Buick

Buick Repair Questions? Ask a Mechanic for Answers ASAP

Ask an Expert,
Get an Answer ASAP!

Buick

Buick Century Custom I am having fuel level and fuel tank

Customer Question
I am having fuel level...
I am having fuel level and fuel tank pressure problems with my 2002 Buick Century. The fuel pump is OK at the moment, but I am planning to replace the fuel pump assembly and the fuel tank pressure sensor to see if I can correct all my problems in one blow. I think all the problems may be related to the fuel pump assembly. I have a constant check engine light that my mechanic says is related to gas tank pressure. I installed a new fuel cap and that did not correct my problem. The fuel gauge reads either full or empty. but mostly full. I have over 100k miles on this car, and therefore I think I should replace the fuel pump and all the sensors/sending units that attach to this assembly. However; I have gotten myself very confused using internet research. I am not sure of my part numbers, nor exactly how to install them. Secondly, I am not sure what sensors/sending units are attached (or included) to the replacement fuel pump assembly. Would you please review the AC delco parts below for correctness? Also, except for the fuel filter, can I install all of these thru a port in the trunk? AC Delco OEM part numbers:

MODULE KIT,F/TNK F/PMP
Part Number: MU1743
Product Notes:
Fuel Tank/Fuel Pump Module Kit
4DR ; Incls strainer
Per Vehicle: 1; Years: 2002-2002

SENSOR,F/TNK PRESS
Part Number: 16238399
Product Notes:
Fuel Tank Press Sensor
Per Vehicle: 1; Years: 2000-2003


Fuel Filter GF578
Submitted: 6 years ago.Category: Buick
Show More
Show Less
Ask Your Own Buick Question
Answered in 11 minutes by:
9/6/2011
Buick Mechanic: Dave Nova, Buick Technician replied 6 years ago
Dave Nova
Dave Nova, Buick Technician
Category: Buick
Satisfied Customers: 19,452
Experience: ASE Master Certification. GM World Class Certification
Verified
Hello and thank you for using JustAnswer. My name is XXXXX XXXXX I will do my best to help you with your Buick problem.

The fuel pump assembly on your vehicle will come with a new fuel level sensor and a new fuel tank pressure sensor. If you purchase the fuel tank module kit, this should get you fixed up. The fuel tank must come out of the vehicle to replace the part.
Ask Your Own Buick Question
Customer reply replied 6 years ago
Are you sure that if I order the AC Delco MU1743 fuel pump assembly, it will come with the fuel tank pressure sensor? Also, is there fuel level "sending" unit that is included in the assembly? Thirdly; in my internet research, I was convinced there was an access plate in the trunk for this assembly? Dropping the tank is beyond my expertise.
Buick Mechanic: Dave Nova, Buick Technician replied 6 years ago
Yes, I am sure that the fuel pump assembly listed comes with both the fuel level sensor and the fuel tank pressure sensor.

You are correct about there being an access panel. Remove the carpet liner from the trunk floor and you will see the access panel. Remove the screws in the panel.

graphic
Ask Your Own Buick Question
Customer reply replied 6 years ago
When I see pics of the MU1743 assembly, there are no "parts" attached to the top of the pump assembly. I was under the impression that the fuel level "sending" unit, and the fuel tank pressure sensor/sending unit were mounted on top of the assembly? I think what has been troubling me is that AC Delco listed separate part numbers for these sensor/sending units?? Also, can you provide me with a high level step-by-step procedure for doing this replacement? Additionally; I expect to find some corrosion on the old sending unit (& wiring). This car used to be in a road salt area, and my guess is that corrosion may be the true cause of my problems. Anything I should look out for, or do?
Buick Mechanic: Dave Nova, Buick Technician replied 6 years ago
I am certain the MU1743 does come with both the sending unit and the fuel tank pressure sensor. I have attached a picture below. The black piece on the side is the sending unit. The float shown in the picture is shipped separate so that it will not get damaged, it simply snaps into the black piece. At the very top of the unit is where the fuel lines attach, as well as the electrical connections. It does not show well in this picture, but the black piece at the very top is the fuel tank pressure sensor. All AC Delco fuel pumps that are listed as "Modules" come complete with sensor and sending unit.

graphic
Ask Your Own Buick Question
Customer reply replied 6 years ago
Can you provide me with a high level procedue for de-installing and installing? Also, what about my question regarding corrosion
Buick Mechanic: Dave Nova, Buick Technician replied 6 years ago
The connections are on top of the fuel tank and are sealed, so I do not expect that you will encounter any corrosion there.


