Hey Guys,

I have successfully accomplished a 2JZ-GTE swap on my '02 Lexus GS300 but am facing an issue with the wiring.
So I managed to get the engine swapped at a local garage here and everything went well except for 2 issues related to the electrical's.

1. Engine Coolant Temp Gauge - The electrician is not being able to get the Temp Gauge to work. I've shown the car to 3 different electricians and all say the same. One offered to hard wire the Sensor to an external gauge which I would have to mount in the car. Is there any other option I can do to avoid external gauges?

2. A/C Temp Relay S/W - I didn't really understand the issue but from what I have understood is once the compressor goes on it won't go off till i switch of the A/C, which I've been told is not good for the compressor in the long run. Is there any way to sort this issue.

Any help from you guys would be really helpful as I am really looking forward to driving a 2JZ-GTE.

 

Moving your post to the Lexus GS300 1998-2005 Build Threads sub-forum

Others more familiar with GS's will be able to answer your questions with more expertise and direct experience but from what I do know concerning 2JZ-GTE swaps including those using Aristo engine sets:

1) At least as this applies to swaps into SC's the main issue here relates to having a proper ground for the dash instrument cluster coolant temp sender. The 2JZ-GE and 2JZ-GTE use different values and unless I am incorrect the JDM 2JZ-GTE's and USDM/UK/EURO/EXPORT 2JZ-GTE's use different cluster coolant temp senders... even though all 2JZ-GTE's have two coolant temp sensors on the engine's upper bypass elbow: one two-wire type for the ECU and a one-wire type for the dash gauge.

With an EXPORT 2JZ-GTE swap's wiring on an SC300/400 the options are to wire in a 330-ohm resistor in-line on that sender's circuit but when I did this specific swap (with a 1993 SC300) I did not have to wire in the 330-ohm resistor even though I was warned that I would probably need to. I can't explain why it worked in my case but my factory SC300 cluster coolant gauge works as it should.

...However that being said it's only as accurate as it was before which is to say that it's good for noting cold startup to "normal" operating temperature and it's good to tell when you're in danger of an overheat condition but it will not tell you an accurate moment-by-moment reading of engine temperature... and it never did with the stock engine anyway.

For my car (again, an SC300) I got both the dash engine temp gauge working and I also bought a classic style 52mm VDO Vision Black coolant temperature gauge that I installed in a little aftermarket panel (3D printed by the AutoExtrude company) where my center console's ashtray and DC port used to be (I installed a DC port elsewhere in the console). For the VDO temp gauge signal I used a Mishimoto aluminum in-line coupler with a 1/8" NPT thread for the sender and installed this in the middle of the upper coolant hose with water flowing directly from the engine into the radiator's top section. The signal wire goes into my cabin and since that aluminum coupler can't provide a ground connection I ran a ring terminal with a separate ground wire to one of the standard engine bay grounding points to complete the circuit.

You can use any matched gauge and sender option you wish for of course to have this added monitoring feature in addition to your standard instrument cluster engine temp gauge. As for mounting any additional gauge I do like the quality of AutoExtrude's products and they do offer a twin 52mm pod and 60mm twin pod gauge holder for GS300's. I am not sure what other gauge mounting options exist.

Aside, I think some additional gauge monitoring for Volts, Coolant Temp, Oil Temp and Oil Pressure are good things to have in a turbo swap car but this is up to personal preference.

2) The A/C Temp Relay Switch seems to be a wiring quirk specific to Aristo 2JZ-GTE engine swaps and the GS chassis. It wasn't something I had to factor into my EXPORT 2JZ-GTE swap on my SC so I cannot speak from any experience with it but it should be well covered in Gerrb's big 2JZ-GTE wiring harness thread: https://www.clublexus.com/forums/per...made-easy.html

Please note however that his thread focuses specifically on how to convert most JDM 2JZ-GTE harnesses to work with an SC300/400. However within that big thread of his he DOES cover the issue you are seeking answers to (the GS/Aristo A/C Temp Relay Switch). For more direct pinouts for your specific donor harness and GS chassis I recommend looking here: http://wilbo666.pbworks.com/w/page/3...ngine%20Wiring

I hope this helps a bit and good luck!