I'm still trying to find the answer to the everpresent dillema of wiring up the LS1 in a 3rd gen. How have you guys that have done the swap gotten the gauges hooked up? Did you replace the factory ones with aftermarket, or did you somehow splice into the TPI harness. Any help would be appreciated. Thanx.

 

Your TPI gauges are analog. Meaning they do not rely on the ECM. So you need to keep the gauge harness in the car. The tricky part will be the tach and speedo. If you are keeping the original TPI trans that solves the speedo question. The tach on the other hand will be very difficult because the LS1 uses a CDI type ignition. You may be able to splice into the LS1 harness and grab the signal wire it uses to feed the tach, but I am not sure what that signal consists of.

 

Im still not sure about what tranny I will be using. I may keep the 700r4 and build it up a little bit to handle the extra power. So if i do that, I will be able to use the existing speedo stuff, right? You may have answered this in the post above, bit just to be safe, whats the deal with the amp, fuel, oil pressure and temp gauges? Thanx. I've been having a heck of a time finding answers to these questions.

 

I do not think the tach will be a big issue. The sppedo is where is gets tricky. Unfortunately, it is not reccomended that you use the 700r4 with the ls1 setup. The 4l60e is computer controlled in conjuction with the ls1 pcm. Hence engine management and transmission functions are tightly coupled. Some how the engine will need to know what gear it's in.

You may be able to work around this by using a pcm programmed for a manual trans, however, I believe you will be sacrificing tunability and performance.

There are several wiring kits available. The problem I am encountering are the exhaust, engine mounts and trans mount.

Good luck.
BILL

 

I see your point with the transmission issue and how it's computer controlled. However, the TH400 tranny's aren't computer controlled either and there are no problems. I believe that there are certain settings and parameters that are altered or turned off with LS1 edit. This is a program used to tune and alter the computers settings (just making sure, b/c i didnt know if you were familiar with it ) . As for the wiring kits you mentioned, can you give me more info on them?? Thanx for your advice!

 

Check these links:

http://www.painlesswiring.com/harness4.htm
http://www.speartech.com/factoryharnessinfo.html


There is another company in PA that makes custom harnesses, but I forget their name. Give me a few days to search through my links.

BILL

 

Thanx for the links. I've seen the speartech harness, but the problem is that they want $950 for it! As for the painless one, unless I'm missing something, it's a stock harness. I'll still have the same problem of interfacing the gauges.

??????????????

 

The painless kit will splice into your existing harness. If you are not interested in that one this is a plug and play harness

http://www.hotrodlane.cc/LS1-Harness.html


Here is another:

http://www.centechwire.com/catalog/f.../efiprice.html


BILL

 

Ok, so the one from Centech will solve my problems as far as the speedometer, and the tach will work fine anyway. How about the other gauges? Are the sending units on the LS1 the same for these gauges as they are on the thirdgens?

What other road blocks have you encountered during your project that I should be aware of?

By the way, thanx for all the help. Sorry if I'm being a pain in the A$$

 

As far as I know the sending units are not the same. However I am told that you can use the ones from the original engine (oil press, and temp.) This makes sense since those guages are not supported by the ecm.

The two biggest road blocks I am encountering are the exhaust. I need to run a cat or cats to pass the VA sinffer test. Unfortunately, there are clearence issues.

Second is the A/C. It looks like my frame will have to be notched to allow the compressor to fit in place. There is an A/C delete pully available from GM if you want to go that route. This is not an option for me. My car has working A/C, hence this is an absolute requirement for me.

Again, engine and trans mount will have to be fabricated. There will also be some monkey business with the trans cable. In your case it will be worse because you want to retain your 700r4. I am not sure how will handle the detent cable.

Obviously, you can eliminate this problem by using the 4L60E. You will also be able to program shift pionts for different senarios as well.

 

Hey Nasty Bird, I have some advice for your LS1 swap, lend me some $$$$ and we can do it together , j/k anyways good luck cause I'll be coming to you soon for some help.

-Ryan-

 

So the sending units are different, but I'll be able to transfer them to the LS1 block? That would be sweeeeet! Yeah, I got lucky b/c my car sits a liiiitle bit too low so I'm exempt from MD emissions. As for the tranny, I've decided not to go with the 700R4, but go 4L60 or possibly T56. I really want the T56, but I think that will make the swap just that much more of a pain in the butt. I've heard of the problems with the a/c, mine is on it's way out anyway. The other solution that I saw for the clearance issues was to use coil packs off of an LS6 truck motor. Instead of the square coils like on the f-body LS1's, they're rounded a little more and allow for a little extra clearance. The website that i've gotten most of my info from used a 4th gen tranny mount and crossmember I believe....i'll check on that again. Have you solved the whole motor mount issue yet or are you still fighting it?? Just wondering so you can give me a little advice on how you solved the problem. Thanx again for the help. :hail:

 

from what i got from john at speartech.com, thirdgen resources made custom engine mounts for the ls1 install on his 3rd gen. He aslo said roy would peobably be selling them as a kit to potential 3rd gen ls1 swapers like my self. boy is next summer going to be fun.