LS1 swap and interior, dash lights gauges ect

[OhNoJoe]

This may be a stupid question. When you do an LS swap there is the wiring for the motor, pcm, MAP ect ect ect..... then there is the VATS which is hacked off and the pcm is flashed. But what do you do about your gauges interior lights cruise control cigrette lighter ect ect ect???

[TravisH]

um, cigarette lighter? 12v+

When you do a LS swap you aren't gutting the interior and electrical of the truck and replacing it with f-body parts. Headlights, signal lights, dome light, brakes, its all your domain.

You may be able to hook up your stock gauges but everyone I've seen replaces them with aftermarket, I think a large part is to get the speedo working, you've got an electrical signal instead of mechanical. If thats the only hurdle you could get an adapter unit but those are pricey.

I think cruise is controlled by the stock ECM so you should be able to work it in but I don't know the parts needed for it. They'd probably be different depending on your throttle type

[jkade]

It is about cheaper to swap all the guages instead of trying to make the factory speedo work. If you where running a th350 or 400 then you could keep the factory speedo and make the computer think the trans is a 6 speed.

[OhNoJoe]

thanks for the replies. I have looking on the web for a few weeks and it seems to me that the build threads sort of rn out a gas or juice (pun intended) when it gets to these little details. Plenty of stuff on mounts and pinout and trans and engine harnesses I just want to make sure that I can go into unexplored land (for me anyway) before I drop cash for an LSX

[shifty]

If it seems that way (threads fizzle out), it's because when you get as far as a lot of us do by the 10th or 15th page of our build threads, you lose track of what your "never-swapped-a-GenIII-engine-builder" will find informative or worthwhile.

when you get in that deep to a build thread of your own, you have enough knowledge of the system and yourself to realize that:

a) this swap isn't for you. "i quit!". the project gets sold off or you run outta money or patience - either way, same outcome.

or

b) you don't have the knowledge to complete the task, so you find someone else to do that part for you and you forge on. understand, you aren't required to do everything yourself, but if you're like me, you walk in an idiot, and walk out the other side knowing how to get one of these up and running from nothing in a few days, just by figuring out the first time.

or

c) you actually get to a point where you grasp the reality most of us GenIII swappers now know: there are a thousand options, you just gotta pick one (do i go digital or analog? do i want to spend big $$$ to keep it stock, or spend a few bucks to go aftermarket? etc.)

if you end up at option (C), you will understand what you choose for gauges greatly depends on what tranny you're running and how your computer was tuned in relation to your tranny.

if you're like, "what?", i'll break it down:

if you bolt up a 700R4 or TH350, all you gotta do is use stock speedo cable + stock gauge. it's up to you man. pick your poison - go with a standard-ish tranny, and spend the hard work finding out how to bolt it to that GenIII block, then use stock tailshaft and speedo. or, go with a modern tranny and either use an electric gauge running off the PCM. or, go with a modern tranny, and pay $500 to get a new tailshaft, install it, and use your stock speedo.

you gotta understand - a lot of stuff in this swap is solely based on what you choose to swap in. you'll understand - but not until you're neck-deep in the swap already.

as for tach, i suppose there are other options for that, too. but my reality is .... if i can simply run a wire from my PCM over to an electric aftermarket gauge, and WHACKO WHAMMO,
it's done...i'm gonna do it


i'm not trying to be cynical in this post, so i hope you don't take it the wrong way.

i truly believe a GenIII swap is one of those things you either dive in head first, plan it out after reading some threads, and DO IT, or forget about it. if you're getting hung up on what gauges to use, and this is stopping you from moving forward, what are you going to do when you try to replicate what me or one of the other guys with our tranny crossmember, and it doesn't work for you? will you quit, or will you come up with something and make it work?

i wish i could say there is a roadmap for all of this....get started on it. get it all bolted up. when you get stuck, consult some of our threads. if you need more help, make a post asking for it.

good luck to ya.

[OhNoJoe]

Hey Shifty,
All good points. I have read many of your post here and at the LS1 forums. As well as printing off a number of them.

I've already committed myself to doing it. (well 90% anyway) However, its freakin cold this time of year and I thought I would nail down so of my unanswered question.

I have done lots of reading and have about 30 web pages bookmarked. So it's not like I'm asking the kung-fu master to hand over the pebles lead me on my jorney.

But then again I've never done anything like this with all this cumputer stuff and probably lack some very basic understanding so I've a little nervouse and excited.

My viewpoint is like I have read on other forums either learn this computer stuff and FI or be stuck in the past with old tech.
Your post have been very helpful.

[JMac11]

Mid LT1 project myself, trying to decide how to morph the two wiring harness together. Ideas?

