68 longbed 5.3/4l60e
 

Hello everyone. My name is mike. I've been here for a while, lurking in the shadows. You guys have helped me with a few problems already. Wanted to start a build thread to show it off and get the needed help from you guys. I've been scouring this and others sites getting parts list together and figuring out where to get them and where to get the computer flashed and harness redone.

I have a 68 c10 with 70 monte Carlo 350 2 barrel, th400. I've blew it apart and blasted it back in December '10. Full suspension rebuild kit from LMC and converted to 73 style power disk brakes and added a front sway bar from cpp. Cleaned up and painted the metal interior. All while using it as my daily driver. New windshield and installed a split back window. Got the disk break conversion, used fenders, set of centerline dragline wheels and cowl for free from the guy that did the concrete work in My back yard.

Well now comes the big step. Yesterday I bought a 02 5.3 out of a silverado 1500. And will be picking up the trans tomorrow. Got the Dow pedal but need to get the tac tomorrow as well. Found out the salvage place gave me the wrong computer and I swapping that out tomorrow to.
Just figured out I can't upload pics from my I pad. So I gotta wait till later to post pics.

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Re: 68 longbed 5.3/4l60e
 

Make sure that is actually a 2002 engine as the TAC and throttle body are different for the 2000-2002. The reason I say this is they are not as common as the 2003 up DBW systems. Your harness should have blue and red connectors on the PCM, if they are blue and green its not an 02. Just a heads up.
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Re: 68 longbed 5.3/4l60e
 

http://i669.photobucket.com/albums/v...8/SDC10990.jpg
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Re: 68 longbed 5.3/4l60e
 

That's a problem I noticed when I got home. The harness had red and blue but PCM had blue and green. I asked about the pedal for drive by wire and the parts puller went out and gave me a pedal out of who knows what. And didn't give me a tac. But I can straighten it out when I pick up the tranny Monday.

Is there a way to tell if the tac and pedal are 02 or not. I've got the pedal. Unsure what year. Still waiting on the tac. Pretty positive the throttle body it 02. The engine seams pretty unmolested.

Anything else I should watch out for. Any info Is greatly appriciated.
Thanks.
Mike
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Re: 68 longbed 5.3/4l60e
 

An '02 TAC will be all plastic, not plastic with aluminum base. Pedals are metal not all plastic. Does your throttle body have 2 plugs, one on each side?
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Re: 68 longbed 5.3/4l60e
 

http://i669.photobucket.com/albums/v...fd9ebe7262.jpg
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Re: 68 longbed 5.3/4l60e
 

I think it dose. On on throttle actuator( passenger side) and one in same area but drivers side.
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Re: 68 longbed 5.3/4l60e
 

Thanks I'll keep this in mind
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Re: 68 longbed 5.3/4l60e
 

That's an '02 so you're good there. You need the all plastic TAC.
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Re: 68 longbed 5.3/4l60e
 

Thanks all plastic got it.
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Re: 68 longbed 5.3/4l60e
 

So let me know if I'm wrong.

This is a return less system, so I'll need a corvette filter/regulator.

The truck exhaust manifolds won't work. I'll need to find some trailblazer or corvette to fit with the least amount of modification. Or swap headers from thorley ect.

I can use the adapter from my old ps pump to adapt the ps lines.

The 5.3 came with hoses for cross flow radiator so I'll most likely be able to use my stock radiator.

Th400 yoke won't fit the 4l60e. So I'll need to find a yoke.

The 4l60e is longer so I will need to have my drive shaft shortened.

I can use the stock trans crossmember, just move back and maybe drill a couple new mounting holes.

For general operation of trans and ECM I'll need a 4 connection break light switch(I don't have LED tail lights )


Is the connection for computer tuneing or scan modules (OBDII port?) in the engine harness? Or is that something extra I need to add?

With the 5.3's upgraded amps should I worrie about the stock wiring harness? Or should it be ok?



Am I missing anything?

Thanks for any suggestions or info.
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Re: 68 longbed 5.3/4l60e
 

Here ya go.

Re: 68 longbed 5.3/4l60e
 

I actually had only a couple hours with it the other night because it was Africa hot in my garage and had to work the next day. I haven't been home since. I'll take a pic when I get home Monday and let you know.

Thanks a lot for the feed back. I've been searching here for months. There is like 30 new bookmarks in my favorites so I can reference back when I start.
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Re: 68 longbed 5.3/4l60e
 

Getting the tank in. Not as easy as the brothers article say it is but oh well. Picked up a filler neck and door from a 07 silverado. Once I get the bed back on I'll graft in the door behind the rear wheel in the bed side.

