Fuel injector parameter changes not giving expected results on speed density

352Ford · 10-01-2007, 11:18 PM

I am trying to tune a speed density 1988 mustang.

The engine is a very basic rebuilt 9.6:1 302 (306) with gt-40 heads, pro products intake, 70mm TB and 24lb injectors.

In my mind the only things that I should really need to get changed to get the thing running pretty well (at least in the ball park) is the injector parameters (high slope, low slope, breakpoint, min PW, and injector offset vs batt voltage)

Well changing these parameters to the following doesn’t seem to change a thing (running pig rich at idle/unloaded)

High slope: 24.5
Low slope: 30.5
Breakpoint: 1.925
Injector offset (both stock and modified)

Even when I changed the low slope to 40 and then 50, it didn’t do a lick of good.

I even put everything back to stock settings and changed the engine displacement scalar from 1.5236 to 0.092783 (19/24= .7966; .79166*5.0=3.9583; and 3.9583*.02344=.092783) thinking that it was a load/VE issue relating to the whole SD thing with no change.

If the Data logger was not working I would be pretty convinced the tweecer isn’t working at all, but it is so alas…

Any ideas why these drastic changes do nothing and any ideas of what to change to get results?

I don’t seem to have a min PW scalar or function; do you think that could be it?

Thanks guys

Hillbastard · 08-21-2008, 06:58 PM

Sounds like the changes are not taking, you should see change with putting in 50 for injector slopes, big change, so I would try to troubleshoot your file saving\uploading procedure.
The best Teecer site on the web is EECTuning.org, but it is mostly mass air specific, but they should be able to help you.
I read all I could find on the DA1 tuning possibilities which isn't much, at least in layman's terms anyway, but have yet to tune one or any ECU strategy for that mater so I am of little help but admire your unconventional setup, stick to it, everyone will tell you to go mass air but if it is not a challenge it's not worth doing.
From what I can gather all the methods used by mass air tuners (for the most part) are applicable to speed density just think VE table in place of mass air meter transfer function.

Hillbastard · 08-21-2008, 07:00 PM

Just noticed the date on this, hope the dude is still alive.

10-01-2007, 11:18 PM	#1 (permalink)
352Ford I make my own Join Date: Aug 2007 Location: Seattle, WA Posts: 2 View this user's gallery iTrader: 0 / 0%	Fuel injector parameter changes not giving expected results on speed density I am trying to tune a speed density 1988 mustang. The engine is a very basic rebuilt 9.6:1 302 (306) with gt-40 heads, pro products intake, 70mm TB and 24lb injectors. In my mind the only things that I should really need to get changed to get the thing running pretty well (at least in the ball park) is the injector parameters (high slope, low slope, breakpoint, min PW, and injector offset vs batt voltage) Well changing these parameters to the following doesn’t seem to change a thing (running pig rich at idle/unloaded) High slope: 24.5 Low slope: 30.5 Breakpoint: 1.925 Injector offset (both stock and modified) Even when I changed the low slope to 40 and then 50, it didn’t do a lick of good. I even put everything back to stock settings and changed the engine displacement scalar from 1.5236 to 0.092783 (19/24= .7966; .791665.0=3.9583; and 3.9583.02344=.092783) thinking that it was a load/VE issue relating to the whole SD thing with no change. If the Data logger was not working I would be pretty convinced the tweecer isn’t working at all, but it is so alas… Any ideas why these drastic changes do nothing and any ideas of what to change to get results? I don’t seem to have a min PW scalar or function; do you think that could be it? Thanks guys

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08-21-2008, 06:58 PM	#2 (permalink)
Hillbastard Registered User Join Date: Dec 2007 Posts: 2 View this user's gallery iTrader: 0 / 0%	Sounds like the changes are not taking, you should see change with putting in 50 for injector slopes, big change, so I would try to troubleshoot your file saving\uploading procedure. The best Teecer site on the web is EECTuning.org, but it is mostly mass air specific, but they should be able to help you. I read all I could find on the DA1 tuning possibilities which isn't much, at least in layman's terms anyway, but have yet to tune one or any ECU strategy for that mater so I am of little help but admire your unconventional setup, stick to it, everyone will tell you to go mass air but if it is not a challenge it's not worth doing. From what I can gather all the methods used by mass air tuners (for the most part) are applicable to speed density just think VE table in place of mass air meter transfer function.

08-21-2008, 07:00 PM	#3 (permalink)
Hillbastard Registered User Join Date: Dec 2007 Posts: 2 View this user's gallery iTrader: 0 / 0%	Just noticed the date on this, hope the dude is still alive.