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Discussion Starter #21 (Edited)
Wiring

This can vary depending on your setup and what kind of harness you use, and if you decide to use some of the stock wiring, fuses, and relays. Lt1swap.com is your friend. Almost everything you need to know, regarding pin outs and wiring, is on that site. You honestly don’t need much from the stock PCM. I kept my A/C and got all the wiring info on that from the post on here from that one guy Jose. Also kept my ABS, and luckily all the wiring for that is separate from the PCM. I cut out all the wires I didn’t need from the stock connectors and separated what I did. Then I opened up the whole stock harness and pulled out all the unused wires. Wrapped up everything in cloth tape. Made a new harness for the fuel pump, since the new harness had its own fuel pump relay. I used the stock fan relays and wiring by using the signal wire off the stock PCM. I went with a new harness for the engine to keep it simple. Didn’t want to drill into firewall so I put the LS PCM in the stock location and fuse box not too far away from it. Could’ve done a better job at hiding all the wires, but I was in a rush to get it running. And to keep it simple for all you b body guys, this is what I used from the stock PCM. Keep in mind this is for a 95 so I don’t have a tach signal to save off the PCM:


Red connector

Pin 10 - sec fan DK BLU
Pin 11 - prim fan DK GRN
(Ground signals for relay)


Black connector

Pin 1 - A/C request signal DK BLU
Pin 8 - VSS speed
Pin 21 - A/C clutch status DK GRN



Clear/Gray connector

Pin 14 - brake switch PPL
Pin 15 - park neutral signal org/black (optional)



Blue connector

Pin 3 - PCM ign feed PNK
Pin 8 - A/C clutch control DK GRN/WHITE
Pin 9 - Check engine light
Pin 12 - A/C refrigerant pressure sensor RED/BLACK
 

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Discussion Starter #22
Make sure you have good grounds! And gauges are tied in differently besides speed and tach. I used an adapter and the stock oil pressure sender to keep my stock gauge working. Volt meter is easy, fuel is tied into sending unit and separate from PCM, and temp is the only one I have to buy a sender for.
 

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Discussion Starter #23
Adapter for LS motor and stock oil pressure gauge
198091
 

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Discussion Starter #24
The work required is not a concern of mine.

Thanks for your perspective. I was hopeful that I could re-use my Dennys driveshaft. I guess I won't really know for sure until I actually get everything in and measure.
If you use KDS mounts or Dirty Dingo sliding mounts and a 4L60e, even LS, you can get away with using your stock driveshaft. Even stock crossmember can be used for a LS 4L60e. Make sure you use a camaro oil pan or Holley 302-2 to get the proper clearance and to have room to move the motor forward or backwards. 4L80e will definitely require driveshaft work no matter what. With the motor slid all the way back, with the KDS mounts and Dans crossmember, my driveshaft length measured out to 56” from the transmission seal to the u-joint bearing cap surface.
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Make sure you measure with the car on the ground and suspension loaded! Luckily for me, I had my gas tank out and had enough room to fit underneath the car behind the rear end. Some might get a different measurement due to different mounts and other parts and variations, but if you use what I mentioned above, it should be pretty close.
 

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.....The GMPP LS376/525.....
Dan,

From people I know and from what I've come across on the forums, pretty much everyone I know of with the '525' crate were disappointed with the (ASA) cam in that motor. Very fussy with disappointing power.

Take it for what you think it's worth......but unless you're concerned with the warrantee, I would recommend getting the base LS3 and upgrading it with the cam and valve springs of choice. Very easy to make more power with a more streetable cam.

KW
 
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As above.
The one and only 376-525 I have "met" personally was on the dyno here ( rental just watching)
It sounded really cool and was somewhat lack luster in performance.
The calibration in the matching GMPP E67 controller was a bit of a joke.
There were "glitches " in tables that were in my calibration 10 years prior.
Also, If you did go E67 , you likely will have a little uphill battle with Cruise and AC control.
 

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Discussion Starter #27
Here’s a little tip.. complain about the GM controller not working when you first get the engine, or if it’s still under warranty, and I bet GM will send you a terminator x system 🤭
 

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Discussion Starter #28
Exhaust and shift linkage

I live in California and getting long tubes is not that easy, and what is available is pretty overpriced. So I went with some shorty headers that were recommended by a few people. Cheap eBay s10/universal headers. Just make sure you order the correct bolts to bolt up the headers though, because the ones that come in the box are standard not metric. Comes with exhaust flanges too.
198285


Headers fit well and Just had to trim the ear off on passenger side of trans for exhaust flange to fit. Driver side is pretty tight and had to bang body weld a little out the way. Flange was turned a little so it wouldn’t touch trans ear. Stock shift linkage barely clears header but it doesn’t touch.
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Nothing to difficult about the shift linkage. Removed the arm off the stock 4L60e and put it on the 4L80e. Then I just cut the shifter linkage a little at the end, so it wouldn’t hit the frame, and with a little effort I got it in. Had to bang heat shield a little to clear park but it still shifts good and feels like stock.

