Fuel pump install '97-'03

[jem270]

Fuel pump install problem.

I bought the dealer fuel pump.

Part #25179344 $540.00 (I paid $440.00 by whining and asking for wholesale price)
MODULE, F/TNK F/PMPSENDER & PUMP. W/SEAL. CODE WFR.
After VIN 238198

I have the 2nd design pump so this is my part number.

It took me about 2.5 hours. Most of the time was trying to install the new one. I started with ¼ tank of gas per service manual.

I started by taking all the carpet out of the trunk. I laid some carpet on the trunk so I could lay and reach the pump. I took off the access panel and the pump was covered with dirt/grime. I sprayed it with some cleaner and hosed it off. It looked almost new. I then disconnected the battery and released the fuel pressure at the Schrader valve and loosened the gas cap.

I marked the lines before I started to remove them. I figured out how to release the outer lines by squeezing the clear parts which are clips. I had to reuse them because they did not come with the new pump. The inner line was strange in that there is a black ring on the end you have to squeeze to release it. I had to use a small screwdriver to help pry it off.

I used a pair of snap ring pliers to remove the snap ring. The pump was stuck down. I had to use a screwdriver to carefully pry it up. I guess the old O ring was holding it in. I pulled it straight up and tilted it slightly so the float will come out. I had looked at the new one to see how to tilt it.

I looked inside the tank with a flashlight and I was surprised how clean and rust free the tank was.

I took the new pump and tilted it to clear the float and put in the tank. The O ring on the new one was already in position on the new pump. Service manual said to install O ring on the tank before you install pump. I moved the O ring to the tank and pressed the pump down. It would not go all the way down. I tried many positions and it would go almost all the way but would not go the last 1/8 inch down to clear the snap ring. It was difficult to put much pressure on it while lying on my stomach. I also tried to install the pump with the O ring already on the pump and had the same problem.

I decided to pull out the rear seat bottom and top. The bottom just pops out and the top is held on by two nuts on the bottom. There was a foam flap on the back and I pulled it from the bottom and just tucked it under the windshield.

At this point I slapped myself because it was MUCH easier to get to the pump. I just sat cross-legged and was able to do everything. I still had problems getting the pump all the way down. I guess the problem was compressing the O ring. I got my son to push down on the pump with the back of a hammer and put pressure on it and I moved the snap ring around and got it into place. I had him put minimum pressure on it because the pump is made out of plastic and expensive. The snap ring has to be exactly in place because it will only fit one way. There is a little lip it has to clear. Look at the old one before you take it off.

I then took the old clear clips off the old pump and installed them on the new one. Look at them before you take them off. They only go on one way. I then attached the 3 fuel lines and the electrical connection.

I hooked up the battery, tightened the fuel cap and turned the key to run a couple of times and let the fuel system pressurize. I started the engine and it ran. I checked for leaks and everything seemed good. I put everything back together and told my son to test drive it and fill it up with gas.

He called from the gas station and said gas was flowing out of the bottom of the car. He drove it home and I took out the back seat bottom and top. I took off the inspection cover and the top of the pump was wet with gas. It appears that the O ring must have gotten pinched and did not seal. Next step is to take it back off. Problem is tank is now full of gas. I dried the top of the pump off and drove the car about 20 miles. The top of the fuel pump is still dry but the sun has set and it is now dark. I will drive it again today when I get home from work and try to burn off more gas. Service manual said to have less than ¼ tank of gas in fuel tank.

I will take the pump off again and this time I will lubricate the O ring with Vaseline (I read somewhere that it helped). I will try to reinstall the pump with the O ring already on the pump. My legs are still sore from lying in the trunk. Wish me luck.

Any opinions/advise welcomed and much appreciated...

[richtazz]

Getting that seal seated properly is the hardest part. Be patient, take your time, and if you have the pass thru armrest in the back seat, that may be a more comfortable access point for you. If you don't have the pass-thru rear seat w/armrest, you could also remove the lower seat cushion (two pull tabs in the seam of the carpet and lower cushion, and the rear seat back (4 bolts along the bottom (2 also anchor the rear seatbelts) and then lift the seatback up to disengage the top of the rear seat cushion. Then you may have more room to move to get that o-ring seated properly.

[jem270]

Thanks for responding.

I guess what I'm curious about is if I should install the pump with the O ring on the pump or on the tank. The service manual says to put the O ring on the tank and install.

Also can I use dialectric grease or motor oil to lubricate the O ring. I will buy vasoline if I need to.

