again with FN348 Cranking Pw ECT questions
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again with FN348 Cranking Pw ECT questions
My injector size and engine displacement are accounted for, but I had to keep bumping up the higher temp values (above 160) to where its beginning to make me nervous:
-65536 5.70
-40 5.70
0 5.22
40 2.50
80 1.21
120 0.82
160 0.49
200 0.49
65534 .0.49
-65536 5.70
-40 5.70
0 5.22
40 2.50
80 1.21
120 0.82
160 0.49
200 0.49
65534 .0.49
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- Posts: 5085
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- Location: Metairie, LA
- Vehicle Information: Work Truck
'19 F-150 3.3L
Re: again with FN348 Cranking Pw ECT questions
yeah thats a bit higher than id expect could be some vapor lock issues
try reducing the crank pw and increasing the pump prime time to test
try reducing the crank pw and increasing the pump prime time to test
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- Posts: 67
- Joined: 2021 Mar 31, 17:29
- Location: Victoria, BC CANADA
- Vehicle Information: QH, TunerPro RT 5, GUFX_220418.xdf, A9L2_220405, DECIPHA_220505.ADX, 395w, AFR 195CC Renegade heads, Comp XE274HR cam, Siemens-Deka V 80lb/hr (shorties), Mass-Flo-EFI style 4bbl throttle body with GM maf on top. Custom long tube headers, sidepipes, 5 spd manual.
Re: again with FN348 Cranking Pw ECT questions
Thanks. It was at .42ms for 200+ ECT but when I switched the injector data to the stuff Chris at PAS pointed to, it was only provided for 43.5 psi (dropped from the 55 I was running).
I think you’re pointing to the key element. Main issue is restarting after getting fuel (embarrassing when it doesn’t go vroom!). I’ll report back after increasing pump prime time & dropping PW.
Sean
I think you’re pointing to the key element. Main issue is restarting after getting fuel (embarrassing when it doesn’t go vroom!). I’ll report back after increasing pump prime time & dropping PW.
Sean
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- Posts: 67
- Joined: 2021 Mar 31, 17:29
- Location: Victoria, BC CANADA
- Vehicle Information: QH, TunerPro RT 5, GUFX_220418.xdf, A9L2_220405, DECIPHA_220505.ADX, 395w, AFR 195CC Renegade heads, Comp XE274HR cam, Siemens-Deka V 80lb/hr (shorties), Mass-Flo-EFI style 4bbl throttle body with GM maf on top. Custom long tube headers, sidepipes, 5 spd manual.
Re: again with FN348 Cranking Pw ECT questions
Nope, no luck. Increased pump prime time (from 3 seconds) to 6 seconds after lowering higher temp cranking pw from .49 back down to .42 ms.
Parked warm car, left it for 10 min to let it heat soak sitting in my garage, would not fire. 2nd attempt it sputtered once during cranking, but no start. Pushed the pedal to the floor for third attempt to make sure I didn't flood it, no difference.
Anyone else dealt with this???
In my case, .42ms of pw amounts to 25% more than calculated requirement.
Sean
Parked warm car, left it for 10 min to let it heat soak sitting in my garage, would not fire. 2nd attempt it sputtered once during cranking, but no start. Pushed the pedal to the floor for third attempt to make sure I didn't flood it, no difference.
Anyone else dealt with this???
In my case, .42ms of pw amounts to 25% more than calculated requirement.
Sean
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- Posts: 5085
- Joined: 2021 Feb 15, 12:23
- Location: Metairie, LA
- Vehicle Information: Work Truck
'19 F-150 3.3L
Re: again with FN348 Cranking Pw ECT questions
That verifies she wants more then.
Yeah its not uncommon for some engines to want more fuel on crank especially when warmed up.
Yeah its not uncommon for some engines to want more fuel on crank especially when warmed up.
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- Posts: 67
- Joined: 2021 Mar 31, 17:29
- Location: Victoria, BC CANADA
- Vehicle Information: QH, TunerPro RT 5, GUFX_220418.xdf, A9L2_220405, DECIPHA_220505.ADX, 395w, AFR 195CC Renegade heads, Comp XE274HR cam, Siemens-Deka V 80lb/hr (shorties), Mass-Flo-EFI style 4bbl throttle body with GM maf on top. Custom long tube headers, sidepipes, 5 spd manual.
Re: again with FN348 Cranking Pw ECT questions
Obviously my goal is to use the lowest ms value I can to work at warmer temps, but I’m trying to calculate the upper limit.
I was running the same injectors at 55psi in my first tune (using different data). The new data works vastly better in every respect, but I didn’t want to alter any of the manufacturer’s values to start, so I reduced pressure to 43.5 psi to match what was provided.
Since pressure impacts injector flow, if I had a working FN348 (.42) ms value at 55psi, doesn’t it mathematically calculate that at 43.5psi that same volume of fuel would require something approaching .47ms?
Am I on the right track?
Sean
I was running the same injectors at 55psi in my first tune (using different data). The new data works vastly better in every respect, but I didn’t want to alter any of the manufacturer’s values to start, so I reduced pressure to 43.5 psi to match what was provided.
Since pressure impacts injector flow, if I had a working FN348 (.42) ms value at 55psi, doesn’t it mathematically calculate that at 43.5psi that same volume of fuel would require something approaching .47ms?
Am I on the right track?
Sean
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- Posts: 5085
- Joined: 2021 Feb 15, 12:23
- Location: Metairie, LA
- Vehicle Information: Work Truck
'19 F-150 3.3L
Re: again with FN348 Cranking Pw ECT questions
you have to factor in offset difference too
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- Posts: 67
- Joined: 2021 Mar 31, 17:29
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- Vehicle Information: QH, TunerPro RT 5, GUFX_220418.xdf, A9L2_220405, DECIPHA_220505.ADX, 395w, AFR 195CC Renegade heads, Comp XE274HR cam, Siemens-Deka V 80lb/hr (shorties), Mass-Flo-EFI style 4bbl throttle body with GM maf on top. Custom long tube headers, sidepipes, 5 spd manual.
Re: again with FN348 Cranking Pw ECT questions
Is offset a time (ms) multiplier? There is a measurable difference in offset between the injector data I have swapped. I’ll see if I can figure it out. Does a % value difference between the old/new offset equate to a percentage change in ms of pw?
Sean
Sean
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- Posts: 5085
- Joined: 2021 Feb 15, 12:23
- Location: Metairie, LA
- Vehicle Information: Work Truck
'19 F-150 3.3L
Re: again with FN348 Cranking Pw ECT questions
no
offset is the actual msec time that injector takes to open once its powered on
if you've reduced the offset by .25 msec then you need to increase cranking pw by .25 msec to get back to where you were for a given voltage
offset is the actual msec time that injector takes to open once its powered on
if you've reduced the offset by .25 msec then you need to increase cranking pw by .25 msec to get back to where you were for a given voltage
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- Posts: 67
- Joined: 2021 Mar 31, 17:29
- Location: Victoria, BC CANADA
- Vehicle Information: QH, TunerPro RT 5, GUFX_220418.xdf, A9L2_220405, DECIPHA_220505.ADX, 395w, AFR 195CC Renegade heads, Comp XE274HR cam, Siemens-Deka V 80lb/hr (shorties), Mass-Flo-EFI style 4bbl throttle body with GM maf on top. Custom long tube headers, sidepipes, 5 spd manual.
Re: again with FN348 Cranking Pw ECT questions
Awesome. Thanks for making it understandable!
Sean
Sean