Fuel Pump Woes

After getting my car mostly back together after months up on stands, I fired the engine. Other than an exhaust leak somewhere in my new system, everything was fine. Several days later I tried to fire it again and it just cranked and cranked. I had precisely ZERO fuel pressure at the port on the fuel rail. Even applying 12v to the pump via the test wire near the UH fuse box, or the connector at the back of the car the pump didn't make a sound. I ordered a new Delco pump and sock, which came the other day.

The worst parts of dropping the tank are working under jack stands, which I hate more and more with each passing year, and one fuel line disconnect that would NOT let go, no matter what I did with my Lisle tool. It finally gave up after a long struggle. No idea what that's about, as the second one was no problem.

A transmission jack with the adjustable "arms" for holding a trans removed works well to support a gas tank, thanks to its large, flat pad. I used a 2x4 scrap across it to spread the load even more. My garage was nice and warm from my heater until I had to open the damn door to get the tank out.


What also sucks is that I don't think I can use the existing sender assembly, since the lines have crusty rust. I'd hate to button everything back up and have a line develop a pinhole leak. What say you?




The B+ gray wire for the fuel pump looks pretty messed up at the connector for the pump itself. The wire insulation is missing as the wire enters the connector, and there are heat marks on the insulation above that area. The other side of the connector has evidence of clear melting at that connector. I'm assuming this is related to my lack of a functioning pump, but what would have caused this? Applying 12v directly to the + terminal of the pump doesn't do anything, but a continuitb test between terminals does show continuity, for whatever that's worth.




I could not figure out how to get my camera to focus on this area properly, even with the macro setting on. But I think you can see the melted area.




Waiting for me to have time to make progress, and for a sender assembly to arrive if I do indeed need to order one.

I think Fred Kiehl has one listed on his parts page, off the top of my head, I think it was $70 or $75. Send him a PM. He will probably post.

Tom

Take your pump back, and get the sender that includes the pump. Be glad you don't need to repair the lines on the car that connect to the sender. Been there, done that.

If the fuel lines were the only concern, I'd say rebuild them. You can pick up tubing repair sections with the flares ready-made at an auto parts store. A selection of plain tubing the next size up (or next size down) can be used as a repair sleeve (or insert). Using a tube bender, prepare the new pieces. Cut the old lines back to good pipe, and thoroughly clean off all surface rust down to bare shiny metal. Ream the repair sleeve (or the pipe itself for an insert) with the appropriate size drill bit for the tightest fit that will still slide in. Then silver solder or braze in place. It works very well.

However, in your case that melted connector means something was either corroded heavily or the pump was drawing excessive current. Continuity could mean a dead short, which would certainly explain the melted connector. It is unclear whether you mean the new pump or the old pump won't spin with 12v applied directly, but even if the new pump works fine, you still have that damaged connector to deal with. The last place you want a poor electrical connection is inside a half-empty fuel tank! So unless you can source a new fuel pump connector somewhere, I'd go with a new sender. That goes double if it's the new pump that won't spin.

If your new fuel pump does not come with a new connector, let me know, I have many new ones laying around, provided it looks like the one you have shown. The new AC Delco pump should have a new connector as part of the kit. Double check the ground for the fuel pump, a poor ground can cause the circuit to overheat. But more than likely, with the connector melted, it was poor terminal fit onto the spade of the fuel pump.

Sending unit still availabile from Rock Auto.

silverfox103 wrote:

I think Fred Kiehl has one listed on his parts page, off the top of my head, I think it was $70 or $75.  Send him a PM.  He will probably post.

Tom

Thanks, Tom. I'll see what he has.

jayoldschool wrote:

Take your pump back, and get the sender that includes the pump.  Be glad you don't need to repair the lines on the car that connect to the sender.  Been there, done that.

The fittings on the end of those nylon lines are rusty, but the insides look clean and the lines aren't kinked so hopefully I dodged that bullet.

