I'mStock

I purchased a 1998 LS400 with a "bad motor" with the hopes that it was a timing belt issue (didn't know VVTi 1UZs were interference at the time). When the car arrived I had my mechanic look at it and eventually it became clear that the engine was done (dropped a valve). So I ordered a "JDM" 1UZ VVTi off eBay and swapped it in.

The car runs great, only issue (aside from some valvetrain noise ) is that the temp and fuel gauges are a little off. When at "normal" temps, the gauge will sit at 2 o'clock and no, it's not overheating. At first I thought maybe the ohm scaling between the USDM and JDM CLT sensor was the culprit, causing the ECU to see a "higher" temp than normal but after running out of gas at just below 1/2 tank (yes, I ignored the low fuel light) I realized something else was up.

When I fill up, the fuel needle wont budge for 150-160 miles, my "E" is basically at 3/8ths of a tank... I initially hoped a fill-up would maybe reset the float but I wasn't so lucky.

Anyone experienced anything like this?

PureDrifter

iTrader: (10)

Why don't you just swap in the USDM gauge temp sender into your japanese motor?

The gas gauge issue should be unrelated.

black_LS

Perhaps you have a grounding issue somewhere.

I'mStock

At this point, laziness. I've only been driving the car for a couple of weeks so it's still just "confusing" It hasn't reached "irritating" yet...

I'm inclined to agree with you on the fuel gauge, seeing as to how swapping motors should have zero effect on pump/sender/etc...

I'mStock

Swapped in the USDM coolant sensor, no change.

PureDrifter

iTrader: (10)

yep, you broke it

I'mStock

Alright, bumping in hopes of some new insight...

That's what my temp looks like once warmed up. Car isn't hot, all fans function as they should, that's just where the needle sits. My fuel gauge is about an 1/8th away from bone dry.

@TaninAuto I will box this mother****er up tomorrow if you say you've seen this issue before and can fix it.

TaninAuto

We repair gauge issues at least 1-2 times a week on 98-00 LS400.

From the looks of it your RPM is going bad too, it's reading low.

Probably need a minimum of fuel / temp replacement.

celsior123

I have a rhd celsior and same problem. Temp gauge sitting high and the gas guage broken. The low fuel light comes on at about half way mark

I'mStock

I work at a Toyota dealership (parts dept.) and ended up stealing the diag laptop and hooking it up in my LS, ran some tests on my cluster and figured out that it is, in fact, my gauge cluster. Where my temp sits "high" is actually only 188* or so and my fuel gauge is "empty" at about 1/4 on the gauge itself.

Called my local Lexus dealer and ordered the two gauges for $118/$155 (cost + 10%) and am going to give this repair a shot.

dicer

And Tanin could likely do it for way less. And they won't just give it a shot.

I'mStock

I was quoted $369, $300 for parts and $69 to diag. I've already diag'd and ended up getting the parts for cheaper, albeit marginally.

Don't get me wrong, I'm not trying to take anything away from their service, they were very helpful and responsive while I was inquiring with them about the job but I kinda like to "DIY" so here I am.