Update: fuel delivery problem, 250 GTE

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Zanny1
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Update: fuel delivery problem, 250 GTE

Post by Zanny1 » Mon Sep 22, 2014 9:56 am

Spent the weekend trying to sort out the fuel starvation problem on my 1962 GTE. As you may have read in a previous post, the car would run out of fuel and die at freeway speeds. Around the block it worked just fine.
1. The FISPA electric fuel pump was non-op when I bought the car. I removed and dismantled the pump, but could not get it to work on a continuous basis. As described on this site, I installed a Facet electric pomp in it's place. Test drive produced the same results, solved as soon as the electric fuel pump switched on. I also replaced the rear fuel filter.
2. Out came the mechanical fuel pump. What a PITA. The pump would not clear the chassis and I did not want to remove the studs or lift the engine. I took the front cover off the lower part of the pump (where the diaphragm connects to the rocker) which allowed clearance over the studs. A $140 rebuild kit from Rutland's was installed. Diaphragm looked fine but top gasket was all but disintegrated. Everything was cleaned, the spacer surfaced, and put back on the engine. Test drive - same results.
3. Replaced all the old fuel lines. 3/8" hose works good for the 10MM replacement, as does the 5/16" hose for the 8MM original. Permatex aviation sealant was used with the original fittings, which were simply 'screwed' onto the rubber hose and clamped. It doesn't look original but does look good. I'm not going to pay $10 per inch for 5' of original style hose. Test drive - same problem.

So it is obvious the mechanical fuel pump can't deliver the volume of fuel required. Yes, I read several articles about reducing the thickness of the spacer to increase the stroke on the pump, but that's no guarantee it will work. So it is staying put.
What I'd like to do is splice in another electric pump between the mechanical pump discharge line and the site-glass fuel assembly. This could be hidden out of the way, give a reasonably stock appearance, and "deliver the fuel" full time.
Has anyone done this? Would the mechanical pump charge the electric unit and create too much fuel pressure?
At least now I can drive the thing without fear of getting stranded.
Your ideas are appreciated. Thanks.
Mike
1962 250 GTE #3177

Steve Meltzer
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Re: Update: fuel delivery problem, 250 GTE

Post by Steve Meltzer » Mon Sep 22, 2014 12:36 pm

Before you add another pump, have you measured the fuel pressure just before the carbs? Should be 4-5 PSI, I believe. If you have good pressure, than the problem must be further downstream, either in the fuel rail, or carbs, right? s
steve
meltzer, "“With a Ferrari, whatever it is, it’s a $1000. If that’s what it is.”"
'66 330 GTC, '72 Daytona-red, did they make any other colors?

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Zanny1
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Re: Update: fuel delivery problem, 250 GTE

Post by Zanny1 » Mon Sep 22, 2014 9:42 pm

Steve Meltzer wrote:Before you add another pump, have you measured the fuel pressure just before the carbs? Should be 4-5 PSI, I believe. If you have good pressure, than the problem must be further downstream, either in the fuel rail, or carbs, right? s
I don't think it's the fuel rail or carbs, since the motor runs fine at all speeds with the electric fuel pump switched on. As you know, the electric pump in the rear of the car feeds the fuel rail from the rear of the rail, as opposed to the mechanical pump which feeds the fuel rail from the front after passing through the site glass/filter..
Mike
1962 250 GTE #3177

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tyang
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Re: Update: fuel delivery problem, 250 GTE

Post by tyang » Mon Sep 22, 2014 9:52 pm

Hi Mike,

It would be a shame to come this close and give up! Did you try running the car off the electric pump, plugging up the front of the fuel rail and seeing what kind of flow was coming from the front line off the regulator? With the car running off the electric pump, you can rev the engine,and watch the feed from the line from the mechanical pump into a container to see it's flow.