I don't see a package deal for the updates Delco version of the sender with a Delco pump included. I see sender/pump combos made by Delphi and Spectra. I have been warned off Spectra, and one fellow on the Impala board reported a Delphi failure after 25 miles. I haven't researched enough to know if the Delphis are held in high regard overall...?

buickwagon wrote:

If the fuel lines were the only concern, I'd say rebuild them. You can pick up tubing repair sections with the flares ready-made at an auto parts store. A selection of plain tubing the next size up (or next size down) can be used as a repair sleeve (or insert). Using a tube bender, prepare the new pieces. Cut the old lines back to good pipe, and thoroughly clean off all surface rust down to bare shiny metal. Ream the repair sleeve (or the pipe itself for an insert) with the appropriate size drill bit for the tightest fit that will still slide in. Then silver solder or braze in place. It works very well.

However, in your case that melted connector means something was either corroded heavily or the pump was drawing excessive current. Continuity could mean a dead short, which would certainly explain the melted connector. It is unclear whether you mean the new pump or the old pump won't spin with 12v applied directly, but even if the new pump works fine, you still have that damaged connector to deal with. The last place you want a poor electrical connection is inside a half-empty fuel tank! So unless you can source a new fuel pump connector somewhere, I'd go with a new sender. That goes double if it's the new pump that won't spin.

I like your idea of the line repair, but while I used to do some silver soldering for my dad during his HVAC days, I do not have confidence in successfully performing that task.

It is the old pump that I applied battery voltage to at the + terminal. I did not test the new pump, which I will do once the sender is in the tank but before the tank is bolted up.

I did get a new connector from NAPA for the in-tank connections. A fellow on the Impala board mentioned that the aftermarket in-tank harnesses have ground wires that are too small; he ran thicker wire and soldered the connections.

If I get a new, updated Delco sender assembly I believe that they fixed many of the wiring/terminal weaknesses that plagued these. That, combined with a new Delco pump would hopefully keep me from having to drop the tank again.

I would like to know what a "dead short" inside the pump would look like in there? Also, where would the corrosion have to be to melt that power wire? On the terminals?

I agree that any kind of electrical/heat issue in a fuel tank is unsettling to think about.

Bull wrote:

I agree that any kind of electrical/heat issue in a fuel tank is unsettling to think about.

Nothing to worry about there. The air/fuel mixture in the tank is too rich to ignite a fire, not enough oxygen to support combustion.

I put a Spectra combo in my 94 a year ago. It's done year round duty for about 15k miles so far. There was nothing wrong with my OE pump, the sender lines were going (like yours).

gmtech wrote:

Nothing to worry about there. The air/fuel mixture in the tank is too rich to ignite a fire, not enough oxygen to support combustion.

In theory, yes.

In theory, one can extinguish a cigarette by tossing it into a pool of gasoline too. I've even seen it done.

But I'm not going to try it myself.

Delphi makes the pumps for AC Delco. I have a buddy in the parts business, and he says that Delphi makes a good pump. There can be a bad pump in any line, but Bosch has NOT served me well. The first one lasted 30 days, and the replacement lasted for 1 1/2 years. My 92 now has an AC Delco in it for about 3 years, and it is running fine. I have an AC Delco in my 91, and it is acting like it has a bearing going out after 2 years.

Yes, I have a sender unit for an LT1 wagon. It is in very good condition with almost no rust. I understand the desire to install a new one, and it is a valid reason. The reason I rely on used ones is the cost. I check them for proper function, and feel comfortable using them.

The part of the sender that is the most fragile is the holder for the float arm. The nylon part gets brittle and the clip sides tend to break off. I reinforce the seating of the arm with a tiny tiewrap. Just do not allow the tiewrap to interfere with the end stops of the arm.

I have yet to personally see a gas tank fire start inside of a sealed (gas cap on) fuel tank. If there has been such a case, I am unaware of it and I stand corrected.

