5.3L (LM7) into OBS Sierra Classic

Sorry about the title ripoff 1BADC10 :laugh:

Well, this is my topic about the 5.3L swap I am doing on my project truck. The project truck is my 1980 GMC 3/4 ton 4x4, which currently has a TPI 350, SM465 3 speed standard with granny gear, and an NP205 transfercase. It started life as a 2wd 3/4 ton with a 350 / TH400 combo, with a lot of rust, and is slowly being worked towards being a nice tow rig for the summer :) My donor rig is a 2000 GMC 1/2 ton 4x4 with a 4l60e that was rolled 12 times last August.

I plan to run an NV4500 5 speed standard behind the 5.3L, and an NP241 passenger side drop transfercase. The 241 has a 40 tooth toner ring similar to the newer transfer cases, so the speed sensor shouldn't be a problem. My truck will have an electronic speedometer from a 90 - 91 truck, which should be compatable with the 4000 pulse per mile output signal from the ECM, factory tach with a signal doubling module I'll have to either buy or invent, a stock temp sending unit on the passenger side head, with a mechanical oil pressure gauge hooked up to the spare port that you can tap above the oil filter. Exhaust will be true duals, with out cats, so the rear two O2 sensors will be eliminated, and I plan to run F-body manifolds to avoid frame modifications. I am also planning on eliminating the EGR. I'm hoping to make this install as close to factory as possible, so I am hoping to run the stock air box, fuse block, ECM mount etc.

Now, for the questions! The engine harness seems pretty straight forward, basically leave it the way it is, but I need to get pinouts for the blue connector that goes between the engine harness and the cab harness, and if my assumption that the little 3 wire connector coming off the engine harness to the chassis harness is infact the fuel pump wires. More than anything, I'm hoping to figure out what all I can eliminate from the stock wiring, so I've got as clean of a setup as possible. I then plan to make a complete wiring guide out of what I learn for others to use in the future, so there isn't quite as much figuring to do when starting one of these swaps :)

Here are a few pics of my project truck, engine, and the donor truck:

http://www.zieglerdigital.ca/public/.../01.07.GMC.jpg

http://www.zieglerdigital.ca/public/...L/03.07.01.jpg

http://www.zieglerdigital.ca/public/...L/03.07.02.jpg

http://www.zieglerdigital.ca/public/...L/03.07.03.jpg

Nice title, Russ... :rock:

You'll find that I've posted (or have possession of) the wiring schematics for a 2000 Silverado (2wd). I doubt there's very much difference b/t the 2wd & 4x4 harnesses (engine-wise). Are you planning on wiring with the NBS fuse block? If so, it'll be easier, but if not, relays are your best bet for circuit reliability.

I'm sure you've read my thread backwards and forwards. If you still have questions, ask away. I'll post what I know, and others will help if you cannot find what you need on this site. :hshake:

Good luck! Git-r-dun. :smile:

Your thread, and one on LS1Tech have me pretty comfortable with what I have to do to get this sucker up and running again, the only thing I will have to add is the circuits for the check engine light, alternator light, diagnostics port, and AC stuff :)

Ok, couple of questions:

1) Fuel Pressure Sensor. Does a guy need to install one, or can it be deleted?

2) Fuel level sensor, same as above, do I need it, or can I live with just the stock sending unit for my factory gauge?

3) Low coolant sensor. I noticed the truck ran in limp mode if it was disconnected, but I cannot find any mention of it on the ECM pinout... Is it something I need, or can I use my stock rad with the stock overflow bottle?

4) AC sensors. My cab does have AC, but I will not get around to hooking it up for a while. I again noticed the truck ran in limp mode if I disconnected either sensor... Is it something that has to be hooked up, or do I have to get it disabled in the prom?

5) Since my truck has a standard tranny, what kind of an input is the ECM looking for from the clutch safety switch? My truck does not have one...

Thanks!

Russ

<div class='quotetop'>QUOTE(SierraClassic &#064; Mar 7 2007, 01&#58;24 AM) [snapback]85546[/snapback]</div>

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Ok, couple of questions:

1) Fuel Pressure Sensor. Does a guy need to install one, or can it be deleted?

2) Fuel level sensor, same as above, do I need it, or can I live with just the stock sending unit for my factory gauge?

3) Low coolant sensor. I noticed the truck ran in limp mode if it was disconnected, but I cannot find any mention of it on the ECM pinout... Is it something I need, or can I use my stock rad with the stock overflow bottle?

4) AC sensors. My cab does have AC, but I will not get around to hooking it up for a while. I again noticed the truck ran in limp mode if I disconnected either sensor... Is it something that has to be hooked up, or do I have to get it disabled in the prom?

5) Since my truck has a standard tranny, what kind of an input is the ECM looking for from the clutch safety switch? My truck does not have one...

Thanks&#33;

Russ
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Check engine light... uh... hmm... I haven&#39;t added that yet. I just keep my laptop handy when I drive the truck. Alternator light? When the volts gauge drops below 12V, I&#39;ll start looking to get to my final destination ASAP. I didn&#39;t make provisions for that. I did tie-in a diag port. There&#39;s a connector on the engine side of the harness that you can cut and splice in what you need. I found a descent interior harness off eBay, so I just used the stock connections.

