330 GTC impressions and a couple questions

The mechanical pumps on 330s are old and tired. They often seem to be unable to supply sufficient fuel. When I got my 330 - a LONG TIME AGO (so things may be different now) - the car would not run on the mechanical pump - I had to use the electric pump all the time. At some point, I rebuilt the mechanical pump but it didn't help much. The car would now idle and run at low speeds on the MP, but it would not accelerate normally on maintain cruising speeds.

In the end, I always ran my car on the mechanical pump.

 

Run both pumps all the time. No harm is done . Are you pulleys perfectly aligned they should be.

 

your hot weather operation is consistent with my experience, need to keep fuel pressure up to keep from stalling, don't recall if the 330 had return lines to the fuel tank from the electric pump...which would aid in keeping the fuel cooler... the car needs air flow from movement... it is not a car that wants to be driven in traffic on hot summer days... check both of the electric fans turn on at proper temp, the thermostat can go out of spec delaying switching on and fan motors fail too often

re throwing belts... could be in the a/c clutch not having a smooth transition causing the belts to go slack or creating too great a load as the a/c transitions on/off too abruptly...

 

My 365GT is actually wired to run the electric pump all the time, and has been since I got it-- 23 years and at least 20,000 miles ago.

The autoflux switch just turns the little blue light on...

 

Just to make sure, I run two electric pumps in tandem, the original Fispa (click click) and a modern unit (bzzzzz) , I have them plumbed in line. I also replaced the original one-position paddle switch with a two position switch that activates the original pump when flipped down, or the modern pump when flipped up. Of course I needed to run another wire back to the new pump to take advantage of the two position switch, so now I have two redundant electric fuel pumps. The new Lucas switch is easily found so all I had to do was swap the plastic paddles, it can't easily be distinguished from the original.

I also spent an incredible amount of time and energy getting my mechanical pump to work under all conditions but we'll see how long that last. I also think the stuff California tells us is gasoline is part of the problem.

I also found a simple way to get an idea of how your pumps are producing, flip the gas door up, there is a small fuel return tube right below the filler neck. It should be producing a healthy piss stream of fuel when the car is idling, if not, you may have a problem. It should even produce when the car is being reved up, at least my car does.

 

Don: The 365 GT 2+2 was designed to run electric fuel pumps. Someone at the factory made an executive decision!

 

Then what are the "autoflux" switch and light for?

 

My mech pump wasn't working very well on my old Queen. I rebuilt it, but also used a thinnest gasket I could find to move the pump body closer to engine, thus increasing the stroke of pump. I could use the mech most of the time. Electric had to come on for starting, idling in traffic (vapor lock) and long pulls in a few gears.

Bill

 

On the GTC a blue warning light on the tachometer is illuminated when the paddle switch marked "A" is activated to run the electric pump. The "A" stands for "Auxiliary" but considering all the trouble it takes to get the mechanical pump to properly work maybe it should be marked "P" for primary!

Even the original Fispa electric pump is a little finicky, with the bridge, lever and solenoid, it looks like a miniature circus show when it's working, this is why even after restoring the mechanism I added a modern redundant pump.

Tom in SoCal

 

Couple of notes, from my experience with both, the Bendix pump puts out more fuel then the Fispa, and your car's drivers manual says to turn the electric pump on in traffic. So you are better off with the Bendix, (though I do miss the clicking).

 

Did you happened to record outputs of pressure and/or volume for both ?
Were both or either new, (freshly) rebuilt or used ?
Just curious.

 

Timo: Most of the rebuilt FISPA pumps we test put out 2.5-3.0 psi. The original "Silver Cap" Bendix pumps put out 3.5-4.5 psi.

 

Jim...having two different GTCs over a 20 year span I had issues with the mechanical pump as others have mentioned. I had it rebuilt on both cars. On the first I "shaved" the spacer that insulates the mechanical pump from the case. That adjustment did increase the throw of the rocker helping keep pressure with the mechanical. But even after rebuilding the mechanical pump the Fispa was a requirement in hot driving conditions whether temperature or traffic related. My guess is that Ferrari knew they had a problem and added the Fispa as a bandaid. Just a guess though.

