Thread: EFI Tuning

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I've been struggling to get my SBF 347 EFI tuned, and had made some adjustments to the injection map using the Handheld Calibrator LED's fed by the base narrow band O2 Sensor - it has Red (Lean), Amber (14.7:1) and Green (Rich) LED's, and theoretically should work for a street tune but I was getting exhaust pops and other problems that had me a bit baffled. Last week I ordered a Wide Band O2 controller and gauge, and this weekend made a little box to hold the indicator, LED and calibration PB along with an adapter pipe for the O2 sensor. Sunday afternoon was test day, and I was amazed at how badly I had messed up the fuel map. I think my narrow band sensor response is a little slower, but mostly it is simply that the range measured is only 14 to 15 AFR while the wide band range is 7.35 to 22.39 AFR - the narrow band resolution is so tight, and the response is so fast that it is actually just a switch. With a red LED you know you're above 15AFR but no idea how lean, and with green you only know you're below 14AFR. Being able to watch the AFR change throughout the power band is such a powerful tuning tool it actually makes it a fun exercise to make an easy pull, note areas where the mixture is off, and to have an idea of how much adjustment is needed in the map to bring it back to the sweet spot. This is the Innovation controller unit I picked up for $170, and my home-made setup to make it functional for tuning. The exhaust extension simply slips over the baffle tube and clamps with a hose clamp. Works slick!!

Good post Roger.Catch me up on your build.If that one of the Fast systems??.

Originally Posted by 1gary

Good post Roger.Catch me up on your build.If that one of the Fast systems??.

No, mine is Edelbrock's ProFlow XT which is an all inclusive kit. Edelbrock uses the FAST system hardware in their ECU, but they package it and do their own application firmware and software. The Innovate controller/guage kit comes with Bosch wide band O2 sensor, gauge (blue or red display), calibration PB and LED, interconnecting cables, O2 bung and a CD with manuals & software to reprogram the controller for other fuels.

glad to see you're getting it sorted out. wide band is way easier to tune with than NB but............. self tuning ECUs are about the same amount easier than WB alone . I finally went Holly HP and haven't looked back since.

under what conditions were you getting "popping"?

Russ

Originally Posted by lotsatoys

glad to see you're getting it sorted out. wide band is way easier to tune with than NB but............. self tuning ECUs are about the same amount easier than WB alone . I finally went Holly HP and haven't looked back since.

under what conditions were you getting "popping"?

Russ

Russ,
I had leaned out the map in the low to mid-range and was getting "lean pop" from the headers. When I added some fuel it smoothed out, and brought a lot more power to the ground. Talking to Edelbrock, if I install the wide band sensor and wire it in to the ECU they can send me a firmware version that makes it self tune, but I've got it very close to optimized now, so I'll likely leave it alone.

After I had the fuel map sorted out I was still getting some occasional "stutter & pop" during acceleration. I started watching the O2 display and the handheld LED's closer, and what I found was that I was going lean when I hit it, but it recovered within a second or less. The map was good, but my "accelerator pump" curve was too lean, even though I had steepened the curve a bit, maybe 5% earlier in the day. I picked up that handheld unit while on a test drive, dialed it to "Transition Fuel" and added fuel until it stayed just below mid 14's on throttle action across the range - I could not believe it wanted 20% more fuel in transition! Backed the macro correction out of the handheld calibrator, and went back to the curve on the laptop and added 20% through the idle and mid-range and the stutter & pop was gone! HOORAY!! Today Edelbrock sent me a new Crank Fuel curve to try, and that seems to have solved my starting inconsistencies. Now if I can just keep my hands off of those curves......

Originally Posted by rspears

Now if I can just keep my hands off of those curves......

Are we still talking about the EFI system?

That's great news about your tuning. The precision of EFI is remarkable for an old carb guy like me!

Originally Posted by 34_40

Are we still talking about the EFI system?

That's great news about your tuning. The precision of EFI is remarkable for an old carb guy like me!

OK, that brought a smile to my face Too old for any other curves, Mike.
Yeah, the EFI provides lots of adjustability, but I'm not sure changing jets might not be easier sometimes. I tend to like to tweak graphs & tables, and before long it's all messed up and I have to backtrack...

