jaybone

Anyone know where (starting in the trunk) can I find the wire coming from the sending unit... I believe its tan in color... ha.. I have a constant empty and figure i'm going to work my way forward....


68' 442 Convert...

oldcutlass

Disconnect it from the sender and see if it goes all the way past full with the key on. You can follow it up from there.

RandyS

It becomes part of that wide flat ribbon cable that runs from under the back seat forward to the firewall.

jaybone

So I unplugged the lead in the trunk to the (new) sending unit and the fuel gauge went all the way up past full.... I plugged it back in and it went right back to empty.

Hmmm

oldcutlass

Everything is fine between the sender wire and the gauge. Somehow something is shorting the circuit at the sender.

Allan R

Check the ground wire coming from the tank to the chassis. It connects to the body just in front of the rear foot well on the left side.

jaybone

thanks guys.. sorry for stupid questions.. I have the car in an urban underground "community" garage.. so its hard for me to really work on it like I would want to...


This leads me to the part that I had someone else put a new tank and sending unit in.. because I just don't have the workspace to do it myself.. and now the tank is leaking when its building pressure I can only assume because they clogged up both vent hoses with bolts..... and now I'm guessing didn't even ground the new sending unit...


But they got the bill right tho... lol.. thanks,, keep you all posted..

Allan R

If they installed the new tank? Take it back if it's leaking and be there when it's dropped. Did you order the replacement tank or did they? This should be strictly a warranty repair since it appears to be a result of their workmanship.

jaybone

I will be taking it back.. they had me order the stuff.. I got it all from summit and had it shipped there and they installed all of it...


yeah the leaking is on them..


Gauge operation, I wasn't sure if it was working before it went to them because this car sat for 7-10 years... when I found the car the gas cap was off, so I just wanted to put a new tank and clean everything out before it was started...

oldcutlass

Is there another wire on the post to the sending unit? Again something is shorted to ground.

Allan R

The old tank was likely just fine and prolly just needed to be flushed. What brand replacement did you get. Hoping it was Spectra Premium - they make the best tanks and also provide the new gasket and locking ring that works.

I guess I'm just one of those guys who's lucky enough to have the space to work in, and doing the work myself gives me the knowledge it's been done right.

Hope your problem is resolved soon. The ground wire comes off the sender and runs toward the front of the tank to the grounding location. The new fuel sending units tend to have a shorter ground wire than stock.

Allan R

Just a thought. They might have tried to ground the sender to the sender locking ring which is dumb and may be the cause of that leak too. The ground may not even be hooked up, which is highly likely in this case.

jaybone

ugh.. I'll have to stand there when they drop the tank.. It pains me, because I'm a very detail oriented guy.. fix it right, fix it once... solder, heat shrink all that good stuff... I have a feeling whatever it is, its a mess.. of all new stuff and that makes it worse.. lol


thanks for the info guys.. i'll let you know what I find..

Fun71

No, that would not cause the issue you describe. Open circuit = gauge reading way past full. A short in the line that directly grounds the sending unit and bypasses the pickup in the tank would cause the gauge to read empty.

jaybone

anyways.. as a slight update... got to work on the car a little today... The shop installed the proper vent hoses and the little plastic valve... This solved all of the fuel leaking issues... Seems like from the build up of pressure, it was forcing the fuel out of the weakest links....


Then checked the ground wire.. Looked grounded to the body correctly...


And the sending unit wire comes up into the trunk and goes where its suppose to....


I'm going to remove the back seats tomorrow to see the condition of the wires running to the front of the car...


this is what I used... lol.. For $29 bucks the ease of out of the envelope and onto the tank was priceless!


http://www.ebay.com/itm/69-70-71-Che...c8b0d7&vxp=mtr

oldcutlass

Since you performed a quick check of the wiring way back at post #4, which shows the wiring from the tank all the way forward is good and the gauge is working properly. Your problem is definitely at the tank sender. you are getting a constant ground to your wiring there. No need to pull the seat or look else where.

jaybone

Yep you were correct... all fixed.... thanks to all for dealing with me! haha


While I was under there I also saw one of the reverse light wires sandwiched in the bumper support.. so I corrected that.... Which then led to an entire day going thru all the rear wiring in the car..


(as a note, this car really hasn't been on the road in 10 years until the other day... So there are quite a few things that need going thru)

oldcutlass

Well done, now on to the next project.