD servo, Trans Go and all the toys. (It could use a Beast Sunshell which I didn't know about at the time). Using that trans could be a good option to start off.

Sorry if I have a lot of questions... like many of you... I want to do this on the cheap but get good results.

ls1nova71

iTrader: (4)

I think your best solution would to be to get a game plan sorted out and stick to it. Trying to set it up for a lot of different combinations is going to cost more in the long run. Just buying an MSD box, carb intake and carb to get it running is going to cost more than going fuel injection in the first place. Figure out exactly what you want, and work toward that goal, this will be your best bet to get it "cheap but with good results" as you said you are wanting.

OldBBody

That is true... I realize that but spending $1000 on intake/carb but having the car running with a carb for 2 or 3 years is better then continually sitting still. Not converting the wiring harness could save $700... and not purchasing a 4L80 could save another $700-1000 and not needing to modify the trans cross member could save another $500-700. So yeah... I might be spending a $900-$1000 up front but it would be money well spent when I have a running driving car instead of being stuck in the garage. As is I haven't driven the car in 5-6 years. Getting it moving is a priority. I am not wanting to cheap out but I am trying to get moving in steps while looking toward the future.

lsxRanger94

Here's a video from agearhead4life Roadmaster swap.

He has the same user name on here.

the_merv

iTrader: (88)

All what you want to build. Me personally I PROPERLY wire the setup....as in if it's a 60E it gets setup for a 60E, if it's a 80E it gets wired PROPERLY for a 4L80E, not that "Adapter Harness" bullshit.

A good Tuner will know how to make the Segment Swap to make the 80E work on a PCM when they tune it. If they don't know what a Segment Swap is, then you fire them and find one that does.

gofastwclass

iTrader: (2)

Merv, you are as subtle as a sledgehammer as always - but I like it and you are exactly right.


To the OP, like LS1Nova71 said... you can get it running with fuel injection for less than you think. The first issue is you have to get a complete engine (harness, PCM, intake, injectors, accessories, etc.). For budget concerns, stay in the Gen III 5.3 / 4.8 ranks and don't allow yourself to be put off by the "little" 4.8, they are still amazing engines. Likewise, don't get 6.0 or aluminum block envy - prices for them compared to their smaller or heavier brothers are insane and gain you next to nothing on a street car.

Your car is already fuel injected so you have 3/8" high pressure poly feed lines and a 5/16" return to a fuel injected tank with an internal pump. Swap in-tank pumps for $100 - done. Someone did a brief write-up on how to make a tool that presses LSx style fuel fittings on poly line and I did another sharing my experience. It works, I've used it on a couple of cars.

If the truck intake fits, use the truck rails with the regulator built in - free with the engine.

Don't get talked into braided lines and AN fittings, there are several less expensive (and fully reliable) ways to get fuel to the engine. The factory doesn't use that wasteful, excessively expensive crap and neither should you.

If you want this done on the cheap, you are going to have to start making stuff and looking for deals instead of buying everything new. Look at build threads like mine or LS1Nova71's for budget home-made build advice.

I build my own transmission crossmembers, mounts and other stuff because they aren't exactly rocket science - if you are handy with a welder.

If you shop smart and have a decent bit of fabrication skills, you should be able to get that car reliably moving under stock LSx power for $2000 or less using the factory fuel injection system.

Another thought... don't get hung up on mileage. I have never bought an LSx engine with less than 100K on it nor have I had a single problem with any of them. On the other side, I just did the PCM for a guy with a 30K Gen IV 5.3 engine and he spent more on the engine than I did on my entire swap!

the_merv

iTrader: (88)

Lol..I've learned that straight forward is the key..not a whole lot of details and get right to the point. Less confusion and the job gets done..

ChevyOwner

No the AN fittings and Stainless braided lines are not needed.

But GM has used stainless braided lines on cars.
16mmx1.5 o-ring to 3/8 quick disconnect on the other. They are the factory lines off my car.

OldBBody

lsxranger... thanks for that video and the user name of that LSX'r. I appreciate it. I would like to chat him up about that swap.

I really want to know about what he did to his wiring harness.

I am wondering about what wiring harness mods are needed for my car if I went carb and still wanted the gauges to all work.

Merv... I agree with you... that is why I am here... just trying to figure out if I can do this in steps and if so... which steps need to be done the right way the first time.

gofast... I originally wanted a 5.3 but because the Caprice is such a big car... I am going after a set up that offers some extra torque. I really feel that the LQ4 6.0 offers the best foundation for TQ but also for building off of for the future. The 243/799 heads are a perfect example of what COULD be swapped to the LQ4 in the future... and on top of that... the cathedral port heads are the best for a primarily street driven car.

You did touch base on something I am always worried about and that is cost. The 4.8/5.3 are substantially less then their big bore counterparts and that makes finding an complete drive train is easier to get. Getting one of these smaller engines does have its advantages. They are still a great foundation. Either engine could still be installed bone stock... ran for a while... pulled out later... built into a stroker and still use the 243/799 heads.

Anyway guys... I don't want to turn this into an engine thread... if you want to bench race with me some more (which I always enjoy)... lets all discuss engine possibilities further in my thread found here...

https://ls1tech.com/forums/conversio...est-bbody.html

Thanks for all the input. If anyone has any advice about what wiring harness mods need to be done for a carb conversion let me know... or I can start a new thread in the carb section too.

JB

gofastwclass

iTrader: (2)

True, however I was not completely clear as I meant the AN style fittings. GM uses what they want / need where they want or need it which is great. There are several examples in the GM lineup where braided line of various types have been used over the years. One thing they don't do is use a fitting to an adapter to a hose to another adapter to a fitting which is necessary in most AN installations on vehicles that aren't dedicated race cars.

For an example of what I mean, try to run high pressure fuel from a stock GM tank with push lock connectors to a stock GM LSx push lock fuel rail using braided lines. Last I checked there was no direct push lock to braided hose fitting available meaning two fittings on each end of every hose.