Recently completed the 5.3/4L60E swap in my 1967 Buick Skylark convertible. I'll list all of the parts I used for the swap off the top of my head and the codes & symptoms.

• 5.3 w rebuilt 862 Heads & Trunion upgrade out of a 2000 Chevy Tahoe
• 4L60E 2wd transmission with what I believe is the stock converter (used the Speedway spacer to connect to the flywheel)
• ls6 intake/fuel rail/LS injectors
• Full length Speed Engineering Headers ~ No exhaust ran yet
• PSI Conversions wiring harness
• Lokar Throttle Cable setup
• Howards Cam 112 degree lobe sep Valve lift .561 Intake - .571 Exhaust
• New timing chain
• New O2 Sensors
• Melling oil pump
• GM Performance Oil Pan
• Champion 3 Core radiator w Dual LS1 fans
• New drivershaft
• Walbro external pump with Corvette fuel pressure regulator
• The Right Stuff front disc upgrade with Power Booster

Symptoms

• Engine runs great
• Starts up after the pump is pressured up right off the bat
• Fuel pressure has been tested & is a steady 63psi in all gears P-R-N-D etc
• Alternator has been tested and is good (This will eliminate the question of the Alternator later in the post)
• Trans shifts through all the gears while on jackstands ( Got the car up to 65MPH on the stands)
• When the car is driving after being warmed up ( basically running at 20+ MPH and the brake is depressed the motor drops RPM'S really low 200ish and dies. I'll post the video of the car dying and upload the pics of the codes that it has thrown. Im pretty much stumped at this point. I unhooked all of the boosted vacuum lines and plugged them and it still does dies. I thought it was a vacuum issue until then. Any help would be greatly appreciated. Maybe I'm missing something here.

YouTube video of the car running/dying:

 

Nice car. What is your idling RPM set to? Does your tune have any idling air added to it? Maybe 10% extra could be required.

Rick

 

What is the duration of the cam? Sounds pretty lumpy..
Also, is the tranny unlocking when you hit the brakes?

 

I'm not sure to be honest. I had it tuned off Ebay, he had good reviews. Idle is between 800-900RPM

 

Cam duration is ADV - 272IN/281EXH & @.050 22IN/225EXH

I TCC switch wired correctly, but I cant tell if it is unlocking

 

Yeah that's why I asked; it sounds like it MIGHT not be unlocking. Then when you brake it WILL stall. You might want to get a better tune. That cam should not idle so rough by the sound of it.

 

Its a pretty good sized cam & that's straight headers. Think the tune might be the issue?

 

221/225 isn't THAT big, idling-quality-wise. Good cam, though! Should be peppy! But you might want to get the tune checked to see if the idle calibrations are right, as was said above.

 

Suggestions on getting a better tune? Not many resources locally here in Ohio.

 

If you can, put your tune up here and someone knowledgeable will look at it and possibly see where it might need help. There are some tune-savvy guys around here...

 

I really wish I could, but I mailed it to the guy and he sent it back a few days later.

 

So you do have it? Download it and put it up here. Or am I missing something?

 

Download it off the actual ECM computer?

 

If possible..

 

If I had the ability too I would.

 

Where in ohio are you located? Big 3 racing in n.e ohio by medina will throw it on the dyno. They tuned my last ls swap and were great to deal with.

 

I'm in Piqua, Ohio 45356. I have tune from HPtuners. I'll post it in a little bit. I talked with the guy that tuned it yesterday and he said it probably needs the idle bumped up a tiny bit & the DFCO adjusted. I'm not too familiar with fuel cutoff. But It makes sense I guess that it dies when braking and the RPMs drop.

 

Here is the current tune on my Buick.

 

Anybody able to help with suggestions on this Tune? I'd love to drive this car before the snow flies. Kind of at a stand still until I can figure out what is making it Fall on its face when braking after its been running a few minutes. I also noticed after that happens, it doesn't want to start back up very easily...I have to give it a little throttle to keep it running or get it started at first.

 

Putting exhaust on my car made a huge difference in the way it idled, Also wanted to say nice car and Good luck, looks more like a 66 than a 67?? either way nice car. .