cold starts are perfect and immediate, but warm starts and i have to be on the gas to get her to turn over. the basics are a 331 stroker with a vortech s-trim and 42's with a pro-m 77mm to match. what should i be looking at in the tweecer to get this resolved? im using a j4j1 bin with all the basics changed, but no changes to anything regarding a/f.
car wont start when hot.....
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I found some info from an older thread back in 11-05 that may help so
I just pasted it here for you
Three fixed parameters in the pcm fuel tables come into play when talking about startup.
1) Time
2) Load
3) ECT
We are dealing with two fuel tables.
1) fuel_table_base_OL
2) fuel_table_startup_OL
The base table is where you see the commanded ratio and it is used during warm up conditions.
The startup table is where you see values that are subtracted from the base table to give you a fatter ratio and time comes into play here.
You asked about hot start conditions so lets use that as an example.
btw, we're gonna use an unmodified j4j1 file for our little example.
Say you've been driving around and go in the house for a while and decide to go somewhere else. When you start the car for the second time, the ECT is 180*
Most NA h/c/i combos will idle at a load of say about .20 to .30 so we will use that load factor.
Looking at the base table you see the pcm is commanding a ratio of 14.302 at that load value and ECT.
Looking at the startup table in the 180* temp column at 0 to 6 seconds you see the value of 1.716. Notice as the time increases, the value decreases until finally at 40 seconds, the values in the table are no longer used.
Here are the commanded, startup, and final ratio values
00-06 secs cmd 14.302 startup 1.716 final ratio of 12.586
07-10 secs cmd 14.302 startup 1.487 final ratio of 12.815
11-20 secs cmd 14.302 startup 1.259 final ratio of 13.043
21-40 secs cmd 14.302 startup 0.572 final ratio of 13.73
At this point in time, you most likely go from Open Loop to Closed Loop conditions and the O2's are calling the shots to achieve the pcm's goal of 14.7 CL happiness.
The Fix is to go to the 210 & 240 ECT columns in the startup table and zero out those entire columns. If need be, you could always play with the values in the 180* column as well.
Grady
I just pasted it here for you
Three fixed parameters in the pcm fuel tables come into play when talking about startup.
1) Time
2) Load
3) ECT
We are dealing with two fuel tables.
1) fuel_table_base_OL
2) fuel_table_startup_OL
The base table is where you see the commanded ratio and it is used during warm up conditions.
The startup table is where you see values that are subtracted from the base table to give you a fatter ratio and time comes into play here.
You asked about hot start conditions so lets use that as an example.
btw, we're gonna use an unmodified j4j1 file for our little example.
Say you've been driving around and go in the house for a while and decide to go somewhere else. When you start the car for the second time, the ECT is 180*
Most NA h/c/i combos will idle at a load of say about .20 to .30 so we will use that load factor.
Looking at the base table you see the pcm is commanding a ratio of 14.302 at that load value and ECT.
Looking at the startup table in the 180* temp column at 0 to 6 seconds you see the value of 1.716. Notice as the time increases, the value decreases until finally at 40 seconds, the values in the table are no longer used.
Here are the commanded, startup, and final ratio values
00-06 secs cmd 14.302 startup 1.716 final ratio of 12.586
07-10 secs cmd 14.302 startup 1.487 final ratio of 12.815
11-20 secs cmd 14.302 startup 1.259 final ratio of 13.043
21-40 secs cmd 14.302 startup 0.572 final ratio of 13.73
At this point in time, you most likely go from Open Loop to Closed Loop conditions and the O2's are calling the shots to achieve the pcm's goal of 14.7 CL happiness.
The Fix is to go to the 210 & 240 ECT columns in the startup table and zero out those entire columns. If need be, you could always play with the values in the 180* column as well.
Grady
grady, i dont see those tables. i am using the cbaza strategy. the closest i can find a match to those tables are for the a9L.I found some info from an older thread back in 11-05 that may help so
I just pasted it here for you
Three fixed parameters in the pcm fuel tables come into play when talking about startup.
1) Time
2) Load
3) ECT
We are dealing with two fuel tables.
1) fuel_table_base_OL
2) fuel_table_startup_OL
The base table is where you see the commanded ratio and it is used during warm up conditions.
The startup table is where you see values that are subtracted from the base table to give you a fatter ratio and time comes into play here.
You asked about hot start conditions so lets use that as an example.
btw, we're gonna use an unmodified j4j1 file for our little example.
Say you've been driving around and go in the house for a while and decide to go somewhere else. When you start the car for the second time, the ECT is 180*
Most NA h/c/i combos will idle at a load of say about .20 to .30 so we will use that load factor.
Looking at the base table you see the pcm is commanding a ratio of 14.302 at that load value and ECT.
Looking at the startup table in the 180* temp column at 0 to 6 seconds you see the value of 1.716. Notice as the time increases, the value decreases until finally at 40 seconds, the values in the table are no longer used.
