...And not cutting the dreaded hole. Can it be done? Has anyone ever tried?

The more I look, the more it looks like this can be done. The fuel line disconnects (steel to rubber) are just rear of the rear drivers side axle.

I hate to drop the rear end...actually I'm in a situation of fix it fast or sell it.

I've done every check I could find here for the pump and figure the pump is dead.

-At the relay, jump the orange and tan wires...no pump running
-At the relay, checked Ohms at the tan wire and a good ground...shows shorted out...could this be my problem instead of the pump?

Since the search function is on the fritz here, I havent had any luck searching out any info for dropping the rear end...or is there a tech article for that?

What tools, what bolts, what order... I have no clue where to start.

I guess my 2 questions are:
1. Can the tank come out to replace the pump without dropping the rear end?
2. Full Ohm resistance for the tan wire, is the pump still my problem or could this just be a wire problem?

Ideas?

 

its really not as bad as a job as it sounds, well... depending on if you live in the rust belt or not.... anyhow, its one of those things that - the way it is is the way it is and you coulda been halfway done with the amount of time you spent figuring out a different way to do it.

 

You don't HAVE to pull out the rear end to remove the gas tank. It's just easier to do it if you do. You can undo the brake line where it mounts to the rear end and remove the shocks and springs and lower the rear end down as far as it will go. You will need to remove the exhaust or rotate it out of the way as I did. I've done it solo. In that case it's just a lot easier to be able to get under the gas tank with a floor jack to help suport it. The tank must be dropped and rotated 90 degrees to get the filler neck out without cracking the solder joint to the tank.

Lon

 

If you dont have the guts to cut the hole, then stop wasting time and drop the rear end. you should be able to drop the rear end, drop the tank, change pump, re-install tank and rear end in less than 6 hours, 8 hours max.

Average labor rates for the rear end on our cars is only about 4 hours for R&R. Add the tank and pump in, which is another 2 hours max.

I'd just cut the hole, make the cut neat, if done right the removed plate can easily be tacked back in place and sealed with seam sealer.

 

Exhaust is bolted at the cat...I made sure they did that last time I had a cat back put on.

No access hole has been cut, I pulled the carpet to check...and I don't intend to cut one.

Car is an Illinois car, all it's life, and from looking underneath, it appears the rear end, tank, or drivesahft have never been pulled. Not bad for a 275,000 mile car. Rust looks typical for this area.

I figured there was some catch that prevented the tank coming out...ie rotating it to get the filler neck out. It's got 10+ gallons of gas in it too....dangit.

I'm still stumped about the tan wire having full ohms (pegs my ohms reader on my voltage tester). Is that normal? Does that occur even if the pump is good? That wire being grounded out leads me to beleive the voltage aint reaching the pump. My gas guage is reading pegged too, even with the ignition off and the key out. Would that indicate a bad sending unit? A short somewhere?

The funky fuel guage reading and the pump not working happened at the same time. No maintenance was being done on the car at the time either. Fine one day then the guage went bezerk and the pump won't prime.

I really want to rule that out before I start knocking on some rusty bolts.

Ideas?

 

I'd check the wiring for some shorts. If worse comes to worse, and you do drop the tank, replace EVERYTHING that goes up there, and replace it with performance parts. Better than stock pump, better wiring, better sending unit, everything. Replace it all. It's one of those jobs that you'll do once, and NEVER want to do again, so you'd better make sure nothing else fails up there during your lifetime.

And I fully agree. No hole already, then don't cut one. It's a hack job.

 

Maybe.
If both the gauge and the pump stopped working at once, that would point to an electrical issue. They both share the same ground.

One place that you probably did not check (or at least I didn't find it mentioned her) is connector C313. It is behind the passenger seat, on the wall, right in the middle. It is accessible from underneat. It's practically above the rear differential. I had a fuel pump problem one day, measured the tan whire and came up with some 50kOhm resistance. I went directly for the floor jack.

If you measure the tan/white vs black wire on that connector and it doesn't show a few ohms, then you can suspect the fuel pump.

Btw, the fuel gauge uses a purple wire (same C313 connnector) and if it reads full, it might be just a bad connection at C313 again.

Hope this helps.
Lou

 

Before you do anything find the positive and negative wires from the pump (as close to the pump as possible). Measure for 12V+ on the positive and check continuity between negative to ground. Why look into a huge project that *may* not fix your problem?

And seriously, drain your tank it'll make your life easier.

 

The deed is done.

I had already pulled the carpet and pinholed the wires there. Gets a full 12 volts at key turn so, wiring was good there.

Jacked it up, pulled the wire connector above the differential, hacked up one of my cheapo xtension cords and poked 12 volts directly into the pump...nothing heard, so the pump was definatly dead.

Bought a 59 dollar Airtex pump from Oreilleys{Sp} and pulled the rear and the tank.

Slapped a new orings and a fuel filter too...put it together, shot starter fluid in the intake and fired it up. Actually runs better than before.

