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Just completed my top swap..first test drive left mewith concers...

jlgp2007nc

jlgp2007nc

New member
Car idles and cruises flawlessly...I'm using the starting HP Tuners thread on here to do my tuning and that may or may not be where I'm going wrong? P.E. is disabled, but I'm not beating on the car. Scans aren't showing any knock, but once I get to around 2800 RPM I can just hear the blower building boost, then she falls all over herself. No vacuum leaks. No coolant leaks. No head gasket leaks. Full oil and coolant.

I'm thinking lean misfires? When the stumbling, hesitating, bucking happens my wideband does flash super lean each time...like off the charts lean...
 


That's what I figured. Throwing power enrichment back on and writing a program right now. I read that 11.7 air/fuel is a good place to start.
 
Haha holy crap. I had to command afr to 10:1 just to get into 1psi on the 4inch pulley....and still only showed up as 11.4 on the wideband.

1.8 alum. roller rockers
home blended heads
ported, blended Gen V
Intense pushrods
SD headers
 


I think the way you are changing your numbers is causing this issue.

Set up your PE to like 35-40% throttle.

If you are changing the Commanded AFR, you need to zero out the other AFR adders. Make the add vs rpm to 0 across the whole thing, make the AFR correction base table to zero, then set up how much timing you want to run while WOT. This how I do and it works fine for me.


Make sure you have all the correct injector data in the PCM, seeing how you did a top swap you must have had to switch injectors.
 
You're right and I know I shouldn't have been throwing so many numbers around so soon, I just wanted to be able to make it down the road. I have to double check the injector data.
 
Thanks a ton fivefingerdeathpunch for the heads up. My fuel injector table was all kinds of messed up. Got that set straight and the fuel trims took a dive...dealt with a little KR and now I'm in business.
 
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etyjaha4.jpg
 


So I decided time open her up for the first time since I've done the swap. Nice quiet little back road with no residential.

Slammed it and felt a slight loss of power after a few seconds and immediately let off. Transfer didn't shift where I wanted and the engine spun all the way up passed 5600rpm.

11psi on my boost gauge

Check engine light and misfire on cylinder #1. But it didn't sound like a completely dead cylinder. Snatched off the blower belt and babied her the couple miles home.

No overheating, oil level was a bit higher than normal but didn't see milky crap or smell coolant on the dipstick. No loud Knocking.

Threw another plug in cylinder 1 and idles just as smooth as top swap day one now.

Time bomb is ticking.

Saving up still for a SC bottom end and hopefully this one will last until then and I'll drop a pulley, pull some timing and add a some fuel and run it til it's done.


ry3y8u3a.jpg
 
that sucks.. I am really concerned about doing a top swap as all these topswap failure threads keep popping up..
 
There's nothing to be worried about top swapping, clean up, change your oil, torque to spec. It's just a gasket job after all. If your tune is good and your job is well done, you're fine.
 
how long have you had your topswapped for?
just sucks seems like everyday a new thread pops up about topswap issues.
 
To stress you out, my top swapped L36 spun a rod shortly after, did a bad job. But the one I did on my friend's L36 has been holding through all abuse and about 6k miles.

Then again with my own cars I've always had the worse of the lucks.
 


Grimsin said:
how long have you had your topswapped for?
just sucks seems like everyday a new thread pops up about topswap issues.
Click to expand...

I've got about a thousand miles out of it already and last night was the first time I really opened it up. I haven't driven the car yet but When I put in a new plug it idled just fine. We'll see what happens When I put it on the road this afternoon.

I'm not surprised about the failure I did hit 11psi and leaned out to 12.1:1. I already know the NA bottom ends aren't prepared for what the top swap is throwing out.

Be afraid lol....top swapping high mile stock NA bottom ends will always inevitably lead to engine failure. All you can do is do a good job at install, keep everything clean, torque everything down properly and use good parts.

I'm not out of the game just yet!
 
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