Rumblefrog

Will the stock ECU (from an '89 Mustang GT) properly adapt to upgrades? For instance, if the stock 19 lb/hr injectors are swapped-out to 24 lb/hr injectors and the Mass Air meter is upgraded to a 70 mm, 24 lb/hr calibrated unit, will the ECU properly control the air fuel mixture?

enix187

Yes, for the particular thing you just mentioned its called tricking the ECU, bigger injectors + bigger vam and the stock fuel maps will compensate just fine, with that setup the ecu still thinks its running stock parts, but those two mods aren't necessary until heads/cam/intake install, and they aren't necessary until the car is running properly. Most drivability/running problems that a car exhibits after modifications like that are due to a car that ran poorly before.

To answer your question though, the A9L computer is a great piece of equipment that can compensate for a lot, its the rest of the car (fuel/exhaust and such)

Rumblefrog

I'm running 24 lb/hr injectors, a BBK 70mm meter calibrated for 24 lb/hr injectors, GT-40 intake, AFR 165 heads, E303 cam, 1.7 roller rockers. My engine runs well but runs extremely rich as indicated by the eye-watering exhaust, gummy build-up on my valves and lots of soot on top of my pistons.

This is all in a '74 Bronco. I had the harness and computer married to the Bronco by someone else, and I've never been quite certain that it was done right (It all came out of an '89 Mustang GT). I just discovered that RJM makes a retrofit harness for the early Bronco, and it looks quite easy to install, but I don't want to bother if the "stock" ECM can't operate these upgrades properly. I'm considering changing to the FAST fuel injection Multiport retrofit system (uses my existing intake, injectors and fuel rail). However, I'd rather stay with the Ford system if it will run properly with my upgrades.

Thoughts?

AdderMk2

just go get it tuned.... duh

mjr46

before such is done...one should always make sure the car is running properly, meaning no efi management issues as a result of misinstallation or improper install of parts and or faulty components, a tune will only mask an underlying issue....OP, FIRST RUN A KOER TEST AND CHECK FOR CODES....i ASSUME YOU ARE RUNNING OS SENSORS ON THE VEHICLE??? AND Fuel pressure is properly set???