Fuel Pump failure - 3rd times NOT a charm!

Colltech

Colltech

'85 and '83
I've just had my THIRD electric fuel pump fail, even thought the car has never been driven on this pump - i.e. its BRAND NEW as was the previous pump that failed.

Quick review:

1983 X under complete restoration. It runs but I do not drive it as its largely disassembled. I occasionally start it for fun but it never leaves the driveway.

When I bought it 17 months ago, it had a working Bosch fuel pump. After sitting a year, I went to start it but the pump was dead. I purchased and installed a new Airtex 2182. Tested it and it worked fine. Let it sit for a few months, went to start it and again, the pump was dead. NO usage - no sediment - no rust in the tank - just electrically dead. I swapped it under warranty (lifetime) for a new one. Installed the new (3rd) pump, it tested and ran fine. That was 3 weeks ago. I just went to start it up and guess what? DEAD!

I thought perhaps it was getting power even when the key was off but that does not appear to be the case.

I've checked the voltage across the terminals:

Key off = 0.00 V
Key on = 0.00 V
Key and AFM flap open = 12.4 V (battery is a little low)

What could possibly be causing brand new fuel pumps to electrically fail from just sitting there unused???

I've posted about this problem recently and got a lot of good advice, most of which made sense if the pump was in use and the tank was dirty or the amperage was wrong. But these failures are happening with a clean tank and zero use.

This makes no sense to me. I'm hoping what of you "electrically wiser" members can help me figure this out.

Thanks in advance!

Ed (Colltech)
Austin, TX
 
Fuel Pump failure update

Just got off the phone with Airtex support. They suggested draining the tank and replacing with fresh fuel. He claimed that old fuel just "sitting" in the pump can be highly corrosive.

I have my doubts that even terrible fuel could corrode a pump from the inside in just three weeks but I am willing to try anything at this point.

Whatever the state of the fuel, the car runs fine on it. Luckily there's not much in there.

I'm still very interested in hearing other opinions on this problem.

Thanks

Ed
 
Have you tapped the pump directly with 12V while it is on the bench? The wiring in most cars are run through harness and hook up with other components. It has been my experience especially ignition that there can be fandom draws due to bad wire connections. So try a direct lead from a good battery. I doubt the fuel will effect the electrical but ethanol mixes can gum things up after sitting for a while.
 
Geez Ed... I have THREE thoughts...

First off, as I don't know... is this pump a MOTOR or a VIBRATING COIL?

A motor has an impeller and if there were corrosion issues... I would expect a diaphragm-type F/P to leak into the coil area or to just split the diaphragm and just not move any gas.

The motor variety I guess would leak into the motor windings and short them out or the rare possibility of eating away the impeller. Both these corrosion scenarios are really a reach if you ask me.

1. Dump some STA-BIL into the tank and run the engine. It has corrosion inhibitors... Wait ten years and see what happens.

2. Ensure there is a good CHASSIS to ENGINE ground... and also that the pump is THOROUGHLY grounded. (Strap near LR tire from trans to chassis... pull, clean and re-torque.) Add another ground strap up top between engine and chassis.

3. Whichever TYPE pump you are using, use another.

Granted, I am grasping at straws here as well. But these are things you probably have not tried yet... and all the rest you have with little success.

Oh... I lied... One more FOOL-PROOF method!

4. Carry a good working spare pump on-board. Works every time as "Murphy was ans Optimist"!
 
Fuel pump problems

Its a "rollervane" pump. Yes, I bench tested it on a good 12V battery - its dead - just like the previous other two were dead.

I just completely drained the gas tank - even jacked up the front to get it all out. I will say that I was very unimpressed with the rate of flow coming from the tank outlet but the gas that came out looked pretty clean - no sign of rust or particulate matter.

Even if the tank was FULL of crud, the problem here is that pump stops working from SITTING UNUSED!

This one is a mystery to me.

Ed
 
Did you check to see if there is any kind of voltage at the wires going to the fuel pump motor when everything is turned off?
 
If you've got rust in the tank some particles can get lodged in the impeller and cause it to lock up. How do I know??? Because I destroyed a perfectly good pump the Bob Brown gave me. Worked for awhile and then just stopped. Bob performed an autopsy and it was clogged with rust. Anyhow, that's my story and it may be relevant for you...
 
Colltech said:
I will say that I was very unimpressed with the rate of flow coming from the tank outlet but the gas that came out looked pretty clean - no sign of rust or particulate matter.
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These kinds of fuel pumps are funny, they can take a lot of abuse but some things are particularly fatal to them;

Fuel starvation; meaning not enough fuel or poor supply like with a clogged outlet screen. Fuel tank makeup-air restrictions can cause this as well. Are your charcoal canister and related hoses working right? I thought of this when you said you weren't impressed by the flow when you drained it. The 12mm pipe should supply a good flow when allowed to drain, especially with the cap loosened.