198289
 

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You might want to do a little google on O2 sensor placement.
Those are inviting condensation - moisture damage .
You could also bend that linkage frame bracket , and shorten the shaft so it can't touch the frame rail. Might be an illusion but it looks pretty close.
Of coarse , just my opinion
 

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Discussion Starter #30
You might want to do a little google on O2 sensor placement.
Those are inviting condensation - moisture damage .
You could also bend that linkage frame bracket , and shorten the shaft so it can't touch the frame rail. Might be an illusion but it looks pretty close.
Of coarse , just my opinion
This was just a mock up before it got welded in. O2s were turned and facing different direction now. And shaft was cut at the end and bent a little to fit properly. Doesn’t touch Frame whatsoever. Actually shifts into gear better than it use to with the 4L60e. Pics don’t really do justice as seeing it in person. I appreciate your input though! Definitely can help someone who doesn’t know about any of that.
 

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Discussion Starter #31
Had the PCM tuned last week and what a difference. This motor just wants to keep pulling up top, stock, where my old LT1 use to max out.. Shifts nice and firm too. Definitely doing gears and upgrading stall next. I’ll upload the vid or post the link once vid is up of my tune sesh. Includes a burnout or 2 😏
 

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Discussion Starter #32
Haven’t posted on the A/C yet because I have not had the chance to charge it. Been dealing with another car this past week but once I do, I’ll post all the info on what it takes to get the A/C working like stock. I want to make sure everything works before I give any advice in that area. But in the meantime here’s some pics that weren’t already posted on some of my prep work. Changing out heads, oil pan, and all the gaskets and other little stuff that needs to be done.
 

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Discussion Starter #33
Don’t forget about the rear main seal and barbell! Don’t have any pics but I can assure you I definitely changed them. Those are a must!
 

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Discussion Starter #34
Excuse the language I was a little excited 😁
.. this was my 2nd or 3rd day driving it and you can see the problems that arose so quickly lol.. All good now though. A/C works just like stock too. Will write up on that soon enough, but honestly I got all my info on that from that one guy Jose who posted the info on a wiring harness LS swap.

 
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Discussion Starter #35 (Edited)
A/C

So like I mentioned before, I got my info on the A/C wiring from the post mentioned above. Everything works like it should but there are a few things that are not mentioned in Jose’s post. If you are using a truck motor with a truck tuned PCM, it gets a little tricky. This is for an 0411 PCM with DBC. In order to get the PCM to read and power the correct pins for the A/C, you have to use a 98-2001 truck or car tune. The pin outs are on lt1swap.com but under the car section, not the vortec/truck section. Reason for this is that these year models came with manual A/C with a pressure switch, just like our cars. The problem I kept encountering though, no matter what year, or truck, or car, is that the fans are always on no matter what. It’s a problem with 2001 and under tunes not being able to run electric fans correctly since the vortec motors did not come with them. In order to fix this, you have to use a 2002 tune with an OS of 12212156 for electric fans to run correctly. Problem with that OS and tune is that you lose A/C because GM switched over to using a low pressure switch and HVAC module to control A/C. I have yet to find a tune that can run fans at the proper turn on temps and control the A/C like stock. At least for my setup. 5.7 LS1s might be different since f body’s came with manual A/C and electric fans. Tried using a F body tune as a base and segment swapped the trans and engine settings and had the same result. Living in Cali I obviously wanted my A/C, so to solve this problem I’m using a thermostat to control when the fans come on. I used a 2001 truck tune to keep my A/C. Thermostat works perfect. Got one for each fan and they work with A/C too. If anyone can find a 6.0 4L80e DBC 2wd tune that can control MANUAL A/C and electric fans correctly, I would really appreciate a copy of the
bin. Trust me, it’s a lot harder to find than you think. Without HPTuners at least. Even with them, I couldn’t find a tune. Until I find the proper .bin, it works for now. Anyway, here’s how I wired the A/C to keep the stock controls working.

Stock LT1 PCM pin outs to LS PCM

Black Connector
Pin #1 - A/C Request - Goes to Red Pin#17
Pin #21 A/C Clutch Status - Red Pin#18

Blue Connector

Pin #8 - A/C Clutch Relay - Red Pin#43
Pin #12 - A/C Pressure Sensor - Red Pin#14


Now on the high pressure switch plug (the one going into the condenser line), there are 3 wires that you have to connect. Gray, Red/Black, and Black. If you wired the pin outs from above first, then you’re really only hooking up the gray wire to 5V ref.

Pic is for reference. Stock Wire colors are different
198517

Gray Wire - 5V ref - Goes to Blue Pin#45

Black wire
- Ground- Already grounded through stock harness ground as long as you don’t cut it. If cut Blue Pin#60

Red/Black Wire -
Already mentioned above. It is the A/C pressure signal and goes to Red Pin#14

Last thing to connect is the vacuum line coming out of the stock harness to the LS intake. Some people may over look that because they have no idea what the hose is for. It is on passenger side towards rear of engine going into intake, incase anyone didn’t know. It’s the only vacuum line coming out the wiring harness. Everything else related to the A/C can be kept as is, assuming you are using the stock HD6 compressor. If not, you just have to splice into clutch wiring for w/e compressor you’re running. Stripping off all the tape and loom off the stock harness first, I was able to trace out the stock wiring for the A/C and didn’t have to cut any of the pigtails off, so this made it pretty easy to hook everything up. This is how I wired up everything and it’s working perfect and blowing cold.
 
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