I have never felt anything like this in any F/I car...

Say im in 3rd and want to accelerate i hit the gas and the boost goes up but the power isnt there....then it feels like boost hits hard as **** then it slows, then pulls hard, back and forth its liek choppy.im not bogging down either....say im going 40 in 3rd or 4th...it will happen....could it be the spark plugs? I have the BKR7E's gapped at around 35 i think.....i cant pinpoint this problem....Drive by sensor??

If i go WOT it pulls hard...no choppy-ness at all..only on part throttle acceleration...

anybody have any clue??

 

any other mods done to yer car?

 

Good question. I just redid some of my MAP limit v. RPM tables because my tune was pulling boost up high. Are you using any datalogger?

 

GM STG 1
Intake Mod
BKR7E Plugs @ 35
2.85" Pulley

shouldnt be doing this.

note- I have felt this for a longgg time.... before mods

 

MY throttle was choppy like that before I tuned. It had to do with a hiccupp in the fuel map if i remember right. When I had the MAF-t it would still do it. But now since using HPT I have no problems with choppiness.

 

try gapping the plugs at .40 or .45, you and i have similar mods, or it could be the intake mod, check everything, even disconnect yer negative terminal on yer battery fo 30 mins.
i used to have this when i first got my intake and stage 2 pulley, then i switched to a 2.85, and plugs and i havnt felt since.

 

doesnt it get better milage at a higher gap or run diff or something i have read...what is the diff between a .35 and .45

ANYBODY!!!

 

When did you get your last reflash?? Are you up-to-date??
Wop

 

I have the stage 2 flash done on June 1st.

Have the plugs at .032 and felt "missy" under load today. Drove around for about an hour and it felt a little better. Hmmmmm.

 

Changed the plugs to NGK Iridium ($75 CDN for a set of 4 with taxes) and nice and smooth idle etc, but the hesitation is still there at 3\4 throttle. Gapped the plugs at .040".

After I changed the plugs I let my mechanic take it for a rip and he said the same thing about the throttle position. Only happens when the throttle is at a certain point. WOT is ok and half throttle and cruising is fine.

I am taking it to a GM shop hopefully next week for a peek at the driveby sensors.

At least now I know it is not the plugs or the gap.

 

Well I highly doubt they will be able to determine that anything seriously wrong with your drive-by-wire sensors, otherwise you'll have DTCs.
More likely the delivered fuel in that range is a bit "out" due to your intake and/or exhaust mods. Sombody that knows what they're doing with HPT could likely tune it out for you.

How is your WBO2 connected?- seperate bung??

WOT

 

A bung drilled into the exhaust. 12.2's to 12.8's not rich enough?

 

this is the same issue that i have had since day 1

i find its worse under med to heavy acceleration in 2nd around 3000rpm
Stage 2 (GM) didnt fix it but i did notice that with the stock filter it is not as bad as when i have a drop in kn filter

also gapping th eplugs didnt help
let me know when u find the prob cause i gave up

 

Well I know what it is.

WOP is dead on the money.

Went for a cruise and did the part throttle thing and the instant it did the hesitation\ bucking thing I looked at the WEGO. It had gone from mid 13's or so to mid 16's then back to 13's. Leaned out and richened up back and forth ......surging.

The program is off. I guess when I looked at the WEGO before I looked a little too late to see the fluctuation.


Once again WOP hit the nail on the head.
Thanks WOP.

 

LOL
Well if you have a misfire your 02S will flop around like that as well...
Wop

 

LOL.

If it isn't the tune, what else would it be? I guess what I mean is, could it be something other than the tune?

 

Why would you put Iridium plugs in your car. That makes a hotter spark, wich is bad in a f/i car. thats why every one gets the one step colder plugs, to prevent detination and other problems.

 

They are 1 step colder. Instead of copper they are Iridium.

 

Im comfussed.....Doesn't that defeat the whole perpose of Iridium plugs. I thought that they are the finnest spark and hottest spark you can get.

 

The heat range is the same. BKR7E's and BKR7EIX's are the same except for the conduction. The only difference is the metal. Iridium has a very high melting point, 4450 degrees, which is supposed to give it a very long life compared to a plug with a different metal property. Which is why they are so expensive.