Blk91stang said:
1) Yeah, this was BEFORE tuning.
2) I question why you ask about the 12:1 FMU as this plays NO role in startup and running, only under boost does the FMU restrict the return line to increase fuel pressure.
3) My name is Matt, not Tim.
4) Your correct, I don't know much about tuning. If I did I wouldn't have paid $700 to get my car properly setup. I wish I had your knowledge
.
5) Obviously your resume doesn't include driving a mild 302 with 42# injectors everyday so I think I'm in good shape here.
Pulled the chip, car still runs good. I think you need more knowledge about these cars before criticizing others. I only stated the injectors did not give me a problem and your panties got all in a twist.
Sorry for the hi-jack, as my opinion has already been stated.. just backing it up....again..
...and I think you should gain at least some clue of subject you're talking about before giving advise that is potentially harmful.
Being able to start a car and have it idle does not indicate that it runs correctly.
Running a 12:1 ratio FMU with 42lb injectors is insane, yet your post would have one believe that this is ok.
Very well, "I don't think so Matt."
If you know nothing about tuning then why would you even consider offering advise on the subject? The 20% that I mentioned above (+/- %5) is an actuality. Not something pulled out of the air. There are several things regarding the electronic tuning of an EEC IV that need to be considered when swapping out injectors including but no limited to: Battery Voltage vs. Injector Breakpoint, Injector offset, Open vs. closed loop Pulsewidth, Cranking pulswidth, and high and low injector slopes for the size injector being used. The adaptive control in an EEC IV is very limited in what it can do on it's own. Just starting a car and idling with a set of 42 lb injectors can put you BEYOND the adaptive control's ability to trim fuel (it's outside the before mentioned 20%). As RPM and injector demand rise, so do the differences between amount of fuel that the EEC "thinks" it's sending and the amount of fuel that is actually being delivered. The Mustang EECIV was programmed with fuel tables specifically designed to run a 19 lb injector (with the exception of the 93Cobra). The reason that that is significant is let's say for instance:
At full load and 3/4 throttle, the EEC tells the injector to pulse 10 times for each and every stroke. Now remove the 19s and install a significantly larger injector in it's place. The EEC doesn't know the difference so it pulses the same and dump a LOT more fuel than it's aware of.
Take the same scenario at 4600 RPM and assume the pulsewidths is twice that. The differences between the two injectors in volume of fuel delivered has increased even more! Maybe at 2300 we delivered twice as much fuel... but at 4600... now we're dumping 4 times that fuel or even more depending on what the differences are between the those two injectors. In this case we're talking about a difference of around 202% in the amount of fuel a 42lb injector is capable of delivering when compared to a 19.
Having a meter calibrated do coincide with a fuel injector is a neat trick! It works great in a great many circumstances. Unfortunately it won't compensate for injectors that are 36, 42, or larger without additional tuning. The differences in the scalers that I mention above grow wider and wider the further up the RPM that you go.
Most of your attempt at post bashing so far has been pretty senseless. If your car ran so great, why the $700 for a tune? You must have just had it burning a hole in your pocket.
And you're right, if you knew what it took to tune, you'd likely not have had to spend that kind of dough to make it run correctly although I've got no gripes about custom chips whatsoever. It's the right way to tune EEC fuel injection along with some of the many user programmable units that are available (some of which I mentioned above).
You're apparently under the false impression that you're the first person to run 42s in a 302. LOL Good call. Go back and reread the entire thread, do a little homework, then come back and tell me what part of my posts were incorrect.
Here's a good place for you to start:
http://fordfuelinjection.com/files/EECIV_Inner_Workings.pdf
It's apparent that you took my first post as an attack instead of an effort to give some clarity to the original poster. Regardless, it's still correct.