Now... for fuel, I have an external mount fuel pump (255lph-rated) mounted to the frame rails. You may want to drop the tank(s) and drop in an in-tank pump. There is a p/n posted somewhere here, or on PT for that. Just be sure to replace any low-pressure fuel hose (rubber lines) with fuel-injected hose (or braided lines). If the 5.3L&#39;s intake has an integrated FP regulator, I don&#39;t "have" to worry about buying an aftermarket regulator. Let&#39;s not forget to install a filter in the line too. Low pressure filters will not due. Get a high pressure quick-connect or NPT-connection (screwed) type.

Your stock level sender should work well with most aftermarket gauges (providing you&#39;re going that route). I spent the extra on gauges b/c using the stock cluster with the paper element on the back would be a hassle to get it to work. Plus, to get an adaptor kit for the digi-to-analog speed signal would cost me the price of getting a complete gauge package. The aftermarket kit was what I wanted.

Low coolant... you will need to use the coolant bottle out of the NBS truck anyhow. The cooling system is a pressurized system. Transfer it over. Plus the connector is on the NBS harness.

Cannot comment on AC stuff b/c I have dealt with that issue yet. I am hoping to use the stock NBS compressor, but the in-cab component uses solenoid to force air to close valves to regulate switching functions for heat, max AC, low AC, and econo-mode (vent). I haven&#39;t put much effort in researching this since the truck&#39;s been down for a while.

Clutch Safety Switch - I am assuming this is a function that prevents you from starting the vehicle in gear. Is this not like the P/N safety switch? Does the donor rig have an A4 trans? If so, I&#39;m sure that is what that&#39;s for. If not, I have no clue... maybe someone can help with that. If you&#39;re getting rid of the 4L60E in the donor (if that&#39;s what it has), wanna "donate" it to a worthy cause? :laugh: Nevermind, it&#39;s a 4x4 trans. Couldn&#39;t use it anyhow.

You could have the 4l60e if you were a bit closer, only 50 000 miles on it from the factory, but I&#39;m a wee bit far away :D The project truck is the one with the standard, and I assume the ECM only uses the input to control wether or not it will energize the relay / gain some insite on when you are shifting. I don&#39;t mind rigging something up for the second part, but I would prefer to have the ECM just start the truck regardless of if the clutch is down or not.

Check engine light should be easy, just provide ground to my existing service engine soon light (truck currently has TPI)

Fuel pump I was planning on a walboro 255lph in-tank pump, already know which one I need :) Is there any problem with running high pressure rubber fuel hose from the rear of the rig to the front? I have steel lines right now, but they were never intended to be permenant, and are not bent or anything... I&#39;d run the hoses up on the inside of the frame rail, and make sure they are well secured :)

I&#39;ll see what I can do to mount the NBS rad in my truck, but mine is a 73-80, so I am not entirely sure if I&#39;ll be able to pull it off yet...

As far as the gauges go, I already know exactly how to make my analog speedo work, and still make the ECM happy as well. Oil pressure is mechanical, and water temp is easy too, just buy the S&P adapter for my stock sending unit.

I was just wondering if the ECM needed an input from the tank pressure sensor, and the level sensor to run properly, or if the pressure sensor is only used for the EVAP / level sensor for the low fuel alert / gauge?

Well, I got the whole engine pulled today&#33; Discovered something that has me worried -- The rad has a chunk of side tank missing at the bottom where the little round stud thing used to be, and there is was absolutely no coolant in the engine at all... I did run the engine like that, once for around 5 - 10 minutes :sad:

Should I be worried and pull the heads, or stab it in, and see what happens? :eek:

Other than that, no broken parts or wires anywhere, should be a pretty reasonably straight forward swap from here :)

Though, this does raise the question, do I find myself a new rad from another NBS truck, or can I somehow rig my old one in?

Rig up the old one. Stab the engine and don&#39;t worry about it. No need rebuilding something if there&#39;s nothing wrong with it. If you find something wrong, it won&#39;t take long to pull it out.

Well, what do you guys think I should do for my tranny?

My truck currently has an old SM465 standard transmission in it. That is a 3 speed tranny, with a granny gear. I really like standards, and personally don&#39;t trust autos very much, any truck I&#39;ve had with an auto has self destructed in very little time...

Also means that my truck is already set up with a hydro clutch setup, with all the pedals, the standard tranny reverse lights etc.

I&#39;ve already bought an NV4500 I plan to drop into my truck instead of the SM465, so I&#39;ll have a 5 speed standard with overdrive. I also bought the proper transfercase needed to bolt onto the back of the NV4500, which will provide the correct VSS signal the PCM needs, and also drops on the proper side of the truck.

However, its proven to be a real challenge to bolt the NV4500 up to the 5.3L. I&#39;ve got a few ideas of how I may be able to get around most of the problems with the recessed flywheel / pilot bearing, but I am concerned about how I&#39;ll start the thing, as suddenly the starter will be too short as well.

So, that brings me to consider putting a 4l80e into my truck instead... It has the 32 spline output shaft, and adapter I need to bolt my NP241 t-case one, and is fairly reasonably beefy too. However, it has a lot of parasitic losses, and I&#39;m still not a fan of autos regardless... I can probally get it reasonably cheap, but it will still cost me a fair bit...

Do I hold out and figure out the starter issue with the flywheel, or do I stab it in with an auto?

BTW, 4l60es are out of the question, my truck is frequently used to haul water, and up to 8 quads on a 18 foot flatdeck trailer. I&#39;ll burn it up real quick...

http://eshop.advanceadapters.com/commerce/...product_id=2540

Bingo&#33;

I think this may be exactly what I need&#33; Just kinda expensive... 700 bucks before shipping, which will be around 150 in itself...

I suppose, if I cannot find a cheaper route, I can always fall back onto this, lol