Fuel sender - KE 38/55

[Jammcn07]

Does anyone know if eBay or the likes do a new fuel sender or a refurb kit or the likes for A KE38/55 fuel sender ??? 

Mines not cutting the mustard.....

[altezzaclub]

Can you adapt one of these $50 ones??

https://www.ebay.com.au/itm/FUEL-GAS-TANK-GAUGE-SENDING-UNIT-FOR-TOYOTA-COROLLA-KE70-TE70-AE70-79-87/132616051279?hash=item1ee0885a4f:g:06kAAOSwVRxb2nqF

[parrot]

Sometimes they will respond to a little TLC.  But that winding looks pretty cactus doesn’t it

[Jammcn07]

Yeah it’s basically stuffed

[Banjo]

Fuel Level Sensor/Sendors are a pain, when they get old & wear through the resistance wire, as yours has. 

Basically you don't have too many options, as I've never been able to find an aftermarket one, specifically for the KE30/35/55 Rollas.

They were never perfectly linear in operation to start with, so if looking for an alternative, then the angle of movement from dead empty to completely full, is the issue.

I bought one, cheap off ebay once, that was suitable for a Toyota Supra, but could never get the linearity correct.  Maybe, an electronic adaptor could correct this, but I never went that far.

Temperature guage & Fuel guage issues, in the same car, can often be the result of a damaged or U/S voltage regulator, as both guages use the same low voltage regulator.

In some Rollas it is 7 volt, others 8 volt, & I think I came across one that was 9 volt.  There is even one early one, that uses an electro-mechanical regulator.  I put in an external 9V regulator years ago, & it solved all my guage problems.

Corolla Guage Issues Link

Any time, I've ever come across an old Corolla, with the fuel tank still on-board, I've whipped the fuel sender out. Out of about 3-4 attempts, I've only retrieved one, that was any good; which now sits on my shelf, awaiting the day, the one in my KE30 eventually fails.

But don't throw away your complete fuel sensor from the tank.  If the resistance winding is worn out, but the pivot arrangement is still reliable & works, it may still be useful, by fitting a special Hall Effect IC, & an associated magnet, so that the original guage can be used.

The following article describes it.

Hall Effect IC used for Fuel Guage Sensor

Might have a play one Saturday afternoon, when it's raining !

Cheers Banjo 

 

Edited July 8, 2019 by Banjo

[Jammcn07]

Does anyone know what wire I need to try and re-do this sender?

 

[Banjo]

Hi Jamie,

                 Usually, fuel tank sender units use a Nichrome wire to make these resistance devices.  However, as there are lots of different Nichrome wires, & I don't know specifically which one, Toyota used.

They come in different thicknesses, & can be enamel coated, or not.

You would need one about the same cross sectional area, & O.D. without enamel  

 You would have to find out the "ohms per foot" of the wire Toyota used all those years ago. 

You could dissemble your sender carefully, & unwind the bobbin. Then take the longest length you can extract, & measure it's resistance over a given length, & work it out.

Commonly, the resistance can be as low as say 30-40 ohms per foot.

Lots of trouble & mucking around, & no guarantee it will ultimately work.

The real problem is, that when they get that old, the pivots & other electrical connections, are also suspect.

My best suggestion, is to find a new sender unit, from a later model car, & modify it to fit your fuel tank, using the existing sender unit mounting plate.

This is reocurring issue, & there are a lot of posts on this forum about worn out fuel sender units.

Here is just one of them.

https://www.rollaclub.com/board/topic/9780-ke55-fuel-sender-issues/#comments

Cheers Banjo.

 

 

 

 

Edited July 23, 2019 by Banjo

[Banjo]

Hi Jamie,

                 Usually, fuel tank sender units use a Nichrome wire to make these resistance devices.  However, as there are lots of different Nichrome wires, & I don't know specifically which one, Toyota used.

They come in different thicknesses, & can be enamel coated, or not.

You would need one about the same cross sectional area, & O.D. without enamel  

 You would have to find out the "ohms per foot" of the wire Toyota used all those years ago. 

You could dissemble your sender carefully, & unwind the bobbin. Then take the longest length you can extract, & measure it's resistance over a given length, & work it out.

Commonly, the resistance can be as low as say 30-40 ohms per foot.

Lots of trouble & mucking around, & no guarantee it will ultimately work.

The real problem is, that when they get that old, the pivots & other electrical connections, are also suspect.

My best suggestion, is to find a new sender unit, from a later model car, & modify it to fit your fuel tank, using the existing sender unit mounting plate.

There are plenty of posts on this forum, about the fuel sender units. Your issue, is a reoccurring problem, when they get this old.

Here is just one.

https://www.rollaclub.com/board/topic/9780-ke55-fuel-sender-issues/#comments

 

Cheers Banjo.

 

 

 

 

Edited July 23, 2019 by Banjo

[parrot]

Clearly not something you can pull apart and refurbish yourself.

I would seriously consider taking it somewhere for specialist repair such as

http://www.howardinstruments.com.au/

 

[altezzaclub]

Take a multimeter to a wrecker and try a few of them. There's a couple of KE55s in the local wrecker here, there must be some near you.

I've had the Ke70 red light die on a couple of them new, so I keep a couple of spares.

[Jammcn07]

UPDATE

So, I got the sender unit repaired. New plate and resistor wire done here in Perth WA at Speedline instruments. 

Now, I drained the tank just enough to thrown the unit back in, put 20 odd liters in it and the gauge came up off the E mark to about 1/5 or  1/4 approx.... Happy days, or so I thought.....

Then off to the petrol station and filled her up, it took another 20 litres. At my estimation that's probably some where just short of 50 litres, Now without Gregorys guide I cannot remember the ke38 tank capacity, but I'm guessing its dam near full and i couldn't get anymore in it at the pump.

 

Now my bloody gauge is ready just over half. For me its ready exactly half a tank less than whats in there.... ANY ideas why ?

[altezzaclub]

Banjo will know the ins and outs of matching the resistance in the meter with that in the sender.. 

Take the plug off and earth the wire going to the sender unit, then see if the gauge goes to full. If it does, the problem is in the sender unit. Then take the unit out and manually move it to full and see if the gauge reads full. That is the mechanical side, if the gauge reads half when you move the arm manually its an electronic problem.

After reading this I bought a $50 for the KE70, and while it has a red light  now, it doesn't read full when the tank is full either!  When I get the time I'll do what I've just said you should do!

[Banjo]

Hi Jamie,

                 Sorry about the late reply, but I've been "off the radio" for a few weeks.  Your problem is probably related to that "pesky little guage voltage regulator, I referred to in my links earlier in this thread.  Unfortunately, you are going to have to remove the instrument cluster, & measure the volts on the regulator on the back of the cluster.  Depending on the model the voltage can be anywhere between 7 - 9 volts.  If the voltage is OK, then your problem is, that the resistance wire used to repair your sender, has too high a resistance.  If however, the voltage is low, then you need to replace the voltage regulator, which powers both the fuel & water temp guages.

If the voltage regulator is damaged or burnt out (very common), you will have to replace it with an adjustable aftermarket one, from the likes of Jaycar, or Altronics.

If  the voltage is OK, then you will either increase the volts  to say 12V, by shorting the regulator out, although, I suspect, that may still not get your fuel guage to read full scale.

There is another possibility, that the guage itself is "crook", (high resistance) but this is highly unlikely.

Does your water guage also read low ?   That info might assist.

 

Cheers Banjo

[parrot]

I’d be going back to speedline