93 Es300 Fuel Sender Recalibration

[LumpyLou]

My 93 ES300 gas gauge shows only 1/2 or so after a fill up. On two different instrument clusters. I changed the instrument cluster with a second hand one to cure dim needles and had hoped to cure the fuel gauge problem at the same time. Needles are now good, but the second cluster fuel gauge behaves just as the first one did, so presumably the problem is not the gauge itself.

I acquired this car only a few weeks ago. I've recently changed the fuel rails and all the injectors, (again salvage yard parts) because I found rust evident in parts of the system. (Been working on an intermittent rough engine with white smoke that doesn't smell sweet.) Now I'm going into the fuel tank to see what I may discover there, and again I'm thinking about maybe curing my gauge problem while I'm there.

Reading around here and other places this fuel gauge problem seems not uncommon on Toyotas. Somewhere during the last few weeks I came across an article or posting explaining how to 'recalibrate' the fuel sender to correct this problem. Seems to me it had something to do with adding resistors in the line or somehow modifying/adjusting it's signal output when there's nothing otherwise physically wrong with it. But for the life of me I can't find that article again, and I'm suspecting there's a good chance it may turn out to be relevant to my particular case once I've run the standard tests on this critter.

So, can anyone either provide some information for me on how I might conquer this fuel gauge problem, or does anyone recognise this 'correcting the resistance' of the fuel sender information I'm talking about and could they provide a link for me?

Lumpy

[amf1932]

Most likely the sensor(sender) or wiring in the fuel tank is defective.

[SRVCM]

Most likely the sensor(sender) or wiring in the fuel tank is defective.

Im currently working on a fix for this problem as I installed LED's in the dash and after re- installing cluster the fuel guage is out of adjustment. I really dont think it is the signal coming from the fuel sending unit. I believe the problem may lie with the voltage at the guage. Ill be working on this for the next few days.

[camlex]

somebody told me not long ago that he used marvel mystery from orailly.

give it a try.

Hope that helps.

[SRVCM]

Well, I figured out the problem with the fuel guage not reading correctly. It appears that the extra weight of the SMT LED and the two resistors was enough to throw it off. I added a little bit of solder to the brass weight and semi calibrated it by spinning it seeing where it stopped. Once I got it to randomly stop in various position I felt it was aduquately calibrated not having the equipment and all to do a more professional job.

In essence, if the fuel sending unit is operating properly and you have original needles your guage should read correct. If it doesnt then the guage would be suspect.