Debris; meaning any kind of dirt, rust, sand (which can be invisible when wet). Some tanks have coatings (plating, sealant) that eventually comes off and can form a fine powder only visible when a sample is dried. Any of this kind of debris can be passed by the pump but clog it up after sitting for a spell.

Pour a gallon or so of alcohol into the tank to rinse it out with. It will also absorb any water and contaminants like rust dust that tend to hang out with the water.
 
Fuel pump

Yep - first thing I checked was to make sure it was NOT getting voltage all the time. See my post above for the voltage results - only getting juice when the key is on and the AFM flap is open. 0 volts the rest of the time.

Ed
 
One more thought Ed... After the engine fires,

what is the voltage level generated? Should be no more than 14.2 VDC.

(Another shot in the dark... but 16 or 18 volts could cook the windings and the pump won't restart next time.)
 
Black-Tooth said:
what is the voltage level generated? Should be no more than 14.2 VDC.

(Another shot in the dark... but 16 or 18 volts could cook the windings and the pump won't restart next time.)
Click to expand...

Yes over volting a motor for long periods will kill a motor. If there is 16 - 18 volts there will be other problems with other components. My line of thought was a low voltage leak with low amps when everything is shut off could be wrecking the motor, but as I write I am thinking that would show up in the form of a dead battery. High volts would boil the battery. So next thought is check the leads to the fuel pump for voltage with engine running (problem sans fuel pump) for over voltage and then with everything on for low voltage and low amps. When you start the engine and the electrons start moving they have to go to different components in the car. Electricity will take the path of least resistance. So if there are bad connections any where, that electricity is going to make a detour down an easier road. There just might not be enough juice to do the job by the time it gets to the pump. This could cause the motor to go bad. You could probably get an idea with a charger hooked to the battery. Automotive electrical is a strange thing. Just because the connections look good doesn't mean they are. Just thinking out loud here.
 
Fuel pump failure

Thanks to all for your responses. They are all exactly the litany of things that I have suspected as well.

Here's the problem....I install a NEW pump - test it and run it for just a few minutes - it works perfectly. Then, I shut it down and go back to doing metal and body work for a couple of weeks. Then I go to start it again and its DEAD. Three times this has happened.

The battery is NOT losing charge - even after weeks. I've tested for a voltage "leak" to the pump - its 0.00V.

It can't be a crud stuck impeller because it ran fine before being shut down and no gas would have passed through it while just sitting there.

It is dying from sitting unused.

The GOOD news is that Airtex has a lifetime warranty and the AutoZone guys just hand me a new pump when I walk in (they don't even ask me what I want anymore!).

I will try one more new pump today but I am at the point of believing the exact same thing is going to happen again.

Ed
 
Very stupid question, but you mention you are doing body work? Are you doing any welding to the car? I ask as you can damage some electrical components if everything is still connected up. Usually it is just disconnecting the battery. I am sure you are careful and probably know this already, just thinking outside the box here...
 
fiatmonkey said:
Very stupid question, but you mention you are doing body work? Are you doing any welding to the car? I ask as you can damage some electrical components if everything is still connected up. Usually it is just disconnecting the battery. I am sure you are careful and probably know this already, just thinking outside the box here...
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That is not stupid at all. It could be grounding through the winding or bushings somehow. Info on my tig welder warns about the effect of welding frequencies close to watches and computer electronics etc. Mig or stick not as touchy but could ground through. I have gotten a thrill when leaning on my work while putting a fresh rod in the stinger with the welder still on.
 
Fuel pump

Welding was completed long ago (floors).

Pumps work fine as soon as they are installed. They work fine until I shut the car off and let it sit (less than 3 weeks for the last pump). Then, BANG - they are go dead.

Whatever is affecting these pumps MUST be happening when the car is not running. However - there is no voltage going to the pump when it shouldn't be.

I just completely drained the tank and suctioned out the remaining gas from both the main drain and the breather tube at the bottom of the tank. I saw no rust or particulate matter coming out.

Ed
 
I'd go with "bad batch of pumps" and not put too much more worry into it.

Lifetime warranty and easy to get to are plusses!

Think of it this way.......What would you rather have, a bad run of fuel pumps or a bad run of brake masters? :)
 
Dan Sarandrea (Phila) said:
I'd go with "bad batch of pumps" and not put too much more worry into it.

Lifetime warranty and easy to get to are plusses!

Think of it this way.......What would you rather have, a bad run of fuel pumps or a bad run of brake masters? :)
Click to expand...

He doesn't know if the brakes work because the car will not run.:wall: I guess you could put in a new pump run the car and then remove the pump and let set for a few week and then reinstall the pump and see if it runs. If it does then let it set a few more week and see if it runs. You seem to have everything we mentioned covered so I am :confused:
 
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