Fuel Pump 1998 Buick Park Avenue 3800

Mikerizer

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1998 Buick Park Avenue, 3800 (3.8L), 136K miles NOT turbo injected

Here's the story...this is my brother's car. He was running quite low on gas, and pulled up to the pump. As he was waiting on the person in front of him to pump their gas, his car stumbled and quit. He pushed a few feet to the pump, and put $20 gas (8 gallons) in it. It never cranked again.

I pressed the bleeder valve at the fuel rail, and at first got some air and fuel. He tried cranking it so much that I had to hook up my booster cables to his battery. I ouldn't hear the fuel pump priming up, but there was a lot of traffic noise.

Do you agree the fuel pump is probably toast? I'm pretty sure it's the original, with 136k miles on it.

How do I go about getting 8 gallons of gas out of the tank?

Any general guidelines or step by step procedures would be greatly appreciated! We will definitely be using a GM fuel pump.

Thanks for your help!
 

sunny

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You need to just turn the key on without cranking a few times. You will have to wait about 10 seconds between turn ons. This should reprime the fuel system for you. If you still get no pressure then I will agree it is probably the fuel pump.
If you change the FP yourself remember you will have to remove the rear half of the exhaust in order to get the tank down on that model. It's a bit difficult at times even with a lift so you may opt to tow it to a shop. Just a little heads up for you.
 
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NickD

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On any GM vehicle I have worked on that does not include a 98 Buick is a short dangling lead you can apply 12V to, to directly test the fuel pump for both voltage and current draw, helps to have a manual as they are not easy to find. If you can find the fuel pump relay, well still need a manual, as one of the leads goes directly to the pump. Eight gallons isn't too bad, adds about 48 pounds that could be easy with a helper. If all else fails, find the gas outlet tube, jury rig a hose to it and can siphon it out from there. Didn't work on my Supra, because that ethanol swelled up the check valve as well, couldn't get a drop. Did have a Honda inline pump, must of pitched it when I was doped on pain killers. Fortunately, that car had a fuel sender access plate, so I could siphon from there, but had 18 gallons.

That platform I built for dropping my AT on my floor jack was a big help in dropping the tanks, gave me an extra hand as that tank had to be angled to clear the permanently attached filler tube, also a big help on that super heavy aux tank on the motorhome. But a helper would have been the easiest.

Just about every vehicle I have owned plus relatives and friends, the fuel tank had to be dropped at one time or another, would like to shoot the people that decided to put the fuel pump in the tank, always a miserable job with challenges as to how to get the fuel out. See on the net that aftermarket in-line pumps are available, but sometimes a problem as to where to install them, and quite expensive. But for the price of the in-tank replacements, seems like you should get more than a slot car DC commutator motor drive a tiny plastic impeller. Those brushes don't last forever, pump runs all the time, and it's output pressure has to be greater than the regulator so you have fuel return to cool the pump. Ha, also read in the instructions on the new pump to keep the fuel level at least 3/8's full as fuel is needed to cool the pump. That translates to my 18.5 gallon fuel tank being reduced to about 11.5 gallons.

With one of my kids constantly driving on fumes, I opened his old unworking pump, was actually in very good shape with plenty of brush life left, but one of the brushes was crystallized with heat and snapped into two. After he got all dirty helping me and paid for a new pump with his then minimum wage job, he finally learned to treat a 1/4 full tank as an empty tank, it's all relative. Really a PITA job.
 

Gus

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Check fuel pressure and power to pump....access the pump through the trunk....don't have to drop tank....don't have to remove the fuel....
 

Mikerizer

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Sunny: tried turning the key back and forth several times, but didn't wait 10 secs between. There was a lot of traffic noise, so I couldn't hear a thing. Right now, the car is in my Dad's back yard, so I'll give that a shot...I never did get any pressure at the fuel rail bleeder valve though.

NickD: if you find the engineer(s) responsible for an inside the tank fuel pump, I'll buy the ammo and the pizza! :mad:

Gus: If I don't have to drop the tank, you're my HERO! :thx

Thanks to all...I'll do some more troubleshooting based on your tips, and post back...it'll probably be Thursday evening before I can get back to it.
 

Mikerizer

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Latest and greatest news...

I did peel back the trunk skirt, and found what looks like an access panel to the fuel pump. It's kind of a pear shape, toward the passenger's side of the vehicle, just behind the back seat. I'm going to take the back seat out, so I can get to it from both front and back. THANKS, GUS! :thx

I also tried turning the key back and forth at 10 second intervals...it was getting a bit of gas to the bleeder valve, but no pressure. When I tried to crank it, it sounded like it hit once, then ran dry.

I also swapped the fuel pump relay out with a known good one; no change...all the fuses are good, too.

I'm planning to crack this one open this weekend; I'll post back with the results.

Thanks to all!
 