REMOVAL PROCEDURE

CAUTION: Fuel Vapors can collect while servicing fuel system parts in enclosed areas such as a trunk. To reduce the risk of fire and Increased exposure to vapors:
  • Use forced air ventilation such as a fan set outside of the trunk.
  • Plug or cap any fuel system openings in order to reduce fuel vapor formation.
  • Clean up any spilled fuel Immediately.
  • Avoid sparks and any source of ignition.

NOTE: Clean all of the following areas before performing any disconnections in order to avoid possible contamination in the system:

  • The fuel pipe connections
  • The hose connections
  • The areas surrounding the connections

IMPORTANT: Always maintain cleanliness when servicing fuel system components.


  1. Relieve the fuel system pressure by removing fuel pump relay from underhood fuse panel and then crank the engine over.
  2. Remove the trunk carpet.
  3. Remove the fuel pump access panel nuts.
  4. Remove the fuel pump access panel.
  5. Disconnect the Fuel Tank Pressure (FTP) sensor electrical connector.
  6. Disconnect the fuel sender electrical connector.
  7. Clean the fuel pipes, and fuel sender assembly to prevent possible fuel contamination during removal.
  8. Disconnect the quick-connect fittings at the fuel sender assembly.

IMPORTANT: The retaining fuel sender assembly will spring-up when the ring is removed.


  1. Hold down the fuel sender and remove the fuel sender retaining ring.
  2. Remove the fuel sender assembly.
  3. Clean the fuel sender assembly sealing surfaces.
  4. Inspect the fuel sender assembly sealing surfaces
  5. Reverse procedure to reinstall.
Ask Your Own Buick Question
Buick Mechanic: Dave Nova, Buick Technician replied 6 years ago
Please let me know if you need additional assistance with this.

David
Ask Your Own Buick Question
Customer reply replied 6 years ago
Do I need to do anything special to "prime" the new fuel pump? -- On the fuel filter, is there a special tool needed to remove the old filter? I assume that once I have the old fuel pump out, I can replace the fuel filter before I start up the new fuel pump?
Buick Mechanic: Dave Nova, Buick Technician replied 6 years ago
No special procedure required to prime the fuel system. Cycle the key on and off a few times and the fuel system will be good to go. The fuel system is a recirculating type, so all air will be pushed out of the system automatically.

The ideal time to replace the fuel filter is while you are servicing the pump before you start the new pump while no pressure is in the system. There is a quick connect fitting on the inlet of the filter, just squeeze the two tangs in to release the fitting. Needle nose pliers are helpful here. The outlet fitting is threaded and just uses two wrenches (5/8 and 13/16) to remove.
Ask Your Own Buick Question
Customer reply replied 6 years ago
Exactly where am I going to find the fuel filter? I think it is somewhere near the driver's door? -- Secondly; I went to order the fuel pump assembly and below is the pic of the top of the MU1743. Note that they show the sending units mounted on top of the assembly? Is this the same as the pic you sent me in the earlier post? I want to be sure I am getting the right part..graphic
Buick Mechanic: Dave Nova, Buick Technician replied 6 years ago
The picture of the unit you have in the picture is correct. The white electrical connector is for the pump and sending unit. The black electrical connector is the fuel tank pressure sensor. The tubes are the fuel line connections. These too are quick disconnect, just squeeze in the tabs on the end of the lines with needle nose pliers to release.


The fuel filter is located on the cross member just in front of the fuel tank

graphic
Ask Your Own Buick Question
Buick Mechanic: Dave Nova, Buick Technician replied 6 years ago
.

Anything else I can assist you with on this?


.
Ask Your Own Buick Question
Buick Mechanic: Dave Nova, Buick Technician replied 6 years ago
.

Please click the Accept button so that I may receive credit for helping you. If you need any additional information, please do not hesitate to ask. I will be glad to provide follow up information even after you click Accept. Thanks again for using justanswer.
Ask Your Own Buick Question
Customer reply replied 6 years ago
Last question. I am having trouble finding the AC Delco MU1743 assembly at a reasonable price. Several places are trying to sell me the AC Delco MU177 assembly, which they say are the same thing. When I look up the MU177 it shows that it fits Olds Intrigue and Buick Regal for 2002 (my year), but does not list Buick Century. Are they really the same? My gut is telling me to hold out for the MU1743.. Your thoughts?
Buick Mechanic: Dave Nova, Buick Technician replied 6 years ago
The Buick Century and Regal are identical platforms (chassis underneath vehicle). The fuel pumps are identical. The GM part number that I have for the pumps are shown below. Any good parts store can cross the number over to AC Delco for you. When I cross the numbers, this is what I get. If the MU177 for sure fits the regal, then it will fit the Century as well.

