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Gas gauge is driving me nuts


rockfangd

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Hi all. I know this has been brought up before but could use a few opinions.

I have had 3 Caddys in a row with the gas gauge problem, All 3 go nuts under half a tank, First was 1 99 Deville, second was 01 eldo, third and current is my 97 Deville.

I am tempted to cut the wire for now at the pump so it reads full all the time til I can fix it.

I have tried chevron techron multiple times, even multiple tanks in a row.

I have tried other (cleaners) and nothing works.

Anything under about 11 gallons and the gauge jumps to full, then seconds later empty, Of course it dings and the message comes up.

The part to fix the sender is 100.00

A whole pump unit is about 200.00

I am torn as to whether to replace the whole unit or to take my chances on just replacing the sender part.

For now I have been just filling it twice a week and have been reading the fuel used.

My 96 Never did this, my 97 SLS luckily has never done this, but from what I hear it is a very common problem.

I am changing the pump unit on the 97 SLS because the pump got loud and is bad. I was thinking about putting the sender from the SLS on the Deville but would hate to waste my time.

Would be very nice if they had the access over the tank. Would save me from having to pull 2 tanks down.

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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With my 2002 Monte Carlo all I did was replace the fuel level sensor and all was good. It was less than $50 tho if I recall.

The worse part however is needing to drop the tank, I did it on a 95 and it wasn't fun, but I did it without a helper.

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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I had to do this on my 98 Concours. At the time (probably 7-8 years ago) I bought an OEM pump with the sending unit off Ebay for a very cheap price. It fixed the problem and I have had no problems since. Today I am a little more nervous about buying off Ebay as who knows what kind of parts your actually getting, you hear about the cheap Chinese crap with OEM lable. Also the OEM stuff use to be cheaper on Ebay now it seems they are asking the same price as the dealer. Anyway I thought dropping the tank was a pretty easy job, the toughest part was removing the ring that holds the pump in. I bought the actual tool to remove this ring (any excuse to buy a new tool :-) and it didn't work at all for me (kept slipping off), I ended up using a brass punch and hammer which worked fine.

Good luck.

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Hi all. I know this has been brought up before but could use a few opinions.

I have had 3 Caddys in a row with the gas gauge problem, All 3 go nuts under half a tank, First was 1 99 Deville, second was 01 eldo, third and current is my 97 Deville.

I am tempted to cut the wire for now at the pump so it reads full all the time til I can fix it.

I have tried chevron techron multiple times, even multiple tanks in a row.

I have tried other (cleaners) and nothing works.

Anything under about 11 gallons and the gauge jumps to full, then seconds later empty, Of course it dings and the message comes up.

The part to fix the sender is 100.00

A whole pump unit is about 200.00

I am torn as to whether to replace the whole unit or to take my chances on just replacing the sender part.

For now I have been just filling it twice a week and have been reading the fuel used.

My 96 Never did this, my 97 SLS luckily has never done this, but from what I hear it is a very common problem.

I am changing the pump unit on the 97 SLS because the pump got loud and is bad. I was thinking about putting the sender from the SLS on the Deville but would hate to waste my time.

Would be very nice if they had the access over the tank. Would save me from having to pull 2 tanks down.

Why would you cut the wire to make the gage read full?

It sounds like the sending unit needs to be replaced. When I replaced the fuel pump on my '97 (it was only putting out 28 PSI), the pump and sending unit was all one unit.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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I think that fixing the cut wire with a weatherproof splice is a non-trivial job in itself.

Dropping the tank is an easy, if dirty and a little time-consuming, if you have a lift and a helper. If you are on jack stands and a creeper, it's a lot tougher, particularly if you don't have a helper. Using an access port in the spare tire well is better, when your car has one.

If you plan on driving the car more than a year, I would get the new AC/Delco or equivalent OEM quality from Rock Auto or other reputable source like GM Parts Direct and not look back.

For prevention, if you run regular gas in your Cadillac, you might think about a tank of high-test, or at least a bottle of Techroline, once every few months to keep the tank including fuel gauge sending unit, throttle body, and fuel injectors clear.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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I debated cutting the wire to make the gauge stop going nuts. the new pump module has a pigtail that has to be spliced in anyway.

I ordered a new pump module this morning. Might as well.

I only run non ethanol premium so that should not be a issue.

I have dropped the tank on these before. Worst part is the heat shield that gets in the way around the exhaust.

And as for the ebay prices that is correct. The prices on things oem have skyrocketed. higher than other places.

I will probably have to wait til spring to change it as the weather is unpredictable and my Seville is tying up my garage looking shiny

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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How do you find non-ethanol gas??? The only places that I can find call it "racing gas" and sell it by the 5-gallion can, can included, for $$$ that make it impractical for road use.