[shifty]

Originally Posted by OhNoJoe

I have done lots of reading and have about 30 web pages bookmarked. So it's not like I'm asking the kung-fu master to hand over the pebles lead me on my jorney.

But then again I've never done anything like this with all this cumputer stuff and probably lack some very basic understanding so I've a little nervouse and excited.

I think I understand completely - I can't tell you how many times I PM'ed FirstGen asking him stupid questions that I'm (quite frankly) embarassed about right now.

Like I said, I hope you don't take my post the wrong way, and thanks for mentioning that my posts have been helpful, I am not writing them for myself.

I haven't done a writeup on my gauge setup b/c it's still not installed (no point in gauges if the truck ain't rollin due to clutch stuff, which I got the last parts for this week).

Anyway...

All I can really say is ...

You can plan ahead....to a degree...but if you plan too far in advance, you spend money that you shouldn'ta spent. I spent about $1200-1500 that I didn't need to already.

I personally hit a snafu when ordering my gauges ... I ordered a model of Autometer electric gauges that reverse-glows...this one: http://www.autometer.com/cat_gaugeop.aspx?sid=61

(put your mouse cursor over the "View Illumination" to see what the gauges do. thought it would be better for night driving, which i do a lot of)

The snafu was, I ordered all of them, and all of the small gauges came, but the tach and speedo 5" gauges (important ones) were backordered and took 8 months to get here. This basically left me uninterested in working on the project.

I ordered these part #'s:

Autometer Ultra Light II / 5" gauges:
autometer 4989 - speedo
autometer 4998 - tach

Autometer Ultra Light II / 3-1/8" gauges:
autometer 4992 - voltage
autometer 4953 - oil pressure
autometer 4937 - water temp 100-250
autometer 4913 - fuel level

More information about my screwing around with the gauge cluster can be found here: http://67-72chevytrucks.com/vboard/s...2&postcount=93

The entire thread for that single post is here, which includes another member's GenIII swap and his gauge setup: http://67-72chevytrucks.com/vboard/s...d.php?t=201368

Again -

* Decide whether you would want all factory looking, something that looks factory but is new, or just something with all of the modern conveniences.

* Make a choice now on your tranny. This is going to influence your gauges, whether you're going electronic speedo or analog (speedo cable).

* You probably will end up needing to use electronic tach OR you could look to see if some manufacturer has an adapter to convert the electronic signal from the GenIII engine into something your stock gauge understands. Autometer has a lot of converters and adapters, and may be of help.

* Decide if you're going analog or electronic on your oil pressure and water temp gauges. You DO have a choice. There is a hole (this is in my thread) in the rear passenger side block that has a bolt in it - you can remove it to retrofit with water temp like I did. Likewise, with the oil, you can drill+tap the pan (takes 5 mins, no worries with metal shavings) on some of the GenIII's using a stock provision above the oil filter. Otherwise, if you go electric, Autometer has all the sending units you'll need, and possibly other gauge companies will too.

* Volts ... this is a no-brainer.

* Fuel ... make sure you get a fuel gauge that supports 0-90ohm. Again, no-brainer.

So, that sums it up - basically, you can absolutely go analog (stock) with everything except maybe the tach, depending on your tranny. But you don't necessarily HAFTA have the tach, y'know? And hell, who knows, maybe the signal wire from the PCM on a GenIII will supply a voltage good enough to use a stock looking tach, or maybe you can retrofit a tach from a later model car that would look nice in the gauge cluster.

Ok, I'm tapping out now I think you sucked me dry of info

[shifty]

Originally Posted by JMac11

Mid LT1 project myself, trying to decide how to morph the two wiring harness together. Ideas?

I don't think I would.

I would go to Speartech to get a wiring harness. And I would keep your two harnesses separate, but this is my personal opinion.

What parts would you want to tie together, exactly?

[Andy4639]

I know my applacation is a bit differant than you all's but what I did was install all the senor's for the TPI unit. I left all the factory gauges as they are. If you have to you can add more senor's for the LS-1. The engine block should have multiple places you can add them.

[shifty]

oh, and here are some mockups if you like seeing options. this is what the Ultra-Lite II gauges look like in a 3-hole and 7-hole gauge cluster during the day (gauge faces are black at night with white lettering and orange needle)

i have changed my mind ten times on gauge clusters. first i was gonna use a 7-hole cluster and merge a 3-hole blinker/dummy light setup between the tach...but it looked too weird having new gauges with an older school blinker insert in the middle hole. so then I was going to do a 3-hole dash and remotely mountthe other four gauges, but i wasn't sure about that either.

then i got a glovebox door and started playing with custom gauge layout designs, since the glovebox door fits in the gauge area perfectly with minimal hacking of the dash.

anyway...yeah...haven't gotten them figured out yet.