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78 spider fuel pump

2811 Views 21 Replies 7 Participants Last post by  jkirshtein
old 3 port pump was intermittently giving up so switched to a 2 port Bosch from centerline.
Installed with a little bit of plumbing and electrical work, and now car doesn't start.
Pump is pumping fuel and also checked return line.
Definite fuel issue.
Any ideas??
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maybe the air hasn't all bleed out yet? How long did you run the pump? Try a shot of starter fluid. It will quickly confirm if it's a fuel problem or something else.
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Gas in the tank? I've been tripped up by this more times than I'd want to admit.
You see flow from the fuel lines at the injection pump?
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A 78 should have the high tank outlet and in-tank lifter pump. These commonly fail. Additionally, the rubber connector hose from the in tank pump to the pipe often fail.

The three-port pump was better at pulling fuel up from a low fuel level than the newer vane type pumps. Anything amiss in the tank-to-Bosch section will cause you troubles.
78 was a crossover year for Alfa. Seems our cars are a mix and match of some old and new features, depending on the time of year they were manufactured. Early 78s like mine didn't have the In Tank Pump. If yours is a later 78 it probably does. If you have the in tank system you should check to see if that pump is clean and working. Also change the filter sock and especially the step hose. If the hose is original its probably cracked. When you initially turn the key on, does the fuel pressure light illuminate for a few seconds before going out, or just flicker quickly? The PRV for our year car is not located in the front main fuel filter, it was in the 3 port pump. Changing to the 2 port leaves us without a pressure relief valve. Also, the pressure between the old and new pumps is a bit different. If you have had Wes Ingram rebuild your pump recently, he rectifies this by installing a 1/16 restricter in the return line orifice in the SPICA pump. If you haven't had it rebuilt by him recently, or at all, you may need to install one. This may or may not be the cause of your issue, but good info to have never the less. Also, Wes recommends changing all the fuel lines when installing a new fuel pump as good practice.... Make sure your new plumbing is correct. The return line goes from the forward fuel line connection on the SPICA straight to the tank?. The 12mm(1/2 inch) hose connecting to the inlet side of the new fuel pump has to make a 90 degree turn. Make sure that the hose isn't kinked.
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I believe the 78 would only have the in tank boost pump if the recall was done. If no tank pump then the main pump is trying to suck fuel over the top outlet of the tank...gonna be kinda hard until the air is purged. Can it even draw the fuel if the pump is dry? A really bad design I think.
By “crossover year”, I meant they were usually delivered with the over-the-top tank outlet, but no in tank lifter pump. The original three port pump was a positive displacement gear pump, which in theory could usually create enough suction to lift the fuel up out of the tank. The service letter addressed the “usually” in that design.

The modern Bosch pumps use a vane impeller, and aren’t much good at creating a workable suction once they’ve lost their prime.

So, a working in-tank pump is necessary.
I don't know about the recall, so I can't speak about it. I have an early model 78, without the in tank booster pump. Fuel is fed into the system through fuel line outlets at the Bottom of the tank. This was the design on S2 models until mid 78 when Alfa installed the redesigned fuel delivery system to alleviate cavitation of the pump. (Or so I've been told) I don't remember seeing a top supplied systems that didn't have a pump. How would you get the fuel from the very bottom of the tank? As per Wes Ingram.. "In later models, Alfa fitted a small in-tank boost pump attached to the bottom of the fuel gauge sending unit assembly. Cars with boost pumps will have connections for two components on the top of the tank (one for the fuel level and one of the boot pump). Within the tank, the pump is connected to the top flange fittings by a rubber hose. It supplies fuel under positive pressure (3.5 psi) to the main supply pump. Alfa's thinking was to reduce the chances for vapor lock cavitation and to prevent loss of supply to the main supply pump during hard cornering with low fuel levels". Here is a link for the OP. It may help with some of the issues you are having.
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I believe the 78 would only have the in tank boost pump if the recall was done.
I'm always up for learning, and a good read.....Thanks
Still not sure why my 78 is Bottom fed...Very Strange.


The date of production and the date a car is registered as being often digress. I've got a 1959 car that carried a registration listing it as a 1961 for several years.

It doesn't really matter.