Here's a web site for people who know of non-ethanol gas can post the location, and the rest of us can search for ethanol-free gas:

http://pure-gas.org/

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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I had to do this on my 98 Concours. At the time (probably 7-8 years ago) I bought an OEM pump with the sending unit off Ebay for a very cheap price. It fixed the problem and I have had no problems since. Today I am a little more nervous about buying off Ebay as who knows what kind of parts your actually getting, you hear about the cheap Chinese crap with OEM lable. Also the OEM stuff use to be cheaper on Ebay now it seems they are asking the same price as the dealer. Anyway I thought dropping the tank was a pretty easy job, the toughest part was removing the ring that holds the pump in. I bought the actual tool to remove this ring (any excuse to buy a new tool :-) and it didn't work at all for me (kept slipping off), I ended up using a brass punch and hammer which worked fine.

Good luck.

You can say that again, the ring WAS hard to get back in place it was similar to the water pump in its locking mechanism.

When I changed the pump I also changed the filler pipe that was corroded through.

You are right dropping the tank wasnt hard it was cumbersome to get back up where it belonged and hard to keep centered, the fuel inside created instability even though it was an eighth of a tank full, I did it with a floor jack and large square piece of plywood.

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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We have Fastrac markets here in Upstate NY. And Atlas.

I replaced the filler tube very recently. It was rotted

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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Rock Auto carries filler tubes. To me that means that there is a significant market for them.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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To be honest the oem ones are better.

When I had my 96 I bought one from the south that was original and like new.

Aftermarket does not always fit great, and not always work too well

My new one is aftermarket and I cannot pump full flow with the pump. Anymore than half trips it.

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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To be honest the oem ones are better.

When I had my 96 I bought one from the south that was original and like new.

Aftermarket does not always fit great, and not always work too well

My new one is aftermarket and I cannot pump full flow with the pump. Anymore than half trips it.

No turbo-tunes for you, not with that pump.

Half is probably more than enough, but I know GM well enough to believe that every spec for every part has a rationale, and not all of it is margin. So, don't start it cold in below-zero weather and romp on it to get a quarter-mile time before it starts to warm up.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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Lol I was talking about the filler tube kicking the pump of at the gas station. My new aftermarket pipe causes the trigger to cut off anymore than half squeeze of trigger

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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Years ago I had a car that did that, and eventually it stopped. Perhaps there's a vent or some such that isn't working right.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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To be honest the oem ones are better.

When I had my 96 I bought one from the south that was original and like new.

Aftermarket does not always fit great, and not always work too well

My new one is aftermarket and I cannot pump full flow with the pump. Anymore than half trips it.

The Guru use to say what kind of parts do you want to buy, factory that have been spec'd and "tested" to work specifically for your vehicle or buy aftermarket parts that have been spec'd but not tested. It might be just me but I have had enough issues with aftermarket parts that I really don't want to use them unless I have too and this is coming from a former parts guy (aftermarket) for 7 years. Not saying I am right just my opinion :-)..

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I ran the other way from that one. May be good but I wonder why it is only 40.00. That is the 97 unit though. Unfortunately the 97 was a one year unit.

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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$40 is a steal, great rating, maybe they fell off a truck :-)

The level sensor alone is more than that

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Note that most people who buy on eBay will give feedback once the package is inspected and everything is great. After the tank is dropped, the parts replaced, everything hooked up, and the tank buttoned up, AND the car driven for a few weeks (or months, or...), it's too late to go back and say, well, it didn't work exactly like an AC/Delco part.

I think eBay is a great place, but the vast majority of it is an international flea market, and there are some great items on it that may not wear well, such as "Tech II" units that are illegal knock-offs that may work well but are not necessarily reliable and are certainly not maintainable. I was about to buy one when I saw a post here from someone who provided a link to an article, which discussed some guy who was buying Chinese illegal knock-offs and selling them to people in CA and neighboring states as real GM Tech II units. GM got a huge judgement, which apparently approximated the cost of genuine GM units in the numbers of knock-offs sold, because the amount was "lost revenue" damages.

I would never buy a car part from eBay that is difficult or expensive to replace unless I knew the vendor, like CardioDoc on Wheels.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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I installed one of those 60$ jobs in a 02' Deville I have had for 4 years. I run the car hard back and fourth to FL twice a year and zero issues. Even rock auto sells a nice 120$ pump if you wanna spend xtra money.

Cadillac Jim: I bought one of those 600$ illegal Tech 2 on ebay 4 years ago I think. I use it often and it's flippin' awesome!

Edited by barczy01
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The Chinese knockoffs are around $200 and sometimes less, much less. For $600 you probably got a real one.

If it's brand new, with the GM and division logo decals unattached, and it's under $350, it is probably a knockoff. There are real used ones out there, and $600 is a good price for one. They rolled over to a new OEM for 2013 or thereabouts, so there are a lot of used ones that some dealers surplus when they get the later model.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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I purchased the Airtex/wells one off rockauto.

So I have 2 pumps to install.

I bought the Delco unit for my Seville. For my Seville I use strictly oem parts only unless I have no other choice.

But for my DD Deville I am willing to make some exceptions, especially when I have a bit already tied into it.

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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