Quote:
Originally posted by QuantumMotorsports
Listen man, if you're so smart, think about it, one of two things is happening when people swap HO computers and injectors onto the harnesses in the 80s cougars.
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First off, he never said where the non HO was from.
Quote:
Originally posted by QuantumMotorsports
1. The motor ends up MFI or batch fired as you call it, and each bank is fired by one of the pins on the computer which is used to fire one of the HO's individual injectors. So the fuel sits in the intake port for a fraction of a second before the valve opens and draws it into the cylinder. There is the same amount of fuel being delivered as in the sequentially fired HO engine, so if you think it would run rich just because the fuel would sit in the port for a little longer, you're wrong, because it does that in the MFI setup too. The reason they have 14# injectors instead of 19# is because the upper intake is different, the throttle body is smaller, the cam is a lot different, the heads are different. They all flow less air which means less fuel is needed. The 14# injectors are not because it is batch fired.
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Wrong. It would make a huge difference. That's why the batch fired systems work the way they do. If what you're suggesting would work smoothly, don't you think they would have done that? That's why I said you should write a book; you've figured something out that they couldn't. As far as the injector size, I've got a '95 4.9L that is batch fired, and it has 14 pound injectors. My buddy in Valencia has a '96 with Sequentially fired injectors, and he has 19 pounders. His cam and intake are identical to mine. Under the same pressure, a larger injector will flow more fuel with the same pulsewidth. Since the injectors are only being pulsed once every 4 strokes, versus once every other stroke, the injector size was increased. If they simply changed the pulsewidth, they would run into problems at higher rpms.
Quote:
Originally posted by QuantumMotorsports
2. It is possible that the diagram you have is for certain non HO engines and that the cougar's non HO engine harness is sequentially fired. This is probably the case, because the intake plate on top of the intake says "Ford 5.0 - SEFI" which stands for Sequential Electronic Fuel Injection. This is probably what is going on. The harnesses on cougars, t-birds, and probably crown victorias from 1986 up to 1994 which is when they started putting the 4.6 into cougars and t-birds, were all SEFI. I donno what engine that diagram is from but all of the non HO engines that I know of (are they used on another vehicle?) are SEFI.
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All of the 5.0's used in Ford trucks and vans were non HO until '93. Every single one was batch fired. After '93, they were HO engines, complete with SEFI. The Crown Vics used everything. Even the police Crown Vics through '91 still had carbs, and didn't use any fuel injection. There were many possible combinations a person could come across, but the best plan for converting a non HO to an HO is to replace the ECM, the injectors, and the harness.