Got the call from current performance today about harness and computer. 3-4 day till its ready.

Still need a obd2 harness and a th350 yoke.
Got fans from a 99 .

http://i669.photobucket.com/albums/v...0b87f0e725.jpg


http://i669.photobucket.com/albums/v...5e9731fcc1.jpg

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Re: 68 longbed 5.3/4l60e
 

Here is a pic of drivers rear of the engine. Confirming return style fuel system.



http://i669.photobucket.com/albums/v...eb0443ca26.jpg
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Re: 68 longbed 5.3/4l60e
 

Yep, the fuel pressure regulator with the vacuum hose on it is a give away.

Where is your fuel pump mounted?

Re: 68 longbed 5.3/4l60e
 

This is my daily driver so I'm not mounting a pump or filter yet. Not gonna do the 5.3 till oct.
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Re: 68 longbed 5.3/4l60e
 

Today I got the filler door and plumbing in. The door was easeyer then the tank was.
Question- there is a ground wire that is on the 07' filler neck. Dose that need to be grounded, or can I snip it off?

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Re: 68 longbed 5.3/4l60e
 

I'm pretty sure the ground is just a ground so static doesn't spark near the filler neck area, and is thusly just a CYA item for modern trucks, not needed. It may also be a ground from something like a carbon cannistor, which was deleted and so it also is not needed.

Re: 68 longbed 5.3/4l60e
 

The original tank did not have a vent. I'm guessing the new one dosen't need one either for now. But once I get the 5.3 in and the external fuel pump hooked up, will I need one then? I have 3/8 hard line from the tank along the frame to below the drivers door. I was planning on mounting the pump there and running braided line from the pump to the fuel rail with standard 3/8 rubber line as a return.
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Re: 68 longbed 5.3/4l60e
 

THe ground wire on the fuel filler is there because the filler tube is mounted in plastic, and the tube is hooked to a rubber hose, neither are good conductors of electricity, so they put a ground strap to the body static electricity from blowing things up while fueling. Rare, sure, but stranger things have happened. I would ground it if it were mine, would take about a minute to do, so why chance it?

Re: 68 longbed 5.3/4l60e
 

I wouldn't use standard 3/8 hose for a return (or anywhere else in the fuel system). I was informed that the high volume of fuel that will be running through the fuel lines in this type of fuel system, will eat it up the inside of a regular fuel hose, causing it to come apart from the inside out, getting trash in your fuel system. Save yourself the trouble and hassle and run good steel braded or similar type fuel hoses where steel lines aren't used.

Re: 68 longbed 5.3/4l60e
 

Did you modify the inside of the bed for your new filler?

Re: 68 longbed 5.3/4l60e
 

Ya, had to notch out the bed a bit. I will make a cover for it later. It will bolt in so I have access later.http://i669.photobucket.com/albums/v...e353ed1839.jpg
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Re: 68 longbed 5.3/4l60e
 

Trying to figure out gauges. Really like the auto meter old tyme white. Temp, oil,volt I've figured out. But scratching my head over fuel.

Can this gauge be adapted to the stock sending unit some how?
It's 230 ohm and I think mine is 90 ohm.

http://www.autometer.com/cat_gaugede...earch&gid=3400

Re: 68 longbed 5.3/4l60e
 

Is there certain years of trailblazer manifolds that fit? Or any 03-09 will work? And is 80 bucks free shipping a good price?
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Re: 68 longbed 5.3/4l60e
 

The brown truck came today. Yay!! Brought me all the fuel system and some adapters for,stock gauges.

http://i669.photobucket.com/albums/v...a3bc6bd0a4.jpg
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I have a concern. The adapter above the oil filter doesn't look like the ones I've seen here that you guys have been tapping for the stock oil pressure gauge. Dose this mean that my engine had an oil cooler? And if it did where is the return port? how do I plug it? Did 2002 silverados with 5.3's come with oil coolers?

http://i669.photobucket.com/albums/v...88c6ee4034.jpg

Re: 68 longbed 5.3/4l60e
 

I have the same adapter. I bought it new and ran a 1/8-27 NPT tap through it without having to drill it for threads. (I did have to use a smaller drill bit to have an opening for the oil to reach the sender) Dont over tap the block fitting. What I mean is, the NPT tap gets wider at the top, so if you run the tap all the way in, it wont have the ability to seal against the sender. I think I may have done this but since the motors not in the truck I havent been able to check.... you can find aftermarket billet ones that are already tapped but they're not cheap...

