2002 Ford Mondeo Engine

There can be insurmountable differences from one year to the next, and with four years difference, it is almost a sure thing, but it depends what those are. All cars went through big changes from '95 to '96 models. Other than that, common changes include the number and spacing of ignition timing cutouts in the flex plates, (this is a big cause of no-starts when using a '97 flex plate on a '98 truck), location of sensors, even the angle of injectors. You can be sure some sensors will be different, so the wiring harnesses will be different as well as the Engine Computers.

There will be mechanical changes too. The locations of exhaust manifold bolts, pipe outlets radiator hose locations and diameters, the location of the AC compressor and power steering pump can be different requiring different hoses. The shape of the camshaft lobes changes often to fine tune specific characteristics of engine performance under various conditions. Using the wrong camshaft can cause minor irritations like hesitations and sputtering to excessive emissions and failure to pass emissions tests.

You have to know what the differences are to figure out if you can work around them. I use the Rock Auto web site a lot for reference. You can look up a part for the '02 model and the '05 model. If they show the same part number, you'll know they're the same for both years. If the part numbers are different, you'll know they're different, but you won't know why unless you can tell from the pictures.

I would look up the injectors to see if both engines call for the same part numbers. The Engine Computer looks at the resistance of the magnetic coil in each one, and thereby, the current flow, and it looks at the voltage spike, or "kick" that they develop when they are turned off, to measure how they're working and if they're opening at the right time. There can be very subtle differences that cause them to work properly and flow fuel correctly, but still trigger a fault code. In that case you don't have to replace the engine. Reinstall the old injectors from the old engine.

You also have to look at the signal that triggers the firing of the injectors. Usually that's the camshaft position sensor, but if it's the crankshaft position sensor, that's where those notches in the flex plate are often different between years. Those that trigger off the vibration damper can be different too.

Also, don't assume the injectors are okay just because they're new. As one corporate trainer used to say, "We not only sell you new parts, we sell them to you pre-broken"! Switch injector number one with one of the other ones, erase the fault code, then see if the code sets for cylinder one again or the cylinder you moved that injector to.

Keep me up to date. I had a house fire so I have to drive into town to sit in the library or a hospital cafeteria with wireless internet, and I don't always make it every day. I will be back though to see how you're doing.