BogeyJH

I have a problem with my new-to-me 1994 LS400. :( Please take a look at these images (click image for larger view). I don't know what this part is called, nor its function. There is a cable and a hose running from the bottom of the part into the firewall. There is also a hose running from the part off the driver side and curving down behind the engine. Anybody know what this is and/or what might be involved in repairing it? I can probably do it myself if it is fairly straightforward and doesn't require any specialty tools.

I just bought a 94 LS400 Anniversary Edition last week from a friend who had it for 6 years, ~60K miles. It now has 133,600+ on the odometer and runs and handles absolutely fantastic for a 6 year old car. Oh wait... I just did some math. It took both hands and a few toes... Hey! This car is 13 years old! ;) I have always had an affinity for this particular LS (pearl white / silver). Having been a passenger in it 4-5 days a week at lunch for 6 years, I know it is a solid car. So when he decided to sell it, I was first in line. :D

I spoke with the previous owner of the car at lunch today (we work together at an RF engineering company). Turns out the gas gauge exhibited the common symptoms I read about in the forum (i.e. - indicating lower than full with a full tank) before it died altogether. He also said that for a couple of days after an unrelated service at the dealer, it worked normally. It then returned to the common failure mode for a while before eventually dying. In addition to poor low temperature stability, one of the disadvantages of aluminum electrolytic capacitors is the finite capacitor life due to breakdown and degradation of the electrolyte. We theorized that the degraded electrolyte within the caps may have been temporarily restored to a functional state and then failed after encountering a succession of mechanical shocks or vibrations. He had received an estimate to repair the gas gauge, but figured the cost was greater than the inconvenience. He is an excellent engineer and I commented that it is amusing to me that he makes his living designing, troubleshooting, and otherwise working with electronics but chose to live without a gas gauge and an intermittently blacked out climate control LCD when the fixes were well within his capabilities. He really dislikes working on cars, no matter the nature of the repair, so he never researched DIY repair of these minor problems. Otherwise, he was good about keeping up with the maintenance on the car, but always paid someone else to do it. At any rate, this new information is encouraging to me in that the problem will very likely be solved with the replacement solid tantalum caps. I'm hoping the LCD on the climate control module is not too far gone to be corrected with new caps (it's only partially dark in cooler weather). johnls400 seemed to think that the LCD issue is cap related. This weekend I'll download the instructions and tackle these two if I can squeeze in some time. Many thanks to all of you for your input.

I saw your post during my search. I really appreciate the detail you included. Is there any indication that the defective capacitors can cause the gauge to stick at empty and/or didable the low fuel indicator?

Howdy from a newbie in Texas. I just bought a 1994 LS400 Anniversary Edition. My first Lexus. I bought it with a known problem with the gas gauge that seems to differ from the postings I foiund on the subject. The needle is always in the lowest fuel position and the low fuel indicator never lights. I had thought this might be a float issue but thought that the fact that the low fuel indicator doesn't function might rule that out. I have also considered that this may be a connection problem. However, there are quite a few references to the instrument cluster circuit board capacitors, which got me to thinking of the possibility that this could be related to other failures for which replacing the caps did the trick. The electronics are right up my alley as I am fairly handy iwth a soldering iron when I need to be, but I don't really want to risk going into the instrument cluster unecessarily since there are no other issues in that area. Does anyone have any history on this failiure mechanism? Any insights would be most welcome.