Performance of the Spica in high altitude

[Rosenmöller]

Hello
I do hope that I found the right titel for this thread.
But anyhow this is what has happened:
I just returned from a trip to the Alpes a yearly event of the german alfa BB.
This was the first time i participated because it`s quiet a bit of a way from the Baltic Sea ,where I life,up to the Alpes. ( 750 miles)
Lots of differentAlfa from a 1972 1600 Guila to the newest 3,2 Liter Spider all together 30cars.
A few series 3 Spiders , but with carburetors were also there.
In the normal altitudes I was not able to follow these Spiders. This then my first question:
Is the power and performance of the Spica inferior to carburetors? Or is my pump ( Redone by Wes only 1,5 years ago ) just not tuned in a proper way?
Second experience was while climbing up the passes I lost power going further up. The car was not performing as it should. With an altitude of 1,75 miles, this is PAsso di Stelvio in Italy, I was running at 5000 reffs with the car coughing and spitting the fuel pressure light came on ( due to the hot engine ) and I just about made it up top.
Also idle was down to under 500 reffs in the higher altitudes which makes it difficult to drive the car because it will always stall as soon as I took the foot of the accelerator, and unfortunately I only got two feed.
In the "Fuel Injection Roadside Fault Analysis and Repair " and also in the original manual I found a few answers, but not really for this problem. At least the second thing could have something to do with the Barometric Compensator.
Any help is welcome.
Greeting from Germany
Bernhard

[Bill]

Bernhard,
Not sure how much help I can be as I live at sea-level, but I did take a trip to the Rockies last summer and drove my Spica '78 up to 12,750 ft. and experienced a couple of the same effects you experienced. My idle did drop and I had difficulty keeping it from stalling at stops. Also the power was cut in half at least. Less than half the air at that altitude so the Spica will run very rich in spite of its compensators, and the engine will produce way less power.
I did stop and lean adjust the mixture when I was at high altitude for the day, but set it back after coming down below 5,000 ft.

I belive if the Spica pump is tuned correctly and in good working order, it should do a good job of compensating for altitude changes without too much fuss.

[Roadtrip]

The engine will produce considerably less power at higher altitudes, so that's normal. However, the barometric compensator should expand a little and lean out the mixture. Bill went to almost 13,000 feet which is extremely high for any normally (non-turbocharged) aspirated engine to work satisfactorily. The new EFI systems do a much more accurate job of metering the fuel correctly. The Spica system is crude by comparison.

One guess may be that you were doing a constant power-on climb for thousands of feet of altitude. The barometric compensator can only reset the mixture if the throttle is closed momentarily from higher rpm. What happens is the little clip on compensator link disengages the verticle notched lever, and the expanded BC pushes the link down, and the clip engages a lower (leaner) notch on the verticle notched lever. While climbing, I'd go to neutral occassionally and "blip" the throttle to reset the lever to see if that helps.

I doubt that the BC has failed. If the BC fails (gets a hole in the sealed bellows), then the internal spring will expand the bellows greatly. That will usually result in a full lean mixture and an undriveable engine. Even at altitude or with a engine under considerable load, you should NOT get a low fuel pressure light. Low fuel pressure would cause the symptoms you describe. Did you open the filler-cap to the fuel tank to make sure that the fuel tank was venting correctly? How old (and what type) is the fuel supply pump in your car?

[Rosenmöller]

@Bill
that was actually one thing I was thinking to do, to lean out the micture
@Roadtrip
I went for a constant power drive up the Hill, that means 1,25 miles altitude with in 30 miles . So no chance to blip the throttle by accident, but I will try next time on purpose. I always thought not to go of the throttle would be better. As you wrote in your above mentioned book the engine when very hot can cause the problem of the low fuel pressure light coming on. My pump is 2 years old and the typ you descripe in your other guide and I did change the fuelfilter and I did restrict the whole in the orifie at the outlet of the FI pump.
Thanx for the real fast answer so far.
But what is about my first question the performance Spica - carburetors ?
Greetings from Germany
Bernhard

[turbolarespider]

Quote:

Originally Posted by Rosenmöller @Bill that was actually one thing I was thinking to do, to lean out the micture @Roadtrip I went for a constant power drive up the Hill, that means 1,25 miles altitude with in 30 miles . So no chance to blip the throttle by accident, but I will try next time on purpose. I always thought not to go of the throttle would be better. As you wrote in your above mentioned book the engine when very hot can cause the problem of the low fuel pressure light coming on. My pump is 2 years old and the typ you descripe in your other guide and I did change the fuelfilter and I did restrict the whole in the orifie at the outlet of the FI pump. Thanx for the real fast answer so far. But what is about my first question the performance Spica - carburetors ? Greetings from Germany Bernhard

[nv-alfa]

I regularly take my Spica Injected spider to 9000+ feet, and most of them are longer climbs where I have to blip the throttle as Roadtrip describes, or else it doesn't want to make any power. Mine idles a bit low way up there too, but has never died.