Gus

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Like I said, disconnect the harness at the fuel module......attach test light to terminals "B" and "C", grey and black.....turn key on, test light should light for two seconds.....crank vehicle, test light should be on constant.....if you have power, and there was no fuel pressure before disconnecting the harness, you need a pump.....
 
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NickD

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It's nice to know if you have an electrical problem before dropping the tank, kind of painful to drop the tank, replace the pump and learn you have a bad ground that is easy to repair. Try to get as close as humanly possible to the pump, electrically speaking. I prefer using a current limited power supply that has an adjustable voltage and shows current to make absolutely sure. If the pump does run, and the odds are against you, a voltmeter as close to the pump as possible to verify it's not a low voltage problem. If the battery voltage is 12.2 volts should see at least 12.1 volts at the pump. Just once I ran across dirty relay contacts and was only getting 9 volts, kind of erratic at the pump, that was an easy cure.

On the GM vehicles I have worked on, normally there is a short harness with a connector on top of the tank to make dropping the tank a bit more convenient, that is where I do my testing, as close to the pump as possible. That connector exposed to road slush is also suspect. Normally with a bad pump, applying 12 volts shows zero on the ammeter, can jack up the voltage to 20, still zero. With only two volts on my Supra, current started to skyrocket toward 30 amps, knew that pump was stalled, and taking it apart to see the swollen plastic on the armature proved that. Normally find broken or practically no brushes left on GM pumps for the open circuit. Your Buick should only pull about 4 amperes under full load, but I see they use the same pump in S-10 applications with almost twice the fuel pressure, and they pull closer to ten amperes. That's 140 watts, and they really need a lot of gasoline for cooling.
 

Mikerizer

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Thanks...I'm planning on removing the access panel in the trunk, and test for power to the pump before I remove it.

I do have an additional question...when we were trying to jump it off (the battery ran down from trying to crank it), the temp needle and fuel level needle both went around 360 degrees, and pegged out on the bottom of the low side peg on each gague. How do I get the temp and fuel needles to spin back to their home positions?
 

Gus

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You are not going to like what I'm going to say.....you have to pull the cluster, and remove the clear plastic cover and physically move the needles.......since it is your own vehicle, I would drill a small hole in an out of the way place in the clear cover and sneak a wire through it to move the needles...

A decorative plug or picture or what ever, can eliminate the hole...
 

Mikerizer

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I was afraid that would be the case. I was hoping there was some kind of trick to reset them to their home positions via jumping a wire or something... ouch
 

Mikerizer

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Gus said:
Like I said, disconnect the harness at the fuel module......attach test light to terminals "B" and "C", grey and black.....turn key on, test light should light for two seconds.....crank vehicle, test light should be on constant.....if you have power, and there was no fuel pressure before disconnecting the harness, you need a pump.....
I should have printed this and taken it with me. I was by myself, so I'm not sure I could have done it anyway. Here's what I've found so far (I'm doing the best I can here):

1. The battery is dead, so I hooked up my jumper cables...I was getting 11.67 volts at the battery

2. There are two harness leads at the pump. I'm assuming the 4 wire is for the pump, and the 3 wire is for the sending unit. I checked all four terminals on both and got this (ignition key in the ON position):

On the 4 wire connector:
Terminal A, Brown wire, 11.13 volts
Terminal B, Tan wire, 0 volts
Terminal C, Black wire, 0.01 volts
Terminal D, Black wire with stripe, 0 volts

On the 3 wire connector:
Tan wire, 5.02 volts
Green wire, 0.02 volts
Black wire, 0.01 volts

I wish I would have had someone to turn the key while I was testing voltage...

All fuses under the hood, and under the back seat, checked out OK. I swapped the fuel pump relay with another relay (power windows, maybe?) and had no change.

I can't even begin to tell you how happy I am that the fuel pump is accessible without dropping the tank! I removed the back seat, and it's a piece of cake to get to!
 
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Bob G

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There is a simple way to check if your pump as gone kaput. First you need to make sure your battery is up or use a jumper. Now you need 2 people for this, remove the gas cap and put your ear to the filler hole, then have someone turn the key to the on position (do not crank the starter), when the key is turned on, if the pump is working you will here it hum charging the fuel lines for a couple of seconds & then turn off. If you don't hear it start then it's kaput.
 

Gus

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Mike, don't take offense....but are you color blind?

Try cleaning off those wires, the dirt may be fooling you....A(purple, never seen it brown) & D are for the sending unit.....B(grey, could be mistaken for tan over time) and C are for the fuel pump...attach a test light to B and C....key on, lights for two seconds....crank, on solid......the 3 wire is the tank pressure sensor....

You definitely want to know if you have power on B and C....
 

Mikerizer

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;D ;D ;D

I may be color blind...I hit 40 hard this year, and almost everything is going kaput on me (I said almost everything). :-[

I was working in the dark last night, and could only find a 25 or maybe 40 watt bulb for my drop light...I better go by the A,B,C,D rather than color.

I'll check it again, with the help of my brother (who owns the car) with some daylight remaining early this evening.
 
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