I've seen fuel pump connectors burned up way beyond the example shown with no evidence of a fire inside of the tank, other than an overheated connector. I've also seen the power wire shorted directly to the ground wire inside the tank and blowing a fuse. I'm sure there was one heck of a spark that took place just before the fuse popped. But again no fire. Lack of oxygen to support combustion. The overly rich condition inside the tank smothered the ignition source, similar to the example cited below.

gmtech wrote:

Nothing to worry about there. The air/fuel mixture in the tank is too rich to ignite a fire, not enough oxygen to support combustion.

buickwagon wrote:

In theory, yes.

In fact.

In theory, one can extinguish a cigarette by tossing it into a pool of gasoline too. I've even seen it done.

Not theory, it's been done, as stated.
But I'm not going to try it myself.

My instinct is always to buy the best parts and equipment. But, that is often painful or impossible from an economic standpoint.

I just ordered the Spectra for $112 shipped (after tax) from Amazon. It's the assembly with the hanger, sender and pump.

I guess I will return the Delco pump and strainer I bought previously and hope the Spectra lives a long life.

Do any of you feel the need to beef up the ground wire for the in-tank harness? Sherlock9c1, or maybe it was some other fellow on the big board calls for it.

My stock pump and wiring seem to have made it all these miles, but if there is anything I can to to enhance the longevity of the new pump, I'm all ears.

Perhaps I will practice soldering and try my hand at soldering the connections at the bulkhead and pump.

buickwagon wrote:

gmtech wrote:

Nothing to worry about there. The air/fuel mixture in the tank is too rich to ignite a fire, not enough oxygen to support combustion.

In theory, yes.

In theory, one can extinguish a cigarette by tossing it into a pool of gasoline too. I've even seen it done.

But I'm not going to try it myself.

Reminds me of when a friend of mine flipped his cigarette into a steel tub full of about 5000 22LR fired cases.It ignited with such force that the can was lifted off the ground about 2 feet.Ignited the sound deadener lining the walls of the indoor range for about 10 feet in both directions,was tough but we got the fire out.Bottom line is never allow any flames of any kind near anything that can ignite PERIOD!Yes I know its not related to this conversation but you had to be there!Admins/Mods,do your thang!  

Bull wrote:

My instinct is always to buy the best parts and equipment.  But, that is often painful or impossible from an economic standpoint.

I just ordered the Spectra for $112 shipped (after tax) from Amazon.  It's the assembly with the hanger, sender and pump.

I guess I will return the Delco pump and strainer I bought previously and hope the Spectra lives a long life.

Do any of you feel the need to beef up the ground wire for the in-tank harness? Sherlock9c1, or maybe it was some other fellow on the big board calls for it.

My stock pump and wiring seem to have made it all these miles, but if there is anything I can to to enhance the longevity of the new pump, I'm all ears.

Perhaps I will practice soldering and try my hand at soldering the connections at the bulkhead and pump.

Use rosin core solder, and heat sinks between the plastic and where you are soldering to prevent melting of the plastic. An alligator clip should work.

gmtech wrote:

I have yet to personally see a gas tank fire start inside of a sealed (gas cap on) fuel tank. If there has been such a case, I am unaware of it and I stand corrected.

Fuel tank fires (Hollywood notwithstanding) are very rare Most fuel tank fires involve rupturing the tank (eg: Ford Pinto, GM pickup, Crown Victoria) or static electricity while filling*. Those ignited by electrical energy within a sealed tank are extremely rare, not to mention extremely difficult (and therefore expensive) to prove. The NTSB will expend these kinds of resources (eg: TWA flight 800) but in the case of an automobile fire, there's not much left to look at, especially in the case of a plastic fuel tank. The average Company Officer will scratch his (or her) head for a bit, shrug his shoulders, write "undetermined" or "leaking fuel tank" on the fire report and move on to the next one in the pile. The value of an individual automobile is not enough to trigger an investigation by the Fire Marshal -- not up here, anyway.

