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Tuning Issues

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Z

Zio667

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I have a newer 2.5R engine in my T-Maxx with about 1/2 gallon run through it. It was properly broken in by the instructions included with the engine.

At factory settings, with it warmed up, if I punch it, it stutters. If I slowly accelerate I can get to full throttle, but it will stutter at the shift. If I richen the HSN, it eventually runs great at full throttle and shifts, but it puts out ALOT of smoke. I think too much. What is strange is it will still get up to 270 even running richer than factory. Both compression and pinch are good.

I also had to richen the LSN quite a bit (about a full turn). Using the pinch test, it will run for about 3-4 seconds before stalling.

The idle gap looks right. I measured it with a gauge pin while setting the truck up...

Everyone says to lean it down from factory for performance...I don't get why my truck needs to run so rich...

It is kind of sluggish off the line which is a bummer. But, it has good top end.

I did seal the carb base, pinch bolt, and back plate with RTV.

Any ideas? I want to pull wheelies and bash this thing without having to check the temp every single minute.
 
Tuning Bible
Print this and keep it with you while you tune, it's the best advice you can get. I have two copies printed. One that sits on my workbench for easy access when I bash at home, and one that stays in my toolbox for trips to the track, parks, etc.
 
Seal it. If it's smoking good, you know the lsn isn't lean and it's getting hot, it's sucking air from somewhere. Check the head bolts, header, coupler, hsn housing and fuel system first. You may find the problem without having to pop the engine off. If those things fail, seal the carb throat, backplate and header with high-temp, sensor-safe Rtv. Use a dab of Green Slime or Vaseline on the needles.
 
Everything has been sealed like you suggested. It doesn't seem to make a difference. The only spot I could think an air leak could be is the front bearing. There is definitely oil coming from it. How much oil leakage from the front bearing is acceptable? How can I seal the front bearing and rule this out?
 
i had the same problem just yesterday....turns out i had to put everything back to stock and retune i also apparentlyhad some bad fuel?? i use the lsat of a friends fuel and got it retuned and as soon as i tried to use my fuel again all the problems returned...
 

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