Has anyone else fine tuned a fitech for efficiency?

[ShagWagon]

I been running mine for about 10k miles. It runs great but I only get 7.5-9mpg and dont really understand how the best way to set up the parameters for best efficiency is. Maybe I’m already there, but it seems I should be getting better. I just dont have the know on what to set or why. Maybe I just don’t understand the effects of 30” tires,4bbl intake, and performer cams impact on mpg. Not a lot of info out there for AMC360 but maybe we can share and figure out the best base settings for our rigs so I can go from there.

[wiley-moeracing]

is your temp sensor working?( the one for the fuel injection system), if you can connect to the system and see real time while running you may find out something is not working correctly.

[ShagWagon]

is your temp sensor working?( the one for the fuel injection system), if you can connect to the system and see real time while running you may find out something is not working correctly.

That’s something I would of never thought of. I’ll check it tomorrow if I find time. Seems to work ok as it reads about 143 or so as a max cylinder temp when it’s gets warmed up and starts at about what the outside ambient temp is to start cold. Is that the one to check?

[Crankyolman]

These guys have been very helpful to me https://www.fitechefituning.com/


One thing I've learned is that the Fitech coolant temp sensors have a known issue with reading low. Mine did, I replaced it with a Delco sensor. It starts self learning when the temp reaches 140 but if the temp doesn't get above 170 the system stays in warm up mode which adds extra fuel and causes problems with mileage.



I haven't done a mileage check since I got everything running correct but I haven't done much to it besides adjust IAC step and PWM, The experts tell me the numbers look good and it runs good but I'd really like to get better mileage than it did with the carb.

[ShagWagon]

Hahaha so you guys are telling me that 143 isn’t a normal operating temp?

Man I would feel dumb. Especially knowing what a thermostat open up at 185-210. I just never made that connection.

What cyl temp does your dashboard display say when warmed up?

[Crankyolman]

Hahaha so you guys are telling me that 143 isn’t a normal operating temp?

Man I would feel dumb. Especially knowing what a thermostat open up at 185-210. I just never made that connection.

What cyl temp does your dashboard display say when warmed up?

I just found your post at fitechtuning

(https://fitechefituning.com/fitech-e...r-gas-mileage/ )


I see your coolant temp is 177-179. Your log doesn't look all that different from mine but I can't say I'm getting any better mileage. If your interested here is a link to my latest data log so you can compare.

https://1drv.ms/x/s!AtllmUWFvoeUgi4lFoi6BmhHps48?e=jWyYfv

I have a 180 or 185 thermostat and had the fitech sensor in the thermostat housing and it never got over 170. I never removed it from the housing when I got the Delco. Because my intake doesn't have a hole for a 3/8 sensor I wound up installing the Delco sensor in the heater hose at the back of the block. My normal running coolant temp taken at that location according to my handheld controller is between 190 and 201 but cylinder head temp shows 140-143. I'm not sure how they come up with that number.


I kind of wish that Austin Dehaas guy who has that fitchtuning website lived near me so I could just pay him to tune it for me.



It will be 2 weeks before I have a mileage number for mine but I was getting a consistent 9 MPG with the carb. I hope you figure out how to get better mileage so I can do the same.

[FMJBT]

I went from around 8 mpg with an Edelbrock 4bbl card to around 11 with the Fitech. Temp sensor this winter was registering 170-ish when warmed up, now I'm seeing 180-190 range with summer temps. Still having a persistent issue with it taking a lot of cranking to get started and stay running despite a lot of tuning with the PWM settings. Aside from that the system is definitely an improvement over a carb.

[ShagWagon]

I just found your post at fitechtuning

(https://fitechefituning.com/fitech-e...r-gas-mileage/ )


I see your coolant temp is 177-179. Your log doesn't look all that different from mine but I can't say I'm getting any better mileage. If your interested here is a link to my latest data log so you can compare.

https://1drv.ms/x/s!AtllmUWFvoeUgi4lFoi6BmhHps48?e=jWyYfv

I have a 180 or 185 thermostat and had the fitech sensor in the thermostat housing and it never got over 170. I never removed it from the housing when I got the Delco. Because my intake doesn't have a hole for a 3/8 sensor I wound up installing the Delco sensor in the heater hose at the back of the block. My normal running coolant temp taken at that location according to my handheld controller is between 190 and 201 but cylinder head temp shows 140-143. I'm not sure how they come up with that number.


I kind of wish that Austin Dehaas guy who has that fitchtuning website lived near me so I could just pay him to tune it for me.



It will be 2 weeks before I have a mileage number for mine but I was getting a consistent 9 MPG with the carb. I hope you figure out how to get better mileage so I can do the same.

Yeah I see it now lol. Does it make sense that the cylinder temp is colder than the coolant temp? Not to me. I thought that was what it was reading as my running temperature . I’ll compare it to my analog gauge today to see if it’s on or close to the fitech sensor.

