coolguywalt

Well, after driving for like 45 min. yesterday, the fuel tank ws humnming....LOUD!!! So I popped the hood and checked the fuel pressure and it was bouncing around from 13 psi to 25 psi. Bad fuel pump, right? When I got out of work, the car felt like it was going to die when I was trying to accelerate and stop. Anyone else ever have this problem? I already ordered a Walbro 340 HP from Auto Performance Engineering for 113 with EVERYTHING!!! Anyone know how long it should take to drop the tank and get it all back together?

aklim

With the proper tools, less than 3 hours.

coolguywalt

Well, do you know like what size sockets I would need? I have a pretty basic set, goes up to 15 millimeter and 11/16th ...should I be allright?

aklim

Do yourself a favor and empty the tank first. Also because of the age of the car, buy yourself a couple of gas tank straps. You might get lucky and be able to reuse it but maybe not. You will have to drop the rear end so you will need more than jackstands to be comfortable. I would say a hydraulic lift with a support stand for the rear end would be good. Basic socket sets are good. Some extensions and plenty of bolt penetrant would be good for the rusty bolts.

Kwiksilverz28

You can do it with tall jackstands. No problem. The only thing that took me longer than 2 or 3 hours was that the filler neck looked liked it leaked where it attached to the tank (thought I had smelled gas back there before, so made sense). I knew there was a recall for that, but that had long since expired, and a new tank was quite a bit, so I cleaned it and wire wheeled it (prayed for no fumes & sparks), and JB welded it. Let it dry, then painted the area to prevent rust. Other than that, the job was not bad....

kandied91z

are you sure you weren't out of gas......when they go they just go and you wouldn't hear much of anything.

aklim

I don't know about our pumps but on my wife's Benz the pumps were external and when we suspected it was going bad we tested it by running the pumps manually. One was noisy and the other took more current than it should have and both were bad for sure.

coolguywalt

Well, yea,....when I drive it for awhile, the voltage goes down when idling. I also can hear the pumps at 50mph, over the exhaust and radio. That, to me, says something ain't right. I pulled over again today and the FP was at 34psi, right before it started to get REALLY noisy, so, I think the pump is sucking all the power from the charging system just to get enough fuel to keep the car running. Does anyone by chance know the largest size socket that I will need for the job? The biggest size I have right now is 3/4"

kandied91z

well you never know, some people over look such things. the stock pump is relatively quiet. however i'm use to my old procharger booster pumps and my current 340 walbro, etc. which is very loud.

aklim

You would need to hook up a battery to the pump with a DVOM to take amperage loss thru the tank pump and know what the proper amp draw is. I know MB has a certain spec because we checked it but not sure if GM has that spec. However, noise is not acceptable from the pump. Buzzing is alright if it is not too loud but also your pressure is way low.

Before we go too far, lets start with the basics. Are you sure your filter is good? Also are you sure the Fuel Pressure Regulator is good? You want to have it pressurize it like when you are starting and see if it holds the pressure. Also you can crimp off the return line and see if it builds up the pressure and thel release it to see if it can hold the pressure. Maybe the pump is being worked too hard because you have a bad FPR.

coolguywalt

It will only do it adter I have driven a long time I found ut yesterday. The pressure at start up will be 42 PSI and will hold steady for over 2 hours. The gas tank is never driven with less that 1/3rd of a tank. I make sure of that. I am in the process of moving and don't have much time untill later tonight so I will pull the tank and fuel filter tonight hopefully.

aklim

If at startup it is 42 psi and still that when you turn off the key and after a couple of hours, I would suspect the pump. Get a good one and change the gauge sender while you are at it. And also the gas tank straps.

kandied91z

the sender.....yep i should have done that one. how much is that anyone know?

aklim

I forgot but any GM dealer should be able to tell you that. I would replace it just because I don't want to do it all over again should the sender fail later on

stanghunter211

A sending unit is gonna run around 3-400 bucks depending on where you go. They are not cheap. I don;t know about just the sender itself. I am in the process of replacing everything basically from the driveshaft back on my car. You can check out my progress here.
http://cs5.simplehost.com/~sanger/fo...read.php?t=370

Lota new parts on the way, including a gas tank, walbro pump, new rear end, LCA's, Panhard, brakes, rotors, lines, torque arm, driveshaft,... you get the idea. Its not that bad, and theres an aftermarket compnay that sells new gas tanks for 275 I believe. Not bad, the cheapest I could find, so I bought one.