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I read that the actual gauges go bad on these cars. Common problem.
But before I go into the dash wanted to ask about this one 1st.
Car was parked for 10 yrs. 1st time the ignition was turned on after it sat
the fuel gauge moved to "Full". Then in a few seconds dropped to empty.
I swapped the fuel pump and exercised the float arm and float.
It rises and falls freely. Does this sound like a gauge issue?
Or sending unit? Troubleshooting ideas to narrow It down?
Thanks!
The fuel gauge can go bad, yes. I don't think it is exceedingly common but it happens. I found that mine wasn't good at 189k a few years ago after replacing the fuel tank sending unit (which could have also been failing for all I knew at the time). Before I replaced anything I observed the gauge would only read up from full to 1/2 or so and after that I had to guess how much fuel I had.
A new in-tank sending unit didn't cure my issue so I got a new cluster fuel gauge, removed the old one and installed that. I do think it is possible to restore an old malfunctioning fuel gauge as well. Tanin Auto Electronix may do this but I'm not sure.
Generally what I suggest is replacing your fuel sending unit and the gasket that seals it against the fuel tank first. It is not a difficult repair to do yourself. Just remember to disconnect the battery to avoid any electricity in those external (to the tank) wires and make sure you don't have a full or 3/4 tank when you do it. Access is very easy from the trunk. Take a quick reference picture to remind you of where the external tank wires go... however it is very straightforward when you look at it. I don't recall the correct torque specs for those 8mm bolts but that figure is listed in the SC300/400 TSRM.
If that does not solve your issue then move onto the fuel gauge. The fuel gauge itself is removed from the side of the cluster. It has been a while since I did it but it's not terribly hard even though it requires a bit of careful disassembly. Getting stubborn cluster harness connectors loose with some delicacy as to their age is a bit annoying.
Thanks! I did do a search and did read your post. Will head in that direction.
Pull it out and see if it can be cleaned up / tested, or replaced.
Am still looking for a good drawings for this car. Just bought it and am finding the Lexus drawings are lacking.
Is there a better web site / source with part numbers? Or on line service manual I can down load?
Thanks again for all the help!
What I am finding on line... #11 showing the fuel gauge sending unit, but not showing the fuel level sending unit with float?
Am thinking that's most likely the issue. And its not on the drawing...........
photo in my trunk...
photo from ebay, what I think its going to look like. I went ahead and bought it. Its from a 93 SC400, works and was $34.00 shipped.
So not much to loose.............
#10 in that simplified Toyota EPC picture should be the sending unit. It isn't a very good drawing of it, no.
The sender unit you have found on ebay should be the correct one if it is from a 93 SC400. It's the same part for both cars. Give that a try first if it is confirmed to work and see if there is any change... but hold onto your original sender just in case you aren't sure of the result.
I have a 1993 LS400. The gas gauge is stuck at below Empty. The Low Fuel warning light on the dash works fine. Tried to remove sender unit from trunk, but can't get it out - it catches on something inside the tank. I have only about 3 or 4 gallons in tank. Any suggestions on how to get it out? Someone suggested cleaning it might help. Thanks.
02-10-17, 09:29 AM
Fuel gauge issue? or sending unit?