With the old pump in hand, I poked 12 volts into it (just to see what makes these pumps die), I could barely hear the pump motor trying to run, kind of like a weak grunt coming from the pump. So I cracked it open..it had a very fine black silt deposited in the intake channel of the pump. Its a miracle any fuel was able to flow thru that thing. Diagnosis...pump was working too hard to push fuel into the system thru a microscopic hole clogged with crap. Plus, this car has ~270,000'ish miles on it. The pump was the original ac delco pump. Not bad at all.

The tank was fairly clean...for an 18 year old tank... I wiped a shop towel around to remove most of what I could see and put it all back together.

Remember, I am in a crunch for time since I have sold our home and will be moving out in 2 weeks. Wife said, the car has to be running or we gotta sell it...I have to agree but wanted to give it a good shot before I sold it.

So, I may regret the Airtex pump and not having the tank cleaned. But Its running and I'm happy. Once I"m setteled (moving to Alabama) I plan on swapping the 305 out for a 350, keeping the TPI on it and putting something than the 2.73 gears in the back. When the gears are swapped, a better pump will go in. It'll continue to be a daily driver.

My fuel guage is still messed up tho. Before the pump swap the guage was pegged past full, now, with a full tank of fuel, it reads ~3/4 of a tank...gonna drive it a while and see what it does. Checked it with an ohm meter while I had it out and got 0 readings when I moved the float up and down...pot must be gone too. That'll be fixed...later
----------
Oh...draining the tank happened quite by accident.

Hacked up one my water hoses...wouldn't gonna happen, all the hard fuel lines sit right at the end of the fill tube.

I put my 13 year old under the car to disconnect all the fuel lines. He unclipped the return line first and presto...it began to siphon out all by itsself.


I grabbed 2 five gallon buckets, slid them under there. Thirty minutes and 3 PB and J sandwiches later it stopped draining. I think there was maybe 3 gallons left in the tank when we dropped it out.

 

Where do you get a better sending unit?

 

Y'know, I found one not too long ago. Might not have been "better" but was at least new. And now I can't seem to find it anymore. Bollocks. I was planning on using it whenever I decided to drop my tank (prolly with the axle drop). Gonna keep looking.

 

any measurements or pics on cutting the dreaded hole in the floor pan???

 

the sending units normally just get gunked up, if you takem apart and clean all contacts well with rubbing alcohal and reassemble it normally fixes that problem, at least in my experience...

 

Fuel pump access door and cutting the fuel lines then splicing them back together; hands down best mod I've ever done. You basically cut a flap in the center of the console hump. Mine had 2 grooves, I cut front to back right beside those grooves and pulled out the flat peice of metal, I did this with a pair of tin snips so it was as bad as it could humanly possibly be. When it was done I made a gasket for it and bent a plate out of some sheet steel then held it down with a couple real short self tappers. I have had that fuel pump out 3 or 4 times now and each time I get in there there's no rust or anything crazy. Trust me I thank myself EVERYTIME when I have to mess with the pump. Oh btw before I did the access door, I pulled the tank out WITHOUT dropping the rear end; I removed the shock bolts on top, twisted the tank to the side and kicked it from the back, it finally came out but the filler neck had to be bent a bit to get it back in.

 

well i got the hole cut, going to get the pump and stuff later tonight. we're just going to replace the pump, and harness and do some cleaning in there since we went through the trouble ne ways. i really dont feel like being stranded again due to pump issues. at least not for a while. poics comming later :-)

 

ive replaced my fuel pump by cutting the hole, i just put the carpet back ontop of the flap and everything is fine.

 

One of the reasons some auto manufacturers stopped putting gas tank access "doors" in the trunk floor was because of all the heat they got about the ruptured gas tanks in the 70's and 80's. If the door/cover isn't strong and firmly attached , it can provide an avenue for flames and smoke in the event of a rear end collision. And it will vent directly into the passenger cabin.
Check this link: http://bestaccident-attorney.com/carcrashfires.html and many others on this subject. The best position for a rear fuel tank is ahead of the rear axle. This is the opinion of many experts in the automotive industry and government agencies. The Camaro and Firebird have the tank aft of the rear axle and ahead of the rear bumper, in the infamous "crunch zone". Make sure that whatever mod you make is as rugged as possible. Perhaps two .035" sheet metal layers, one below the deck and one above.

 

I've replaced 3 fuel pumps in 3 differant camaros and not once have I needed to drop the rear. All I did was jack up the rear of the vehicle as high as I could get it and let the rear end sag down, It gave me more than enough room to get the tank down....but on the other hand I did cut off the exhaust at the bend near the axle to help.

 

Wrong page of the book there. The gas tank is not aft of the axle, its directly above it.

 

Remove your muffler and drop your exhaust pipe where the holding bracket is, then those 2 bars that go across the rear unbolt them and make sure the car is lifted a good height off the ground and your in business, ive dropped a tank and reinstalled in a abut 3 or 4 hrs