If you really want to give up, you can hide a second fuel pump back by the newly installed facet pump. There is a small piece of soft hose that goes between the filter and the hard line going to the mechanical pump. You can tap in at that junction and have the pump push through the mechanical pump.

Tom
'63 330 America #5053

Suebian330
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Re: Update: fuel delivery problem, 250 GTE

Post by Suebian330 » Tue Sep 23, 2014 7:16 am

Zanny,

just another thought:

In the past I had the same problem at another car (not a Ferrari). The final solution was that the needle valve inside the float chamber had to less clearence to open. So the float chamber got empty by higher fuel consumtion. It was a single carburator model. For the three carbs you might realize if all cylinders starve or just a few if this is the case. I do not think all three Webers will have the same problem.
I also have a Facet pump and on my car. The delivery volume should be far enough to feed the 3 Webers without the mechanical pump.

Dieter
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#8741 330 GT2+2[/b]

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Zanny1
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Re: Update: fuel delivery problem, 250 GTE

Post by Zanny1 » Tue Sep 23, 2014 9:44 am

tyang wrote:Hi Mike,

It would be a shame to come this close and give up! Did you try running the car off the electric pump, plugging up the front of the fuel rail and seeing what kind of flow was coming from the front line off the regulator? With the car running off the electric pump, you can rev the engine,and watch the feed from the line from the mechanical pump into a container to see it's flow.

If you really want to give up, you can hide a second fuel pump back by the newly installed facet pump. There is a small piece of soft hose that goes between the filter and the hard line going to the mechanical pump. You can tap in at that junction and have the pump push through the mechanical pump.

Tom
Tom, could the "regulator" cause this problem? I presume that the top of the site glass filter/fuel bowl contains some sort of regulator, but I cannot locate any adjustment or service data. One thing I have noticed is that the fuel bowl is sometimes full and sometimes almost empty, when using the mechanical pump. I suppose I could also check fuel volume upstream of the fuel bowl and then downstream to see if there is a difference. Thanks for the suggestions.
Mike
1962 250 GTE #3177

kare
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Re: Update: fuel delivery problem, 250 GTE

Post by kare » Tue Sep 23, 2014 5:43 pm

Adjustment is on top of the regulator. It controls the spring inside that cuts of pressure.
250 GT 2+2 3197/GT

Steve Meltzer
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Re: Update: fuel delivery problem, 250 GTE

Post by Steve Meltzer » Tue Sep 23, 2014 6:24 pm

here's a shot of the regulator with an arrow the regulator screw.
NB: This is from a 330 GTC, NOT a 250 GTE. s
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steve
meltzer, "“With a Ferrari, whatever it is, it’s a $1000. If that’s what it is.”"
'66 330 GTC, '72 Daytona-red, did they make any other colors?

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Re: Update: fuel delivery problem, 250 GTE

Post by 250GT » Wed Sep 24, 2014 7:31 am

Zanny
after reading the beginning of this thread .
it will be clear the fispa mech pump is the "bottle neck"
I suspect a mistake inside the pump( i.e turned or wrong placed valve)
you can simply connect the pressure regulator direct to the fuel line with elect. pump doing the work alone.
and he runs fine (Bypass the mech pump).

Steve nice pic.
Please tell me the function of the little hole in front of the word Turino.
is off topic but you are all hungry to get a higher level.
but will cost points at PB.
So maybe better not explaining ?

ciao
C.

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Zanny1
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Re: Update: fuel delivery problem, 250 GTE

Post by Zanny1 » Wed Sep 24, 2014 10:31 am

250GT wrote:Zanny
after reading the beginning of this thread .
it will be clear the fispa mech pump is the "bottle neck"
I suspect a mistake inside the pump( i.e turned or wrong placed valve)
you can simply connect the pressure regulator direct to the fuel line with elect. pump doing the work alone.
and he runs fine (Bypass the mech pump).