regal GM # XXXXX AC Delco MU1743
regal supercharged GM # 25344968 AC Delco MU1741

century GM # XXXXX AC Delco MU1743
Ask Your Own Buick Question
Buick Mechanic: Dave Nova, Buick Technician replied 6 years ago
Was this information helpful to you. If you need more assistance, please let me know!!
Dave Nova
Dave Nova, Buick Technician
Category: Buick
Satisfied Customers: 19,452
Experience: ASE Master Certification. GM World Class Certification
Verified
Dave Nova and 87 other Buick Specialists are ready to help you
Ask your own question now
Customer reply replied 6 years ago
I have just received the AC Delco MU1743 fuel pump assembly. It contains a "new GT280 Chassis Electrical Connector". It does not mention if I have to replace the original or not? It "implies" that I have to replace it? My questions are: Is this new connector different from the OEM? If I have to replace it; can I do it from inside the trunk (i.e. enough slack to pull the old connector up into the trunk to replace)?
Buick Mechanic: Dave Nova, Buick Technician replied 6 years ago
The connector is a new design, your old connector will not plug into the new pump. There is enough slack in the wiring to change out this connector from inside the trunk, just did this same repair on a Bonneville a few weeks ago. Simply match up the wire colors on the new plug with the factory wires. Not too hard to do.
Ask Your Own Buick Question
Customer reply replied 6 years ago
Follow-up. I am in the process of taking the old pump out and have run into a couple of problems. First; I can not seem to figure out how to "disconnect" the three fule line quick connects! The two outer ones are different than the center one. Someone said I needed a special tool? How do I remove these three with simple tools? -- Secondly; I saw somewhere that there was also a special tool to remove the pump locking ring? How can I also remove it with simple tools? -- Third; I have more than 3/4 tank of gas. To have to siphon some of it out?
Buick Mechanic: Dave Nova, Buick Technician replied 6 years ago
The tank will not need to be siphoned down. When you pull the tank module out, it will have fuel in th elower sump so be careful to pull it straight up then pour the fuel back into the tank opening.

There is a special spanner wrench for removing the locking ring but you can use a hammer and punch or hammer and flat bladed screwdriver to turn the locking ring. Counterclockwise removes the ring.

The quick disconnect fittings have tabs that extend from the fittings, squeeze these in with a needle nose pliers to release. After the lines are removed you will need to transfer the plastic retainer clips over to the new fuel pump module.
Ask Your Own Buick Question
Customer reply replied 6 years ago
will now try to qet the quick connects off now and let you know
Buick Mechanic: Dave Nova, Buick Technician replied 6 years ago
Okay, let me know.
Ask Your Own Buick Question
Customer reply replied 6 years ago
OK; got the old pump and the new one in place. I took "before" pics to be sure I got everything lined up, but am having a problem getting the lock plate to turn and lock. It "appears" that the pump is all the way down, and the lock plate is in the correct position. I get the lock plate started to turn (tits start over the lips of the holes), but no matter how much I bang on the plate to make it turn fully into place, I can not make it move into the final lock down position?? It only has to turn about 1/4", but it will not budge? I have put a large screwdriver on it and hit with a rubber hammer (trying to keep sparks down). Do I have to really slam it; or do you thinkt that the pump is not fully down; even though it is in the correct position?
Buick Mechanic: Dave Nova, Buick Technician replied 6 years ago
The pump has a single locating tang, if this tang is aligned properly then you will just need to use more force. The rubber mallet is absorbing a great deal of force, use a real hammer and you should be able to get it to turn. It does require a good whack. Also try hitting on opposing sides.
Ask Your Own Buick Question
Customer reply replied 6 years ago
I pulled out the pump and compared the rubber sealing ring with the OEM on the old pump. The new AC Delco rubber ring was "thicker" at the flange at the very top. I put the old/OEM rubber ring on the new pump.. reinstalled... couple of taps of the hammer and it slid into place nicely. It does tick me off that I went with AC Delco (lot more money) so that I would not have these problems.. Will probably not finish the job til tomorrow as I have to splice in the new connector; and then change the fuel filter before I can crank it up and check for leaks... Thanks for your help..
Buick Mechanic: Dave Nova, Buick Technician replied 6 years ago
You are welcome. The new seal is thicker on purpose. This is to prevent vapor leaks from the fuel tank. It is normally okay to reuse the old seal if it is undamaged.
Ask Your Own Buick Question
Customer reply replied 6 years ago
I old seal looked just fine. Giving how much I had to hit the hammer to get the lock ring to click into place, I do not think I have to worry about vapor leaks.. However; I ran into another problem. I went ahead and replaced the new connector that came with the new pump to the main power supply. Surprise Surprise.. It would not fit between the two vertical posts on the locking ring; as the OEM did! I had to take the ring back off; rotate it a 1/4 turn; and then put it back on. One of the vertical posts was so close to the pressure sensor connector, that I had to connect it before spinning the lock ring into place. Its tight, but I think just barely. My question for you is: I ordered an AC Delco because I thought it was the OEM; am I wrong? Will put on the fuel filter in the AM and test..
Buick Mechanic: Dave Nova, Buick Technician replied 6 years ago
The AC Delco is the OEM part, but just like lots of other companies, they have several suppliers for the same part, so design changes can occur.
Ask Your Own Buick Question
Ask Dave Nova Your Own Question
Dave Nova
Dave Nova
Dave Nova, Buick Technician
Category: Buick
Satisfied Customers: 19,452
19,452 Satisfied Customers
Experience: ASE Master Certification. GM World Class Certification

