Hi guys,
I installed a ford 302 efi engine from a 1990 crown vic in a 74 F-250 using a Ron Francis wiring harness. The engine has been rebuilt and since it is a 25 year old set up all, (and I mean all) the sensors have been replaced as have the injectors, fuel pressure regulator, air bypass solenoid, coil, cap, rotor, plugs, and plug wires.
It runs rich and throws 42, 92, and 75 trouble codes, as there are no provisions for a brake on/off circuit I am wondering if the 75 code could be causing my 42 & 92 rich codes. I have been told that the 75 code will prevent the computer from going into closed loop operation and result in the engine running rich. Does anyone know if this is a valid argument; or know somewhere that will program this function out of the computer system?
It has a ECC-IV computer with a MAP sensor,(also new).
Thanks, I'm at my wits end trying to figure out the problem, the vacuum reading also seems low to me, fluctuating between 16 and 17 inches at idle.
Cylinder compression 165 lbs. or more on all cylinders and timing is correct.
Any help, insights, or suggestions will be greatly appreciated.
John

 

Did you make the mistake of replacing the original 14lb injectors with 19lb perhaps?

 

No, the replacement injectors are stock as is the camshaft.

 

Not sure if you've resolved your issue yet, but brake on/off should mean just tapping into the brake light switch and tying it into the right input on the pcm.

I'm in the middle of swapping a similar engine into my '87. Wiring up the newer pcm is proving to be a learning experience.

 

The problem is that I am using a Ron Francis wiring harness and there are no provisions for the BOO circuit.

 

Well that's not cool - especially for a commercial harness. I'm piecing one together from the factory harnesses and am trying to make it look as stock as possible.

Is there possibly an older pcm that doesn't require the BOO input? Still learning myself so it may be a rhetorical question.