Cold start wont stay running...

[caffeine]

Well I know on my cars the voltage is usually higher on a cold start (around 14.1V or so) and then lowers to around 13.5 when fully warmed up

[3400-95-Modified]

I did copy all the tables that are related to those injectors that I had access to and no it didn't fix the starting issue. I'm going to keep on digging for some other coolant/fueling related tables but those aren't necessarily specific to the injectors alone but more so the engine... Right?

I know my cam is a big part of the problem and it seems like it just doesn't open up the IAC to reach cold idle speeds at all. I can't do any tuning today due to heavy rain but I will be investigating the bin today at work.

After reading about dead times online I did see that they are more of a fine tuning tool and not something that will correct a cold start stall. To get it running all I have to do is tap the throttle and then it seems to take over fine.

[AleroB888]

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.....

You could try going back to everything that worked well for the 28s, but only change the injector flow rate. Then bias the IAC by routing a very small amount of air around the throttle body, such as a small tube with a restriction. I have had some OEM setups where the throttle body has a tiny hole in the plate to make air adjustments.

So it runs good once warmed up, or not? Dies when it goes into closed loop?

[3400-95-Modified]

Runs like a champ once warm and has very little issues idling... Only driving problem that I can describe is if I leave it in D and coast and it goes into decel enleanment and if I make a turn after slowing down quite a bit it will try to re-fire out of enleanment mode and sometimes stall... That could also be due to the engine trying to recover and the PS pump load at the same time. If I leave it in OD it's fine.

The only other thing I can go back to regarding the 28lb injectors is the full VE table and MAF table... I already reverted the bottom half of the VE table to that which I also smoothed out to hopefully eliminate surging...

I could probably just adjust the TB blade a tiny bit to allow more air by it, but ever time I've done that the engine now idles off the throttle blade and not the IAC so when you snap the throttle open then closed it would stall easily... Right now it wont stall when you rev it.

Vid of it starting... This is the best it's been in a while, I made an adjustment to the IAC airflow value... I dropped it by 25% thinking maybe the TCE TB doesn't flow as much air through it as the OEM one did... not sure how much that will change if anything. The digital display that I turn on after it's running is my Nitrous controller, I enabled it so you can see the RPM it's idling at. It was around 60-65* this morning... not as "cold" as lately.

[AleroB888]

At the end of the vid where it stalled (or shut off), did you quickly take your foot off the pedal or gradually?

Did it switch into closed loop before that point?

I can't think of anything to tweak that would affect it except maybe Spark vs ECT. It almost seems an electrical connection is somehow loose till it heats up.

Or that a vacuum leak has caused the PCM to "learn" it's way into a rough starting mode.....

[3400-95-Modified]

At the end of the vid where it stalled (or shut off), did you quickly take your foot off the pedal or gradually?

Did it switch into closed loop before that point?

I can't think of anything to tweak that would affect it except maybe Spark vs ECT. It almost seems an electrical connection is somehow loose till it heats up.

Or that a vacuum leak has caused the PCM to "learn" it's way into a rough starting mode.....

I didn't touch the throttle at all in that vid... That was all controlled by the IAC at that point. The rough start I'm referring to is the first initial stall. Typically it will do that over and over again until I give it throttle to start but this time it grabbed on the second crank.

Also I only have to give it throttle for a second to kick off then letting completely off it will idle fine.

I'm starting to wonder if it's as simple as I just don't have the idle set high enough for 40-50* temps with my cam...

Current table

Deg C----Trans not----Trans Enga
-40----1521.68----1472.461
-30----1521.68----1472.461
-20----1521.68----1472.461
-10----1458.203----1408.398
0----1381.055----1331.25
10----1318.359----1267.969
20----1243.164----1192.578
30----1181.055----1129.688
40----1036.719----985.1563
50----947.0703----896.6797
60----918.5547---- 870.3125
70----918.5547---- 870.3125
80----918.5547---- 870.3125
90----918.5547---- 870.3125
100----918.5547---- 870.3125
110----918.5547---- 870.3125
120----918.5547---- 870.3125
130----918.5547---- 870.3125
140----918.5547---- 870.3125

[AleroB888]

In addition to a little more air coming in if you push the gas pedal while starting, the TPS can affect spark timing commanded. Does the TPS read zero rotation when throttle blade closed, or have reasonable voltage? TPS can cause some weird problems, too.

[3400-95-Modified]

Yes the TPS reads either 0.00 or .39 volts when attempting to start it.

Here is a log I made of it starting then dying immediately... No throttle input by me at all.

start-stall.csv

Another log earlier of the start stall, then start with a bit of throttle and it taking over itself.

Start-stall-start-run.csv

[SappySE107]

What is your IAC count at idle warmed up?

[3400-95-Modified]

23-28 is the typical average. I'm seeing as low as 19 this AM and that might have been in neutral, not sure.

[SappySE107]

Not bad then. Ive had issues with that being higher, and having to set the throttle stop plate so that number is about 10. Helps if the IAC isn't doing all the work but you don't want to go so far that it isn't doing much of anything either

[3400-95-Modified]

Yeah I've had issues with both sides of the spectrum and found that around 20's is a good number... Its helped prevent my car from stalling after a rev mostly.

I'm trying to just bump the requested idle up some to see if that alone helps... I guess I am asking a bit much for this cam to fire and idle at 1000 rpm when its 45-50* out.

[SappySE107]

Nah, try some more fuel in the open loop closed throttle table.

[3400-95-Modified]

I replaced the fuel pressure regulator because that was bleeding down way too quickly and causing the cranking delay, that's now gone and I'll mess with the fuel tables next week sometime... Trying to get a good 1/4 time for this year this weekend.. So far only run was a 12.9@107.