Here are the commanded, startup, and final ratio values
00-06 secs cmd 14.302 startup 1.716 final ratio of 12.586
07-10 secs cmd 14.302 startup 1.487 final ratio of 12.815
11-20 secs cmd 14.302 startup 1.259 final ratio of 13.043
21-40 secs cmd 14.302 startup 0.572 final ratio of 13.73
At this point in time, you most likely go from Open Loop to Closed Loop conditions and the O2's are calling the shots to achieve the pcm's goal of 14.7 CL happiness.
The Fix is to go to the 210 & 240 ECT columns in the startup table and zero out those entire columns. If need be, you could always play with the values in the 180* column as well.
Grady
Decrease the crank-fuel plusewidth and increase the IAC on the functions that I posted and it will take care of your problem.
Gee Roger 
Those tables have been around for as long as I can remember
I have seen some say on the Tweecer site the newer software
(which I don't use btw) has had some of the definition names
changed but I could not say if those two tables are in that group
I would also say the method BobCat put up has a focus on the
cranking time period where as the info I gave is for after the
motor has fired
I've seen some say they divided the old and new size inj for a
starting place to tweec with the cranking stuff. You are just
trying to cut down the fuel as the new inj is now much
larger than the old
Grady
Those tables have been around for as long as I can remember
I have seen some say on the Tweecer site the newer software
(which I don't use btw) has had some of the definition names
changed but I could not say if those two tables are in that group
I would also say the method BobCat put up has a focus on the
cranking time period where as the info I gave is for after the
motor has fired
I've seen some say they divided the old and new size inj for a
starting place to tweec with the cranking stuff. You are just
trying to cut down the fuel as the new inj is now much
larger than the old
Grady
well that would explain it. i have the newest version of the software installed.Gee Roger
Those tables have been around for as long as I can remember
I have seen some say on the Tweecer site the newer software
(which I don't use btw) has had some of the definition names
changed but I could not say if those two tables are in that group
I would also say the method BobCat put up has a focus on the
cranking time period where as the info I gave is for after the
motor has fired
I've seen some say they divided the old and new size inj for a
starting place to tweec with the cranking stuff. You are just
trying to cut down the fuel as the new inj is now much
larger than the old
Grady
That Sucks
You'd think the latest and greatest would add more options
NOT
Take them away
Maybe they are just named something different
The Base OL table has load on the left and ect on the top
The Startup OL table has time on the left and ect on the top
I took a quick look at the functions BobCat talked about.
It would seem to me you could find some help with the function
fuel_crank_PW_multiply_ECT
My reasoning would be since your current inj's are about twice
the size and you are talking about hot issues.
You could try half the value for temps 150 and up
Grady
That seems counter productive
A lot of those names were the same across the whole self tuning
community with EEC Tuner and the various software revisions
for Tweecer ..... up until this latest version
Its no wonder most of those "really smart peeps" on the Tweecer site
have abandoned CalEdit and started to use editors that work
with the bin file.
Yet ... One more valid reason in my eyes ................
I'll just stick to Good Ole V1.20
It works and the bugs are fairly minimal
Looks like I'm gonna be less and less of a help for others as time
marches on
Grady
Yes Sir
I don't know if I could call it handy as I don't remember where I got
it stashed but ... I got it somewhere and I can dig it up if you wish.
If you wanted to see those tables .......
A easy way for you to see them unmodified and my tweecs to them
would be for you to download the file of my complete j4j1 tune
in screen shots from my site.
Grady
if you could find them that would be great.....if not, i refer to the screens on your site. thanks for all the help grady.
well joe came over this morning and we got the surge down to a minimum. the tps voltage was way off reading 1.3 when we started. it is now sitting at 0.95 which brought it down form a 750rpm surge to maybe a 100rpm jump. once we get the timing set 100% im going to focus on the hot start issue a little more. the reason i mention what we did is the car seems to run a bit longer now on hot start than it did before.
Do you have a wb and if so ... what is it showing currently at idle
What are your K's now doing
Here are a few things ... but ... you may have already done them
Low slope at 42
High slope at 50.4
Load in breakpoints for 42's
Cut your minimum pulse width in half
Grady
i do have a wideband, but as of now it isnt in. i switched mid pipes and need to get another bung welded. im going to try a few of those things and see if any of them help.....thanks again for all the help grady.Do you have a wb and if so ... what is it showing currently at idle
What are your K's now doing
Here are a few things ... but ... you may have already done them
Low slope at 42
High slope at 50.4
Load in breakpoints for 42's
Cut your minimum pulse width in half
Grady
No Prob
Really ... for Closed Loop Tuning ... since you can datalog
You can use the K values and obtain a very stable tune without a WB
Lots of good info about slopes, breakpoints, and other stuff which pertain
to dialing in all the inj values can be found in EEC Analyzer.
Let us know about your progress
and
A bunch of folks run 42's over on the Tweecer site
and
Their search engine is fairly decent
Grady
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