Dont know whether this is the right place for this question but I hope someone can help me out. I have to replace the fuel sender unit in the tank of my 71 'lark, Do I have to remove the tank to do this ??o No: Thanks Bruce
yes. It might just be a ground wire. That seems to be a common problem. I am dropping my tank today. I decided to put in a new tank and sending unit along with all new lines while I was at it. It also gives me a chance to "clean up" under the trunk floor area.
I replaced my working original sending unit, as it was 40 yrs old and not really in that good of shape while I replaced my tank. Rusty and with a non-existant sock, I replaced with a brand new repro unit. MISTAKE . Nothing but problems since. I've heard it from more than one person too. I'm looking at finding an original one and having it rebuilt. Replacements are junk.
Hey Kevin, who did you get your repro sending unit from?? I just got one from Year One for the GS and would like to know if it's the same source as yours. Thanks!!
I replaced mine about 2 years ago and the gas gauge that used to be steady now swings back and forth like a needle on a stereo system. I bought mine from Rock. I guess sometimes 40 year old parts are best left alone!
Ooohhhh... I didn't want to hear that part about having to drop the tank. My gauge has been fine, until last week. Put over 100 miles on a full tank, and the gauge moved barely below F. Then, when I was going around a big bend, it suddenly dropped to just below 3/4. Drove the rest of the way home, and it seemed normal. Reading about 1/2 by then. The next morning, started the car, and it was FULL again! It's a magic, self-filling gas tank. I wish I had one of those on the daily driver. Only available on a Buick!
Check the ground wire on the sending unit - sounds like it might be a grounding problem (especially the "back to full" part). Ray
The one I am about to put in is from Rock Auto....Any way of testing these things before installation?? Bruce
If you still have the old one, you can get it rebuilt and calibrated by Otto Instruments in Brisbane. Not cheap, but they do a good job.
I don't recall who it is from, as I didn't place the order. I just added my order onto another Members order as he was in the process of getting a new tank, and the supplier had senders.Sorry.o No:
I think all the sending units these days are coming from the same manufacturer, no matter who you buy it from... Mine new unit reads 3/4 when the tank is full. When I installed the new sender, I emptied the tank and did a slow fill in increments to check the gauge, and it is accurate all the way to 3/4. So, not a big deal.
Honestly if I have any of the issues mentioned I would throw a fit:rant: The gas gauge is a big deal to me because I use it as a constant to show any changes in either my driving style, amount of travel or change in engine efficiency. A gas gauge that doesn't give accurate consistent readings makes that all the more difficult. I suppose what I'll do is buy the best quality unit I can find and then try to find a place that will calibrate it. Does anyone know the ohmic range our gauges are set for?
Try adding some Techron concentrate fuel system cleaner to a couple tanks of gas before you take it apart. I had the same type of issues on my '66 vette and this solved the problem with the sending unit.:TU: :beers2:
Of Course if you'd like to step the fuel system up at the same time, you can order one of Robb Mc's sending units. You can always step it down to stock fuel line until you are ready for 1/2" lines. http://www.robbmcperformance.com/products/1069_gmsend.html
If this is getting terribly off topic I'll start a new thread but I have a quick question.., Using that sending unit what setup would you recommend Larry? I see it mentions no in tank sock, so where would be the best place for an inline filter?, also what would be the best way to reduce the lines down to a factory size? Should I run a return line? (My new fuel pump has a return provision) I want to completely revamp my fuel system as the flaws in my current setup really keep me from winding through the gears before running out of gas Thanks for the help
Hey Kevin, the one i bought from Year One is a new Delco unit. I'll let you know how it performs in a week or so after i install it.
So, after filling it yesterday, now I'm WAY past the full mark. Reading about halfway across the "hot" warning light.
I knew someone had some NOS GM units for sale as well as repo's. As an official expert on this subject I have been trying to fix my problem for two years. I have dropped the tank like 4 times. I assume my tank is the original but I found the units work fine but maybe a design flaw. My tank has baffles and the float on the units hits the closet baffle. I have returned the repo units for new ones...all the same. I found this out due to the rust on the baffle, you could see where the float was hitting it. I even tried to bend those baffles but to no avail. I think since then it does work better until i filled it up, it only when to 3/4 full but hasn't moved too much and I have been driving it a lot. I went as far as dropping tank and keeping unit hooked up and manually moving float watching the gauge work properly. My thoughts are to somehow cut that baffle area our or find an NOS unit to compare at some point.
