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Old 09-18-2010, 07:37 PM   #1
fourseasonsandles
Scooby Specialist
 
Member#: 94816
Join Date: Aug 2005
Chapter/Region: Tri-State
Vehicle:
06 STI EFI Tuned
Rspc block, GT30, 272s

Default Shaking at idle and running lean - was just tuned yesterday..

I just finished my build and had it tuned yesterday. All seemed well until this afternoon.

First the mod list:
*Rallispec street series shortblock
*Kelford 272 cams with Ferrea valve train
*Deatschwerks 850cc injectors
*ATP3076r IWG Turbo
*APS DR525 FMIC
*APS hard inlet
*KSTech Weldless TGV Kit
*Grimmspeed A/O Separator
*KsTech 73mm CAI - matched for APS FMIC
*Cobb Catless TBE
*Cobb Lightweight Crank Pulley
*Ported Stock headers w/ Stock Xpipe and Perrin UP
*Walbro 255 Fuel pump
*NGK Copper Spark Plugs LFRGA-11 gapped to .028"
*Hallman MBC

The car was just tuned yesterday at EFI logics on 93oct and ran awesome the 350mile drive home. Then, I took the car out this afternoon for a ride and only boosted once on the way to my destination. Then on the ride home, I went WOT twice and all was well. Then about 1/2 mile from my exit ramp on the highway I gave it a little gas to go from a 55mph zone to a 65mph zone and then the car started to shake.

My wideband read around 10, which it is supposed to at WOT and my boost was at about 20psi. These are the normal numbers since I was tuned at EFI and even double checked with Chris before I left to make sure I should be reading 10 on my wideband. I did not get any CELs or flashing cruise lights.

I limped the car home and let it idle. The engine is visibly shaking and the car is running lean at idle around 15.5+. Normal idle for the car is around 14.7.

I did see that my rear diff, battery and brake lights would flicker earlier today after getting a tank of gas, but did eventually go away. So, I thought first we will try a different battery. Swapped the battery and no change on the shaking or running lean. I put the "newer" battery back in the car and still ran the same.

At this point I am thinking a bad injector. If the car wasnt making spark, it would go rich correct? Since the car is lean, I am guessing it is not getting as much fuel as it needs. It would also make sense if one of the cylinders is not firing, causing the engine shake.

It is late Saturday and I have a call into my tuner, into Deatchwerks and another local shop that cleans injectors. I dont intend on fixing anything today or even this weekend.

Compression: on a cold motor
#1 120
#2 120
#3 125
#4 120

Any thoughts or help would be appreciated.

**Data log posted in post #5
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Last edited by fourseasonsandles; 09-19-2010 at 02:00 PM.
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