Automobiles Forum banner

cold start/ hot restart

1K views 9 replies 2 participants last post by  TheArchitect 
#1 ·
my cold start is great, car fires up just fine, if you try to rev it or drive it, it dies, I'm using a iic on a vr6. You can drive through it till it warms up but its annoying, and on a hot restart it cranks and cranks unless you mat the throttle and after multiple cranks it will fire. any help would be great
 

Attachments

See less See more
2
#3 ·
I have the csv file up there. It does drive and it drives pretty good, I'm using MAP only throttle and I'd like to fine tune the fueling a little better on the cold start, I'm thinking of a stock vehicle that you can fire up and drive 10 seconds after key up and I cannot do that, ( am I wrong to think that with a stand-alone?). I'll go fire it up and do a log from a cold (60 F) start up and put that one up, the one I have above is after running for a few mins as I forgot to click "start log" :frustrated:
 
#5 ·
Other than a short triggering glitch early on, your data looks fine.

One comment though, how do you know what the AFR is to be able to tune the CLT based multiplier?

Looks like you are using v1.02 firmware. It has features that allow you to setup a richer mixture for some time after startup.
You also have full control over the temp multiplier tables, which is almost undoubtedly where your problem is.

OEMs achieve reasonable driving fairly quickly by having a well sorted map, proper air and coolant temp compensation, and having a fast wideband sensor that can take closed loop control of the engine in less than 20 seconds after startup.

So that I am clear, there is not much of a point in worrying about cold start and running parameters if the basic mapping is not yet right. If there are any holes in your "at temp" mapping, get them resolved first as having a hole in the map will be even worse at colder temperatures.

This and pretty much all other standalone ECUs have enough maps and compensation for an OEM driving experience, provided you spend the time to tune it out.
 
#6 ·
Thank you for looking at this,it means a lot. I have a wide band, I did mess with the post fueling and it helped with my lean tip in on cold start, it seems " studdery" when cold still, its pretty solid when its at normal temps. still a bit " twitchy" and I figured its from the DBW with no TPS input
 
#7 ·
Oh and what do you think about my hot restart taking so many cranks to fire up and having to mat the throttle, not rich enough? and back to the cold start, I think I'm gettin a lean pop in the intake if I stab the throttle, too much timing?
 
#8 ·
EuroWrench said:
Thank you for looking at this,it means a lot. I have a wide band, I did mess with the post fueling and it helped with my lean tip in on cold start, it seems " studdery" when cold still, its pretty solid when its at normal temps. still a bit " twitchy" and I figured its from the DBW with no TPS input
The wideband doesnt seem to be connected to the ECU, so you cant correlate the AFR with any of the ECU data.
Cold temps will require a richer AFR than at hotter temps since fuel will fall out on the cold intake walls and ports.
Are you setup for MAP input for the acceleration enrichment source?

Lastly, you should increase the logging speed to fast as it will go, 1 log per second is tough to see tip in effects.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top