Fitech help sought.

I searched and couldn't really find any help but hoped someone here might be able to. 
 

just put a used fitech on our bronco.  It came off of another bronco also with a 351w.  
 

it fired up, ran a bit rough but runs ok now.   Haven't driven it but am playing with it in the garage. 
 

the problem I'm having is it isn't starting without turning the the key on and off two or three times to give it extra fuel (the prime shot). 
 

I turned up the enrichening for all of the temp zones and that helped but basically I can't figure out how to double the length of the prime shot as I need more fuel. 
 

In reply to jfryjfry (Forum Supporter) :

Where can one find on line documentation?

For the rough-running, is your Bronco also a 351W? The older Windsor 302's and 351's had different firing orders.

If the EFI is calibrated for a different ECT or IAT temp sensor, that may play into how it runs too.

Can't find a manual on the fitech website, but I imagine it's just an email away.

We've had a few threads about them, this one came to mind: https://grassrootsmotorsports.com/forum/grm/learn-me-drop-on-carb-replacement-efi-fitech-etc/155684/page1/

I have a fitech and for the last two years have not been able to make it live up to the advertising. I fully believe it can work, but it requires a lot of EFI know how. Your new hobby is learning EFI. 

What I have learned is that the Fitech should be able to run your engine on the base tune.. Reload to as factory, answer the 3 questions on cylinder count, engine size and ?? and it should start and run reasonably well. If if does not, go looking into the engine and the rest of the system.

Vacuum and exhaust leaks are consequential. Use a smoke machine to check .

If I understand your post, you ARE getting a prime shot, but it is not enough. Assuming that you have already cranked the prime shot to max, why does your engine need so much fuel to fire? The more common situation is people lower or shut off the prime shot.

Pete

It fired up and ran a few times but then started needing ether to fire.  Still ran fine and I figured out that it is getting fuel but not enough.  
 

it is weird that most people have to knock theirs down and I've had to add fuel.  
 

when we had the carb on it it didn't need an abnormal amount of gas. 
 

I have thought about just doing a factory reset and starting from scratch. 

Has it changed, or always been this way?  If the reset doesn't work, check the fuel supply. 

See a lot of bad injectors and failed fuel pressure on the FB Fitech page. 

Not tracking fuel pressure is a major design flaw in the TBI products. It is critical to performance and hard to monitor. I drove around with a gauge taped to the window when investigating that parameter.

The issue I have is that the Fitech only works well when the ambient temperature is hot. If it dips below 70 degrees it runs like crap and stalls at intersections.  The current weather has been teasing me with how well it COULD work.

I don't have a lot to add, but have a Bronco with a 351W that will eventually get aftermarket EFI (probably MS), so relative to my interests.

This may be a dumb question, because I don't know the specifics of Fitec, but if it was previously carb'd, was the fuel system modified to work with the pressures required for EFI?

Fuel pump and injectors check out?  

NOHOME said:

See a lot of bad injectors and failed fuel pressure on the FB Fitech page. 

Not tracking fuel pressure is a major design flaw in the TBI products. It is critical to performance and hard to monitor. I drove around with a gauge taped to the window when investigating that parameter.

 

The issue I have is that the Fitech only works well when the ambient temperature is hot. If it dips below 70 degrees it runs like crap and stalls at intersections.  The current weather has been teasing me with how well it COULD work.

Sounds your cold start settings are incorrectly set and if you have a temp sensor that is out of whack, that will make the problem worse.

Watch the temp sensor with a gauge and compare it to what the ECU thinks it is, you might find something is off.

Tuning for various outside temperatures and engine temperatures is much of what takes the longest for tuning.  The other is just getting it started the first time from scratch.

In reply to Stefan (Forum Supporter) :

Nothing to do with the temp of the engine, it is actual ambient temperature. 

I never installed the Fitech temp sensor. Even Fitech now admits that it does not work, but they keep sending it.

