In-Tank Pump shot?

andy303 · #1 (**permalink**) 05-31-2008, 09:48 AM

Greetings, Alfa newbie here. Well, new to US models. I lived in Italy from '82 to '85 and owned several back then.

Coincidently I recently acquired an 84 Spider in decent shape but with various minor issues. I have a lot of experience with MGs and Triumphs but "modern" Alfas are still new to me.

I have only had the car less than a week and today on the way to work today it began to buck and stumble like it was low on fuel. I made it to work, but barely. Having been lurking and reading posts here I know that the fuel guage can be unreliable, so I assumed it was reading 2/3 full, but that the tank was actually empty. I grabbed a 5 gallon can and after a trip to the gas station I was surprised that the tank would only take about 3 gallons before being completely full. I test drove the car and the previous stumble is gone.

From the above I believe that the main tank is being primed only by gravity with a very high fuel level in the tank, and that the in-tank primer pump is not working. Anyone else have this experience?

Pertinent facts: the PO replaced the main pump and filter. The main pump is "loud" but I have read that that could be normal, or the sign of an over worked main pump.

Ciao, carri amici,
Andy

**Gubi** · #2 (**permalink**) 05-31-2008, 10:06 AM

Could be. I posted instructions for in-situ testing of the in tank pump in the thread below.

2 issues: Gas tank pressure?? & slight high pitch hum behind seats

There's also a short rubber hose in the tank that runs from the pump to the hardline. If that cracks you could have similar problems.

andy303 · #3 (**permalink**) 05-31-2008, 10:12 AM

Thanks Tom, I 'll run that test tonight.
I already have the pump, sending unit, sock, and hose on a "wish list" at IAP.

andy303 · #4 (**permalink**) 05-31-2008, 11:13 AM

I also noticed that the white and black check valve shown in your linked thread is missing. How critical is this thing?

andy303 · #5 (**permalink**) 05-31-2008, 03:59 PM

Tom: As suggested in your linked thread I jumpered the pink-white pump connection to the + term of the battery and nada - no hum. With the engine running I found with a test lamp that there was current in the pink-white wire.
New pump time I reckon.

Ciao!

**Gubi** · #6 (**permalink**) 05-31-2008, 04:12 PM

Sounds like it. Also be sure to order a new filter sock for the pump, and you might as well order the little hose as well.

You've got an '84 so it won't have the black/white check valve. I think the one in an '84 is metal.

**Tifosi** · #7 (**permalink**) 05-31-2008, 04:27 PM

:nod:

Breather valve is plastic, one-way check valve is cylindrical steel.

peterlund · #8 (**permalink**) 05-31-2008, 06:31 PM

I had the same issue. Found the hose had fallen off and the pump and hose were dangling in the tank by the wires..... Good luck!

vf31rhill · #9 (**permalink**) 05-31-2008, 08:22 PM

I just went through this issue on my 88 last week. When I bought my 88 last Dec, the previous owner told me it would not run with less than 1/2 tank of gas and he was correct. Some of the BB folks told me about the in-tank pump. I bought a new in-tank pump and installed it last week. It fixed the 1/2 tank problem, but I gained an immediate new problem. Smell of raw gasoline in the cockpit. There have been many posts on the BB about the raw fuel smell problem. But I was surprised at how quick I got that problem after replacing the in-tank pump. It was instantaneous! I suspect that with the in-tank pump out of action, the main pump was pulling air in from some leak(s) in the system. Once I replaced the in-tank pump, those same leaks are now pressurized with gasoline and are now exuding gas instead of intaking outside air into the system as previously.

I did not have to replace the tiny connector hose in to the in-tank pump, nor did I replace the filter sock. I was able to reuse both although I did add clamps to each to insure thay stay put. That tiny hose is over $30.00 by the way, and not always in stock. The in-tank pump was reasonable - I bought one over the net for about $20.00.

I only mention the raw gas smell problem because it might happen to you as well. I hope not, but just wanted to warn you about it. I am tackeling the hose replacement problem next, to elminate the raw gas smell. I don't know what the boost pressures are, but I am guessing that this system is fairly high, considering the number of posts on smell of raw gas in the cockpit.
Good Luck, Robert

**Tifosi** · #10 (**permalink**) 05-31-2008, 08:54 PM

Robert, you may want to paruse this post while trying to eliminate the smell, but first and foremost, make sure all the hoses at the sender are clamped well (EFI clamps, not wormscrew preferably) and that the sender gasket is in good shape, properly aligned, and fully tightened down with the wee screws.

andy303 · #11 (**permalink**) 06-04-2008, 06:30 PM

To come full circle on this thread I replaced the tank pump tonight and all is well. I do not have any raw gas smells so far, but then I haven't had the car sitting out in the hot sun yet either. There was no vapor check valve or restrictor on my car, just the black and yellow one way air valve. I added an in-line restrictor in the large braided hose that connects to the plastic middle air hose, as shown in the reprint of an Alfa club tech article. Thanks guys for your great advice and help!