Tweec #1: Search For a good idle!

BoostedSN95

Founding Member
Jun 29, 2000
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cc,tx
First of all, I would like to thank you guys for the support. Thanks to your input :nice: I am at the point of doing some basic tweecs.
:D
My first goal is to get a solid idle. Right now my idle is surging and I do not like!:mad:

I have a made a file that includes all of the basic modifications: MAF function, Injectors slopes, breakpoint, MIN pulse width, no smog, no egr, set idle to 800.

I have not changed the injector vs battery offset function yet. I hope this is not to crucial for now. I also have not changed the throttle body scalar. By the way, my version of cal edit show that the units for this number is in kg/hr I have read on ways to calculate this number which include a unit conversion. I assume this is due to prior versions of cal edit.

Now I am going to tell you plan for idle adjustment and would like for you guys to poke holes in my method.:owned:

Once I write the file to tweecer I will start her up. If idle is surging I am going to adjust the duty cycle of the ISC to be 30-40% if it is not there. I will do this by adjusting the bleed screw. I will also make sure the tps is not out of wack.

If the ACT is going nuts like it has been, would this contribute to a surging idle?

On another note: should I try to get rid of the surging before I even try to tweec? This seems like the more logical approach, I just do not know which best.

Thanks:SNSign:
 
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In order of importance or at least "most important".

timing at 10*
FP at 39
MAFTransfer
Slopes
Batt. offsets
.
.
.
then some of the idle stuff.

I would (and it sounds like you have to some extent) built a 30pt MAFtransfer from the 10pt given by Pro-M. and set the inj. to the # for one slope and # x 1.2 for the other (I get them mixed up but you can see what one it is). In doing this use the breakpoint from the GT tune as it will not work properly with the Cobra breakpoint to have diff. numbers.

Look on the eectuning site and you can find the offsets for the 30's. Datalog and make the changes if needed until your set. Alot of idle issues can be caused by a funky load issue if the MAFtransfer is off and or the slope is dumping fuel at low rpms. It is amazing how much a good MAFtransfer will smooth things out.
 
Thanks for the reply. My MAF transfer function is the 30 point off of www.massairsystems.com. I have made all the changes you mentioned except the battery offset. I have found one function off the tweecer board, I do not know if it is correct though.

Also, I do have a question for about the value for injector break point. In th tweecer manual. It gave a number like .000005 and tweecer refreshed to like .0000035 or something like that. Are you saying I should leave it at the stock value. If so, how come? Also, what should the load be for an idling mustang with the fan going?
 
I just copied what the gt file breakpoint had, as the cobra breakpoint with a diff. value in the slopes (cobra setup has the same high and low slope) made things funky. I dont know if I got lucky but it seems to run really well like that for me. I have yet to see what EA says though and will try what it recomends when I do get off my butt.

Be carefull with some of the manual stuff...double check those things as some of the info is older and kinda more for the fox setups. Its been awhile since I looked at it though so things may have been changed/updated.

I would check grady's site out as he has 30's and search his posts for info on what EXACT breakpoint/PW/offsets he runs.
 
Its been forever since I hosed around with all that bp stuff but I do remember it was kinda confusing :scratch:

IIRC, the two values you gave above were displayed in Engineering notation when I was dealing with that stuff.

I think ... it would be :shrug:

.0000035 = .35 E5

.000005 = .5 E5

Math was ALWAYS a sore spot for me when I was a school boy :bang:
so
DON'T let me mislead you here :nono:

My warped way of looking at those values is they look like

35 cents or 50 cents :shrug: Still ... I can't be sure :rlaugh:


Then again ... that stuff may have gone all away with CalEdit V1.30 :shrug:

I see you got a stick trans :nice:

Since you have that good fortune, and are runnin 30's with aftermarket maf, I'd use the j4j1 file.

btw ... You do NOT wanna be using 19# offsets with 30's.

Grady
 
Hey guys, thanks for the info. I was double checking the numbers and I made a typo:nono:

Just for the record this is what I will be using for a base line approach.:flag:

High slope=30.5
Low slope=38.5
Break Point=1.975e-5
Miniumum PW=5.0e-6

These values are from the tweecer manual, I am sure they will be modified a bit.

As for battery voltage offset, I will go with the one from the tweecer msg board. I suppose that is better than nothing.

I will keep ya posted! :nice: :SNSign:
 
UPDATE

I wrote two files that basically addressed everything I mentioned. A) One of them included idle change parameters along a injector offset function. B)The other did not included these two parameters.

