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The fuel gauge issue - what is the actual problem?

914 Views 7 Replies 3 Participants Last post by  ORCoastGuy
2001 Deville DTS.

When I get down to about 1/3 to 1/4 tank remaining, the fuel gauge starts jumping upward in increments, until it pegs-out at 'F'ull.
I have learned to adapt-- I use the DIC readout of gallons used, knowing I have a 17-gal tank, and how many MPGs I can get. (I mostly drive a 20-mile stretch of highway, so the MPG is consistent there.)

I have read a few of the other discussions on here, but I am confused :confused:, because some of them mention replacing the fuel PUMP, whereas some suggest it is something called the fuel 'SENDER" unit...as opposed to the actual pump itself. Perhaps it's different depending on model/year. Can anyone with early 2000s Deville/DTS knowledge fill me in?

My DIY skill level is on the "low end of intermediate." I'm not afraid to take it on, but if this is especially difficult, I may not bother. (This is my only vehicle at the moment, so I can't be without it more than a weekend.) I think I read in another post that my 2001 should have an access hatch in the trunk. (If not, I won't even consider fixing it on my own.) Honestly, I have not looked yet. Too much stuff in the trunk.

Just hoping for some CLARITY here on what exactly needs replaced. Part numbers/links/references appreciated. And then maybe thoughts on whether I should do it myself or not, based on your experience of doing it.

Thanks!
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The fuel pump assembly consists of the pump and the level sender. The level sender is what the gauge gets its signal from.

You can replace either individually, but it's usually worth just replacing both at once.

There's an access hatch in your trunk, so no tank drop necessary. Fairly easy job.
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Re: The fuel guage issue - what is the actual issue?

Inaccurate level sender readings are usually caused by a bad resistance strip on the sender (the fuel "gauge" is a simple voltmeter), bad wiring/connector or the gauge itself. The sender itself is always the first suspect in these cars. Sometimes - sometimes - the use of cheap gas (low detergent additive package) allows sulfur deposits to build up on the resistance strip and wiper, causing inaccurate voltage to the gauge. Sometimes - again, sometimes - a good fuel system cleaner like Chevron TECHRON (a component of Top Tier gasoline) can clean the sulfur deposits. Sometimes.

Here's the fuel pump/level sender assembly. More pictures in your section of www.rockauto.com.

About an hour of work with hand tools, patience, some wire splicing and magic words. There's a "How-to" video in the RockAuto site, your car, fuel/air, Airtex pump INFO tab.

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Re: The fuel guage issue - what is the actual issue?

Thanks, Cabbage and Submariner. Much appreciated!!

So is the existing one physically moving up to 'full' without the float rod doing that? Is it dirty, or could there be some grit/gunk causing it?
What I am getting at is if I should access it, and try to clean it up, without a new one on hand.
On the other hand... I see one on eBay right now for $70. Should I just "Buy It Now"?
Read my edited post. If that level sender is screwed up, simply replace the entire assembly. RockAuto.

Be careful of the Chinese fuel pump assemblies for cheap - they don't (may not) fit/work.
Read my edited post. If that level sender is screwed up, simply replace the entire assembly. RockAuto.
Be careful of the Chinese fuel pump assemblies for cheap - they don't (may not) fit/work.
Thanks again! So, the assembly you pictured-- the actual PUMP is inside the lower housing...correct?
If so, that's the "ah-ha..light bulb on" moment for me, and I can see why replacing the whole assembly is probably the way to go.
(Understood on Chinese-made replacements. This is not an area I would want to chance that.)
Yes, the pump is a high-pressure high-flow unit standing on end in the white tube.

Just a hint - don't habitually run these cars below 1/4 tank. That usually leads to all sorts of problems. On the long run highway trips - just fine - you then refuel quickly. A mostly empty tank breeds all sorts of crap, moisture and corrosion.
Yes, the pump is a high-pressure high-flow unit standing on end in the white tube.
Just a hint - don't habitually run these cars below 1/4 tank. That usually leads to all sorts of problems. On the long run highway trips - just fine - you then refuel quickly. A mostly empty tank breeds all sorts of crap, moisture and corrosion.
Thanks again! Much appreciated!
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