Cold Starting Speed Density Issue

[xtea]

My iat is on the cold side of my intercooler. Lets get that out of the way.

 

My car drives fine when warmed up, it idles fairly ok when warmed up. But on cold starts on colder days the tach surges and struggles not to stall. On even colder days it will just stall if I don't blip the gas. Another odd thing is on low gear shifts r, 1, 2, I get a back fire or some low load stumble, this is while warm.

 

What causes the engine to do this only when cold? My tuner dyno tuned on speed density, but he's recently cobb certified and just learned the "bowl of timing" trick. I don't think he has the vast experience to spot every problem, and from what I've researched adjusting the idle tables and coolant tables yada yada is very challenging anyway.

 

I know the tune just needs to be ironed out, and they will make another attempt tomorrow. But what I am curious is what is happening in the 2-5 minutes before the needle hits C that makes the car unable to find the right AF ratio to run well when cold?

 

Today was a little warmer so it wasn't as bad, but I started using my winter oil pad heater and though it didn't fix it, it did tone problem down a bit. It could've been the oil pan heater or it could've been the ambient temp.

 

Please forgive any inherent ignorance in my questions and correct me where appropriate.

[fahr_side]

First thing, the warm-up enrichment is based on coolant temperature, not IAT. And anyway, at idle you're not making boost so the IAT being before the turbo or after the intercooler won't make a significant difference.

 

You may be ramping down too fast in the CL Fueling Target Comp. A and B tables, so you're dropping to a stoichiometric fuel target too early, while ECT is too low and the heads are still cold. If the problem is worst during the immediate post-start time, like within 30s of start-up, look to see if the Min Primary Base Enrich tables also ramp down too steeply at those temps. You can also adjust the decay tables to have the enrichment go on longer post-start.

[Th3Franz]

VE at cold idle probably needs to be adjusted. Once it's in closed loop, what AF correction do you see when the car is still cold?

[xtea]

Log rolls down the stairs, under the chairs and over your neighbors dog... It fits on your back, its great for a snack, its Log Log

 

datalog67.csv

 

 

When the car is warm AF correction doesn't move much, or oscillates in small fluctuations, nothing major. When its cold is all over.

 

This isn't just a 30 second issue. If its a 68 degree day like today sure, its maybe 30 - 90 seconds. If its colder, it lasts longer. Before I tried the oil pan trick I tried using my coolant oem block heater. That did not work as well.

 

Fahr, I don't know what you said means, but I am going to edit my first post and send a link to the tuner in the morning. Also I owe you pizza and beer with how much you've helped me.