Inliners International Forums General Discussion Engines gas tank and dash gauge problems

i've got a question . i am using a late model gas tank (87 mitsubishi truck without fuel pump ) i my 40 chev panel truck . first ,how can i check the operation of the sending unit . there are two wires at the head of the unit . one might be a low fuel warning light ? also i was wondering about the volt reducer. i bought the one sold for this application so i can use the stock dash gauge and it has 2 exposed wire ends . what side of the dash gauge does this attach to and how?

Dear ??;

You need a sending unit compatable to your stock guage, that's all. They are made in 6 & 12 volt (guage/sending unit) so the reducer is not needed, unless you keep the orginal guage etc.

Good luck. John M., #3370

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I would agree with John that you use (replace the Mitsu unit with) a correct sending unit for your guage. It might require a trip to the local radiator shop to solder the old hole shut and put in a new mounting flange.

If you feel the need to check the Mitsu sender, one of the wires is for a controlled-voltage input and the other is a ground lead to the body. Remove the sender and look at it, you should be able to tell which is which. Then hook a multimeter to the wires and move the lever up and down. The resistance should change in a linear fashion from about 1 or 2 ohms to perhaps 90 ohms.

One of the issues you may find with using the original guage with this sender is the resistance direction. That is, whether it has high or low resistance empty and the reverse when full. Most of the older Chevys were opposite of what is used after about 1970, regardless of car brand. So even if the sender works, you may get an empty reading when the tank is full and vice-versa. That works, but it's kinda ghetto.

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David
newbie #4153

well those are interesting thoughts. so does this mean if i use the stock gauge and the sender is reversed and i were a pessimist would my tank be half full when i think its half empty? back to the point if i go with the 12 volt sender and 6 volt gauge would it matter which side of the gauge i put the reducer on as long as it is inline somewhere . i am thinking it would be ok on the side going to the tank for this is a negative side and i wouldn't have to worry about shorts . am i correct?

Dear ??

None of the above.

You can't use the sender at all. You need to get a guage & sender that are compatable.

You probably can't modify the stock sender to fit a jap tank, so you need a set Mfg. by someone in the insturement business etc.

Start with Auto Meter. If they can't help you they will know someone that can. There is a company that restores old guages but I can't think of them 'off-hand' but AM should know who/where. They are in So. California, Fontana perhaps.

Good luck, John M., #3370

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Actually he should be able to use that gas tank. Those sender units work on ohms not volts.

What you need to do is find the ohm readings on the sender for full and empty. Then you need to find the corresponding readings for the gauge. Then you need an adapter to convert between the two. That "reducer" may already do that conversion for you.

If there are two wires on the sending unit, one goes to the gauge, and the other mostly likely goes to ground. I have no idea which is which.

My '46 pickup has a late model tank but using original sender and gauge. Made the sender fit the new tank (extended the float arm and used a new brass float). Also used this high tech 12 volt conversion item from Chevs of the 40s, part #1119004 to protect the gauge. So far no problems 10 years plus now.

Okay; This may help.

Teleflex makes a universal fuel sender kit.
These work on 4 to 24" tank depths. They have adjustable float & rehostat too.

Model # 90412-P, 90424P, shipping (1 lb) and sell for under $20.00. Made in USA.

Good luck, John M., #3370

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who sell that sending unit?thanks for the help.

It's used in Marine applications.

I'm sure there on the web some where, try dogpile. Let me know it you can't find.

Good luck, John M., #3370

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