I thought I had it figured when I observed that the Fitech IAC temp was always 20 degrees COLDER than ambient.  ( so if it was 80 degrees out the IAC reads 60 degrees) but Fitech tells me this is not a problem and the IAC has nothing to do with ambient air temp. So now looking for other reasons why a HOT engine would be sensitive to the outside temperature ¯\_(ツ)_/¯

Kinda academic at this point because the handheld has stopped communicating with the EFI so I cant make changes any ways, 

So for those of us who have never done a Fitech, do you have a file or spreadsheet that shows all of the things that can be adjusted via the dongle?

NOHOME- in my experience, your observation of IAT temp 20 F cooler than ambient never happens- which suggests that thier temp measurements are rather suspect.  BUT, the observation you see makes a lot of sense in jfryjfry's situation.  The question is- is the calibration wrong for the sensor, or is the sensor wrong?   Or is it even reading something sensible?

And I'd really like to see all of the functions that use that measurement.  The general math effects on fuel is pretty straight forward- but the tweaks take some more work.  Seeing where all of that is calculated can show is there's something in there.

This may be totally irrelevant, but the Fitech system is just an aftermarket TBI.

I went through a few months of having my TBI GMT400 not start without a prime. It ran normally once started, exactly like what you describe.

Fuel pressure was good, it made spark when it was tested, both of the injectors fired normally when running, but it wouldn't prime. Changing computers did nothing.

Baffled me, and the first Tech I took it to.

The answer made zero sense to me, but here it is: It needed a distributor.

As suggested above, it may be something unrelated to the fuel system.

My first guess is fuel pressure is rising too slowly.  You can either monitor it, or wire in a 'prime' momentary switch that runs the fuel pump whenever you push it and see if holding that down for a couple seconds before cranking makes it start instantly. 

Have you been able to do a drive at highway speed?  Any time I have had FI problems with initial prime, there was also an attendant problem with fuel starvation at WOT at highway speeds.  


Check your fuel pump, filter,  power, and grounds.   Especially at the pump, but I wouldn't stop there.  Voltage the vehicle is charging at, and voltage at the pump are both important checks.

My FiTech equipped 351 Cleveland ina '69 Cougar has cold start issues as well.   I've tried to increase the  prime fuel multiplier and the crank fuel settings but they have not resolved my cold start struggles.  In my case, warm/hot start requires no key cycles or throttle application.

Here is what I do now to make the car easier to start.  Two or three key cycles until I can hear the injectors clicking then slight throttle application while I turn the key to start.   The throttle seems to indicate to me too much fuel (allowing additional air with throttle) though that's my guess.  Waiting for the injectors to cycle seems to imply pressure loss back to tank.  I have a dual plane intake (longer intake runners) which people have pointed to as a potential problem though I don't follow that logic.  The car isn't running now due to trans swap.

I need to improve the fuel delivery system with better filtration and part of that install will include a fuel line check valve.

Eric here is what the dongle allows on my system (FiTech 30002)

Crank and Warm-up page

-Prime Fuel Multiplier

-Crank fuel (20f/65f/170f)

-Crank IAC

-Afterstart (20f/65f/170f)

-Warmup 20f fuel

-Warmup 65f fuel

Again, my car is down for work so I am looking at blank tables not my program values.  

In reply to wawazat :

Are all of those single values?  Or functions or tables?

One thing I would note- IF you can read the temperatures, how far off from reality are they?  It very much seems as if the temp data is being read wrong- assuming that the interpretation of it is correct (and unadjustable).

In reply to alfadriver (Forum Supporter) :

Below is the data log format for Fitech TBI.

Based on the number of times that it comes up as a problem, I would put forth that a column under FUEL PRESSURE would be a good idea and a major omission on Fitech's part.

When I took this log, the Ambient air temp was in the Mid 80's yet the IAC is seeing 64 degrees. Within  spec according to Fitech. In my mnd it should be hotter than ambient if anything.

If you bought a Fitech because of their marketing that makes it seem like EFI knowledge is not needed, just picture "day one" when the thing does not work out of the box. Lot of vocabulary to assimilate AFTER you figure how to create a log.

In reply to NOHOME :

Thanks.