Steve nice pic.
Please tell me the function of the little hole in front of the word Turino.
is off topic but you are all hungry to get a higher level.
but will cost points at PB.
So maybe better not explaining ?

ciao
C.
Valves went back in the way they came out. I was not aware that there is an orientation of the valves. Can you explain?
Have considered bypassing the mech pump altogether. Any thoughts on running it dry all the time?
Mike
1962 250 GTE #3177

250GT
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Re: Update: fuel delivery problem, 250 GTE

Post by 250GT » Wed Sep 24, 2014 11:23 am

Zanny,

Both the mechanical and electric pumps have one-way valves that keep fuel from draining back( to the tank). They also keep fuel from just circulating in a circle between the mechanical and electic pumps and not filling the carbs. Usually when our cars have a fuel delivery problem, one of the valves has/ is malfunctioned.

You can by pass always the mech Fispa mech. pump without a problem. Check regulator if right pressure shows up (Steve`s pic above)
Do you have the same regulator like Steve´s ?

Cornelis

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Re: Update: fuel delivery problem, 250 GTE

Post by Steve Meltzer » Wed Sep 24, 2014 11:57 am

C. The little hole in the top of the regulator is to let out noxious vapors. (OK, i have no idea what it's for....Dyke, Tom, Kerry??) s
steve
meltzer, "“With a Ferrari, whatever it is, it’s a $1000. If that’s what it is.”"
'66 330 GTC, '72 Daytona-red, did they make any other colors?

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Re: Update: fuel delivery problem, 250 GTE

Post by Timo » Wed Sep 24, 2014 12:04 pm

Zanny1 wrote: Valves went back in the way they came out. I was not aware that there is an orientation of the valves. Can you explain?
Have considered bypassing the mech pump altogether. Any thoughts on running it dry all the time?
Having never serviced an exact pump in question, but with plenty of experience on variety of mechanical fuel pumps, most have (one way) valve(s) dictating direction of flow and with all due respect, just because you placed them the way they came out doesn't necessarily mean they were placed correctly before...
I've seen them misplaced on new original, new reproduction and "professionally" rebuilt units. But then again, I've seen similar assembly/machining/etc flaws on all sorts of new and/or "reconditioned" mechanical automotive parts over the years and have learned not to take anything for granted. I disassemble and inspect pretty much all new or "rebuilt" (by others) parts before final installation. I've even seen/fixed some quite surprising things on parts or components rebuilt by some of the more highly regarded "specialists", including those in F-car world, but on the other hand I'm first to admit having made some mistakes myself too, probably even some I'm not aware of...
As a side note, I just remembered how years ago I was first time rebuilding a component from a 1950's vehicle that according to factory service manual was "not serviceable" / "only to be replaced with new" and struggled a bit to get it working correctly because the exact order of some its internal parts couldn't be observed before or during disassembly. Turned out there is/was two almost identical ways to (essentially "blind") assemble them and my first, seemingly more "logical", approach wasn't the correct one.
Timo

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Re: Update: fuel delivery problem, 250 GTE

Post by 250GT » Wed Sep 24, 2014 12:29 pm

Steve Meltzer wrote:C. The little hole in the top of the regulator is to let out noxious vapors. (OK, i have no idea what it's for....Dyke, Tom, Kerry??) s
This has nothing to do with Zanny´s problem Steve.

So it can be forgotten or removed.

But it will make some" insanity of details " people sick and judges too clever.

Oh boy, which exhaust color is the right one in side ? really malade.

This little hole is the place for the original Fispa lead tag fixation.

S. hope you can sleep well tonight.


C.
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Steve Meltzer
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Re: Update: fuel delivery problem, 250 GTE

Post by Steve Meltzer » Wed Sep 24, 2014 12:47 pm

Thanx C. I feel better already...ZZZZZZZZZ. s
steve
meltzer, "“With a Ferrari, whatever it is, it’s a $1000. If that’s what it is.”"
'66 330 GTC, '72 Daytona-red, did they make any other colors?

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