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Fresh rebuild, need help starting

371 Views 4 Replies 4 Participants Last post by  zedrone
Idk how many people are still active on here, but here goes nothing. I recently finished rebuilding my 700xx. 11:1 piston, +1 valves, ported, Webcam stage 2 cam, ehs programmer, for mods. Engine ran fine before but I am not having serious issues starting. It will occasionally fire right up with no issue but will die if left to idle too long.
I have checked entire system, fresh gas, good fuel pressure, injector working well, good spark, fresh plug with proper gap, no codes being thrown, no leaks in air intake, good voltage and crank speed, good compression, all sensors properly plugged in, valves in spec, proper timing, fluid levels good . Have tried to run with multiple different fuel settings on the programmer with no improvement. Had my gm certified mechanic friend take a serious look at it and he's also at his wits end.
When it does start and you Give it throttle it sounds very healthy, no bog no valve train noise. Just as soon as it comes down to idle it dies immediately.
I'm going to tear the engine apart for the 5th time tomorrow evening to fix a coolant leak at base of cylinder (iykyk) and check decompression. I'm going to be pissed if the decomp is bad on the cam they sent me. Also ordered an scs connector tool thing to reset a sensor I forget which one.
Hope somebody can help.
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I guess a little noise you should hear valves,
very minimal,
otherwise they will overheat.
If you think the programmer is the problem,
try remove it!
It can be a completely wrong stoichiometric ratio
I tried that. I think Webcam sent me a faulty decomp...
The decompressor wouldn't matter after the engine is already on though, it's only there to help it start.
I would check for a vacuum leak, spray WD40 around the throttle body intake base area and see if the engine speed changes. Good Luck
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