Cold start wont stay running...

[3400-95-Modified]

So I'm trying to figure out cold start on my car... It's only been a bear since i swapped in the 36lb injectors... Prior to that with my 28's running around 32lb with upped fuel pressure I never had this issue.

Now I changed the Injector flow values in the ecu obviously and did a VE tune but once back on the MAF sensor it seemed to be worse starting.

I replaced the bottom half of my VE table with my existing and smoothed the entire idle area but still when the MAF is enabled it will fire and grab quick but then when it seems like it's trying to drop down to idle it just dies. You can see in the logs the IAC is open and the IPW has a number so it's firing... the only thing I was really messing with a lot recently is spark... I assume I don't have access to some tables that really matter because I've seen the spark at 19 when in my table it should be requesting 27-31... for the flow/RPM range.

Any insight on this issue?

[caffeine]

Did you change the injector dead times for the new injectors?

[3400-95-Modified]

I would have to say I would if I could have... I don't see a table with that name on it anywhere in the Fuel injector group.

[caffeine]

It will be a table that varies with voltage. Also sometimes called lag times

[3400-95-Modified]

I found a few tables similar to that... And I'm comparing them to a 2003 GP since thats the injectors I have... Tables I'm looking at are

Injector Offset vs Battery Voltage
Low Pulse Width injector Offset vs Pulse Width vs Map
Minimum Pulse Width
Prime Pulse Delay After Powerup

Which should I attack first you think?

[caffeine]

Probably offset vs battery voltage. Although you should also update low pulse width injector offset vs pulse width vs map

[3400-95-Modified]

Updating those tables to see what happens... Crossing my fingers...

[robertisaar]

i would have copied all of them since you have access to known-functional maps for the injectors you're running now(assuming you're running at the same pressure as the L67 they came from).

[SappySE107]

I would be surprised if that fixed your cold start problem. You need vs coolant tables. Cold AF ratios, cold spark timing, etc.

[caffeine]

Injector dead times can have a huge effect on how an engine idles. It affects how the engine runs at low rpms the most.

[SappySE107]

Does it have the same effect cold vs hot on those tables?

[caffeine]

Depends on various factors. I know when I first tried to start my Firebird with 52 lb injectors I could not get it to idle at all. I tried everything to get it idling but in the end setting injector dead times correctly got it idling smoothly.

[caffeine]

Also it's good to keep in mind that dead times vary not only with voltage but also with fuel pressure. So if you're running injectors at a different pressure than stock the dead time table may need adjusting as well

[caffeine]

These are the settings for my injectors. In my case I didn't initially realize that fuel pressure had to be accounted for to get accurate dead times. I didn't end up with a smooth idle until I finally realized that and adjusted the times correctly. They weren't off by a huge amount but it was enough to cause me huge problems with idle and low rpm driveability.

[SappySE107]

Depends on various factors.

The only factor for that table is battery voltage. If battery voltage isn't changed vs coolant temp, then this table is not what you edit to fix a cold start or cold only running condition. There is nothing wrong with what you are saying, but what you are talking about shouldn't have anything to do with this thread.