A few years ago I was driving from Naples to Orlando for the Celebration event in mid April. All was sound and solid for the entire trip....well almost. Just when I pulled off the I-4 exit for Celebration the engine died. As the saying goes it's either electric or fuel related. Confirming I had electric to the Fispa it was clear that the pump had failed. I opened the trunk, removed the lead hammer used for wheel removal and "whacked" the Fispa. The rapid clicking resumed and off I went.

A few weeks later I replaced the Fispa with a Holley pump. I do miss the clickety clack but I now don't worry about being stranded from pump failure.

I think that was the one and only time where "hit it with a hammer" style of repair actually made sense....lol.

 

What a joyfully beautiful thread to read, people actually discussing how to get the best driving experience from their cherished cars, not worried about a points deduct to achieve platino, or a reject item to get Classiche, just honest solutions how best to enjoy real time driving. Almost makes me wish the market reversal goes long and hard so I can once again afford to own a GTC !!

 

The Ferrari fuel system is well thought out. It is a matter of where the priorities are. The pushrod stroke of the mechanical pump is only about .090". This is on purpose to prevent diaphragm destruction at sustained high revs. Ferrari designed the engine for sustained high rpm, and the pump drive is made to sacrifice low speed fuel delivery so it will stay together at 7,500 rpm for hours. The amount of pump stroke required to provide full fuel pressure to a hot engine at 700 rpm would cause the diaphragm to rupture prematurely at 8,000 rpm.

In our vintage racing American V-8's, we used to try to use the original mechanical pumps as well as electric pumps to maintain the original configuration. However, we constantly destroyed the diaphragms in the mechanical pumps, even after going to aftermarket "high performance" pumps. These "high performance" pumps were designed for drag racing and a short period of elevated rpm. On a road course after a 20 minute session at 7,000 rpm, the diaphragm just gave up. Now we "gut" the mechanical pump (so it looks correct) and just run the electrics. Ferrari installed the FISPA units to ensure adequate fuel at low rpm when hot, as well as for ease of cold starting. The factory's one design failure was in placing the electric pump above the exhaust pipes. Back then with the fuels of the day having a relatively high boiling point, that was not a problem. However, today with modern fuels blended for high pressure injection, they have very low boiling points and this causes the pumps to cavitate (the fast clicking with no fuel delivery) easily in hot conditions.

 

Thanks for good reference data.

 

The whole issue of the fuel systems on 330s is very interesting
My 330 GT 2+2 has both the machanical and the electric pumps.
I usually need both to get the best out of the car.
Yes when the car is running v warm either because of a hard drive or because of the weather
I get the vapor trap that's is so often talked about.
Keep the electric one on is my suggestion

Here is an interesting diagram from a previous post
Image Unavailable, Please Login

 

Really? No fuel rail return to the gas tank?

That's not what Tav. 8 of the GTC parts book shows.

Sometime a piece of paper is worth a thousand emails.

 

Great info as usual Dyke. I've always wondered what the rationale was behind the Fispa pump and your post explains it. I still don't like the Fispa, but now I at least understand it and that helps me not like it less . I'm still curious why they didn't just fit another electric pump instead of using a mechanical pump.

I'm not positive, but I think the fuel return line was added sometime during the middle of the 330 GT production cycle. If my recollection is correct, the early 330 GT's didn't have it and later ones do.

 

The 330 GTC and 274 GTB/4 were the first street Ferrari's to have "fuel return" systems. All the previous models did not. The "return" system was designed to help keep the fuel cooler by constantly recirculating excess fuel back to the tank. This was the first attempt to fight vapor lock due to heat, as traffic in both Europe and America was becoming heavier and more congested by the mid-1960's. Also the "return" system provides a pathway for pressure relief caused by boiling fuel due to "heat soak" after engine shut off in high temps. Without the return line, any fuel boiling in hot fuel lines would be forced into the carburetors and cause them to overflow into the engine.