[jem270]

I took the fuel pump back off and the o ring almost fell down into the fuel tank. It appears to have stretched. I lubricated it with motor oil and when I tried to put it back on the tank it appeared much too big. I tried to put it on the fuel pump and it kept falling off. I guess it soaked up gas and stretched. Also it was blue when I put it on origionally and now most of the blue is gone. It appears to have been some kind of paint. What blue was remaining appeared to be shredded and peeling off.
I pulled the o ring off the old pump and it was smaller around and the diameter of the rubber on the ring was smaller. It appeared to be in mint condition so I rubbed motor oil on it and slid it onto the fuel pump. I slid the pump into the tank and it slid down in perfect position the first time I put it in. I had to push just slightly for it to go down into place. It appears to me that the oil made all the difference and probably the first o ring twisted when I tried to slide it down on the tank. I hooked everything back up and the car started and ran fine. I will wait a few days to fill it up again. If it gives me any more problems I will let you know.

Thanks again everyone!

[50jeffrey]

If you could have waited for a few days to get the part, Rock Auto has it much cheaper



Item Price Core Total
ACDELCO Part # MU121 {#25179344}
Category: Fuel Pump

$325.79

[jem270]

We have a local Westwood auto parts that has it listed for $296.81. It is part number Delco 430MU121. I decided to use the dealer part because I had never replaced an electric pump before and I wanted to do it right. If I ever do it again I will use the Delco part.

Like most things, after I figured it out it was actually easy. It took me 30 minutes to pull it out and reinstall it last night.

Important hints not in the service manual:

TAKE OUT THE REAR SEAT

LUBRICATE THE O RING WITH MOTOR OIL

[wlkjr]

Not being a SA or anything, but the dealer that charged you over $500 should have given you some Vaseline. And then kissed you.

[BNaylor]

Originally Posted by wlkjr

Not being a SA or anything, but the dealer that charged you over $500 should have given you some Vaseline. And then kissed you.

Well, Wally look at it from the bright side of things.....Jem saved money on DIY (labor) costs. ..........

I have done three fuel pump and/or level sending unit DIY jobs on various GM "W" body cars to include Grand Prix and never had problems with the o-ring seal or getting the fuel pump pod to fit properly. I use special o-ring grease/lube. Job took no more than one hour last I recall.

Also, as Rich pointed out Grand Prixs with the RPO 1SB option which includes overhead console and rear seat pass through (for skis, etc.) do not require removal of the rear passenger seat. Just unlock and open the rear seat pass through door.

['97ventureowner]

Originally Posted by jem270

We have a local Westwood auto parts that has it listed for $296.81. It is part number Delco 430MU121. I decided to use the dealer part because I had never replaced an electric pump before and I wanted to do it right. If I ever do it again I will use the Delco part.

Actually if you look at 50jeffery's post you will notice that they are the same part #. Rock Auto sells A C Delco as does the GM dealer. You could've saved close to an additional $150

[jem270]

Actually Dealer (Chevrolet) parts manager was very helpful and answered some other questions I had. He agreed to sell it to me for $440.00. Sometimes price is not really that important. Having a good resource person is worth much more. Dealer also gave me a lifetime guarantee on the part and free coffee!

Next time (on another vehicle) I will go with the AC Delco part since I have some confidence.

[BNaylor]

Actually we have a much better GM/AC Delco source with prices and availability that beats or comes close to Rock Auto and GMPartsDirect.com that Wally and I have done business with along with many other AF members. The only problem is we will not allow publicizing his name openly in any forum due to our authorized vendor rules and possible conflict of interest since he is an AF member.

However, in the future just privately email any Grand Prix Moderator (me or Lynn-GTP Dad ) for the name of the source.

[jem270]

Here is some pictures that may help someone else with the install.


This is a picture of the trunk carpet and rear seat removed.



This is a picture of the back seat out.



Here is a picture of the fuel pump before cleaning.



Here is a picture of the fuel pump after cleaning.

[BNaylor]

Thanks for the update and pics. Here are some more pics if you have the rear passenger seat pass through and shows fuel pump pod removed. Unless there are any objections this thread will be moved to our Tips & Maintenance subforum.








Fuel Pump Pod with Pressure Switch Applicable to late '98 and up Grand Prix

[BNaylor]

Due to the technical value, this thread has been moved to our Tips & Maintenance subforum.

[sugurray4u]

Hey guys, this is first post and i really like this forum. I appreciate everyones input and the directions are awesome. I have one problem though and wht is when reading through Jem270 post, i am not quite sure where the Schrader valve is to let the pressure off and wont taking the gas cap off release the pressure. Also, i am attempting to repair a flaky gas guage and have seen where i can just replace the sending unit on the fuel pump but at the same time have read where people have replaced the whole fuel pump and it still didnt fix this problem. Any input I sure would appreciate it...thanks in advance