Edmunds Answers



  • zaken1 06/05/09 2:46 am PST

    If the information you posted about the difference in the fuel systems is correct; that means the information you posted about the 8th VIN character being the same is NOT correct. The 1996 Jimmy was only available with one engine. It had a W VIN code and had multipoint fuel injection. There was no throttle body injection engine available in 1996. But the 1993 Jimmy was available with two different engines; the W engine had multipoint fuel injection; and there also was a Z engine which had throttle body injection. So if one of your engines has throttle body injection; it is the 1993 engine that does; and that vehicle has a Z VIN code.

    The problem is that the 1996 engine has 4 valves per cylinder. But the 1993 engine only has 2 valves per cylinder. For that reason; the intakes couldn't just be switched. You would need to change the entire engine.

  • thewrench 06/05/09 8:19 pm PST

    In response to Zaken1, thank you for the info.
    I have both vehicles and they do each have a W in the 8th position of the VIN.

    The top ends do look different though - even the distributor is different.

    But - if both are W - will the swap work even though they appear different.............?

  • zaken1 06/05/09 10:40 pm PST

    No; even if the engines have the same type of injection systems; the 1996 engine has different heads. And that is why the parts cannot be interchanged.

  • thewrench 06/05/09 11:31 pm PST

    Sorry, I meant will a complete engine swap work? What difficulties can I expect: fuel, distributor, brackets, wiring, etc?

  • zaken1 06/06/09 1:03 am PST

    I hope you realize that it is illegal to install an older model engine in an emission controlled vehicle. The reason for this is that older models produce higher emission levels than newer models. What this means is that you could not pass a smog test; you could never sell the vehicle, or register it in another state; and you would be liable to be fined if the swap was ever discovered.

    On a complete engine swap; I expect the motor mounts will be the same, and the bell housing and transmission will probably bolt up OK. But the computers will be different; and the wiring harness plugs for the computer might or might not also be different. So you may need to swap out the underhood wiring harness; the under dash wiring harness; or possibly both. I don't know whether the exhaust system would bolt up to the heads. I also don't know whether the catalytic converter and oxygen sensors are the same. If those parts are different; you might need to change the whole exhaust system.

    The fuel pump pressure may be substantially diffferent between the two engines: the 1993 "W" engine used a CMFI injection system; but the 1996 "W" engine used a SFI injection system. You'll need to find out whether the fuel pumps put out different amounts of pressure on those two systems. If they are different; you'll need to change the pumps (and if the old style pump doesn't fit in the new gas tank; you'll also have to change gas tanks). I don't know whether the fuel return lines and vapor control system are the same; but I wouldn't be surprised if they are different. There are probably fuel tank pressure sensors on the '96 tank; which aren't on the '93 tank. I expect that the wiring setup which matches the '93 engine will not match the rest of the electrical system for the '96 vehicle. That will cause an unknown number of difficulties.

    The distributor shouldn't be a problem; since it will come with the engine, and you'll have to switch wiring harnesses anyway. I don't know whether the radiator hoses are in the same place on those engines; or whether the radiators are different.

    These are all things that could turn out to be huge headaches. There are few people who would be able to answer these questions in advance. So you'll probably have to sort it all out as you go. I'm just glad that I don't have to deal with this. It could become a terrible nightmare.


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