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Project LQ4 - V8 S10 - Sold.

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Re: Project LQ4 - V8 S10 - Wiring... Ugh.

Cooling system is fully plumbed. Making battery cables:

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Thinking out loud...

If I swap the harness legs for the coils and injectors from one side to the other, that should make all my wires long enough to reach the PCM and power distribution block. Also, instead of shortening long wires with solder joints, I'll just loop and tuck the little bit of extra wire inside the split loom tubing. This will save a lot of time and reduce the probability of a solder joint failure. It will be hidden anyway. Should just be a matter of putting the pins in the proper (new) spots in the PCM, but that's not a big deal since it's all de-pinned anyway.
 


Re: Project LQ4 - V8 S10 - Wiring... Ugh.

Still poking along. All battery cables completed. Charging system circuit and battery installed. Working on grounds next. Then I can test/troubleshoot "live" circuits.

Soldered in the new 3 wire coolant temp sensor plug. Got to use my new Weller soldering iron. That thing is sweet. A bargain at $14.50.

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Re: Project LQ4 - V8 S10 - Wiring... Watch for sparks!

I have heard nothing but good things about Weller irons, even the cheap ones are good.
 
Re: Project LQ4 - V8 S10 - Wiring... Watch for sparks!

The wiring for the AC system has had me really bogged down for the last couple of days. For the most part, everything has been one for one. Pretty straight forward. Receiver/dryer plug, compressor clutch plug, and compressor plug have all been a direct swap. The high side switch had me stumped though. There was no plug for it in the engine harness. It must have stayed with the body harness. (?) Either way, I think I have it figured out now... Had to steal the purge valve plug from the S10 to use as the high side plug for the AC.

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If my thinking is correct, it will go inline with one of the leads (B5) to the compressor, and the lime green wire from the bulkhead connector of the S10.
 
Re: Project LQ4 - V8 S10 - Wiring... Watch for sparks!

will ya look at that birds nest on the floor. lmao keep plugging away. i got faith in ya.
 
Re: Project LQ4 - V8 S10 - Wiring... Watch for sparks!

will ya look at that birds nest on the floor. lmao keep plugging away. i got faith in ya.

What? That little pile of wires? That's just my harness boneyard. LOL! Nothing will be tossed until the truck is running and driving. I've already been through there a couple times to pull plugs and wire.

I got the longest leg of the harness completed. All the trans plugs and the B1S1 O2. Turned out pretty decent.

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Re: Project LQ4 - V8 S10 - Wiring... Watch for sparks!

i figured as much on the pile of wires.

that looks as good if not better then any thing gm ever put out.
 
Re: Project LQ4 - V8 S10 - Wiring... Watch for sparks!

that looks as good if not better then any thing gm ever put out.

Thanks man! Clean is the name of the game here. Nothing fancy. Just simple.

So... No major progress on the harness, but big steps forward nonetheless. I had kind of an "ah-ha" moment when I was looking at the wiring diagrams for the S10. Originally, I thought I was going to have to use a homemade relay/fuse block to power the injectors, coil, trans, MAF, purge and HO2's. (You know, that one that everybody builds from LT1Swap.com...) Well, I found the circuits that originally powered those components on the old 4.3. After a couple hours of poking around with a DVOM and some "T" pins, I traced the circuits from bulkhead connectors and the corresponding fuses. So... I should be able to reuse those circuits for those components, and avoid all that fuse block relay stuff. Just have to decide how I want to divide it all up. Here's what I'm thinking...

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That seems to be a good compromise between what the original circuits were for, and the wire gauge in the harness. I'm giving priority to the coils and injectors.
 
Re: Project LQ4 - V8 S10 - Wiring... Watch for sparks!

That's how I would have done it...

If you ever happen to look in the other misc bs section of the tuning folder, you'll find some bonneville engine mapping. Used to swap a 90 to a 97 drivetrain and then when I used a 99 harness on my 97. Then didn't have DHP to change vin and had to pin a pcm top to a connector. Fun.. one night I mapped all the pcm wires, soldered them, used liquid electrical tape based on the close proximity of them all, and the next morning put it in the car with the 97 pcm, said a little prayer as I turned the key to have it fire up and be happy on the first try.

Wiring can be fun. A little tip for you as you start to get the length/location/loom step ready. Put a zip tie loosely over the wires to help guide them, use tape to hold it to one of them to keep the position correct. Right before loom you put one loop of tape around ...just like GM did.
 