While fuel pressure would be great, OEM's didn't really do that consistently until DI came along, and pressure was moving around by hundreds of PSI.  Then again, we had a system where fuel pressure was very reliable and consistent- either the constant fuel pressure with returnless fuel or constant delta pressure with return system.  It very much sounds like the Fitech has a problem with a consistent fuel pressure make up.

Still, given the system that they have, a correct air and engine temp are incredibly important.  And 20F error being ok is a little far fetched (depending on how it's used).

So- seeing your log- is it a speed-density or and alfa-n system?  The log has data for both kinds of set ups.  With a TBI system, speed denisty should work fine- although and alpha-n system should, as well.

Given the relative simplicity of either system, and the lack of adjustments, my guess is still an input error- either (as you point out) fuel pressure is hardly consistent, or one of the other electrical inputs are wrong.

In reply to alfadriver (Forum Supporter) :

So- seeing your log- is it a speed-density or and alfa-n system?  The log has data for both kinds of set ups.  With a TBI system, speed denisty should work fine- although and alpha-n system should, as well

I would be the guy who bough this because he did not know or ever care to know the answer to this question. I have zero idea what the term "Alpha N" means. (sounds like a Dog Food brand) .  MAP will dictate a load and the temp, TPS  and AFR request based on O2 sensor should figure out  the rest.

To get back on the OP's thread, I highly recommend doing a log. The first thing Fitech  support will ask you for is a 5 min cold start to warm up log so if you need their help best figure how to down load these if you do not already. I log the same drive loop every time so that I can make some kind of comparison for the same situations. The Fitech gives you 3 data points/second, so even a 5 minute loop is a fair bit of data.

How to effectively make use of the logs is something that you have to figure out on your own or hire a tuner to do for you. At $100/hr they might be money well spent.

In reply to NOHOME :

Alpha - N means that the injection uses the throttle position (angle Alpha) and engine speed (N) to determine the amount of fuel to be injected.  Works pretty darned well, as many mechanical systems used this in the way back machine- my Alfa (the gold one in my avatar) has a mechanical injection system that is Alpha-N based on a SPICA made diesel pump.  My car just has an additional major input of engine temp, and minor ones for BP and starting- all mechanical inputs.  And since your log recorded an input called Alpha-N, that is what confused me.

But, yea, a log can be very helpful.  IMHO, tuning is a lot more intimidating that it should be- the core is get what you ask for.  If not, find out why, and fix that.  No fuel injection system *requires* exhaust feedback to run reasonably well.  But it sure helps.

In reply to alfadriver (Forum Supporter) :

Learned something new today.Thanks.

Oddly enough, the Alpha_N seems to map almost directly to MAP rather than any corelation to TPS. Once again, I don't assume Fitech is playing by anyones rules but their own.

Any idea what the term "Alpha" means in this context? I read it as "Alpha as a function of N" where "Alpha" could be fuel as a function of N with N being revolutions. In this case it would be Fuel as a Function of RPM and MAP reading which kind of makes sense.

Alpha = throttle angle.

And that term basically is a map result of the Alpha-N conversion to Manifold Pressure.  And what is happening is that there is a model that takes the engine speed and throttle angle and maps that into an estimated manifold pressure to use for fuel.

Which is actually pretty interesting- as we (Ford) falls back to the exact same calculation when the old MAF systems failed.  Again, I don't see the physics of how this thing works as being faulty- it's pretty straight forward and simple, as well as very published in most automotive engineering publications.  The issue is some bad input- either from a sensor or a pressure assumption.

On a related side note- this is where tuning/calibration gets confusing.  In the previous sentance, the word map means a represenataion of reality in a different form- like a real paper map you used to travel with. 

And doing that gets one confused with MAP, which is Manifold Absolute Pressure.  MAP vs mapping.  Just a funny coincidence of acronyms.  

Alpha is just the first letter of Greek, and for whatever reason, Greek terms are used for angles and other terms.  Alpha is first, so Alpha is throttle angle for this model.  It means something else in a different context.

And not at all related to Alfa.  Which started it's life as A.L.F.A.  

MAP, map, Alpha, Alfa...  great post.

(if that doesn't make sense, I can try again- it's not that clear)