If you've got a bottom exit at the forward left corner of the tank, then forget the conversations about tank boost pump. You should have your pump mounted in the clamp towards the right front of the tank, with the inlet connecting to the rear fuel filter, and thence to the tank exit.

My experience last year reminded me of the problems of skipping steps hoping that providence will take care of things.

My car had sat for at least 10 years without running, with old fuel in the tank. I did a bunch of flushing, and added a new rear filter (along with pump, regulator, etc). Ran briefly, then crud from the tank clogged the new filter. Tried another new filter. Same experience.

Gave up, installed a new tank, a billet, cleanable filter canister, and been happy ever since. I still have the old tank if someone would like to take it to a professional tank cleaning shop and have it done right. A new tank was probably cheaper.
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Thank you for all the help, i did the recall last year with a new fuel tank, intank pump and filter.
Car starts with starter fluid, so it is a fuel problem. I am going to reinstall the 3 port pump and try it.
No knowing, it may be a fuel pressure problem.
I disconnected the fuel one to the Spica and fuel flows.
I disconnected the return line and fuel flows.
I am stumped.
Old pump worked but intermittently would not start unless a little hit.
Maybe I should get the 3 port unit rebuilt.
Just want to drive it. Lol
Have you measured fuel pressure? The early fuel filter fittings have a 6mm screw where you can fit a gauge. Not sure which setup 78 has, but you can fit a gauge somehow. If you have 16 lbs pressure, give or take, the fuel pump is doing its job. Starter fluid is more volatile so the engine might run on it when it won't run on however it is set up for a cold start on gas. Change anything in the setup?

Is there a belt on the Spica pump?
Hey Milford -

I'm thinking that Andrew may be onto something. Few questions first though. Has Wes rebuilt your Spica pump yet? If not, did you reduce the size of the out the new pump's outflow port? Is your fuel pressure light taking longer to go out or does it stay on when you try to start the engine? The reason that I am asking is the Bosch 2 port pump doesn't put out enough pressure for the Spica system. As mentioned above, Wes puts a fuel flow restrictor into his rebuilt pumps to correct for this. If Wes hasn't rebuilt your pump yet you can reduce the size of the of the outflow by sealing it with a little sodder and then using a 1/16 drill bit to drill a new smaller hole in the outflow port. Just something to think about if you haven't already.
I have had FI pumps work just fine on 10-12 pounds. Maybe not continuous WOT, but normal driving. So I wouldn't go drilling the orifice til I knew what I had. Just my thought.
If you have fuel at good pressure at the FI pump, your delivery pump is working as it should, near as I can figger.
Is there a belt on the Spica pump?
You took the words out of my mouth Don....wouldn't that be a kick.
Some of you will be weary of this, but...

Assuming all else is healthy, I do not recommend going with an L-Jet pump and reducing the orifice. I respect Alfa engineering. They wanted FLOW through the Spica. This can be maintained by using an 044 Bosch pump and an inexpensive Holley regulator. A Spica will run with less than seven PSI and the low pressure light glowing. Is that good enough?

Probably not the OP’s current problem. I’m betting the Spica isn’t squirting fuel into the ports. Why?
If you find that you need a Cog Belt you are welcome to borrow the spare one that I have. I'm up in Durham. Probably about 45 minutes from you.

- Drew

I had a funny event today.

My Spider started easily, per normal, drove to the alignment shop, left the keys. Got a call "your car won't start". I drove over. Wouldn't start. Confirmed spark at plug, and fuel pressure good.

Went home, grabbed a couple of tools, went back.


I bought car last year. It had been dormant for a decade or more, but I fixed the dead things. As soon as I got good fuel to the engine, it cranked right up, and I've been driving it regularly since. However I've not yet taken the time to go patrolling around the engine bay looking for things that might need attention, or were left half-open by the PO.

While removing the air cleaner assembly, I immediately noticed that the four inner clamps were all loose. Hmmm? Did I do that? Got the cleaner off, and confirmed that the various wires were where they should be. Then, noticed that one of the hold-down screws for the TA was missing. Using my screwdriver, I found that the other screw was quite loose. Tightened it up enough to hold the TA in place. Turned key. Started on first cylinder.

Check for a loose TA.
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