79 Alfetta gas mileage

[Grant]

Hello all,

I recently drove to Bimmerfest in Santa Barbara from San Luis Obispo after leaning out the Spica a few nights before. So, I figured I got around 20 mpg in mixed driving.

What else should I be checking to improve gas mileage? Do these cars have a vacuum advance on the distributor? According to the AROO's Spica Tune-up guide and Braden's Alfa Bible, the Spica should have a lever with 3 settings for Normal, Cold, and Freezing climates. My Spica has no lever, instead there's just a flat head screw where I think the lever should be, and no markings for the different temperature zones. Maybe my Spica is set for a colder climate?

Any tips?

The car has been impressively maintained the over the course of its life, including a recent tune-up and head work. Block has around 90K miles if I read the receipts correctly. Any tips at all?

[rogerspeed]

You aren't missing anything, the early SPICA pumps had that lever, but very soon became non=adjustable. Asuming it isn't A/C or automatic, a heaDer and exhaust along with the right cams would get you a little better mileage.

[Trevlac217]

Last I checked I got 27 mpg with my Dellortos. That's assuming the odometer reads correctly. The tank was also burned off with many LONG idling sessions in the driveway while working out the tuning issues the previous owner left me with. I would expect the FI models to get better gas mileage.

[Grant]

Do the Euro Alfettas have higher compression ratios?

[Grant]

OK, so leaned the Spica out quite a bit (just over 3/4 turns clockwise on the FCS) but I'm still seeing around 18 mpg with combined driving.

Are the Spica'd cars supposed to sputter and miss for a second after the fuel gets cut and coasting? Do you guys have missing when you first start the car until you "clear the plugs", or atleast, that's what it seems like it's doing.

[superloaf]

Quote:

Originally Posted by Grant OK, so leaned the Spica out quite a bit (just over 3/4 turns clockwise on the FCS) but I'm still seeing around 18 mpg with combined driving. Are the Spica'd cars supposed to sputter and miss for a second after the fuel gets cut and coasting? Do you guys have missing when you first start the car until you "clear the plugs", or atleast, that's what it seems like it's doing.

[Grant]

Hi bob,

My Fuel Cut Solenoid (FCS) is working just fine. I'm not sure how cutting fuel causes the backfire, but if that's how it's supposed to work, that's fine by me. I know it works because when I was adjusting the mixture again today, I forgot to re-connect the wire to the FCS and it was noticeably different when I abruptly lifted off on the throttle.

It's possible my ignition timing was way too retarded. The adjustment was almost to the end of the retarded position on the distributor column, and I was able to advance it quite a bit until I thought I heard pinging at around 3500 rpm, WOT.

I looked at the plugs, they weren't a golden brown color, looked a bit lean, which was what I was aiming for to try to get better MPG, but the porcelain was cracked on at least one of the electrodes. I don't think this was from the brief amount of time I was messing with the advance...it could just be that the plugs are old.

Unfortunately, I don't have a timing light at my school and my buddy that does is at the 24 hours of Lemons.

The AROO spica manual is located here:
Renting a Spica Adjustment tool

All you lurkers reading the forums, you'll have to create an account to download attachments.

[superloaf]

grant, ok, that info is available. cool, because that is such a great piece of info. absolutely great. anyone with spica should follow that for a great running car.

grant, just for basic info, how did your car run when the FCS was disconnected? just curious as i've wondered if this was a good feature or bad.

[Grant]

All you have to do is unplug the wire going to it.

Unless you're careful with the throttle, the fuel cut can make the car a bit jump when it come on and off the gas. I think somehow the later Alfettas were less effected by this, as I remember reading a R&T article which talked about how much better the transition was than the previous year's car they tested (I forgot the actual years though).

With the solenoid disconnected, the car was less jumpy and there was no hesitation when it was time to get back on the gas. It actually made the car drive a lot better after decel. My car always hesitates for a second before it accelerates after fuel cut. For me, it's a worthwile trade-off for gas mileage, but modern EFI is much better at resuming fuel after coasting.

[ckeen74]

Hi Grant,

If you have a Harbor Freight nearby, you can get a timing light for pretty cheap (under $30, I think). To answer the mileage question, I got 24mpg over the drive from San Francisco to Seattle... I think my hand throttle (connected to a SureStart) was pulled out a bit since the cable snapped, and we were going up to about 5000 feet elevation, so I think that affects fuel economy too.

I'm running a used SPICA from APE and have a stock engine with a head with a relatively fresh valve job on it and 115K miles.

[Grant]

That's pretty decent. I, on the other hand, returned about 17 mpg again with mostly city and some freeway driving.

Factory literature states 19 and 25mpg for a 1975 GT.

I still haven't hooked up the wideband, I'm wondering if I"m running excessively rich on throttle tip in, or idle or something...where could all that gas go??

[sfalfa]

Grant,

I always chalked up the mileage to the hotter cams or engine work done on the car (Though I never found receipts for it - I'm 99% certain it's been done). The car is significantly more powerful than any Alfetta I've owned, especially on the top end, where it continues to pull stongly where other Alfettas run out of breath.

[Grant]

Hi Jeff.

I'm wondering if the car pulls better up top just because of the shankle headers and lack of resonator? She's still a bit tepid under full throttle, but it's OK, I really like cruising around and running errands in it.

Unless the pump was modified by Wes Ingram or something, I don't think hotter cams would make the mileage any worse. The fuel delivery system is fixed, so, if I flow more air through the engine because of cams, the Spica won't know the difference, and just deliver fuel based on RPM, air temperature, and throttle load (I'm not 100% sure about the RPM tidbit, but I don't see how it could run well with out knowing RPM). So, if anything, I should get better mileage with hotter cams (that increase low RPM performance, like Euro cams would) because I should have to use less throttle to accelerate at the same rate. I'm in no way an expert, this is just what i've read so far.

I am planning on pulling the valve cover to seal up the gasket a bit, I'll check the cams out and let you know what I find! But, I still have a hunch it has stock cams

[Trevlac217]

Sorry for the slow reply. I've been in training for the last three weeks. No, from what I've seen in my limited Alfa time is that the difference in the Euro engines of that year and the American models are the cam profiles and the use of carbs instead of spica. My car was advertised as having the 10.4:1 CR pistons, but that has not been verified.

[Alfacliff]

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