Red Headed Stepchild-75 Swinger LSX Swap

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MrJLR said:
@YoungDart75

Any updates?


Jeff
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Still going guys. Have ro pin out the harness. ECU checked out good. Was tested on a 2014 tahoe and it started and ran with it. So my guess is something causing the injector pulse bit to make it. Havent made a huge amount of progress lately due to moving, personal stuff, and going to Georgia for a week. Dont worry, havent bailed on the project yet.
 
YoungDart75 said:
Still going guys. Have ro pin out the harness. ECU checked out good. Was tested on a 2014 tahoe and it started and ran with it. So my guess is something causing the injector pulse bit to make it. Havent made a huge amount of progress lately due to moving, personal stuff, and going to Georgia for a week. Dont worry, havent bailed on the project yet.
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Yup....can be a PITA...
Separates the men from the boys!
Just checking in with ya...!

Jeff
 
I'm starting to. I was measuring voltage to the injectors today to verify they were good and I moved some grounds around to make them more solid. Still not firing but I just got some guidance on measurements that I need to take, and if that doesnt work I'm gonna pull the harness back out and check it pin for pin.
 
PROBLEM FOUND!!!

In my barrage of testing and reading and testing again, I measured the 12v power voltage at the Injectors when the ignition was key hot, and checked for the Injector pulse, but never checked for 12v when cranking.

Low and behold after just about giving up. I went home, had dinner with my kids and then thought about testing it when cranking and found that it disappeared when i was turning the motor over.

I quickly hooked up a jumper wire from B+ to the power supply wire that feeds all 8 injectors, and TA DA! She fired right up. Struggling to find the idle spot, and hitting the throttle helps, but she still dies. But that may be due to having the factory ly6 tune(2011 6.0, low lift cam, 50lb injectors) on it and it, and me having the 2008 4.8, 32lb injectors, and much higher lift cam.

Since I've done so much splicing and cutting im going to pull the harness and clean it up since it no doubt could use a once over, and then proceed from there. Here is a short video of it firing up and running for a little bit with me hitting the gas.

 
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Well I got the harness pulled this week and went back through it fixing all the little splices and cuts I made during the trouble shooting. Last night I had about 4 or 5 hours to go over it and fix it all and get it buttoned back up.
2li9ev6.jpg
 
Got the harness back in the car today. Still have to hook up the 12v key hot, 12v battery power and the fuel pump control wire. Then torque down the starter and intake manifold and she will be ready to fire.

I had a leak from injector no.1 before I pulled the harness back out and realised the o ring up top was dry rotted so I replaced all the o rings on the rail side today too before I put it back in.
3spzt.jpg


Also. Idiot me didnt notice the two vacuum blocks on the back side of the manifold came off during all my trouble shooting, so a big part of the reason it probably wasnt idling was the fact I had massive vacuum leaks from the two ports on the back of the manifold. So this time I rtv'd the caps on and I'm letting the seal overnight before I hopefully finish everything back up tomorrow.

Fingers crossed, and lots of prayers and you guys might get a running/idling video tomorrow.
 
Didnt get it all done today but I got the manifold and fuel rails and everything situated and torqued back down. Should have the rest done and a video of it hopefully running this week.
 
Cant wait to see it your getting close that sucker sounds mean in the short period it idled!
 
Since it's almost October......

In the creepiest Halloween voice possible...


ITS ALIVE!!!!

Ignore the smoke, it's just the coating on the manifolds baking in.
 
Pretty sure I have an issue with the MAF, but luckily with an ls, you can just unplug the maf and itll still run.
 
jeffnmo said:
Get it, you're persistence and know how are going to pay off BIG TIME.

Jeff
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Thanks alot. It's been alot of hours digging through diagrams, and searching message boards, searching classifieds, testing retesting and bugging the heck out of some people for advice to get to this point. And my brother finding me alot of parts and keeping me sane.

Nkw it's time to get some hotside parts ready to mount a turbo on this thing, figure out where I'm going to remote mount these coils and make some custom length plug wires once I get them mounted and then finish the battery install in the trunk.
 
Sorry for the crap video. But I had no one there with me to film it. But I finally took the dart out of the storage unit under it's own power. Forgive the hood up. I only went to the end of the row and back to make sure everything was functional and didnt leak. Amazing what happens when u hook up the vacuum line and add the proper amount of fluid.

 
You should feel like you are on top of the world. Great job, I'm cheering you on!

Jeff
 
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