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

-------------------------------------------------------------------

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/index.php?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/index.php?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

[Blacky]

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

We encourage people to use the calibration IDs, they are the quickest and most accurate way of identifying and finding calibrations.
To find a calibration based on it's calibration ID, enter it with curly braces into the Navigator search box and click [Search].
i.e. {B4522}
If you leave off the curly braces, EFILive will find ALL occurrences of that ID - even when it appears in the description of other calibrations.

Regards
Paul

[MCG]

You are all missing his point. He is using LS1Edit and not EFILive. Thus, the calibrations are meaningless to him.

Speaking as someone who used the unlimited license of LS1Edit to tune hundereds of vehicles, after moving to EFILive for tuning, it is akin to coming from cooking on a campfire to cooking in a fully stocked, professional kitchen. The things that you just could not do in LS1Edit you can easily do in EFILive due to a vast amount of the PCM that is opened up that LS1edit doesn't even know about.

I know you have invested in the LS1Edit license (hell, I laid out over $5K for mine), but you should do as I did and walk away and cross over into the light. It will make your tuning SO much easier and quicker. Support for questions like yours on LS1Edit is non-existent. At least over here, you can get an answer. But, you need the tools for the help to make any type of sense.

[Blacky]

You are all missing his point. He is using LS1Edit and not EFILive. Thus, the calibrations are meaningless to him.

Doh!
Yes, I obviously missed the point :oops: :oops: :oops:
Paul

[Blacky]

Stall Saver Calibration.

[eboggs_jkvl]

I've already bought the upgrade. Question is...


Does my 98 have the stall saver function or am I back in the same boat and looking for other ways to stop the car from hunting for idle and stalling?

Elmer


Over night from New Zealand? Dude! That's going to be quite a trick! :D:D

[Blacky]

I've already bought the upgrade. Question is...


Does my 98 have the stall saver function or am I back in the same boat and looking for other ways to stop the car from hunting for idle and stalling?

Elmer

The Stall Saver calibration is in the 98s but in the 98 files I have here the entire table is zeroed out. So maybe it it used - maybe it is not.


Over night from New Zealand? Dude! That's going to be quite a trick! :D:D

It is usually pretty good service from UPS. But we get a head start because we are almost a full day in front :).

UPS call it "overnight", but that is not strictly true. If it leaves here by 3:00pm, it is supposed to arrive in the US at 10:30am the "next" day. So if we ship it at 3:00pm on our Monday (your Sunday night), it should arrive at 10:30am on your Tuesday.

If customs grabs it for inspection, then all bets are off. The best you can hope for is a phone call in a few days saying it has been delayed.

Regards
Paul

[curtbriggs]

In his opening post Elmer says he has EFILive and later Edit, so:

Elmer if you have EFILive, try this, Engine Calibrations, Idle, Desired Idle Speeds. Set your desired idle speeds in all four columns. I had the same problem with the idle in my C5 MN6 when rolling with the clutch in. Initially I had set the idle in the first two columns as I thought the last two were for the slush box. This may not be a total fix but it will help.

Cheers, Curt

[eboggs_jkvl]

Ths is a follow up on my cold problem. I decided to logic this thing out. After reading the scans and ALL OF THE threads I could find on this, every one was opening the TB, raising the IAC and one lone voice said he replace the IAC valve.


I iked that idea, so I replaced my IAC valve and cranked it up. BAM! Dead on idle, no hunting just a rock solid 1100 (it was cold) and it slowly settled down to 850 as the engine warmed up.

I cannot believe that the ENTIRE problem was a worn out IAC valve.

Well, now to get a few scans and miles on the car to check the LTFTs and I can head down to Orlando and get this thing Dynoed for WOT!

Thank you to all who have offered ideas and helpful suggestions.

Elmer

[jfpilla]

Nice going! I would have been tuning on it for a month. :D