All I noticed different between yours and mine was your afr was 1 point set lower and your pump pwm was 2 points higher. I don’t look at it too long. I do t know what it means. Your un a 6cyl right? I haven’t tried to lower my afr settings since I reset everything after I installed a new o2 sensor thinking it wasn’t t working correctly and it didn’t help either. Was going to do so when I figure out or find something to set it too. Need to break out the manual again to remember how it works.

That guy won’t reply to my post for some reason...

[ShagWagon]

I went from around 8 mpg with an Edelbrock 4bbl card to around 11 with the Fitech. Temp sensor this winter was registering 170-ish when warmed up, now I'm seeing 180-190 range with summer temps. Still having a persistent issue with it taking a lot of cranking to get started and stay running despite a lot of tuning with the PWM settings. Aside from that the system is definitely an improvement over a carb.

It takes ten seconds or so to prime. They have setting for both cold start and hot start that you can adjust if your having starting issues. Just need to change them one way or the other slightly in the direction that the crank time improves.

[babywag]

The factory settings for AFR are pretty rich.
Increasing them should result in a mpg increase.

A tuned carb vs. tuned efi HWY MPG should be =
A tuned carb "" CITY MPG will be much better w/ efi due to more efficient use of fuel.
With "tuned" implying it is attempting to hit 14.7 target.

If you want even better HWY mpg increase cruise AFR.
Anything lower than 14.7 will waste fuel/decrease mpg.
Cruising I've gotten excellent results running ~15.5 AFR.

But GM TBI has a lean cruise hack

[Crankyolman]

Yeah I see it now lol. Does it make sense that the cylinder temp is colder than the coolant temp? Not to me.

It doesn't make sense to me either but I don't know what they use to get that number.

I thought that was what it was reading as my running temperature . I’ll compare it to my analog gauge today to see if it’s on or close to the fitech sensor.

With the fitech sensor mine would only get to 170 when idling in traffic otherwise it dropped to 165-168 which put it into warm up mode. I'm wondering if yours might be dropping below 170 when you are driving. Right now I have the hand held controller on "Large gauges" with just the coolant temp selected and have been watching what the temp is doing, which largely is not a whole lot, it goes up to around 200 and just stays there.

All I noticed different between yours and mine was your afr was 1 point set lower and your pump pwm was 2 points higher. I don’t look at it too long. I do t know what it means. Your un a 6cyl right?

Mine is a 360 with a 2 barrel, HEI ignition and TH400, 373 differential gearing. Pretty much everything on my truck is completely stock except the FI and ignition, and maybe the diff gearing, which all the literature says should be 409. I figure we should have close to the same setting but I have no idea what I should change if anything.

That guy won’t reply to my post for some reason...

He's usually pretty quick to respond but sometimes it takes a little time, I've waited over a week to get answers.

It takes ten seconds or so to prime. They have setting for both cold start and hot start that you can adjust if your having starting issues. Just need to change them one way or the other slightly in the direction that the crank time improves.

Mine cranks longer than it did with the carb too. I have been slowly working on that to see if anything makes any difference. So far anything I have tried has only made it take longer. I'm considering turning off the prime shot entirely then start adding for each temperature and situation. If I ever get an improvement I'll let everybody know.

[ShagWagon]

Yeah I’m a 4bbl with performer intake set with the timing control.

You have to adjust the cold start and hot start. If it gets worse then adjust it in the opposite direction. You have to do the cold start every morning adjustment for a little while to get it dialed in. I had to do this.

[ShagWagon]

The factory settings for AFR are pretty rich.
Increasing them should result in a mpg increase.

A tuned carb vs. tuned efi HWY MPG should be =
A tuned carb "" CITY MPG will be much better w/ efi due to more efficient use of fuel.
With "tuned" implying it is attempting to hit 14.7 target.

If you want even better HWY mpg increase cruise AFR.
Anything lower than 14.7 will waste fuel/decrease mpg.
Cruising I've gotten excellent results running ~15.5 AFR.

But GM TBI has a lean cruise hack

You read my data log? That’s at idle for 60 seconds or so.

I think I tried to lean out the settings last year and one of them ( I can’t recall) had some lock on it where I could adjust it max lean. I reset it all after I installed a new o2 sensor so that’s all factory computer learned tuned or whatever.

[babywag]

I did not look at any log...but for any tuning/troubleshooting/etc. a data log should be a good sample of real world driving.
My rule of thumb is ~20 minutes @ full operating temp. before making any changes.

[Crankyolman]

Thank you Babywag, that is helpful to me.



I only have one warm driving log I did on my way home from work one day in fairly light traffic. At 1800-1900 RPM (40 MPH) my AFR was running around 14.3 to 14.8. It is in the mid 13s at idle. I suppose I need to find a day when I can take it for a nice long drive down the highway again and see what the log says.



My daily drive to and from work is only 6 miles in mostly light traffic with a maximum speed of 40 MPH and I'd really like to get at least slightly better mileage.