Originally Posted by rspears

OK, that brought a smile to my face Too old for any other curves, Mike.
Yeah, the EFI provides lots of adjustability, but I'm not sure changing jets might not be easier sometimes. I tend to like to tweak graphs & tables, and before long it's all messed up and I have to backtrack...

Well, at least we're not to old to smile about it... EH?

Sounds like you like to "tinker"....

Originally Posted by 34_40

Well, at least we're not to old to smile about it... EH?

Sounds like you like to "tinker"....

Yep, you've got me pegged! Heard a guy at a cruise last night, "Yeah, ya' got to grow older, but ya' don't have to grow up!"

Originally Posted by rspears

OK, that brought a smile to my face Too old for any other curves, Mike.
Yeah, the EFI provides lots of adjustability, but I'm not sure changing jets might not be easier sometimes. I tend to like to tweak graphs & tables, and before long it's all messed up and I have to backtrack...

Every time you make a major change to the tuning you (should) save the file with a new file name. if you find you went the wrong dirrection you just switch back to the prior configuration. that whole senerio took about 5 mouse clicks and 30 seconds. try matching that time by changing jets and fuel pump cams.

Russ

Originally Posted by lotsatoys

Every time you make a major change to the tuning you (should) save the file with a new file name. if you find you went the wrong dirrection you just switch back to the prior configuration. that whole senerio took about 5 mouse clicks and 30 seconds. try matching that time by changing jets and fuel pump cams.

Russ

Yep, that's indeed the way to go. I think I'm up to file #13, but #7 has alpha suffix's that add ten or twelve in the middle. I often do a "save as" with a "Test" added to the number, and then blow it away if it doesn't pan out. Last night I was on my way to a local cruise, and I realized that the re-configuring of my spark map was not working right so I grabbed the handheld calibrator while stopped at a light, dialed in "Global Spark Modifiers" and was able to take out six degrees across the board temporarily, then go back to the previous spark map when I got home. It's pretty slick, especially if you like to tinker...

Roger

Got the plots/graphs to Corey--he hasn't had time to really get into them but did offer a few guide lines--

At cruise in closed loop it should tune to arond 14.7

on accelleration/wot---12.5 up to peak torque area then lean to 12.8 at WOT top end(about torque peak going up towards peak hp)


your picture doesn't show enough of your o2 adapter to tell if your getting any reversion into the exhaust tip---this has been an repeated area that we see--best is to weld a bung into the header merge area

Originally Posted by jerry clayton

Roger

Got the plots/graphs to Corey--he hasn't had time to really get into them but did offer a few guide lines--

At cruise in closed loop it should tune to arond 14.7

on accelleration/wot---12.5 up to peak torque area then lean to 12.8 at WOT top end(about torque peak going up towards peak hp)


your picture doesn't show enough of your o2 adapter to tell if your getting any reversion into the exhaust tip---this has been an repeated area that we see--best is to weld a bung into the header merge area

Thanks Jerry,
On the O2 adapter, it's a piece of 1.75" tube that fits over a matching center core in my header, and the outer baffle plate is solid so everything flows through that center core tube. The O2 sensor is 7" from the end of the adapter pipe, so I don't think it can get much reversion, but if it needs to be longer I can weld on another section of pipe - it fits on the passenger header and blocks opening that door anyway, so longer is OK. My narrow band that feeds the ECU is in a bung just after the last primary joins the megaphone, about 15 to 16" from the outlet, plus it is baffled.

Thanks for the numbers on A/F ratio. I will put my wide band back on and go check it at the upper end - I may be a bit leaner than that at the top end, which would explain a slight stutter at about 5500rpm yesterday. I'll look forward to Corey's comments on the spark map.

Jerry,
I spent about an hour on the phone with my Edelbrock guy, and he re-mapped my spark to reflect what they have seen on their tuning experience. I've uploaded that into my ECU, and I'll plug in my wide band O2 tomorrow and go cruising to see how it does. I got some really good advice on mapping.