Am I crazy or do Ford ECMs learn with out much programing envoled vs GM ECMs talking late 80s early 90s models. I all my friends that slap heads, cam and injectors and what not on there mustangs seem to never have to go out and reburn there chips and get pretty big HP/Tq gains at the dyno/track. Trust me i know how important it is to always tune a chip when slapping parts on, But i'm just trying to figure out what it is that makes it easy for part swaps with out burning chips on a ford? is it the Ford MAF sensor technology that can self adjust to all most all mods people do?

 

For the most part, MAF is independant of the engine as it only measures the airflow entering the motor. Thats one of the reasonts that it was so popular. With speed density, the actual airflow isnt known. Its calculated from the engines displacement, volumetric efficiency, and from the manifold pressure present, all of which are dependant on the engine. Because of this, with speed density, you must recalibrate the ecm whenever changes are made to the engine. Even with MAF there are things youll want to change with a new combo, but with speed density itll be manditory that changes to the tune are made, or the fueling will be off.

 

As a side note, alot of people have done the same with GM MAF systems. There are limitations with a stock GM MAF system, though, since there are things like the MAF itself, the 255 gms/sec limit, the use of only an 8 bit ADC input, etc. The stock SD ecms are better overall.

 

Just a matter of what you're willing to settle for.

Once your at WOT, there's not much really going on, so close can work OK. But, if you're into having really nice driviblity, easy to use diagnostics, and availaility, then GM beats Ford hands down, IMO.

I haven't heard any real great reviews about a Ford system running well in constant open loop. If you have alot of learn capacity, or should I say, allow for huge corrections, then you can get any system close enough to keep folks happy.

If you want to setup a GM ecm to be really good at *self-learning*
set the BLs/ Int/ limits extremely high/ low, run alot of timing, and allow for alot of timing retard, and you're *there*. Not that I'd recommend doing that. Judging by the number of Fords that have split the V in half, one would wonder, if some of that easy tuning (no compenstation) for tip-in preignition, or pure preignition might not be helping them with that problem.

 

Well said. It is all about drivability. Yeah, MAF will correct on it's own up to a certain point. The real thing is this......if you think that the ECM is a good design (some Ford people) then there is no reason to get engine data and find that it is running very non-optimal. GM guys ?know? the chip needs to be tuned and grab some ALDL data and tune. A lot of GM MAF guys don't tune because it ?runs good?. If they got some ALDL data, then they would be tuning also. Ignorance is bliss, that is what you get with a MAF setup. Not that that is a bad thing. I have a MAF rig and I think it runs OK with mild mods and no tuning. Not as good as my MAP rig did with A LOT of tuning, but still very good.
Look at Mike Davis' website for a small amount of real world MAF vs. MAP elapsed times in the quarter. Keep in mind the ET and how much cushion there is in ETs of that range.

What is the max. flow of a Ford MAF anyway? Is it blind at WOT with major engine mods? If it is then it is just alpha-N at WOT.

 

Grumpy that makes a lotta sence. Very cool about the self learning not that I'd wanta risk it to much I rather not be so dependent on a couple sensors that at any moment could die and risk blowing the motor. So fords are a little wider band for self learning is that what it is? Not like i'm gonna go out buy a ford. My 88 vette has rolled by late 90's Cobra's haha and she's pretty much stock.

On a different note. This ECM bin programming is great. I'd say I'm ok/pretty good at tuning my eprom. But is there a manual or a book with what all everything does. I do understand what every thing does but i rather have it in detail and what they coninside with. I mean i can jump on here and search for it but i rather get the book and just read about it. because I always have to many questions.

anyone out there no where i can get one? or is it a sercret GM thing?

 

Yeah I'm all about SD. It's a little more complex via the chip but it's a much better tune when flowing more air into the motor.

 

I like the Lt1 pcm's best. They use MAF and SD which makes me a very happy person.
I've plotted out the MAF vs MAP vs RPM in a 3D point surface plot... you wouldn't know the difference between running one or the other so long as the transients are covered well in both cases.
The Ford ecm's never really impressed me for the simple fact that they need so much more effort to get tuned. The add on modules, the different processors, the lack of datalogging. Most Ford owners think tuning is getting the MAF recalibrated and adding some kind of MAF translater to richen/lean out the WOT runs. For them, that's it, no datalogging, nothin but the human senses. I like as much sensory imput as possible and GM's do this best. I can use my nose, eyes, butt, AND data from the computer to come to conclusions.
I also like how GM handles decel better. Not as much wasted fuel with the DE and DFCO where as Ford allows the exhaust backfires.

 

Tuning, and especially tuning EFI, is more art, then mechanical.

You can read, and read, and read, and read, and then go out to the car and not have much of it make sense. Yes, you can pick up the very basics by reading, but there's no amount of reading that you can do that'll tell you how you're buttometer is going to interupt things. That's why I harp on good note taking, and doing alot of experimenting.

Ask Roush, or Yates about how long it took them to read a spark plug......
Like I said, tuning is an Art Form, supported by knowing the mechanics of what you're working on.

 

I hear yah about it being art work. I've been on it for about 3 years so far. each time i burn i learn something new.