My swap. 5.3 into a 1990 3/4 ton 4x4 Suburban.

[JCampbell]

Looks great! Dig that color.

[JCampbell]

Have you had an opportunity to get any MPG figures yet? Curious to see the numbers with that TH400.

[y5mgisi]

About 12 mised driving. The problem with my numbers are that as i said, the computer is tuned wrong and my trip to work (which is most of my miles i put on my trucks...) is a whole 4 miles round trip... So, it doesnt even get to operating temp normally! I expect that when its all dialed in and if given the chance to drive normal miles it would be right at 15 as a running average. So not that great, but a bump up from the 10 it used to get!

[y5mgisi]

Got my reprogrammed computer today! Can't wait to see what it does for my mpg and power!
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[83GMCK2500]

Very nice build! Update on mileage and power with reprogrammed ECM?

[y5mgisi]

No... Sadly there is quite a challenge getting a properly programmed computer for this truck. The problem being, im using a camaro harness and o2 sensors. This doesnt jive well with the 5.3 (truck) tuning. Ultimately, right now, im running a 5.3 tune and its nut reading the o2 sensors... So, my power seems about the same as with the LS1 tune, and my milage seems better. But i actually havent driven it much since i got it done, had it re painted, and got my 2012 Sierra. My long/short term plan is to rip the wiring all back out and start back from scratch using a combination of the ls1 harness and a normal truck harness. In doing so i will b e switching back to the truck o2's as well. There is a big list of hindsight issues at play here. So, it will be a while before i start driving it with any degree of consistency again, but when i do, i;ll report. Honestly tho, i feel that the 5.3 in a burb is pushing it. Its plenty of power, but its not got a lot of excess power. I think a 5.3 with a good tune, headers, and CAI is plenty well sufficient. I think if i had it all to do over, i probably wouldnt have done anything different. Its just the situation i was/am in. The old motor was so bad that it wouldnt have made it to where it is now. And i just really like everything about having a LS under the hood! But, In the end, the 5.3 wont stay in here forever. Its a place holder until i drop in a 6.0/6.2/8.1.

Bottom line, I would do a 5.3 swap into anything in a heart beat! THey just run good! They are cheap(ish) reliable, and just fun!

[Ranger6202]

question: i didn't think the harness would make much of a difference, as long as everything plugs in (DBY or Cable and etc...). I agree the O2's will change the tune a little. I'd recommend (rockauto.com) to get a cheap set of o2's for the 5.3.

[y5mgisi]

Lol that wasn't a question. The problem is the Camaro o2s are case grounded qwhile the truck o2s are grounded through the ecm. So the computer is just flat out not reading them.
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[Ranger6202]

sorry if i came off ignorant, i should have phrased it more as a question than a comment. Is it a possibility to ground the O2's through the ecm by adding pins in the right spot of the ecm plugs?

[y5mgisi]

Maybe. Truthfully though, im just not interested in that. I want to take it back to being a little more simple. I dont want so much mix and matching. I want to mostly, completely rewire the whole engine instal to make it a lot more factory as opposed to how i just tied it all in like i did the first go around. It would probably work forever if i went back with the LS1 tune and kept the wiring just how it is and had a tuner custom tune the fuel/spark maps. But thats just not quite what i want. I want it to be a 1990 suburban with a factory 5.3. If that makes any sense.

[NastyBuzzard]

You did an excellent job on your swap. Did you ever get a tune sorted out? Any more pictures of how you mounted the stock air intake box?

[y5mgisi]

Yes i did. In the end it was a simple matter of running the 5.3 tune and re wiring the o2 sensors. Now tho, I have ripped my wiring all back out and am in the process of re doing that. Here is where im at now!

[NastyBuzzard]

Originally Posted by y5mgisi

Yes i did. In the end it was a simple matter of running the 5.3 tune and re wiring the o2 sensors. Now tho, I have ripped my wiring all back out and am in the process of re doing that. Here is where im at now!

Very nice! Sucks to go back and redo it tho I bet.

[mcbassin]

Very nice work on the new harness! It will definitely be worth all the trouble for piece of mind.

[y5mgisi]

Originally Posted by NastyBuzzard

Very nice! Sucks to go back and redo it tho I bet.

Kinda. But i feel like I knew this was coming. When i bought the motor i wasnt very happy about the harness. But i was so excited to have it and get it up and running that i just went ahead and installed it. The more i lived with it, the more it ate at me knowing that i was driving around a hack job. The tags (registration) went bad while i had it down for paint so i figured i would just leave them bad and start fixing some of the stuff that i put off when i was just to eager to drive it.

Originally Posted by mcbassin

Very nice work on the new harness! It will definitely be worth all the trouble for piece of mind.

Might not look like much in the pics but it is turning out really good. I have done one before and learned alot from it on what i wanted out of this harness. And most importantly, just zero hack. Im 100% confidant in this harness!

[y5mgisi]

During,






Pile of unneeded wire from the harness,

[NastyBuzzard]

I hope to channel your patience when I tackle my wiring. I am hoping b/c I am going to integrate the entire wiring harness from my 2001 donor I won't have that big pile of "spaghetti" wiring! Looking good though, patience pays off in the long run as well as having and doing the right stuff!

[y5mgisi]

Now the real fun begins. Turning all this into something that looks pretty.

[NastyBuzzard]

Looks like all thats left is to loom it up!

[y5mgisi]

Pretty much. I still have to make up the fuse block in the cab and route everything just right. This week leading into Memorial day I'm pretty busy so I will probably hardly touch it until next week.

[BigRed76]

Great job on the swap I noticed you used a VDO temp sender instead of the autometer version that most of us have used. How well does that sender work with your factory gauge? The autometer sender reads too low at full temp.

[y5mgisi]

The VDO sender does not work with the stock gauge. Im doing it the "smart" way now with a stock sender for the burb thats turned down to the 12x1.5 thread to thread right into the head. Its pretty popular and a friend has done one also with no problems. The sweet thing is that because its brass, and therefore soft, you can chuck it up in your cordless drill and use a file to turn down the outside until its the right size to run the die over it.

[NastyBuzzard]

What's your plan to mount the pcm this go round?

[BigRed76]

Originally Posted by y5mgisi

The VDO sender does not work with the stock gauge. Im doing it the "smart" way now with a stock sender for the burb thats turned down to the 12x1.5 thread to thread right into the head. Its pretty popular and a friend has done one also with no problems. The sweet thing is that because its brass, and therefore soft, you can chuck it up in your cordless drill and use a file to turn down the outside until its the right size to run the die over it.

That's interesting, I never thought of doing that. Might have to give that I try with mine.

[y5mgisi]

Originally Posted by NastyBuzzard

What's your plan to mount the pcm this go round?

Im going to mount it between the battery and radiator on the driver side using a custom mount.