Ford Muscle Cars Tech Forum banner

1 - 4 of 4 Posts

·
Registered
Joined
·
8 Posts
Discussion Starter #1
So I'll start with my setup:
1974 F100 390 bored .030 over, alum heads with the mass-flo EFI system. The EFI system to my understanding consist of a Mass-air meter has been calibrated by Mass-flo for 30 pound injectors, they're using all sensors including the A9L computer from an 89 5.0 mustang with the exception of the mass-air meter which is off an 02 LS6 vett, the LS6 meter use frequency and the A9L wants voltage so a special converter cable is also required . My issue is this sensor cost @ $500 to replace it from Mass-flo, which is also the sole supplier for it the frequency to voltage is also strange, all in the name of using a 14" air cleaner that I don't care to use.


So here's my question; I want to replace the LS6 meter with a normal Ford meter that will work off the part store shelf and not break the bank if I need to replace it.
What meter can I use and do I need to replace the chip in the computer and get it dyno tuned?
 

·
Premium Member
Joined
·
3,801 Posts
Good question, how easily it can be done though is a bit "it depends"

Your Mass-flo EFI uses a rider chip to essentially change 3 things. There is more the CAN change, but that is about all they change to make it work, and work pretty well

- firing order
- MAF curve
- injector characterisitics

The firing order isn't important as a 390 and 302 are the same, and moreover even if it was on a 351 or a 351 cam it would just really matter at idle and not that much

However, the injector programming is different for your bigger injectors. If it wasn't you could just pull the massflo chip and run a 93 Mustang MAF without the adapter using stock Ford settings.

However if you do that the injector files are wrong

What I did was swap to a Moates Quarterhorse chip, reprogrammed it far more than Mass-flos less comprehensive change by shutting down a lot of options, mostly emissions related and tweaking the myriad of things that you can in an A9L and eventually changed to a blade type late model Ford to allow more airflow than the tiny 82mm Mass flo sensor has. My motor breathes pretty deeply, so having the big MAF setup really helped it up top

It also allowed me to tweak injector slopes, O2 sensor delay, and most important IMHO is change injector timing to match my cam events along with the timing curve, which made more power everywhere and mellowed the idle like I changed the cam

My 489 EFI runs great now but it ended up adding about 1000 in parts and a good summer of tuning and tweaking.
 

·
Registered
Joined
·
8 Posts
Discussion Starter #3
That's great info, I think what I should do then is to save up, take it to a good dyno-tuner and get it all dialed in with a bigger MAF and a cold-air intake. There's some cool looking ones made by Spectre that I think would adapt to the throttle body.

Awesome that you have everything running great on your 427! Nice car too by the way!

Thanks again.
 

·
Registered
Joined
·
10,299 Posts
Agreed with all that. The Mass-Air setup is for folks that just want a "drop-in" system. It's a convenience package. The other up-side to tuning your system with up-rated parts, is you get the tune (or the tuner holds it for you), and if there are any issues, you can get a $50 ECM from the wrecker and re-flash it for your car in 10 minutes. It's also far preferable to using a calibrated MAF, which only tricks the stock-tune ECM into thinking it still has little injectors. Silly rabbit - tricks are for kids. ;)

David

 
1 - 4 of 4 Posts
Top