Recommended Fuel Pump for an 81 zag

[PeterV]

Hello,
I'm new to the beta group. I just purchased an 81 Zagato which appears to have a bad fuel pump. I'll be diagnosing further this weekend, and was wondering what else could be causing the lack of fuel reaching the engine? Do the pumps typically go bad on these cars? Any relays or fuses in hard to find places I should be looking to replace? My Scorpion fuel pump chatters when I first turn the ignition on, telling me it has juice going thru it, and is working. The Zag one is completely silent. If it is the pump, are there any recommended brands/models to use?

Thanks in advance.
Peter

[Jim Keller]

Sigh, ::)
You have probably purchased it from the previos owner because they couldn't get the fuel issue fixed! LOL

Anyway, very common, you have the infamous Lancia Beta "tank sludge", it's like a muddy sand that plugs the pickup sock and over heats the fuel pump causing the pump to burn up, as well as it can't pass enough fuel to develope the 39 to 41 PSI the FI needs. You need to remove the tank and take it to a radiator shop and have it flushed well and cleaned, as well, you HAVE to remove the pickup sock in the tank "FIRST", this is performed with various long nosed tools such as needle nose pliers and screw drivers, you litterally have to "tear" the sock out and you can only access it through the fuel sending hole. Once the sock is torn out and the tank is cleaned, have them use a tank liner to lock down any remaining crud as there is no way to really fully get the tank cleand out and the linning stuff will glue it to the bottom and sides. I used Red Line brand fuel tank liner. You pour it in, roll the tank around so it coates everything inside, (and this WILL plug the pickup sock, as well as the crud, henc the "absolutly" necessary reason to rip the sock out first), let it dry and re-install.
While you have it out, cange all the rear rubber lines, if memory serves me right, there is 21 feet of 3/8" fuel hose and I think it was like 7 feet of 5/8" hose to get them all, it's a spagetti mess! LOL

Tanks easy to drop, drain, disconect the fuel filler hose and lines from the pump supply and return under the car, disconect the vent lines in the trunk at the vent check valve, (I take the valve out with the lines and tank so it is easier to re-conect them one at a time when replaceing them), shove those out the bottom of the trunk, take out the 6 bolts holding the tank to the floor and lower it. nce you get through this, the car is a blast to drive! you'll have a lot of fun

Fuel pumps I recomend are the Master Craft brand sold at places like Autozone, Pep Boys, Advance Auto etc.....you have to ask for a pump for Fiat Spider, (they use the same FI stuff), I always ask for a "1982 Fiat Spider 2000 fuel pump" when asking for a pump, these carry a life time replacement warranty and run about $70 verses our vendors $300 plus for a Bosch unit with a 90 day warranty. Also of course, install a new fuel filter.

Get the tank and sock fixed first or you will just burn the new pump up as soon as you try to drive it, they rely on the fuel flowing to cool the pump

Some folks like to install pre-pump filters as well as the oriinal after pump FI filter to cathch any thing left in the tank from getting into the pump, I have never done this, the pumps will pass pretty good sizd particals, much larger than the sludge in the tank and the after pump FI filte will catch everything prior to going to the injectors, I have never had a problem not using the pre-pump filter and feel it is a waste of time and money, but that is just my simple minded opinion! LOL

Hope that helps! ;D
Jim K

[PeterV]

Right,
Drop tank, remove sock, flush, re-line it, replace fuel hoses, pump w/Mastercraft for '82 2000, replace filter, re-install tank.

Thanks Jim.

[davidb]

Jim is the acknowledged expert PERIOD . The pump/filter gotta go, sock's
a good idea too . If you drop the crossmember get rid of the pressurized
hoses, some folks leave the evaporative emission hoses as you gotta
drop the tank for that but check their clamps ! If you pull the tank hose
drain & syphon you can swab out the tank & magnet it : lotsa rust out .
It's a short term measure w/o having to drop the tank which even Jim
agreed w/some time ago . His way is LONG term/100% measure, my way
halfway/short term . It's your call, depends upon your time/ambition .

[Gregory Smith]

Since you wrote it appears to have a bad pump, you may want to make sure before you go to a lot of trouble.