Re: Project LQ4 - V8 S10 - Wiring... Watch for sparks!

Right before loom you put one loop of tape around ...just like GM did.

Yup. I saw that when I peeled the old harness apart. Couple wraps of tape around the wires, slide the loom down with the tape through the slit in the loom, and continue the wrap over the loom. Keeps it from sliding up and gives it a nice finished look. I bought some special fabric-y Tesa tape just for wire looms. Didn't like the way regular vinyl turned out. Doesn't seem to hold up over time either. We'll see how this stuff does over the long haul.

So... after messing with the wiring a little more, I decided to build the relay/fuse block. I didn't like how small the wires in the S10 harness were when compared to the engine wires, and I was concerned about voltage drop to the critical components. I'm sure there's a way to calculate what the minimum wire diameter should be, but I'm no engineer. So, when in doubt, go big. I will use the switched relay to power the coils, injectors, HO2's and trans. That will be the 4 circuits/fuses in the block. I will use the original circuits for the PCM, MAF, and purge. Not really concerned about those pulling big power, and eventually the MAF will go away. It will be nice to have spare KO 12v sources in the engine compartment for possible future uses.

Also, I figured most of the underneath work was done, so I dropped it back down to ground level. So much nicer not having to stand on a bucket the reach things. I was surprised to see that it actually sits 1/2" taller in the front now vs. when it had the 4.3. Granted everything is still dry, but there can't be that much weight in coolant, oil, and trans fluid.

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Re: Project LQ4 - V8 S10 - Wiring... Watch for sparks!

Amazon delivered! I recently got paid for some trans work I did a while ago. Decided to roll some of it into tools. Also got some other things I needed for the truck electrical.

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I've seen/heard nothing but good things about the Power probe. Figured it would be just about perfect for all the troubleshooting I'm about to do. We'll see if it's worth the $60.
 


Re: Project LQ4 - V8 S10 - Wiring... Watch for sparks!

They work great. Many times people don't even pull out a DVOM anymore and just grab the power probe for checking circuits.
 
Re: Project LQ4 - V8 S10 - Wiring... Watch for sparks!

They work great. Many times people don't even pull out a DVOM anymore and just grab the power probe for checking circuits.

I can see me using it a LOT in the near future.

So, I got the fuse block built and mounted. Then I was able to solder in the wires for the coils and injectors. Tomorrow I should be able to get to the PCM, HO2's, MAF, purge and trans soldered. Still need to grab the appropriate size ring terminals before I can put power to the relays though.

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Re: Project LQ4 - V8 S10 - Wiring... Watch for sparks!

Left side is pretty well complete. It's not perfect, but it should get the job done. (Hopefully). Should be able to start stabbing wires into the PCM plug tomorrow.

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Re: Project LQ4 - V8 S10 - Wiring... Watch for sparks!

Just let me know when it's running lol.

Soon... :th_sinister:



So it looks like the intake is going to have to come off again. Long story short, the LQ4 oil pressure sending unit is not going to work with the S10 harness/wiring. Oh, well. I guess that will let me test the serviceability of the engine with the completed harness. That's on the back burner for now...


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Got some time off work tomorrow during the day so I'll be able to drop this guy off too. Won't be too much longer before I need it!


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Re: Project LQ4 - V8 S10 - Wiring... Watch for sparks!

Oh, also got my ring terminals for the fuse block so I was able to put power to the relays. Power probe shows 12v to everything with key on.

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And all buttoned up. Left side is DONE!

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Re: Project LQ4 - V8 S10 - Wiring... Watch for sparks!

why we need a o/p sensor?

you must be getting itchy by now.,,,so close, yet so close lol
 
Re: Project LQ4 - V8 S10 - Wiring... Watch for sparks!

So it can leak at the plug and drain the oil from the system when it fails? I'd stick an electronic sending unit in it and run a small autometer gauge in the truck somewhere.
 
Re: Project LQ4 - V8 S10 - Wiring... Watch for sparks!

The LS V8's rarely if ever leak from the oil pressure sensor. Instead they just die.

I doubt I've ever seen one fail in the many years I've been working on vehicles and reading up on these motors. Using the 4.3 sending unit on the other hand, couldn't tell ya if those suffer the same failures on the 3800 style.
 
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