fuel pump/sender unit

[jocko]

good evening folks - quick question. Have had a few codes for my sending unit accompanied by an occasional fuel gauge dropping to zero. know i need to change the pump/sender assy in the tank, but would rather hold off a bit for now. I've got just shy of 150k mi on my '01 Z71. As long as the pump is good, I can live with the fuel gauge issue for now. It actually stopped dropping to zero anyway now - just reads a little high, again, can live with that.

Anyway, moving cross country in a month and wondering 2 things -

1. Has an iffy sending unit immediately preceded a total pump failure for anyone? I don't think their functions are linked, even though they are replaced as an assembly, but curious.

2. About how many miles have you all gotten on your fuel pumps before they failed? I have no indications of a bad pump - just the fuel gauge issue.

Thanks for the help!
Jocko

[clinebarger]

If the pump has 150K on it....I whouldnt trust it going crosscountry. Replace it now at your leisure, Just my 2 cents.

[jocko]

thanks clinebarger, you've always given me sound advice.

I've priced the pump at a few places - and I found I've had to ask whether the price they are giving me is for a Delphi (i.e. OWM replacement) pump or a brand x. It's always a brand x. So then they give me the Delphi pump price, if they can even get it. Around $270-$290. Sure beats having the only locally trusted mechanic I know do it for $900.... But the labor is nothing to sneeze at. While it all "looks" simple enough to swap out - have a couple questions for you or anyone that's done this before (and keep in mind I haven't stuck my head under my truck in the past several weeks, so some of these are rather simple).

- is there any way to drain the gas in the tank before dropping it?
- does it all need to be drained - or can it be dropped with a few gallons left in it?
- what about the difficult to connect/disconnect stuff? I seem to recal the evap lines suck to disconnect.
- the sending unit retaining ring - can it just be tapped off with a hammer and punch or do I need the tool for it? (and is there a spark/gas fume hazard?)
- last but not least - is there ANY adjustment necessary to the pump/sender unit (i.e. to make sure the gauge reads levels correctly, etc - or is it simply a drop-in with no adjustment needed? I think it is the latter, but wondered about that.

Thanks again for your time.

v/r,
jocko

[Justin87]

is there any way to drain the gas in the tank before dropping it?
does it all need to be drained - or can it be dropped with a few gallons left in it?

If you have the equipment and or the extra hands it's much easier to pull the bed off and set it behind the tank. Did this with my 00 Z71.

what about the difficult to connect/disconnect stuff? I seem to recal the evap lines suck to disconnect.

Not sure bout the evap line.

the sending unit retaining ring - can it just be tapped off with a hammer and punch or do I need the tool for it? (and is there a spark/gas fume hazard?)

A hammer and a flat blade screwdriver is how I got mine off. Shouldn't have to worry bout a spark or fume hazard if your out in the open. Plus the ring spins off easy enough to not have to muscle up on it.

last but not least - is there ANY adjustment necessary to the pump/sender unit (i.e. to make sure the gauge reads levels correctly, etc - or is it simply a drop-in with no adjustment needed? I think it is the latter, but wondered about that.

Should be just a drop in and no adjustment kind of thing. Didn't do any adjusting when I did mine and the gauge reads just fine.

[jocko]

thanks very much Justin

[Justin87]

Your very welcome Jocko. Hope that info helps.

[danomano]

Try a bottle of Techtron at Wal Mart this is suppose to fix issues the fuel guages.
\
http://www.z06vette.com/forums/f5/so...problem-67842/

[jocko]

i'll do that, thanks!

[60ratrod]

I had/have a similar issue with my 01 tahoe. When i got it from the dealer in june it had 113k miles on it and the level sensor was bad, either reading irregularly or not at all or sometimes right on the money. What i did was replace the fuel level sensor and float(yes it can be done) and now its steady, but i think i messed something up when i reinstalled it and now it doesn't go all the way to full, but it beats the heck outta having it have a mind of its own. If i let it sit for a bit after filling the tank it will almost go to full. I need to drop.the tank again to take a look at the sensor, but haven't been able to do it cause of my work schedule and training detachments. But i think i'm gonna get a delco pump for when i drop the tank to look at the sensor incase its fubar. But log story short is the sensor is cheaper than an entire pump so it might something to look into. I got mine off ebay and that may be part of my issue, but the replacement was easy enough once i got the sender/pump assembly out
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[truckdude239]

Originally Posted by danomano

Try a bottle of Techtron at Wal Mart this is suppose to fix issues the fuel guages.
\
http://www.z06vette.com/forums/f5/so...problem-67842/

i really dont see how that could fix a Gage issuse

[spudz]

Originally Posted by truckdude239

i really dont see how that could fix a Gage issuse

it wont

[Jacfourteen]

Originally Posted by spudz

it wont

x2

[Jacfourteen]

If you replace the pump I suggest using a good quality replacement. I couldn't stomach paying $300 for a good one, so I bought a ebay cheapy (pump only) for $45. That was 3 weeks ago, it worked great....until last night when it died on me and I had to get towed home. Now I get to drop it again and put in a better quality one.

[billsbowtie]

i have had a few of these years of trucks & from what i have seen the fuel pumps like to go bad between 120,000 to 150,000 miles.

[jocko]

thanks for all the great advice gents. concur that a quality pump the way to go - I went with a gm pump. wasn't cheap, but I'll sleep better. Odd thing is that the weirdness in my fuel gauge returned briefly after the install (recall that several months ago it was dropping to zero intermittently then for the past couple months it's just been reading a little high). In other words, about 5 miles down the road (with the assumption that preventive maint on the pump would also cure my slightly high reading fuel gauge) the gauge once again dropped to zero and the low fuel light came on. not just once either- about 10 times in 20 miles. Then poof - it's been perfect ever since. not dropping to zero and is accurate to boot....

had a mech with cooler tools than i'll ever have check it out - the fuel gauge itself passes muster (reads 1/4, 1/2, 3/4, full correctly when tested) and the PCM pins all checked out. All that can really be left is an intermittent open circuit somewhere, and I can't find it and neither could the mech. So, since it's working - and since I have a new pump (so at least I eliminated the risk of getting stranded on one of my frequent cross-country moves) my plan is to carry a roll of black electrical tape with me for the next time the gauge drops to zero. Not to fix a wire - but to stick over the frickin glaring yellow warning light on the dash so I can ignore it.... mission accomplished!

[67ChevyRedneck]

Cool.

My truck needs a new pump, the check valve is going, I bought a gm pump quite a while ago, just haven't been motivated to do it (been driving S10.)

My truck has been doing something funky for years. Whenever I fill the truck up to completely full it does what yours did, go to zero and the light comes on. It only ever does it with a completely full tank. After about a gallon or two is sucked out of it it won't do it again until I fill it up again, I too, am hoping the new pump/sending unit will also solve my problem.

[truckdude239]

Gm or ac delo pump is the onyl way to go with these trucks

[mikemikeska]

If you havent changed that pump yet .It's easyer to remove the bed and pull the pump from the top.