Pre-emptive question

[Spindoctor]

Howdie all!

This is a pre-emptive question in that the car has not arrived yet.
What is on my tuning schedule for tomorrow is a 2000 Vette with a high stall converter, 560 lift 220\224 cam and a screw style charger of unknown make.

The issues for me to resolve:
1) Long crank times to start
2) Continous misfire codes at idle

I figure the long crank time won't be too hard to work out. But, the misfire at idle is probably the crankshaft rattleing away in its caps due to the 'snarly' idle the customer wants.

As usual any and all input is greatly apreciated!

[Black02SS]

I'd disable the misfires at idle. Then take a look at the AFR on a cold start while in open loop (SD). This will tell if the lower portion of the VE table is in line or not. I have found this to cure 90% of startup issues. Dial this in and then the ve table at operating temperature.

[Spindoctor]

Thanks for that heads up-
O.K. so the supercharged Vette shows up and most of the issues were related to too low idle settings for the cam. Made the usual adjustments and its mostly happy at idle.
HOWEVER once on the dyno I came across another issue. This engine will not take any load. Now I have only done three other Vette's so far, but all went as expected.
This one wether I am using the bi-directional to lock my gear or just letting it run on its own, will not pass 3500 rpm at WOT and is bogging down. Both absolute TPS and ETCTPS show 80%+. Unloaded it will run up to redline, but it doesn't sound very strong.
Now I have 27 years diagnostic and can check for any mechanical issues (plugged cats etc) , but before I jump into that I want to make sure I have not missed anything in the software that would cause the inability to produce power (like a protection mode or the like that I may unfamiliar with).

The first issue that comes to mind would be the spark plug gap- factory is .060 they are set to .050. My usual tunes are on 4-800 hp Turbo ricers and I need to set the up at a low .025 to .030 or the sparkplug gap becomes to difficult to ionize.

Its the end of the day and the car is hot and strapped down to the dyno so I am not going to check anything 'till morning.

If I am missing something obvious go ahead and hit me with a stick!

[joecar]

Tim,

GM has issued a TSB in the last few years saying that the factory plug gap has been revised down to 0.040" from 0.060".

What is the actual AFR when it bogs...?

[Spindoctor]

AFR's are at 12.2:1. The bog is coming in at peak torque range so I suspect the plug gap is still too wide. Unless there are objections I think .032 would be a good place to start.
I will find out in the morning and let you know.
Get this- I checked my ALL (some) DATA and it shows the gap should be .060 but,
when you check for bulletins you find the up date that you mentioned for the iridiums at .040.
ALLDATA owes you a beer!

[ScarabEpic22]

Well Tim, hopefully you can get this one figured out soon. Id love to swing by and check out your shop sometime, Im heading back to the west side of the state in about 1.5hrs for the weekend but Ill be back in early october as well. Are you open weekends or just the weekdays?

[Aint Skeered]

I have a friend that had to gap his turbo ls1 down to .025 to get it to run right. it was blowing out the spark it seemed.