Also, I think this is a C5 Vette style block off plate....

Re: 68 longbed 5.3/4l60e
 

So is there a return I need to plug somewhere?

I thought that only HD and other vehicles had oil coolers. Did they lie to me and say it was out of a silverado. I got it from a truck salvage yard so I wouldn't think it was from a car besides having a truck manifold. And the engine doesn't look altered.
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Re: 68 longbed 5.3/4l60e
 

There are a couple of different block offs, the one you have is the one most easily drilled and tapped for a sender. If the engine had an oil cooler, there would be two aluminum lines coming off of it, and it looks completely different. The Corvette uses the same piece but it's already drilled and tapped for the oil temp sender, I don't think you have a car engine. You don't need to do anything with what you have unless you're going to use it for your oil pressure gauge.

Re: 68 longbed 5.3/4l60e
 

Oh so this adapter or block off is not open. It looks like there was a line coming off of it but it is in deed closed. Ok thanks. I thought it was an open port that needed to be closed off or capped. And I need to find the return and cap it as well. But I don't. Thanks for clearing it up for me. Thanks.

Anybody know about the file gauges? Is there a way to adapt the new gauge to old sender? I've search but found only old pOsts. Trying not to change the sender I just installed.
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Re: 68 longbed 5.3/4l60e
 

I'm not sure the new gauge will work with the old sender, but have you called Autometer? They would probably be able to tell you for sure.

Re: 68 longbed 5.3/4l60e
 

Need some help with the new tank and sending unit.

I installed a brothers blazer tank and sending unit. Filled it about 4'gallons at home. Then drove to gas station and put 6 gallons in drove it around and then filled it. Like there is gas at gas cap level full. The gauge reads 7/8 full. When I accel it goes to 3/4. When I break it goes to full. So I drove it till it was 1/8 tank. Only got 120 miles. Knew I got bad gas mileage but not that bad. Filled the tank and it popped of at 10.4 gallons. Back to seeing fuel at the gas cap level. Still at 7/8 tank and 3/4 accel and full while breaking. I'm not to worried about the slosh but can you think of why it would be showing 1/8 tank with 10 gallons still in it. Blazer tanks are 21 gallons right so if At the second fill up I put 10 gallons in it there would have been 11 gallons still in it even though it showed 1/8.

With the old tank E was E. it did go above full when I would fill the tank. when I installed the new tank and it didn't go above full I thought changing the sender fixed the problem but now I have a problem with E not being E.

Grounded the tan wire and it went to just below E. tan wire open fuel needle goes to above full to about 3 o'clock position.

Ay suggestions?
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Re: 68 longbed 5.3/4l60e
 

Ok, I'm a little confused. Does it read 1/8 full or 7/8 full? You said it both ways. You didn't bend the float arm installing it did you?

Re: 68 longbed 5.3/4l60e
 

When it's phisically full it reads 7/8.
When it read 1/8 of a tank I filled it and it only took 10 gallons.
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Re: 68 longbed 5.3/4l60e
 

Sounds like the float arm is bent up too much, you need to pull the sender out and slightly bend the float arm down, so that when the float is at the very top of the tank (floating on top of a full tank of fuel), the the resistor part of the sender is at the top also. It sounds like the float is floating at the top, but the resistor part isn't at the end. Hope this makes sense.

Re: 68 longbed 5.3/4l60e
 

It dose thank you.
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Re: 68 longbed 5.3/4l60e
 

How do I trouble shoot code P0122. Sensor a low voltage on my DbW.
Motor runs fine so far but the only code is P0122. No throttle response. Can this be oahmed out or what. How do i track this down.

Is this problem only between the pedal and the TAC or can it be in the Barnes?

I post a write up when it's in and running
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Re: 68 longbed 5.3/4l60e
 

Pull the split loom back at the throttle body connector....Pull each wire to test them for being broken inside the insulation, VERY common issue on 03-07 DBW trottle bodies.

Re: 68 longbed 5.3/4l60e
 

From throttle body to what? To tac? To pedal? To PCM? There is five wires coming out of the tps.

Engine starts awesome. Idols a little high but I'm not letting it run long enough to get out of high idle.

I get the P0122 throttle/pedal position sensor A low voltage. With tac connected or not and with pedal connected or not.

I'm hoping current performance did quality tests prior to sending the harness out.
I'm enclined to think its a sensor on the engine to tac or pedal more than the harness.
How do I check the tps?
How do I check the pedal tps?

Other than the P0122 code, can't wait to get this thing on the road.


Thanks everyone for your help, really thanks.
Mike
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