Dave Nova is online now

A new question is answered every 9 seconds

How JustAnswer works:

  • Ask an ExpertExperts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional AnswerVia email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction GuaranteeRate the answer you receive.

JustAnswer in the News:

Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.

What Customers are Saying:

Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help.

Mary C.Freshfield, Liverpool, UK

This expert is wonderful. They truly know what they are talking about, and they actually care about you. They really helped put my nerves at ease. Thank you so much!!!!

AlexLos Angeles, CA

Thank you for all your help. It is nice to know that this service is here for people like myself, who need answers fast and are not sure who to consult.

GPHesperia, CA

I couldn't be more satisfied! This is the site I will always come to when I need a second opinion.

JustinKernersville, NC

Just let me say that this encounter has been entirely professional and most helpful. I liked that I could ask additional questions and get answered in a very short turn around.

EstherWoodstock, NY

Thank you so much for taking your time and knowledge to support my concerns. Not only did you answer my questions, you even took it a step further with replying with more pertinent information I needed to know.

RobinElkton, Maryland

He answered my question promptly and gave me accurate, detailed information. If all of your experts are half as good, you have a great thing going here.

DianeDallas, TX

< Previous | Next >

Meet the Experts:

Dave Nova

Dave Nova

Buick Technician

19,452 satisfied customers

ASE Master Certification. GM World Class Certification

Gary

Gary

Buick Technician

1,499 satisfied customers

15 years master GM tech and mater ASE tech

John

John

Buick Master Technician

731 satisfied customers

ASE A1-A8 w/L1 GM master technician.Factory certified with 40 years experience.

George H.

George H.

ASE Certified Technician

531 satisfied customers

ASE Master 15+years

Don - Mo Lurch

Don - Mo Lurch

Buick Mechanic

519 satisfied customers

GM, Chevrolet Cert., Heavy Line Mech, Race Shop Owner, Mobile Electronics.

Ron Z.

Ron Z.

- Buick Tech -

474 satisfied customers

18+yrs experience. State Inspector and Buick Diagnostics

Chris (aka- Moose)

Chris (aka- Moose)

