MASS Flow?

[81autospider]

I want to ask mark if it is possible to upgrade to a MASS air fuel injection system...like the type that Ford used that was so popular with the street rodders...the system is so basic and much easier to work on...and on a personable note, simpler then the Bosch set-up...Mark, could this be a possible swap...I will list the simple components below;
MASS air meter
temp sensor
MAPP sensor
O2 sensor
TPS sensor
EGR sensor

Basically that sums up the components, but without all the fancy components the fiat has...the perimeters of these components to me are much easier to diagnose...usually, if your car starts to run like crap, then you usually have only a couple of sensors to check...with this Fiat I have, I gotta check like everything when something goes wrong.

[Hjulenx]

That is actually more sensors and more complexity then the L-jet system involves. The difference is, and where the diagnostics get easier, is that the Ford system is Digital whereas L-jet is an analog system. The reason you have to check everything when anything goes wrong is that l-jet is very sensitive to disrupted grounds and bad voltage signals; degraded sensors can cause all kind of weird things to happen, and when there is no OBDII hookup to read codes you have to systematically check everything.

Answering your question...yes and no. You can wire you Fiat with all the sensors (though you would only need either the Mass Air Flow element or the MAP sensor, not both). The only thing you couldn't do is use the Ford Computer to run your twin cam...the fuel maps just won't work.

The best solution, if you want modern fuel injection is to go with an aftermarket programmable setup and have a professional shop dyno tune it for you. There are lots of different types and 'ranges' from high end units like AccelDFI and Haltech, to a Do-It-Yourself system like Megasquirt. Any way you go its quite a bit of money, and if you do it yourself, time.

That being said, I have converted my car over to the megasquirt EFI, but I am a tinkerer.

My recommendation? Go through your current system with a fine tooth comb. Clean EVERY ground, check EVERY sensor, replace all the vacuum lines with proper sized silicon ones (http://www.hiperformancestore.com). You will happy and it will be reliable.

[81autospider]

Hjulenx...I was actually thinking of moving the whole system over from a comparable size motor...say a 2.3L Ranger 4 cyl....I was going to remove the whole fiat system and install the Ford OBDII in its place...most of this stuff can be bought on the cheap at the wreckers...do you think that kind of swap is possible?...seems pretty straight forward to me...I'm not trying to convince anyone it can be done...I just want to be very clear on how it can be done...

ECM and harness from donor vehicle
Throttle body from donor Ford 2.3 with TPS for ECM
O2 sensor for ECM easy to R&R that piece
Temp sensor should be an R&R
Match spark trigger to ECM wiring as Ford 2.3 was wired(this could be where things get tough is there are too many wires, unless they can be used to do the same job the Ford used to send signal to ECM)
Install original Ford MAP sensor
Install cold air intake with MASS air sensor

Now at this point it sounds easy...but from what I have read about the MASS air ECM systems, they are not designed around valve sizes and cam lift and duration...they are designed to measure the amount of air going in and matching the fuel amount required for efficient combustion in a given number of engine displacement...so if I found a 2.0L Ford or even a 2.3L, it should not be a issue involving dyno tuning to make it run good...I have seen your swap with the megasquirt system you are using...and that motor looks like it belongs in a F1 race car

It may be more sensors yes, but...at least I can go down to almost any parts store and buy a code reader and have my car fixed it a fraction of the time of tinkering with the Bosch system...plug it in, the code reader tells you what's out of boundary and fix the part...now what's so hard about that?

[Hjulenx]

Well...still wouldn't be quite that easy. While you are right, the system measures the amount of air going into the engine and fuels it accordingly you simply can't just transfer it from engine to engine.

Here are some issues I see:
- The threads on the coolant sensor won't match up.
- Mating the throttle body to the Fiat plenum...
- Spark Triggering...any modern ford is going to have a distributerless ignition setup (Like EDIS or similar). Essentially how these work is they have a 36 tooth (with one tooth missing) wheel grafted onto the crank pulley. These teeth are read by a Variable reluctor sensor to tell the ECM when to fire the coils. You would need to installed one of these pulleys and sensors, which if it is an EDIS setup, you can get them from http://www.millersmule.com


I am still not convinced that a Ford ECU would work well, even after being 'tuned' (IF they can be tuned, since they aren't redesigned to be..) Essentially, any EFI system at its core uses a modified Speed-Density algorithm to meter the fuel into the engine. Something like this:

Mass Fuel Injected = Mass Air in Cylinder / Air Fuel ratio

There are different ways that the ECM calculates the mass of air entering the cylinder. This is where the Manifold pressure sensor or the Mass Air Flow sensors come in. But thats not quite the whole story...as the algorithms are of course an IDEAL case. Essentially the Ideal Gas Law is used.

Mass air = Manifold Pressure * Cylinder Displacement / Air Temperature / Constant

IDEALLY all the air measured by the MAF and MAP sensors enters the cylinders, and IDEALLY the cylinders fill completely with a fresh Air-Fuel charge. There are modifiers to this algorithm which are engine specific in order to correct for no ideal conditions. (Flow effects, harmonic tuning, volumetric efficiency, warmup and acceleration enrichment requirements). Dyno tuning would be required to make it run well, especially since a Ford 2.3L engine has the benefit of modern head design and casting. The flow characteristics, even though its a similar sized engine, are completely different.

Intake manifold design has a lot to do with how things like warmup and cold starting, definitely something you would be concerned about if you want it to run well and reliably. Stuff that needs to be tuned.

To make a long story short, lots of tuning required since you will be fighting Ford's tuning. But it COULD BE DONE, maybe.

Like I said before, I think you are better off with an aftermarket EFI.

[racydave]

It was tricky enough to do the ignition with the Mega-Jolt. It is based on the Ford EDIS. James has had quite a task doin the Fuel injection, and must be a pretty sharp tech.

[bradartigue]

Why? BOSCH L-Jetronic, especially as implemented in the FIAT, as about as easy as it gets.

Not trying to sound harsh but if you think L-Jet is complex then FI might be a bad move in general.