And check your rear fuel filter, mine used to come on after lots of hard driving, and I too thought it was becasue of heat or something -- mine was clogged up really bad.

Oh yeah, and some of these drives are with people in carburated cars. I blow them away at high altitude because my mixture stays right and theirs is way too rich...

[Roadtrip]

Berhard - Hot FUEL can cause a low fuel pressure, not necessarily a hot engine. In parts of the US where we have deserts, the heat reflected up from the road surface in addition to the high ambient temperature can cause problems if it's extreme. That's a good reason to keep the tank fairly full. A full tank can absorb much more heat than an almost empty one.

What was the air temperature and the fuel level when you had the problem?

[Rosenmöller]

@ John
The tank was half full and the temperature was about 95°F.
Is there anyway to check wether the Barometric sensors is working properly without driving back to the Alpes. You know over the wintertime is shortly to begin and this is the right time to work on the car.
@ Eric
Try setting the cam timing to match all of your friend's cars, and then advance the spark by a few degrees. I think a lot of that will be made up.

Oh, and if your engine is tuned too rich, you'll loose power faster- I've noticed Alfa motors really don't like to run very rich- richer than 11.5:1, and hte power drops off very fast.
Unfortunately I`m not a mechanic but I´m willing to learn, like I changed my FI pump by myself.
Could you just explain what you did with your car a bit more. I`ve read in Wes booklet that you can advance the spark abit with todays fuel. What to you mean with setting the cam timing, do I need new camshafts?
Thank you for the replies and your understanding with my poor english.
Greetings from Germany
Bernhard

[turbolarespider]

Quote:

Originally Posted by Rosenmöller @ John The tank was half full and the temperature was about 95°F. Is there anyway to check wether the Barometric sensors is working properly without driving back to the Alpes. You know over the wintertime is shortly to begin and this is the right time to work on the car. @ Eric Try setting the cam timing to match all of your friend's cars, and then advance the spark by a few degrees. I think a lot of that will be made up. Oh, and if your engine is tuned too rich, you'll loose power faster- I've noticed Alfa motors really don't like to run very rich- richer than 11.5:1, and hte power drops off very fast. Unfortunately I`m not a mechanic but I´m willing to learn, like I changed my FI pump by myself. Could you just explain what you did with your car a bit more. I`ve read in Wes booklet that you can advance the spark abit with todays fuel. What to you mean with setting the cam timing, do I need new camshafts? Thank you for the replies and your understanding with my poor english. Greetings from Germany Bernhard

[Roadtrip]

Berhard - You shouldn't need to change cam timing for the engine to run efficiently, even at high altitude. I am concerned on the fuel low pressure light. That light should not come on unless there is a problem. Do you have a fuel pressure test gauge? Most inexpensive automotive vacuum gauges also have a fuel pressure function built into them. You can get them very cheap and easy on Ebay. I'd connect a fuel pressure gauge using a "T" configuration and check the actual fuel pressure. Do not "deadhead" the fuel gauge because the fuel supply pump can produce VERY high pressure. ONLY use a "T" as described in the Fuel Supply Diagnostics Guide.

I'd change the rear fuel filter again. After you remove the old one, open it up and see if it is clogged up with rust/dirt. Have you inspected the inside of your fuel tank for rust? Your car is 30 years old now and northen Europe is very humid much of the time. Condensation form easily in tanks in a humid climate and with large temperature changes.

With the fuel tank half-full, that should allow adequate cooling of the fuel to prevent vapor lock and low fuel pressure. 95F is very hot. I am surprised it was that hot up in the European Alps!!

In summary, I would:

1. Check the actual/exact fuel pressure.
2. Change the rear fuel filter and inspect the old one for rust.
3. Recheck the ignition timing and spark plugs for evidence of rich mixture (dull black soot).

[Rosenmöller]

I firts have to get a pressure gauge and then I will check the system with the old Filters and start changing afterwards.
The type of fuelpump is Bosch number: 0580 464 013
Is that the right one?
Greetings from Germany
Bernhard
Ps.: I will keep you informed and Thanx again

Edit : Is there any other solution for the fuelline from tank to tank fuelfilter despite going so extremly near across the exhaustpipe?

[Roadtrip]

I don't think there is any alternative to routing the fuel line around the exhaust pipe. You should have metal shielding around it. If the original part is missing, you can use some armoured electrical conduit available from a hardware store.

I don't know the numbers of the Bosch pump, but if it is a replacement part for a L-jet injected Alfa, that's the one.

Front fuel filters almost never get clogged unless the rubber hoses are so old that they are deteriorating from the inner lining. The rear filter is the one that usually clogs up.

If you haven't done it already, you might want to run the fuel to very low level, disconnect the battery, then remove the sending unit from the fuel tank and inspect the inside for evidence of corrosion/rust.

[Rosenmöller]

I did clean the tank a couple of years ago, that is why I`m wondering so much about the rear fuelfilter.
Look hear:The Right Fuel Filter?

Greetings from Germany
Bernhard

[Roadtrip]

Hmmm. You fuel tank should be clean. I am going to think about this some more. Vent system clear?