Turn the key on and push the flap of the Air Flow Meter open, this should make the pump run, or at least give it power (verify with a test light at the pump).

Additionally, the ground for the fuel pump is one of the tail light housing mounting studs. This connection can corrode and overheat (pulls the stud right out of the housing) and generally fail there.

[PeterV]

Opened the flap on the AFM and heard small click. Confirmed power to the fuel pump with light. Noticed that the pump began to warm up after a couple of minutes. Not sure if it confirms the pump is good or not.

[Jim Keller]

You would hear the pump if it was running, it is stuck :(

[Will]

I agree with Jim that it's jammed,and although I've heard of people servicing these pumps, I'd think about replacing it. The Bosch pumps scare the crap out of me, yeah we know they are "safe" from the millions of them running around, but inside that pump, the ARMATURE OF THE MOTOR, AND THE BRUSHES ARE IMMERSED IN FUEL! Yep, when Jim wrote that the pump "relied on fuel for cooling", well, that;s an understatement. Sure there's the 'engineer" in every crowd that pipes in with how the fuel can't ignite because there's no oxygen for it to burn, that's all well and good, but what keeps it from turning your car into a Molotov Cocktail when the pump is sucking AIR? And then thre's the pressure- some of the Bosch roller vanes (Rabbit, GTI. etc- ) can put out a whopping 95PSI of preessure. That's significant- more than your domestic water supply which is typically around 80. IIRC the split in the housing is on the low pressure side, but 80PSI can do a whopping good job of vaporizing a mess of fuel- maybe right onto that hot exhaust? No way for me, I'll take a $45 replacement pump that does not sink the pump electrics INTO the fuel. OK engineers and wannabe engineers, go ahead and poke fun of me, call me paranoid, and cite the safety record of the Bosch pump and how German Engineeers are the best in the world. I'll rebut that it may have been the same asshats that tried that sparks-within-a-potentially-but-supposedly-non-combustible-volume before, they named it "Hindenberg". A dead Bosch pump IMO is a great opportunity to lose the damn thing!

[Jim Keller]

Paranoid!

Just bustin ya! ha ha
Actually, gas doesn't burn, it's only the vapors, you can stick a lit cigerete directly into a bucket of gas and it will snuff the cig out, I only know this as I have a crazy farmer buddy that showed me that when I walked far away from his car when he was filling it up at the farm listening to the gas coming up the neck so he knew when to shut off the farm pump with a lit cig hanging out the side of his mouth, that my frined, I thought was NUTS! LOL

[Will]

OK jim, so when you run out of gas what do you think is inside the pump? VAPORS, right? With a 12VDC motor with BRUSHES IMMERSED IN THE (VAPOR).

Which part of the fuel/air/spark equation is missing here?!

I'm guessing that it simply isn't ENOUGH air to support combustion, although if the pump continues to run and adds heat to the equation, I can't imagine it could be safe. Sooner or later it's gotta get down to a vapor mix of about 12:1, right?

Sure, I know the track record indicates otherwise, but if I were submitted that design at BOSCH I would have said "You are F-ing KIDDING ME, right??!!"

Oh, BTW it's illegal to talk on your cellphone in NY because theoretically it can explode the gas station. Now who's paranoid?

[Gregory Smith]

Are you sure the F.I. pump even has brushes? Many high-efficiency electric motors don't.

Oh and the cell phone/gas station safety thing is because of static electricity, which can be generated when your phone rings or beacons. ::)

[Will]

Yes, the Bosch has brushes, and I think the Walbro is more or less the same basic design with a few minor parts variations.

The only static on my cell phone is usually the static I'm getting from the b*tch at the other end of it ha ha!!!

Here's a link to what's inside the Bosch pump, for anybody who's interested- FIAT pumps are identical:

http://www.jag-lovers.org/xj-s/book/83FuelPump.html

[Jim Keller]

Well, I would think you would have to have enough vapors to get an ignition, I am not so sure you can build enough volume of vapors mixed with air in the cavity of the pump and lines, plus all the vents and other safety systems built in........but that's just my blind engineering trust! LOL......that blind trust didn't work so well for Pinto owners though did it! ha ha ha! I haven't taken a pump apart to see how it is put together either so I am clueless