‘74 X19 miles per gallon (mpg) not very good. Likely solution?
- Thread starter tvmaster
- Start date
Ics19
belle macchine!
Seems like you've lost even more mpg since your previous thread a few months back 
There's some tips there too if they weren't checked at the time.
There's some tips there too if they weren't checked at the time.
tvmaster
True Classic
Maybe a couple on this last tank, hence my wonder. Oil looks good at least. Time for some major investigation it seems.Seems like you've lost even more mpg since your previous thread a few months back
What I was initially wondering is if a novice could solve the mystery in their small garage, but this may be over my tools/abilities. But I do know at least one guy who could, and who does have the tools
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Steve Hoelscher
True Classic
Dan is correct. Its not uncommon for the manual choke cable to be out of adjustment.
Also, if you're wondering about the accuracy of the speedometer/odometer, that's easily verfied using a GPS app on your phone. Heck Google Maps and Waze both have MPH readouts on their displays. Many years ago, I changed the ring and pinion on the van with which I towed my racecar. The speedo drive was all electronic and not easy to recalibrate. So I simply used a Garmin GPS as my speedometer, then later the GPS app on my phone, until I sold the van.
tvmaster
True Classic
That's how I measure my odometer, against Google Maps. Seems to be really close to spot-on.
Because your knowledge is extremely good, and you work on these extensively, how many hours of labor, from an EXPERIENCED X19 mechanic, should one expect to at least get a X19 tuned to the best of its current condition/abilities, 3, 5, 10, if major parts are not needed?
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dllubin
Don
Don't assume the timing is correct at higher speeds just because it is OK at idle, especially if the vacuum retard has been messed with. The Ducelier distributor on that car has a very large centrifugal advance which is offset by the vacuum retard. For a good desmog, best thing to do is get rid of the vacuum retard, set static timing to 10 degrees, and recurve the centrifugal advance to get you ~32-35 degrees by about 3,000 rpm.Thanks sir, this is a lot to unpack - but I’ll begin. I’m mostly confident about the ignition timing just because Mr. Old FIAT guy checked and adjusted that when we first got the car. Does it fall out of timing often?
The hoses - this will take studying time. As always, greatly appreciate the time to explain to the newbie
Steve Hoelscher
True Classic
Assuming the car I was working had no other issues then, as Carl noted, my 'spring service/tune-up' would look like this:
Remove the top of the carburetor, blow out jets and reset float level. Reference the mixture and idle screw settings.
Check cam timing
Clean & Gap spark plugs (replace if necessary)
Inspect ignition wires
Clean and gap the breaker points
Check dwell setting
Set ignition timing (this requires an advance light to check both vacuum retard and mechanical advance)
Assuming I am not having to tend to any other issues that arrise from the process this would be an afternoon project taking approximately 3 hours. I should note that all of these tasks I am practiced at and I have the appropriate tools. Although, I haven't had a breaker points type distributor in one of my cars since about 1985. Also, I added the distributor access panel to my '74 so that makes makes the process of dealing with the points and setting ignition timing much easier.
Trips of less than 10 miles. Sounds like a lot of stop and go, frequent acceleration, etc. My E63 AMG does around 13 mpg in that type of driving. Out on the open road I've seen as high as 26.7. Plan a real drive, say 100 miles of open road. You shouldn't have too much trouble finding a nice loop around So Cal. Check your mileage in those conditions. Should give you a much more accurate picture of what your all-around mpg really is. And do you really need the choke? I have dual DCNFs, no chokes at all, and none needed.
carl
True Classic
I don't know about fellow Fiat owners in your area but this kind of thing use to draw a nice group of Fiat owners to your house or one of the club members and all would be taken care of for the price of carry out Pizza and soda. DCfiats has gotten more sophisticated over the years and we now go out for lunch!
Seriously, see if you have some folks in the area who could help you. If you know what you are doing, most of this is very basic and easy to do.
Seriously, see if you have some folks in the area who could help you. If you know what you are doing, most of this is very basic and easy to do.
tvmaster
True Classic
That would be nice. We do have a pizza oven. Guess it's time to join the FIAT Club of America...
tvmaster
True Classic
The '74 needs the choke to stay started for the first minute or so when starting from cold.
Ricardo Borja
el moco
I will ask on a different way, at the end will see what goin on:
could you tell me your numbers on the jets all 4
please don't mix it if you need to take out, one at a time from primary cowl to secondary.
I gain experience on my own setup but my X is a 1500 carburated (1979) water cooled automatic choke.
last year I made a deep cleaned process on my carb for gunk issues,
This year after 10 years to pass my smog test fail, reason? "your car have a big pollution problem"
after to review all my notes over 15 years to take it, I prepared my new set of jets.
regards.
could you tell me your numbers on the jets all 4
please don't mix it if you need to take out, one at a time from primary cowl to secondary.
I gain experience on my own setup but my X is a 1500 carburated (1979) water cooled automatic choke.
last year I made a deep cleaned process on my carb for gunk issues,
This year after 10 years to pass my smog test fail, reason? "your car have a big pollution problem"
after to review all my notes over 15 years to take it, I prepared my new set of jets.
regards.
tvmaster
True Classic
So it didn’t pass Ca. smog then. How’s your mileage?
Ricardo Borja
el moco
I know your X19 does not need to pass smog test, but over the years I have prepared my set of jets to test and my set of jets to run, if you have removed everything from the emissions control, most likely your set of jets may not be the right one for your new carburetion set up.
My X19 the engine is in original stock, it does not run more or less than any other 79' with all the emissions set up. And just to pass the smog test I make a few small adjustments, including the main jet of the low cowl.
Not sure how many mpg it gets but average should be 20 to 24 mpg
kmead
Old enough to know better
You might consider getting a new catalytic converter, they have been shown to really clean up ‘gross polluter’ cars.
My fuel injected X driven in a mixed urban driving mode gets 28 mpg, our Miata gets 29 in the same basic use. On a trip the X gets more in the range of 33 mpg. Both cars end up having to be pushed a bit to keep up with aggressive modern drivers.
As Ricardo points out, careful set up of the base parameters and tuning can make a big difference in how the car performs.
Ricardo Borja
el moco
CARBURATED VS FUEL INJECTION it's a big difference about perfomance (mpg)
But I never thinking about it. and I never made a test of mpg with my "SMOG TEST JETS" but I guess it gets much more than 24 mpg. (much, much more)
My catalytic converter is brand new, and just I install on my X1/9 for every smog test and it's been used for around 100 miles only every 2 years, after to pass I pulling back my cat back 4 tips ANSA MARMITTE style exhaust setup.
dllubin
Don
Back when my car had to pass CA smog every two years, I had a process for quickly turning the engine back to stock. I still have the box of parts which includes a stock intake manifold with stock DMTRA (with stock jets) mounted on it, air pump with plumbing, a stock cam with shims IDed with their specific valve position, and vacuum retard bits. I did the swap so many times that it could be acheived in about 2 hours. Good thing that 74s had no cat or it would have been a bigger job.