My engine idles rich, yet the plugs show lean. I’ve been reading extensively no one article seems to cover everything. Here is what I think I know.
- 1989 5.0 motor.
- Used GT40 intake and heads from an explorer.
- The heads are ported. Upgraded springs and a mild cam for torque.
- The MAF housing is from a 93 fox body. It is 70mm.
- I am using the 94-95 MAF sensor which I understand to be comparable with 19lb injectors. The part number is F2VF-12B579-A2A
- The intake is 65mm from the explorer.
- I retained the 19lb injectors. I don’t believe I am hitting horsepower issues.
- I am using the plugs and coil for 93 GT.
- the computer is the A9L, which was used through 93.
This motor is in a 1975 Bronco. So not all sensors are utilized, but I have done what I can.
Basically the truck idles very rich. After a 9 hour drive it was running poorly so I changed the cap and rotor, cleaned the MAF with MAF cleaner, and changed the plugs. A man who knows 5.0 said the plugs showed signs of running lean. I also know my gas mileage is suffering. I did unplug the computer for 30 minutes or more to reset the computer after changing the plugs and coil.
So logic is, A9L is looking for 19lb injectors data and other components of that period, cap, rotor, plugs, coil, and MAF for 19lbs.
I haven’t checked my timing yet, or pulled OBD 1 data, but that will follow. I understand 12-14 degrees is the target, and to back off a few degrees if things are running lean.
So at idle I’m rich, and 3,000 rpm I’m lean. Anything I should revisit here? I also sprayed around the intake looking for vacuum leaks, but nothing.
Thank you for your help. I don’t want to upgrade to 24lb injectors as I think that requires the injectors, special adapters. Another computer, and a different MAF. I’m close, runs ok, but not quite there. Also seems a bit flat on power on long grades upwards. Hard to hold speed without giving a lot of gas.
- 1989 5.0 motor.
- Used GT40 intake and heads from an explorer.
- The heads are ported. Upgraded springs and a mild cam for torque.
- The MAF housing is from a 93 fox body. It is 70mm.
- I am using the 94-95 MAF sensor which I understand to be comparable with 19lb injectors. The part number is F2VF-12B579-A2A
- The intake is 65mm from the explorer.
- I retained the 19lb injectors. I don’t believe I am hitting horsepower issues.
- I am using the plugs and coil for 93 GT.
- the computer is the A9L, which was used through 93.
This motor is in a 1975 Bronco. So not all sensors are utilized, but I have done what I can.
Basically the truck idles very rich. After a 9 hour drive it was running poorly so I changed the cap and rotor, cleaned the MAF with MAF cleaner, and changed the plugs. A man who knows 5.0 said the plugs showed signs of running lean. I also know my gas mileage is suffering. I did unplug the computer for 30 minutes or more to reset the computer after changing the plugs and coil.
So logic is, A9L is looking for 19lb injectors data and other components of that period, cap, rotor, plugs, coil, and MAF for 19lbs.
I haven’t checked my timing yet, or pulled OBD 1 data, but that will follow. I understand 12-14 degrees is the target, and to back off a few degrees if things are running lean.
So at idle I’m rich, and 3,000 rpm I’m lean. Anything I should revisit here? I also sprayed around the intake looking for vacuum leaks, but nothing.
Thank you for your help. I don’t want to upgrade to 24lb injectors as I think that requires the injectors, special adapters. Another computer, and a different MAF. I’m close, runs ok, but not quite there. Also seems a bit flat on power on long grades upwards. Hard to hold speed without giving a lot of gas.