tip in KR and detonation

[L-Eater]

I posted this over at LS1 tech, too but I thought there might be some specialized experts over here that could help.

OK, quick description of the vehicle: 1994 chev truck with 2002 5.3/A4. Motor is bone stock down to the exh manifolds. Has a Whipple blower making around 7 psi. I just put the combo together, but it is basically a "liftout" from my 2002 truck, where it had NO issues. The problem I am now having is detonation/6-8 degrees of KR when I am cruising at say 65 mph around 1800 rpm or so usually about 20 percent throttle and I quickly increase throttle to 30 or 35%. Like if I just want to speed up to pass someone. When this happens there is almost no RPM increase, and the MAF goes from about 25 to 70 or 80. The MAP reading goes from like 18 to 30+ This is where I think the problem is. I am not showing boost when the KR kicks in, but I think it has to do with the MAP getting maxed out at such a low load/low speed. I guess my question is what tables do I change to correct this? I don't show any KR with a slight gradual application of the throttle nor with a sudden WOT blast, only with the quick "tip in"

The PCM I am using does not have the same segment 1 as my 2002 truck so I have had to go in and manually change the tables to the same values as the program I ran this motor on in my 2002 truck. The only real diff in combinations are the 2002 truck has drive by wire and 3.73 gears and the other truck has 3.08 and cable throttle. Any advice would be appreciated!

[GMCwantsLS1]

This might sound dumb but have you checked your fuel pressure under load? I think a lean condition can cause KR. Just a thought.

[L-Eater]

GMC-no that is not a dumb idea. I checked it Monday evening and believe it or not I had too much pressure! I got it backed down to where I want it (64 at full throttle) it was at like 75! I think it is going lean momentarily but I don't know why. Isuspect it is because of the rapid change in manifold pressure but I don't know enough about edit to know where to look. It is like it needs an accelerator pump shot to "fill in" until the main fueling gets there, but unlike a carb with acc. pump probs, it doesn't have any kind of hesitation or dead spot. Just ping and KR. Anybody else got any suggestions?

[GMCwantsLS1]

You might need to put a wideband on it and monitor the AF ratio. Sounds like you are running lean in that one spot. I guess you could add more fuel in the tables for the range that you are having trouble with. Maybe Allen can chime in and help out. You also might want to reset the PCM since you changed fuel pressure and let it relearn the maps.

[Bandit]

Note: The code (PO332) listed below may not set with LS1 Edit being used. If you give Allen your VIN, he can probaly check to see if the flash update is available. I looked in my mitchell on demand but did not see it yet. Hope this helps. If not, you could always drill out the EGR hole a little bigger.....

Audible Spark Knock (Detonation), MIL Illuminated, DTC P0332 Set (Replace
Rear Bank Knock Sensor and RTV Area Around Sensor) #02-06-04-023A -
(06/14/2002)

Audible Spark Knock (Detonation), MIL Illuminated, DTC P0332 Set (Replace
Rear Bank Knock Sensor and RTV Area Around Sensor)1998-2002 Chevrolet Camaro,
Corvette

1998-2002 Pontiac Firebird

with 5.7L Engine (VIN G -- RPO LS1)

1999-2002 Chevrolet Silverado, Suburban, Tahoe

2002 Chevrolet Avalance

1999-2002 GMC Sierra, Yukon, Yukon XL

2002 Cadillac Escalade, Escalade EXT

with 4.8L, 5.3L or 6.0L Engine

This bulletin is being revised to add Cadillac Escalade and Cadillac Escalade
EXT to the Models. Please discard Corporate Bulletin Number 02-06-04-023
(Section 6 -- Engine/Propulsion System).

ConditionSome customers may comment on a mild to severe engine ping (commonly
referred to as spark knock), usually worse during acceleration and/or an
illuminated MIL. Upon investigation, the technician may find DTC P0332 set.

CauseThis condition may be the result of corrosion of the rear bank knock
sensor due to water intrusion into the sensor cavity. This condition is more
apparent on vehicles in which customers frequently wash the engine
compartment.

CorrectionReplace the rear bank knock sensor and build a dam (wall) around
the sensor using RTV to divert water away from the sensor. Use the procedure
and part number listed below.

Remove the intake manifold. Refer to the Intake Manifold Replacement
procedure in the Engine Controls sub-section of the appropriate Service
Manual.


Remove the wiring harness assembly from the knock sensor.


Remove the rear bank knock sensor.
Install the new rear bank knock sensor. TightenTighten the knock sensor to
20 N·m(15 lb ft).

Install the wiring harness assembly to the knock sensor.


Apply a bead of RTV silicone sealant approximately 9 mm (3/8 in) wide and
6 mm (1/4 in) high along the outside edge of the ridge on the engine block
valley cover around the rear bank knock sensor. DO NOT form a complete
circle. Leave the rear section open as shown.
From the underside of the intake manifold, completely remove the rear intake
manifold seal (foam material).
Install the intake manifold. Refer to the Intake Manifold Replacement
procedure in the Engine Controls sub-section of the appropriate Service
Manual. Parts InformationPart Number

Description

Qty


10456603

Sensor, Knock

1


Parts are currently available from GMSPO.

Warranty InformationFor vehicles repaired under warranty, use:

Labor Operation

Description

Labor Time


J4437

(F-Car)

Sensor, Knock -- Replace

1.7 hrs


Add

(1998-1999 F-Car Only)

To Remove EGR

0.2 hr


J4437

(Y-Car)

Sensor, Knock -- Replace

1.6 hrs


J4437

(C/K-Truck)

Sensor, Knock -- Replace

1.5 hrs


Add

(C/K Truck Only)

With Three Piece Engine Covers

0.2 hr


Add

(All)

Diagnosis Time

0.3 hr


Add

(All)

To RTV Area Around Sensor and Remove Intake Manifold Seal

0.2 hr




GM bulletins are intended for use by professional technicians, NOT a
"do-it-yourselfer". They are written to inform these technicians of
conditions that may occur on some vehicles, or to provide information that
could assist in the proper service of a vehicle. Properly trained technicians
have the equipment, tools, safety instructions, and know-how to do a job
properly and safely. If a condition is described, DO NOT assume that the
bulletin applies to your vehicle, or that your vehicle will have that
condition. See your GM dealer for information on whether your vehicle may
benefit from the information.

WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION

© Copyright General Motors Corporation. All Rights Reserved.


Bandit!