whh333

I have had a time installing a 2001 IS300 engine into my 1999 GS300. I had been told it was a direct swap, but had to change out the transmission and wiring harness. The IS300 exhaust manifold is tighter but seems to be the same mating to the GS300 pipes. It seems the motor mount assemblies are at the same location, but look slightly different, so.....

Does anyone know if the motor mounting is different? Do I have to change out the motor mount frames?

Thanks for any ideas.

whh333

TW99GS300

The harness from the GS300 should plug right into the IS300 motor.
All sensors are the same on the 2JZGE, Same A650E auto trans.
Just use the old GS300 motor mount.

whh333

Thanks for your reply!

I had already switched the harness because the harness connectors seem to be the same except the IS300 engine harness did not have two plugs that go into two colored plastic holders that do not seem to hook to anything and a small black box that goes on the side of the engine bay marked "DIAG". The rest of the plugs seemed to be the same.

I posted about this a couple of weeks ago and was advised to change the harness, which seemed the safest way to proceed.

Even with these differences, does it seem the IS300 harness should have worked? If so, then I will save it, because it does not have nearly the miles on it that the GS300 harness has.

Thanks for any ideas.

P.S. I micrometered the heck out of the motor mounts on the two engines and could find no difference in the geometries--same distances, same angles, everything. I installed the engine and it fit fine. I have not run it yet, so there may still be problems, but I just cannot find any so far.

Thanks again!

TW99GS300

I just recently rerouted my harness. IIRC those color plugs are common ground and positive signals. I would keep those but just my $0.02. If anything, remove the clips that are broken from the GS harness with good ones from the IS. I'd advise cut, solder and heat shrink. Trying to de-pin and repin will cause them to break.

whh333

That was my concern, the IS300 harness is lacking the two plugs that go in the colored holders (even though they do not seem to hook to anything) and the black plastic box marked "DIAG" that clips to the body near the engine computer. Even though these did not seem to hook to anything and there seemed a possibility that everything else would work, it seemed risky to install the engine with such a different harness. The archives have at least one instance of implying that this harness would have worked, though.

I would appreciate knowing if this had been tried by anybody.

I agree with you about the broken clips. I had to replace two of the coil connectors and tie wrap a couple of the other engine connectors.

Might get to the point of starting it today, will keep my fingers crossed it works.

Many thanks.