Balanced the throttle bodies, now it runs worse!?!

caddydaddy

Supercharged
Joined
Sep 6, 2007
Messages
218
Location
Wilson, North Carolina
Ride
2017 Roadster
I balanced the throttle bodies at 4,500 miles on my '17 Roadster. They were off by 20 or so. Now, it has a stumble off of idle when in 1st gear, and after shifting into 2nd. It'll hesitate for a bit, then there will be a big rush of power. I did the ISCV reset and the adaptation a few times, but no positive results from that.
I pulled away from a stop sign today and it stumbled so much I had to put a foot down to stop it from tipping!
The mods I have are a slip on muffler, RamAir and a TuneECU tune. All was fine before I balanced the throttle bodies. Any ideas?
 
The idle speed control is on one end of the throttle shaft the TPS is on the other. If you make adjustments in the middle it effects the other end.
After you balanced the Throttle body did you get the proper voltage on the TPS? Did you have to adjust it?
You did the ISCV and Reset Adaption.
Did you also try the 12 minute tune?
Rick
 
I suspect something is awry the the Tps, iscv adjustments ? Have you also remembered to reconnect any vacuum hoses you may have pulled ? The fact it was running well before indicates something you have or haven't done !
 
I suspect something is awry the the Tps, iscv adjustments ? Have you also remembered to reconnect any vacuum hoses you may have pulled ? The fact it was running well before indicates something you have or haven't done !

I did the ISCV and adaptation reset twice.
The TPS voltage was at the high end of the range, but still within spec.
No hoses were disconnected, all I did was raise the tank to access the throttle shaft screws.
 
Its the adaptation reset. Do the forced adaptation via the warmup cycle, it should help it settle back down like it's supposed to be.

ISCV wont cause the stumble you're talking about, only a fueling issue will.
 
Its the adaptation reset. Do the forced adaptation via the warmup cycle, it should help it settle back down like it's supposed to be.

ISCV wont cause the stumble you're talking about, only a fueling issue will.

I thought the adaptation reset is the same thing as the “12 minute tune” without running it for so long?

I’ll pop the tank back up, check for any loose hoses, wires and see if the 12 minute tune fixes the issue.
 
Adaptation reset will zero out all the self-learned trims. Without having it up to temp and letting it renew the trim table (hidden) it will almost certainly be running lean, quite lean in some cases.
 
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