'93 Eldorado, 4.9L - Bad Fuel Pump?

[kdcing]

1993 Eldorado, 4.9L, 199k miles. Went to start my car this morning, engine started, then died after 1 or 2 seconds of run time. Now, starter engages, engine turns (i.e. battery is strong), however, the engine will not fire up. No codes.

I haven't done much troubleshooting yet, however, I do not hear the faint high pitched whine of the fuel pump anymore and suspect that it is likely bad. It has never been replaced in the 135k miles that I've owned the car. I do not have accommadations (i.e. no garage) to do a drop the tank, so I was wondering if anyone has attempted to cut a hole in the floor of the trunk or back seat to gain access to the pump? Also, does anyone know approximately where the fuel pump access hole would need to be (i.e. in trunk or underneath the back seat?). I know this access hole is probably a crazy idea, but not as crazy as dunking the new pump into a gas can on the passenger seat and running a fuel line to the FPR...just so I can drive this thing to a friend's garage.....hhmmm, hold on a minute.....

[greg-sls]

I had a similar problem with my 97 sls over a year ago. I think the newer Eldos have that access hole you speak of, but I don't think a 93 has one. For me, I had my car towed to a dealer and the price for the new pump was over $900. There are write-ups by those here who have dropped the tank for the change-out, but it sounds dangerous. Maybe check tech tips. Good luck!

[caddydaddy]

I've dropped a tank and changed a fuel pump before. It's not dangerous if you don't have any ignition sources!

[Ranger]

No access panel on the '93. Put a fuel pressure gauge on the fuel rail and see what your fuel pressure is. That will tell you if the pump is bad. I had one replaced on my '92 several years ago. It went on me when I had no time to do it myself. Cost me $400 at a dealer. $900 sounds high.

[kdcing]

On my '93 Eldorado (4.9L), it appears that the fuel pressure guage would be screwed onto the nipple that is located on the fuel rail that is on top of the front cylinder bank...underneath the black plastic beauty cover, towards the driver's side of the cylinder bank...near the distributor. Am I seeing this correctly? Just screw the guage on, turn the key and read the guage? Looking for 40-50psi?

[Ranger]

Yup. Looks just like a tire valve.

[kdcing]

Well, I'm down to replacing the Fuel Pump from above (my condo association rules prohibit the use of car jacks in the parking lot) or selling the car. Not a huge loss as I have definitely gotten more then my use out of it....it is worn. The car's value is only $500-$750 in running condition, so it is hard to justify the $270 labor at Goodyear (+ my $110 in parts from AutoZone).

I'm looking at the possibility of replacing the fuel pump from above by cutting a hole in the floor of the trunk or back seat. I have the back seat fully removed (i.e. seat and backrest) and have pulled the carpeting back in the trunk.

I've attached a picture of a fuel tank that I found on the web. It is a used tank that someone is selling and has indicated that it is for a '93 Eldorado.

My questions for the group:

• Can anyone confirm that the tank in the picture is actually the tank used on a '93 Eldorado?
  
• There is a round hole in the tank shown in the picture....this is where the fuel pump would be installed, correct?
  
• I placed a red dot on the picture...this is the approximate location where an access hole (approximately 1.5"x2.5") is located in the trunk floor for wiring that supplies power for some systems that are underneath the trunk (likely wiring for the Fuel Pump, ELC, etc.). I removed the cover plate and thick rubber seal to have a look around. I can see only about 3-5" into the access hole, but do not see the large hole in the tank as shown in the picture.....this is why I am asking if anyone has seen the top of a '93 Eldo tank...am I looking in the correct location for the fuel pump. My jig-saw is idling.....

[Ranger]

Yes, the large hole appears to be where the pump goes. Jigsaw! Put that thing away (if it's not too late). I don't know how much clearance there is between the tank and the floor, but I would guess you'll cut right through the tank as well, not to mention cutting the fuel lines. A jigsaw has a pretty long blade and stroke. If you insist on cutting a hole in the floor, I'd use a pneumatic die grinder and a cutting wheel or pneumatic nippers.

[kdcing]

...got her going again. It was the fuel pump and replaced it thru the top (i.e. thru the floorboard w/o dropping the tank). Only about an hour to do the actual hole cutting and replacement, but a bunch of research and planning. Some button up work still to do (i.e. patching the hole). More details to follow later.

Originally Posted by Ranger

Jigsaw! Put that thing away

Ranger, thanks for the tips along the way...I've done some stupid stuff, but the jig-saw was never actually pulled out of the tool box...way too much respect for the fuel system.

[Ranger]

So what did you use to cut the access hole? Patching it should not be too bad of a project. Some sheet metal, screws or rivets and some silicone should do the trick.

[kdcing]

....used a 5/16" diameter drill bit and drilled a series of holes in the area that I wanted to open up in the floor board. The holes were spaced with 3/8" - 1/2" of metal left between them. Tin snips were used to cut the metal between the holes. The holes were drilled to make a 3-sided opening in the floorboard...then the metal was peeled back like a sardine can. The metal is relatively thin in the floorboard and my manual tin snips easily cut thru. I had considered cutting w/ a grinding wheel or hack saw but did not want sparks so close to the tank. When drilling the holes, it was imperative to not allow the drill to go thru too far (to avoid drilling thru the fuel lines, fuel tank or wiring).

The local pick-your-own-stuff-junkyard was invaluable for planning this project. I found a Seville w/ the tank already dropped...so that I could see how the pump/sending unit attached. I found a Deville w/ the tank not dropped and was able to open up the floor board from above to determine exactly where I needed to put the hole.

Btw, the picture of the fuel tank that I attached in a previous post was not the correct tank for my car....nor was it the tank used on the '92 Seville or '95 Deville @ the junkyard. While all of the tanks are plastic, the position of the fuel pump was not as shown by the red dot in the previous picture. The correct position is shown by the black dot in the picture attached to this post and is positioned in the hump of the back seats.

An important part of the project is closing the hole back up. Since it is effectively in the passenger compartment, the hole can let in rain, snow, hot air, cold air.....and worse....like exhaust fumes, gas fumes....and liquid gas or fire in the case of a collision or rollover. My plan is roll the "sardine lid" back down, then epoxy the seam w/ a JB Weld type material to make it air tight....I do not want a screw or rivet popping thru the tank after I get it buttoned up.

In the next few days, I'll take some snapshots and post them.

[kdcing]

Double-click on images to make larger.