Car runs like crap cold? Awesome when hot.
 

Since I last put the T/A back together, and the first time I can remember driving it in the winter since the new motor, it seems aweful cold-natured. It'll crank up fine, but before driving has to be warmed up in the drive way, otherwise it runs like crap. Feels like it misses, surges, etc. Once it reaches operating temp it runs great, and you'd better hold on. Anyone willing to lend there expertise as to why it runs so badly cold? Thanks.

Wow...this is usually the opposite of what the LT1 likes.

I would think that since you said it runs like crap till it warms up...that is has something to do with open loop running/tuning(ie cold starts, not WOT mode)

Its so bad that I hate to drive it when its cold though...

Well this is certainly a strange one.
I wish my car liked hot weather, I'll probably have to work on it when the summer gets here because stuff will start dying quicker.
But my car seems to like really cold weather along with about 180 degrees coolant temp. It moves a lot faster then, 1st and 2nd are just gone when you floor it.

But it's probably a sensor somewhere. It's always the electronics with these cars.

I thought it was wierd too, but I've never had the car running during the winter with this engine. I just can't see it being a sensor...but maybe the Inlet Air Temp is a good place to start?

try your oxygen sensors

Brand spankin' new o2s...I replaced them both about 4 months ago.

Im having the same issues. Its all in the tuning. Mine has gotten much better, but still not acceptable IMO.

Playing with the closed TPS spark advance vs RPM, and spark vs MAP vs coolant temp are the two tables which i found to work the best so far.

And, in my case at least, the car LOVES cold air and weather, but engine must be warmed up to run well.

Yeah that is weird but I have the problem too. When I drive from my house to the track wkich takes like 45 minutes, my first run is always the best because the car is warmed up, and the car gets slower if I let it sit for too long. I can't figure it out and I dont bother letting it cool down in between passes, just jump back in. Did you do the throttle body bypass? porbably has nothing to do with your problem but just a thought.

Yes, I did the TB bypass, but I don't think that's it. My problem is more related to like driving in the morning. I've got to let it warm up in the driveway, otherwise it misses and surges and pops and stalls.

Altjar: What software do you use to tune with?

HOLY CRAP...11.98 stock heads...I'm thinking GM 847 cam ;D What valve springs do you run? Do you think that the LT4 valve springs would be fine with this cam?

Im using tunerCATS to tune.

ON 847 cam....

Using k-motion k-800 springs. No chance that the LT4s will work.

hey atljar, your running 11.98 on stock bottom end and heads! Where did you get that cam!

http://dab7.cranecams.com/SpecCard/D...1=Display+Card


Now back on track.

Anyone have a file for a big cam that runs well at initial startup in cold weather that i could look over?