I wrote A to a switch and unfortunately the car just cranked almost started then died. It would basically just crank for a couple of seconds light up for a split second and die. File B did the same exact thing. I am not sure where I went wrong.:bang:

I thought these changes were very strait forward, I suppose I can read the tweecer to make sure it is on there correctly. Any other options?:shrug:
Let me know guys.
 
UPDATE II

OK...

The MAF transfer function was not very happy.

Note to anyone who cares: You should not put in the 30 points on the X Y rows and save them as a calibration.

It seems cal con just takes the 30 points you put in and does what it wants with them. That is the reason my car did not start. I noticed this and quickly loaded the ProM30 file that come with cal edit and the car started up and idled like a champ! :nice: :hail2:

Observations:

1. Idle does not have a hint of surge, and the car sounds solid. The idle is a bit higher than the values I set. It is idling right under 1k rpm, when I put in 850.:shrug:

2. Max Lambse is ~14.2 I did see the lowest value for a bit of 11.7. It was mainly aorund 14 on average. Also the 11.7 values were given the only time the car was actually in closed loop, (maybe a min or 2). Does that mean the car was actually in open loop every other time.:shrug:

3. Spark bounced around between 20-30. When I give it throttle (~2krpm) Advance goes to 39-40. Comments?:shrug:

4. ISC is around .105 at idle. i assume this is 10.% Although the gauge makes it seem like it is .105%.

5. Kamfrs did not budge from 1. Default MIN ACT value is -20 F. Not sure about this business.:shrug:

6. Finally the neither of the o2s actually bounced around as much as I would expect. The highest was around .35 V on HEGO 2 during closed loop. Every other time, they did not get higher than .15 V.:shrug:

Ok guys, I would like your comments and thoughts. I feel pretty good with where I am at. I know the tweecing has just begun though!

BTW:
I just got a new pair of NGK o2s on ebay for 40 dollars shipped! :D whata steal those will be going on there soon!:SNSign:
 
A trick with the older cal-con was to after entering in manually (the only way to be sure is do it all manually) the number in the cell to use the arrow key to enter that cell. The only way it will change for some reason (again at least in the older versions of tweecer) was to key out just entering or clicking to the next cell with the touch pad or mouse did not work. The eec will make "slight" changes from time to time on the trasfer values as it has to do with the code but it should never be off TOO much. Like... .1-.3 or something diff. than you enter.

spark will bounce around and will prob. do that until you get into load

The K's not moving and the o2's not switching alot prob. means it did not get warmed up enough to start...it takes awhile. This is why you will see alot of people say drive around/idle for at least 20min before logging after resetting the batt./K's.
 
I did the same thing. I started my inital tweec by saving one of Caledit's ProM maf transfer then began datalogging (lots of them) and making changes suggested by EA. I got the idle solid by performing the steps suggested in EA. It took a little while but now the rewards are great. Now for the most part all I do is seasonal fan setting changes (i.e. winter, summer etc.):D

I have a buddy that contemplating getting a tweecer. He told me that the dyno guy wanted about $1k to do a custom tune with a switch chip.:eek: I've told him to research these tuning products, given him the websites, explain things to him, Hell I've done everything except pay for it and yet he has done no research except ask the same ?s. I think he's going to pay and complain later. Welp.
 
Update

I have cleaned up all the wiring to the o2 sensors. The wiring had been spliced and bare wiring was showing. I went a head and re did the splices nice and clean with heat shrink. I replaced the o2 sensors. Finally I fixed a some exhaust leaks.

All of these changes got my o2 sensor bouncing better. Also got the kamfrs moving. Idle is great now with those changes. I am just using the prom calibration in caledit.

Dont you love when people update there own posts!:SNSign: :lol: :nice:
 
Update

I have cleaned up all the wiring to the o2 sensors. The wiring had been spliced and bare wiring was showing. I went a head and re did the splices nice and clean with heat shrink. I replaced the o2 sensors. Finally I fixed a some exhaust leaks.

All of these changes got my o2 sensor bouncing better. Also got the kamfrs moving. Idle is great now with those changes. I am just using the prom calibration in caledit.

Dont you love when people update there own posts!:SNSign: :lol: :nice:

Great to see you are making progress :D

Things usually work better when you don't have issues like electrical connections, vacuum leaks, exhaust leaks, and other stuff like that.

If you tried to tune with stuff like that going on ................
It would just be a waste of your time.

Grady
 
ya I am considering getting EA. I am corresponding with Mike from the eec tuning forums who is running my data logs through EA. With the first run through EA is actually liking my setup right now. It has only minimally changed my injector slopes.

I need to find time to do some more data logging and make some more tweecs.