Hello again everyone, another day, another do it yourself project, and another headache. I decided to be proactive and replace my fuel pump now BEFORE it failed and left me stranded. Plus with all the positive feedback about how people have said their car felt stronger after the replacement, I thought this was a win win. Sort of for me ....read on,

I pulled out the sender and replaced the pump and strainer, easy job. back in it went (with some finagling) and turn the key....starts right up, runs great !! No problem right ! Job well done! NOPE, now my fuel level reads full all the time. I had a full tank before I replaced the pump and then drove the car for approx 70 miles. Runs great but the level still reads full. I would think after 70 miles it would be close to 3/4. Agree ? or will it stay at full for more than that? I cant remember it taking this long to come down. Am I just being an overly worried vette freak or do I have an issue ? I am very **** when it comes to repairs and I was very careful putting the pump in and checked all electrical connections prior to dropping it back in. I checked movement of the float too and it was free. I did notice that the sender didnt just drop straight in you have to sort of turn it a little but here and there to get into proper postion. Is that normal as well ? Thoughts ? Ideas ? Do I have to replace the whole sending unit now ? How much ? Ugghhhhh Thanks in advance

 

make sure you didn't jostle the wires to the sender when you changed the pump.... those senders are junk, simply put.

I have a questionable one in mine... I ain't in the mood to spend $300.00 on it!!!! I just refill every 225 miles (city) and be done with it. 300~325 on a highway drive.

 

Hairmetal,

I had the same issue, pulled the pump and the reading hasnt been right since..
I pulled it and disassembled the sender and it seemed to be more accurate but
more or less the same crap.. Guess I gotta go with bogus on this one...keep track
of your miles...

 

Yep same problem here. I found out by runnning out of gas :mad

It used to be very accurate, right down to the reserve, now its about 5 gallons off. I may take it out again to play around with it but its not something I'm in a hurry to do. I can't image what the hell happened to it either.

I'd replace the damm thing but the price for a new one is outrageous !!!

 

I know that you checked it, but it could be that the float arm got stuck when you did the twisting of the unit to put it back in. More likely is the wires to the sensor were disconneted in some way. Last but not least it could be inside the sender unit itself. That is what happened to me when I replaced my fuel pump.

If there is some corrosion or misalignment of the sensor it can stop working correctly when exposed to air for a while as you replace the pump. Since you have done it before, I'd suggest taking the sendor unit back out and re-checking everything. You can use an ohmmeter to see the resistance change as you move the float arm The sensor is a simple a potentiometer. If it is the cause of the problem you can usually fix it yourself with some WD40 an extra fine sandpaper. I had the same problem in that mine stopped working right after replacing the fuel pump just like you.

See my reply in the "fuel sending unit removal ???" thread. http://forums.corvetteforum.com/zerothread?id=802787

Works great now.



[Modified by Mike_88Z51, 3:39 PM 4/26/2004]

 

You might have something with the "exposure to the air". Seems like alot of us have taken out working floats to service the fuel pump and ended up with inaccurate fuel senders.

When I have nothing else to do, I'll pull mine again and try to clean her up, because it does bug me !!

FYI - The sender should read (measure) 90 ohms when full 0 ohms when empty.

 

Thanks to all that posted replies. I will pull the sender this weekend and clean the contacts and test it with an ohmmeter to ensure it works before dcropping it back in. Hate to do things twice ! Ugghh. It sounds as though this happens to alot of people so at least I'm not alone. Ill keep you posted after I address the situation. I actually thought of just dealing with it for now, but its gonna bug me something fierce.

 

When you do pull it again, please take pictures and lets add this as an addition to the fuel pump replacement Tech Tip. If everyone who replaces their fuel pump is made aware of the need to check the fuel level sender resistance and operation BEFORE putting the assembly back in the tank it might save a lot of needless work.