Can the fuel level sender be R&R with the tank still in the car? '81 S model

 

it can be done, but imo, its all to east to drop the tank(two bolts, 3 hoses, and three screws on the filler neck to remove). once the tank is out you will have unlimited working room. in some cases the screws holding the sender to the tank are so rusted that you may have to grind the heads off or use needlenose visegrips.

 

Ah, hadn't anticipated rusted screws because the rest of the hardware on this car has been in good shape.

 

You did not see my post in the other persons level sender thread. You don't drop the tank to replace the sender.
Put the rear of the vehicle on jack stands and remove the left rear wheel. Remove the inner wheel well plastic. Wholla! The sender is exposed. Clean the area of all the dirt that has accumulated and remove the screws and pull her out. :-)

 

you can by removing the drivers side rear plastic inner fender well. as suggested above though, id just drop the tank. it isnt that hard or take that long. then you have have more room to work with and you can service the tank if you need to.

 

I'd rather not drop the tank. It's more work that seems unnecessary. Thanks Doc!

The sender has a completely open circuit. Maybe it can be repaired. Thankfully the guage still works. I grounded it to the brake rotor (closest source of clean metal) and the needle moved. The stock gorund in the T shaped connector still works too.

I wonder whether a GSL-SE doner sender will work. I'll need a different plug that looks like pi, obviously. Maybe I can steal it off the GSL-SE since it's getting a fuel cell (and a 4 rotor lol).

 

Like an idiot I forgot to check which pins do what on my GSL-SE fuel level sender before installing it. The car is an '81 S model which has a T shaped connector with two pins. The GSL-SE fuel level sender has three pins. I will make a connector adaptor out of some stock harnesses I have kicking around.

I've searched the forum and can't find the thread where somebody posted a picture I think from the FSM of a GSL-SE level sender. I believe it showed the pinout, which is what I need. Thanks.

 

As I recall, when looking "into" plastic on sender, left vertical is low level warning light on dash (don't think you will have that so ignore) Right vertical is ground, and horizontal under those is guage. Make sense? I am poor at written descriptions.

 

https://www.rx7club.com/showthread.p...l+level+sender

There ya go Jeff. I knew I'd had that problem before!

Jon

 

Oh, and for reference, anyone looking for a replacement for the car-side connector on the 84-85 models can yoink it from their throttle position sensor if they're carb'd. It uses the same connector but on the S and GS you don't need the TPS for anything useful (maybe emissions?)

Jon

 

Jon, I will respectfully challenge your call that the "horizontal" is ground. In archives post by Darkfrost (with pictures) he suggests the right vertical is ground. The plate behind the connector runs down and under the plastic, and through contact with top of round plate that screws to the tank, provides ground. As Darkfrost points out this contact gets broken over time and result is guage doesn't work. His solution was to solder wire from plate to base to provide ground. I have tried his fix and generated correct ohm reading for functioning sender unit. Given my poor descriptive skills, check the Darkfrost pictures to understand what I'm trying to say.

 

Thanks everyone. I made a connector adaptor but the part that is perplexing me is the guage no longer moves when I ground the signal wire. It moved last year when I checkled it. Hmm, maybe it just needs to be driven for a while to allow things to come out of hibernation.

Another weirdness is the GSL-SE sender. When I first tested it, it was like 104.5 ohms or something. It kept wavering like it had intermetant contact. Then I slapped the bottom of the tank and the reading jumped up into the kilo to mega ohms. That's not right.

There is no gas in the tank so I'll mess with it some more when I get some.

Weird stuff, huh?

 

Hmmm... It's been a long time since I've revisited the question, but it's worth a look.

Does anybody have their Heynes handy? I'm at work and mine's 6hrs away in Kitchener. I provided the page number to the pinout in that other thread, it'd be nice to get a scan of the page so we could see what the pinout is.

Jon

 

Jon is right. You don 't need Haynes when you have online factory wiring diagrams. Looking into the connector, you have three wire colors

- YL
- Y
- B

B: Horizontal connection - ground
Y: Left vertical connection - fuel gauge
YL: Right vertical connection - low fuel level light


This is with the horizontal connection being on the botttom.

http://foxed.ca/rx7manual/manuals/19...g_Diagrams.pdf

pg. 50:18

 

Don't mean to be hijacking, but this is pretty related. I have the intank unit from a second gen on my car and have the 2 wires (minus ground) hooked up properly and i still don't get a reading. IIRC there is only one ground and I have it hooked up with the fuel pump and I believe that one grounds the whole top plate too. Since the fuel pump works fine, that would mean there's a good ground going to it.

 

anyone?

 

Ground the wiring that goes from the sender to the fuel gauge and see if you get a reading.

 

It had a reading last year but I haven't gotten a reading this year. lol It seems the guage is faulty as is the temp guage. No matter I'll probably swap them out and possibly get a 130MPH '83 dash cluster at some point, and a set of aftermarket oil and water temp guages. I'd still prefer it if my stock fuel guage could work though since aftermarket are mostly the GM 0-90 style which is opposite of our 100-10ish Mazda stuff.

Now that there is gas in the tank I had a chance to pull the level sender and work it up and down a few times. The reading varied widely with a few dead spots. I also blew it out with compresed air.

I installed the sender and it is saying I have 40 ohms of gas in my tank. How much gas is that really? Quarter tank?

 

Uhg, my guage doesn't work anymore. My sender does though! It's a GSL-SE sender so I had to add an adaptor to go from PI to a T.

 

When I installed the Autometer gauge and sender, I had to add an additional ground wire from the mounting plate to the chassis. If the sender works, even erratically, then the gauge is toast, I've had to replace 1 of those and 2 oil pressure gauges. Look at the fine white wires on the back of the gauge. If they are brown/black, the gauge is toast.

 

Thanks for the advice about the wires trochoid.

 

According to my Cosmo FSM, 40 ohms is about half a tank. Assuming the senders are similar, of course.