I'm probably being a bit paranoid. But on the balance of things, I rather not trust the melted connector. If you can supply him with a new connector, then I see no reason the old sender could not be rebuilt with a new pump and lines. Anyone know if the fuel level resistor is available as a replacement item for these cars? That would be my luck -- I'd rebuild it and a week later the fuel gauge would quit working.



*Odd fact: Women are more likely to experience this than men. It is presumed that this is because women are more likely to re-enter the car to retrieve their purse or similar, develop a static charge in the process, and discharge a spark in the escaping vapour cloud when they again reach for the filler nozzle to remove it from the tank.

In my searching for the best price on a sender assembly, I did come across one place that specializes in rebuilding them. Their FAQ section cited a price range if $75-150 PLUS materials. So, I wasn't going to save any/much money there.

Jay, is the Spectra assembly "updated" like the newer Delco one is in terms of its design? Were the wires satisfactory? You seem like the type of fellow who would pay attention to these things.

I just helped someone install a Spectra one in November 2013.  Their part has been updated as well, just like the delphi assembly.  Even has a spindly main ground wire too.  

If you solder, make sure you use a good soldering rig and know what you're doing.  A bad solder joint will leave you stranded.

Also, mind the float.  It is prone to getting hung up if you don't get it back into the tank correctly.

sherlock9c1 wrote:

I just helped someone install a Spectra one in November 2013.  Their part has been updated as well, just like the delphi assembly.  Even has a spindly main ground wire too.  

If you solder, make sure you use a good soldering rig and know what you're doing.  A bad solder joint will leave you stranded.

Also, mind the float.  It is prone to getting hung up if you don't get it back into the tank correctly.

Thanks for the reply, and for the great thread you have on the big board about cleaning up a stock unit.

I really don't have much experience soldering, so either I need to practice or just forget it.

Did you modify the thin ground on the Spectra, or do you see it as not being that much of an issue?

Any tricks to getting the float position correctly? I know about the two tabs that help locate the locking ring and sender assembly.

I didn't modify the ground - on a stock vehicle it's a non-issue.

There's another thread on this forum about avoiding a stuck float - search for that and you'll get what you need.

sherlock9c1 wrote:

I didn't modify the ground - on a stock vehicle it's a non-issue.

There's another thread on this forum about avoiding a stuck float - search for that and you'll get what you need.

Okay, I will. Thank you.

The good news is that the new pump works. I got the tank roughly into position, connected the fuel lines and harness and fired the car up.  I only let it run for a few seconds at most since the fuel level is so low.

The most frustrating part is getting the vent hose and fuel filler hose connected to the tank.  It looks like the tank needs to be pulled towards the DS about 1-1.5" to make the connections, but there is no play that way.  I only have the PS strap loosely installed, so I would think it would be easy to shift the tank around.  The straps are located in the "channels" that they ride over on the tank so I would think that means it is positioned as it should be.

Any tricks for making those two connections?  I'd love to get this job buttoned up tomorrow.

When you raise the tank, the tubes may align properly. In its current configuration the tank is probably leaning to the driver's side, which would make the tubes move to the driver's side a couple of inches.

Thank goodness that job is done. I removed the straps and lowered the back of the tank to remove the sending unit and reposition the o-ring, which I had installed incorrectly. I realized that when raising the tank, and without any straps holding it, it was quite easy to get the filler and vent tubes connected. I also smeared some silicone grease into the rubber hoses to make them glide on like butter.

Now I just need to chase an exhaust leak, paint and install a swaybar, bleed the steering and a few other small things and I might actually be able to drive this car for the first time since summer.

Well when I replaced the fuel pump in Ms. Roadie I just unscrewed the filler port from behind the fuel door and dropped the tank with the hoses still attached. I just had to bent the hoses a little to get them to clear the side of the body.