rustyredna

Hello all. I'd like a little help getting my start and idle sorted out, if possible. Currently the car won't start without about 10% throttle input, and won't idle without greater than 5% throttle input as well. The car is running very rich at 10.6 AFR, and I'd like a little guidance before I do any damage, since this is my first time tuning.

Here's my setup:
99 NB with VVT engine. Naturally aspirated
MS3 PNP Pro

Attached is a log and my tune. Please let me know what you think.
Thank you.

Matsie

Hello rustyredna,

First of you're not gonna damage your engine naturally aspirated at idle, that said I noticed a few things in your tables.

You said your car is naturally aspirated but your AFR and spark table are scaled for boosted engines, naturally aspirated engines aren't gonna go above 100kpa. Take a look at your VE table's axis and scale your spark and AFR table like that using the re-bin table function.

Your engine won't start without throttle which likely means it's getting too much fuel, try taking some fuel out of the "cranking pulse".

Your engine is idling very rich, try removing some fuel in the lower left cells in your VE table.

I don't know where you got this tune from but you might be better off just downloading a new base tune for a naturally aspirated engine.

Good luck

curly

iTrader: (25)

Disable idle VE as well, if it ever activates, you'll be jumping between idle VE and fuel VE, making it very difficult to tune properly.

If you're idling at 10.6, and you want to idle at 14.7, 10.6/14.7=.72. So multiply your idle VE cells by .72, it should pull 28% fuel, and idle at 14.7.

rustyredna

Thank you for the responses. Somehow I'd never made the connection between AFR and VE in the form of that equation, so that's exactly what I was looking for. I'll play around with those values to try to get something closer to 14.
As for where I got the base tune, I copied a lot of the values from the trubokitty VVT tune, since the car wouldn't start at all using the DIYautotune base map.