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Discussion Starter #1
Since the EEC Tech Forum is back I wanted to see who has one. I'm having some problems getting the engine to idle at 800 rpm. No matter what I try it stays between 1,000-1,100 rpm.
 

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I had one of the TwEECer test boards for awhile (now run the PMS). Sounds like your TPS is just a tad high. If you have the TwEECer R/T then it will show your TPS voltage readings...make sure it is below 1.00 volts. When you type in the rpm number you want, say 850, how much does the TwEECer correct for? What I mean is...after you click Refresh...how far from 850 did the TwEECer accept?

Troy
 

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As troy mentioned, check your TPS, but also check your throttle plate stop screw. If the throttle plate is opened too much then the ISC may not be able to adjust the idle any lower than it already is. If your TPS is above 1v and your stop screw is adjusted in too far, backing it out will lower your TPS. Adjust it with the ISC disconnected.
 

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Hey Mike G.!!! Figured you'd be back here since the EEC Tech forum has returned. How's everything in TwEECer land? Hopefully all good. Catch ya around.

Troy
 

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I run a eec tuner in my POS
It took me over a year and 2 engines to figure it out but
i got mine working prety well now. It idles like a baby even with 96lb injevtors and a 75Lb MAF.

With a lot of mods means lots more airflow at idle. There is one tag..Desired idle airflow. One of the ways to fix your idle is to make sure the maf voltage in that tag is close to what you really see at idle. Changing that helped my idle problems out along with maf tweaking.

good luck
 

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Discussion Starter #6
The TPS voltage is steady at 0.94v. I've tried the stock A9L settings and it still idles steady at 1-1.1k. The wide band shows the AFR at idle is high at around 18-19. Would running that lean cause a high idle? Under light loads the overall AFR is lean but under high loads it falls to the 11-12 range. Aside from the idle the car runs very well. I know I need to tweak the AFR for light loads but I figured it best to start by solving the idle problem and then move on to other things. I'll check the throttle stop screw.

As for getting the MAF reading right is it better to read the wide band and adjust the lower voltage numbers until the AFR reads close to 14.7? I guess it's a trial and error process? Do I have to clear the computer KAM every time I change the MAF values?
 

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High idle AFR

I have found that a high AFR can be caused by an 'air leak'. In my case the idle fuel trim was showing up as 20%, not enough to turn the MIL on and idle RPM was about 100 RPM higher that what I had set in the Tuner. Poking around looking for the leak I found that the PCV valve had poped out of its grommet. Unmetered air was being drawn in through the floating PCV across the heads and into the intake tube. So the 'intake leak' was realy an 'intake tube leak' around the MAF. I guess with an AutoTap I could have checked the TPS voltage ( which would have been OK ) but it should have flunked the IAC valve duty cycle test ( should be around 40% all accesories off )
Plugged back in the PCV and watched the STFT tick its way back down to 2% in about 15 seconds.
 

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MAF Tweaking

A MAF is supposedly callibrated using a cone on a testbench and as such does not account for the airbox and associated plumbing.
An attemp should be made at callibrating the MAF on the car using a dyno after doing a curve fit on the MAF callibration data and loading that into the Tuner. Shutting adaptive off and setting the OL fuel tables to an safe AFR of say around 12 and stock spark setting try to do a dyno run while watching the wideband like a hawk and listening for detonation. A plot of RPM and AFR will indicate how far you are away from an AFR of 12. Pick a number of points, compute how far you are away % and adjust the MAF voltage or air flow by that %. Smooth out the MAF transfer function with a curve fitter or the GUI plot. Do not worry about the 14.7 the adaptive will take care of that.
Switch back to the stock OL fuel table and make changes to the high load/speed areas as you wish. Adjust the open loop load table.
For the low areas of the MAF curve I use the fuel trim numbers I get with an AutoTap log after clearing the KAM.
My $0.05 worth on tuning a MAF.
QUOTE
As for getting the MAF reading right is it better to read the wide band and adjust the lower voltage numbers until the AFR reads close to 14.7? I guess it's a trial and error process? Do I have to clear the computer KAM every time I change the MAF values? [/B][/QUOTE]
 

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HI guys--I am considering gettin a tweecer. What is your overall opinion of them. Its this or a custom chip
 

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I tuned WOT via WB and idle/low throttle settings via KAM readings. You do have to "reboot" in order to clear old memory when doing this. I found I didn't have to for the quick WOT changes though.
 

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I have a question regarding the use of my tweecer. I have written the A3M bin file to my tweecer. Stop me if Im wrong--It seems like I can make adjustments to whatever I want---hit WRITE and then the tweecer is rewritten correct? Then I just plug that baby into the ecm and it will then run on that program correct?

What would happen if you took a tweecer right out of the box and didnt write your stock bin to it and plugged it into the ecm?

The guy I bought the tweecer from spaced sending me the five position switch so I want to change my timing before that gets here. Is what I described above the correct way to do it?
 

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Ive got an eec tuner on my own car, my fathers procharged '95(previously tuned with new engine in progress) and i have honours on our TT 302 hybrid project(in progress). I anticipating that the turbo car is gonna be a little tricky...
I am also an eec tuner dealer.
 

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slowblown5.0 said:
I have a question regarding the use of my tweecer. I have written the A3M bin file to my tweecer. Stop me if Im wrong--It seems like I can make adjustments to whatever I want---hit WRITE and then the tweecer is rewritten correct? Then I just plug that baby into the ecm and it will then run on that program correct?
Absolutely correct. This is the normal usage of the tweecer, the only suggestion I make is that you save (Write Changes) your changes to disk now and then so you do not have to re-edit your binary if you loose it or overwrite with a not so good tune.


What would happen if you took a tweecer right out of the box and didnt write your stock bin to it and plugged it into the ecm?
I test each unit on an EEC and depending on which one I have on my test bench at the time, it could have any number of different binaries in the default position -- the othe 3 custom positions will be blank. Either way, if it does not match your processor family, the fuel pump will run continuously and the car will not run.


The guy I bought the tweecer from spaced sending me the five position switch so I want to change my timing before that gets here. Is what I described above the correct way to do it?
Yes, that will work fine, you will be writing to the 1st custom position everytime until you get the switch.
 

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Hey Mike, hows that '03 Cobra file coming? Hows the backorder list? I will definately need one, so if the list is growing, i'll give you a call with the specifics and get the ball rolling. I chatted with you about a month ago for a customer of mine...you probably dont remember. Im sure you chat with a ton of people.
 

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hey mike you are everywhere---thank god!!

Ok--how much total timing do you recommend on a stock motor with 5-6 psi? I just bumped my timing up to 12 btdc. I am now getting hard ping under pretty hard accel at around 3k RPM. I adj. the WOT spark advance vs. rpm but of course I havent even floored it yet--dont dare. I also took about 1' out for every psi in the spark table base. I believe the spark table base numbers include base timing. I will be able to data log tom. with my friends laptop to see what kind of load I am at when the detonation begins. This will be a big help.

Original q--how much total timing do you recommend for a 5-6 psi car. I will soon be going to 8-9.

Tweecer seems like it will go it to port in either direction. I faced the cable connection ports toward the rear of car as it would be acc. with a lap top. Oh ya---do you cut the plastic holder for the ecm so the tweecer will fit up in there?
 
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