Start-up issues

[sgfreak96]

Car is tuned using HPTuners and is a custom tune tweaked per the cars mods from the stock tune file. Issue at the moment is the car randomly (but usually) whether hot or cold, or whatever, gets super rich at start up. For about 20 seconds it idles normally, then gets down to the 10s for AFRs. After about a minute or two it goes back to normal.

Please don't tell me to go to this tuner or that tuner who so and so. I am just looking for insight on how to tweak the tune I already have, or what parameters would be causing this. Car has new o2s as well, and runs really strong once it's warmed up.

If you have had this problem how was it solved? Let me know, thanks!

 

[06monera96]

so on start up it goes to 10 points
Idles normal (14.8 points )
Then goes back down to 10 points?


Rich is 14 and below
Lean is 16 and plus.

 

[deebo05]

can you post a log file of it happening?

 

[sgfreak96]

so on start up it goes to 10 points
Idles normal (14.8 points )
Then goes back down to 10 points?


Rich is 14 and below
Lean is 16 and plus.

Starts up, idles around stoich, 20 seconds later goes super rich to the 10s, then goes back to normal and it stays normal until next startup.

 

[sgfreak96]

can you post a log file of it happening?

I'll try to get it logged and I can upload a file for you!

 

[BruceH]

I'd look at your cold motor specific parameters. It's obvious that the motor is doing ok in open loop and then has issues going to closed loop with a cold motor. Then it's ok again once the motor is warm. The only thing it can be is the cold motor parameters common to closed loop.

 

[07 Boss]

I'd look at your cold motor specific parameters. It's obvious that the motor is doing ok in open loop and then has issues going to closed loop with a cold motor. Then it's ok again once the motor is warm. The only thing it can be is the cold motor parameters common to closed loop.

Huh? Closed loop is when you use the O2 sensors to adjust fuel. Open loop is when it runs off of tables. I think he is having open loop issues. When the motor is cold it will not use the sensors to adjust fuel because they're not heated up and reading correctly.

 

[BruceH]

Huh? Closed loop is when you use the O2 sensors to adjust fuel. Open loop is when it runs off of tables. I think he is having open loop issues. When the motor is cold it will not use the sensors to adjust fuel because they're not heated up and reading correctly.

Open loop is used at startup. Once it cycles to closed loop he is having issues. This is because the cold motor tables aren't correct and they are overfueling the motor. Closed loop is used during cold motor operation. The moment you have fuel trims you are in closed loop.

Tables are used throughout closed loop operation. O2 feedback is to correct the table predictions when it comes to fueling but fueling is only a small part of what's going on in closed loop.

Why would you think tables aren't used for closed loop?

 

[boomer9999]

if it starts up ok then the tables for open loop should be good right? Then when the closed loop cuts in as the oxygen sensors heat up and activate the mixture is too rich. Then the computer adjusts the over rich mixture with short term fuel trim. Looks like a tune issue.

Of course tables are used in both closed and open loop. There many tables. A tuner guy could make more sense of this.

 

[07 Boss]

Open loop is used at startup. Once it cycles to closed loop he is having issues. This is because the cold motor tables aren't correct and they are overfueling the motor. Closed loop is used during cold motor operation. The moment you have fuel trims you are in closed loop.

Tables are used throughout closed loop operation. O2 feedback is to correct the table predictions when it comes to fueling but fueling is only a small part of what's going on in closed loop.

Why would you think tables aren't used for closed loop?

I thought it was in open loop for a while until sensors heated up. 20 seconds in I'm thinking he is still in open loop. That is why I assumed there was something wrong with the cold tables. Tuning is not my forte and I must have misunderstood, but if I remember correctly my car takes quite a while to get into closed loop when it is cold. Could be completely wrong though.

 

[Marble]

I think my car has always idled like this at first start up. Goes to 14.8-14.9 immediately, after 5-20 seconds depending on outside temps wideband goes down to around 10-11 then slowly creeps up to 14.9. You can hear the engine start to run differently and watch vacuum change also.

It seems petty darn normal to me. But Bruce would know more. Maybe Lito will hop in here and chime in.

 

[sgfreak96]

Issue has been greatly reduced. Tables for the o2 heaters were adjusted to add more heat to them for a longer period of time. Car still goes super rich but only for like 10-15 seconds and I'm ready to roll! Only one more kink to work out in this tune.

 

[Marble]

Awesome!