Fuel Tank Sending Unit 1936
 

I found a NOS fuel tank sending unit FAA-9275-A that says its for 52-53 Ford passenger car 6-cylinder. I am trying to use it in my 36 but it doesn't read correctly. I thought that all the 6-volt units would be compatible with the 6-volt gauges?
Can anyone here shed some light on this subject. What will work and what will not. Any help would be appreciated.


Thanks Dan

Re: Fuel Tank Sending Unit 1936
 

How are you testing it?

Re: Fuel Tank Sending Unit 1936
 

If its that you installed it in the tank of your '36 and it gave you incorrect readings its probably due to the float arm not being the correct length - too long or too shory....

Re: Fuel Tank Sending Unit 1936
 

I didn't install the sender, I tested outside the vehicle using jump wires for the lead and the ground at the tank, and yes it is positive ground. Then used the jump wires connected directly to the gauge. One jumper from the lead on the sender to the gauge and the other from the positive side of the battery to the mounting plate on the sender and got the same results, which tells me I don't have a issue with the wire going to the tank.


When I hooked the sender up with the jumpers I put the float all the way up in the full position and the gauge was reading Empty. Then I turned on the ignition switch and the gauge would immediately move to full then would start to drop. Sometimes to 3/4 or 1/2 then would shoot back up to Full while still holding the arm in the Full position. If I tried to move the arm down to say 1/2 the gauge would drop to empty and if i moved the arm back up to the full position the gauge would not respond until I turned the ignition off, wait a minute then turn the ignition back on the gauge sometimes would not respond or would shoot to full. The best I can explain it is it acted erratic.


I guess what my main question here is, should this sender be compatible with my gauge? Or is it possible my gauge is not working properly. To my understanding a gauge will either work or not and mine seems to be working?

Re: Fuel Tank Sending Unit 1936
 

I suspect bad/poor connections with the "jumper" wiring giving you erratic readings. The sending unit you have should be compatible with the gauge in your '36....

Re: Fuel Tank Sending Unit 1936
 

Jumpers have a good connection, that is not the issue. Thanks for verifying the senders compatibility.

I'm wondering if the wire from the gauge to the sender on the vehicle may be bad or grounding as I did not disconnected it when jumping straight to the gauge?
Any other suggestions or is it possible I just got a bad sender?

Re: Fuel Tank Sending Unit 1936
 

You can check the gauge with a battery. Something like a "D" cell will work. Connect the D cell directly to the gauge with jumpers and see if it gives a steady reading.

Re: Fuel Tank Sending Unit 1936
 

If the wire going to your gauge was contacting metal along the way, it would show "full" all the time on the dash gauge as I recall.
NOS does not necessarily mean a functional part. Sometimes it means it was returned because it was defective and somehow managed to get placed back in stock.
I'd suggest by-passing the car's wire to the sending unit and making 100% certain that you have a good ground at the sender. That'll tell you if your NOS unit is operating properly.

Re: Fuel Tank Sending Unit 1936
 

Why would a six cylinder passenger car take a different sending unit than a V8?
Just because a gage or sending unit is 6 volt doesn’t mean it is comparable with every 6 volt gage or sending unit.
I can only suggest what others have already posted, especially what Kube has said.
Positive or negative ground also makes no difference.
They work off from ohms.
Keep us posted on what you find. I for one would like to know what the prblem is.

Re: Fuel Tank Sending Unit 1936
 

As a suggestion remove the dash gauge and jumper everything on the bench, if it works there, it is a problem with wiring, loose or dirty connections.

Re: Fuel Tank Sending Unit 1936
 

Ok, will try a couple more tests and will report back my findings.


A big thanks to all who replied.

Re: Fuel Tank Sending Unit 1936
 

The six cylinder sending unit is likely different than the eight cylinder unit because the gas tank is a different size and shape which requires the wire arm to be a different length.

Re: Fuel Tank Sending Unit 1936
 

Early Ford sensors do not work off of ohms (as in resistance), they work by pulsing the current flow from the gauge through the sensor to ground. There is a set of points in the sensor and the raye at which they open and close regulates the current.

Re: Fuel Tank Sending Unit 1936
 

I thought that as well. Just couldn't imagine why Ford would install a different tank for the 6 vs. the 8.

Re: Fuel Tank Sending Unit 1936
 

It is most likely that the points in the new sending unit have corrosion on them. Connect an ohm meter between the center terminal and the case. Move the arm slowly and watch the meter. If you see wide fluctuations in the meter needle, the contact points are dirty or corroded.


Fix 1: move the arm along it full travel several times (50 minimum) and retry.
If fix 1 did not work try fix 2
Fix2: pry the top cover from the sending unit and spray contact cleaner on the points. Be careful as the wires in there are smaller that a hair and easily broken.

Re: Fuel Tank Sending Unit 1936
 

Does anyone have any info on a 1936 fuel gauge as to access and repair?
Thanks