Buick Technician

316 satisfied customers

16 years of experience

< Previous | Next >

Related Buick Questions
Car is running and driving burn keybis stuck in the
Car is running and driving burn keybis stuck in the ignition … read more
Chris (aka- Moose)
Chris (aka- Moose)
Buick Technician
Vocational, Technical or Trade School
316 satisfied customers
Great oil pressure but lifters are ticking. Noise just
noise just started. Coming from below valve covers and follows engine rpm … read more
roy
roy
Associate Degree
3 satisfied customers
2013 Buick Verano fan just stopped. No heat and it's cold in
2013 Buick Verano fan just stopped. No heat and it's cold in the Midwest but not particularly cold today. Any suggestions? I'm from Canada and in Minnesota visiting right now. … read more
Dan
Dan
Automotive Technician
Vocational, Technical or Trade Scho
25 satisfied customers
It's a 2000 Buick century, replaced my alternator, starter,
It's a 2000 Buick century, replaced my alternator, starter, and put in a new battery and doesn't seem like starter is engaging … read more
eauto
eauto
self employed
High School or GED
74 satisfied customers
My driver side window will not work any longer. can I
my driver side window will not work any longer. can I convert it to a manual window … read more
Chris (aka- Moose)
Chris (aka- Moose)
Buick Technician
Vocational, Technical or Trade School
316 satisfied customers
Cigarette lighter stopped working. inside lights stayed on.
cigarette lighter stopped working. inside lights stayed on … read more
George H.
George H.
ASE Certified Technician
Associate Degree
531 satisfied customers
Lost keys. 2010 Buick Lucerne. We have looked everywhere for
We have looked everywhere for owners purse.. Cannot find … read more
Gary
Gary
Buick Technician
Vocational, Technical or Trade Scho
1,499 satisfied customers
No spark. 2004 redezvous 3.4. Replaced crank shaft postion
No spark JA: What is the model/year of your Buick? Customer: 2004 redezvous 3.4 JA: Are you fixing your vehicle yourself? What have you tried so far? Customer: Replaced crank shaft postion sensor JA: … read more
eauto
eauto
self employed
High School or GED
74 satisfied customers
My left front blinker is blinking too fast. replaced the DRL
my left front blinker is blinking too fast. replaced the DRL module and bulb and it worked fine for maybe four days, then it started flashing fast again … read more
Mechanic01
Mechanic01
1,716 satisfied customers
I'm having a volage issue with my 68 Buick GS. My battery
I'm having a volage issue with my 68 Buick GS. My battery voltage fluctuates at the battery terminals from 14 to 12 to 4 to 8 to 12 etc. I've removed the alternator charging lead to rule out a bad int… read more
Mechanic01
Mechanic01
1,716 satisfied customers
I installed a new (not rebuilt enginr in my 1990 lesabre.
I installed a new (not rebuilt enginr in my 1990 lesabre. Shouldn't a new computer have been installed? It has little power. … read more
don
don
fleet superintendent
Vocational, Technical or Trade Scho
12 satisfied customers
Pressure port located 2014 buick buick enclave. Installed
pressure port located 2014 buick buick enclave JA: Besides this, what condition is the car in? Customer: installed new a/c condenser JA: Are you fixing your Enclave yourself? What have you tried so fa… read more
Eric
Eric
Retired
N/A
14,436 satisfied customers
2008 allure. ever had it go forward when in reverse and go
2008 allure . ever had it go forward when in reverse and go in reverse when put in drive ? Shut off ignition for a minute and restart and trans goes forward in drive and reverse in reverse like it's s… read more
Chris (aka- Moose)
Chris (aka- Moose)
Buick Technician
Vocational, Technical or Trade School
316 satisfied customers
2013 buick lacrosse hybrid this car brake main tensioner
2013 buick lacrosse hybrid this car brake main tensioner bolt....we have new tenaioner new bolt.. new belt... but i can bot figure it out how to move tensioner.. in front i can move it to front.. but … read more
Chris (aka- Moose)
Chris (aka- Moose)
Buick Technician
Vocational, Technical or Trade School
316 satisfied customers
The heater /a/c will not work at all. 2003 buick century.
the heater /a/c will not work at all JA: Have you checked the coolant level? Has there been any leaking from the hoses? Customer: no, JA: What is the model/year of your Buick? Customer: 2003 buick cen… read more
Randall
Randall
Auto Technician / Consultant
Vocational, Technical or Trade Scho
69 satisfied customers
I have 99 Buick Park Ave and the rear doors from time to
I have 99 Buick Park Ave and the rear doors from time to time will not open from inside or outside the vehicle. After a while they will reset and work. Child locks are not on.Thanks for help,… read more
Chris (aka- Moose)
Chris (aka- Moose)
Buick Technician
Vocational, Technical or Trade School
316 satisfied customers
I have a 1992 buick park ave it cranks over fine. sometimes
I have a 1992 buick park ave it cranks over fine. sometimes it wont start or dies whenever it feels like it . I have replaced the ign control module and coil. but it still starts when it wants and die… read more
tim37857
tim37857
Mechanic
High School or GED
71 satisfied customers
The engine get bad on my car,I been change 2 engine by now
the engine get bad on my car,I been change 2 engine by now and still not good because it was selling to me the wrong engine … read more
roy
roy
Associate Degree
3 satisfied customers
Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Show MoreShow Less

Ask Your Question

x