OK, Getting frustrated... Damn Cold Idle!

[eboggs_jkvl]

I have the LS6 engine in my Z

My Engine parameters:
3.905" Bore x 3.622" Stroke
Refinished & Magnafluxed 3.622” Factory GM LS6 Crankshaft with Radiused Oil Holes
Custom Machined Factory GM LS1 Block
9.4:1 Compression Ratio
CompStar 6.125" Forged Connecting Rods with ARP Bolts
Diamond Forged Pistons ( -8.66cc,1.314 Compression Height)
Diamond File Fit Ring Set
Federal Mogul Race Bearings
ARE Modified Oil Pump
204/218 @ 0.050 Duration, 0.551"/0.547" Lift, 117 LSA Camshaft
LS6 Timing Chain

Engine Internally Balanced and Blueprinted


Agostino Racing Stage 2 LQ9 Casting Forced Induction Cylinder Heads

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Fully CNC Ported & Polished Intake and Exhaust Ports
69cc Combustion Chamber
2.02 Intake and 1.57 Exhaust Valves
Comp Cams 918 Valve springs
LS6 Locks and Retainers
ARP Stud Kit
Comp Cams Molybdenum Pushrods
LS6 Hydraulic Roller Lifters
Harland Sharp 1.7 Roller Rocker Arms



Problem: Cold Open loop conditions has surge.

What I've already done:
Idle Speed 900
IAC Park 40C and up set to 21
IA in Gear 60C and up set to 8.9 (higher goes into cruise control effect.)
Main VE Table Column 400 x 60%, Column 800 x 80%, column 1200 x 90%
IGN, HiOctane added 2 degrees 400 - 1000 rpm in .08 to .32 range

What I've done has totally corrected the major surge at initial cold start. The engine hits 900 after I start the car and holds rock steady. Now comes the crap...

My driveway is about 30 feet long and slightly down hill. I press on the gas and clutch out to back out of the garage and lift from the throttle to put my foot on the brake to control my speed while rolling down the hill and the engine is NOW surging or hunting for idle and will swing 3-400 rpms +/- the 900 idle mark. If I go back and hold pressure on the throttle it will steady out but if I touch the gas again in any way we go back to hunting for idle and surging. When I get to the street, I can drive away without any sign of a problem but were I to stop 20 feet down the street and sit, the engine hunts for idle again.

This problem is totally non existant when the engine go to closed loop.


I was going to try the RAF table but the PIDs needed to compute it are not selectable on my EFILive.

This: http://www.ls1tuning.com/iboard/inde...showtopic=1136 refers to the RAF as being out of wack when a CAM and heads are messed with but the PIDs to get the data have the dreaded "X" on them.



I sure could use some ideas on this.

Elmer

[GMPX]

I was going to try the RAF table but the PIDs needed to compute it are not selectable on my EFILive.

This: http://www.ls1tuning.com/iboard/inde...showtopic=1136 refers to the RAF as being out of wack when a CAM and heads are messed with but the PIDs to get the data have the dreaded "X" on them.

What year is the PCM, 1997/8 or 1999+, if 1999+ what O.S is it running?.

Cheers,
Ross

[eboggs_jkvl]

The PCM is a 98.

[Tordne]

Not sure if it is the same in a 98 PCM, but check out the Cat Converter Spark table {B5901} and also the multiplier table {B5902}. I have a surge problem during winter and it was because this was removing too much timing.

What you could try (which I did to test) is set the {B5902} table to all 0, and then try a cold start and see if it helps. If it doesn't then at least this is not your problem.

Problem with these sorts of things is that you only get one shot a day generally :(

Hope that helps.

Cheers,

[pekkaz]

So you have ls6 cam... was it like that with stock main VE ?

I slightly doubt the VE should be that much less than stock, could it be running lean and PCM tries to keep it alive with idle motor ?

[eboggs_jkvl]

So you have ls6 cam... was it like that with stock main VE ?

I slightly doubt the VE should be that much less than stock, could it be running lean and PCM tries to keep it alive with idle motor ?

My LTFTs show negative numbers for the most part in cold. So it's rich and fuel is being pulled.

The tuning in the PCM is for the LS1 cam. I'm not sure what the LS6 cam needs.


Elmer

[caver]

I had that as well. part of the problem was the stall saver as the revs drop past that point it winds the idle motor open and boosts the timing which gives a surge.
Raised the rpm at which it kicked in and it made it much better.

[eboggs_jkvl]

I had that as well. part of the problem was the stall saver as the revs drop past that point it winds the idle motor open and boosts the timing which gives a surge.
Raised the rpm at which it kicked in and it made it much better.

Damn if I can find a "stall saver". What table are we talking about?

Elmer

[caver]

B4522

[eboggs_jkvl]

B4522

Sigh...


Must be an EFILive term.

IAC? Generic name please. I don't know what a B4522 is when I look at my LS1Edit tuning software.


Sorry


Elmer