Help - Search - Members - Calendar
Full Version: A different sort of FI question
914World.com > The 914 Forums > 914World Garage
mmichalik
So yesterday, I'm driving to the gym in my Alfa and it starts throwing codes on the dash.
I get the car back home, put the scanner on it and ultimately it was a P0101 code that put the car into limp mode and shut off a couple of other functions in the car.
I knew I didn't want have the luxury of getting a new Mass Airflow Sensor quickly so I went to the auto parts store down the road and got me a can of the MAS Cleaner.
30 minutes later, part is clean and back in the car and the code is gone.
But all of this got me thinking, did the original FI on our cars use a wire senor for the MAF or did it use something even more analog then that? I mean, it was almost 50+ years ago when it was designed.
I've always been afraid of the FI on the cars but, I've been toying with the idea of getting a FI kit from one of the vendors that are now producing them, for the 2056 that I am building.
Yesterday's experience intrigued me and maybe the FI isn't so difficult after all....
930cabman
QUOTE(mmichalik @ Jul 26 2023, 08:25 AM) *

So yesterday, I'm driving to the gym in my Alfa and it starts throwing codes on the dash.
I get the car back home, put the scanner on it and ultimately it was a P0101 code that put the car into limp mode and shut off a couple of other functions in the car.
I knew I didn't want have the luxury of getting a new Mass Airflow Sensor quickly so I went to the auto parts store down the road and got me a can of the MAS Cleaner.
30 minutes later, part is clean and back in the car and the code is gone.
But all of this got me thinking, did the original FI on our cars use a wire senor for the MAF or did it use something even more analog then that? I mean, it was almost 50+ years ago when it was designed.
I've always been afraid of the FI on the cars but, I've been toying with the idea of getting a FI kit from one of the vendors that are now producing them, for the 2056 that I am building.
Yesterday's experience intrigued me and maybe the FI isn't so difficult after all....


What have I heard in the past, "date Italian, marry German"

great, my second wife happens to be Sicilian

Yes, the early Bosch FI systems and reasonably simple.
JeffBowlsby
No wire sensor or MAF in any stock 914. Djet used a manifold pressure sensor, LJet uses an Airflow meter. These are simple systems relatively speaking.
Chris914n6
^^ plus the hotwire system was a couple years after us. LH-jet. First used on Saab and Volvo late 70s and is the basis for all the modern FI.

If the 914 had continued like the 911.... it would have gotten hotwire (maf) in the 90s laugh.gif
technicalninja
I think he's talking about an OBD2 Alfa; something later than 1996.

Please tell us what you are working on.

Every single MAF sensor I've worked on (a shitload!) is what they call a hot-wire sensor and every single one will need to be cleaned during its life.

You running an oiled cotton gauze filter (K&N style)?

You're going to RUIN your MAF with the air flier oil.

You'll have to clean it constantly unless the MAF is a good distance from the filter and even still it will require more frequent cleaning.

I use a dedicated "Electronics cleaner" and then blow dry with 20 psi air.
It's a chore to regulate 175 to 20. Takes me three regulators but I go through the BS as I want to blow the wet cleaner off the wire but i don't want to blow the wire away and you can trash one with 90 psi air.

So, yes cleaning MAFs is completely normal. I would consider that process as a PM that gets done automatically every 30-50K along with removing and cleaning the throttle body.

Doesn't have to be Alfa or European. Anything with a throttle body and a MAF needs these.

The L-jet 914s used a spring-loaded flap on a potentiometer to send the ECU airflow data. AFM (air flow meters) were also used by many and have been replaced by MAP and MAF sensors.
mmichalik
I was working on my 2019 Alfa Romeo Giulia yesterday. That's the MAF sensor that was cleaned.
My question, or statement, was that the simplicity of the Alfa, which has a LOT of computer controls on it, made me realize that fuel injection might not be all that difficult to understand and work with.
Granted, all I did was clean the MAF sensor but, it certainly de-mystified a big chunk of my apprehension.
I appreciate all the input.
I'm going to contemplate setting up one of the complete FI kits, that our esteemed vendors have come out with recently, on my 2056 that I'm building.
Dave_Darling
The D-Jetronic system used in the 1.7 and 2.0 914s used a Manifold Pressure Sensor to estimate the amount of air going into the engine from the air pressure inside the manifold. (With compensation for things like engine temperature, air temperature, and so on.)

The L-Jetronic system used in US-spec 1.8s did measure the air going into the engine, but it didn't use a hot-wire or hot-film system. It used a spring-loaded flap in the intake. Air coming in pushed the flap out of the way, and the amount that the flap (or "barn door" or "vane") was pushed was roughly proportional to the amount of air going in.

In both cases, the resulting information was used by a very funky analog electronic computer which told the injectors when to open and close. No look-up tables or anything digital.

Oh, and the European-spec 1.8 motors used dual single-throat carbs. Even more analog.

--DD
GregAmy
QUOTE(Dave_Darling @ Jul 26 2023, 07:55 PM) *
The L-Jetronic system used in US-spec 1.8s did measure the air going into the engine, but it didn't use a hot-wire or hot-film system. It used a spring-loaded flap in the intake. Air coming in pushed the flap out of the way, and the amount that the flap (or "barn door" or "vane") was pushed was roughly proportional to the amount of air going in.

The 80s loved the vane-door flappy measurer MAF. Even the 1.6L Miata, released in 1989 and used through 1992, used it.

It's interestesting that the bad-ass Motronic 1.2 as used in the vaunted 962 used the wire MAF. It was all about how much computing ability you had...and L-Jet and D-Jet had almost none (as I like to describe it, "a bunch of resistors and diodes flying in formation".

Today's even-cheapest EFI are heads-and-tails above any of that. It's like the old "you have more computing power in your pocket than Apollo had".

GA
This is a "lo-fi" version of our main content. To view the full version with more information, formatting and images, please click here.
Invision Power Board © 2001-2024 Invision Power Services, Inc.