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Thread: Strange happening with Flex Fuel

  1. #21
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    It's boost referenced 1:1. The inectors are new along with the fuel pump and regulator. Fuel Inector Clinic supplied the info and offsets, flow rates that were particular to this set of injectors.

  2. #22
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    Here's the data sheet that they supplied.
    I set my base pressure at 43.5 PSI to help with the idle. Originally I tried 58PSI but the idle fueling would swing. My best guess was because the inectors were non linear at 58psi. 43.5 seemed to solve the idle fuel swings. These inectors may be a bit too big, but I didn't want to have to buy another set if 1050's werre too small after more mods. the latest E85 pull to 6500 rpm, IDC was 79%.

    https://fuelinjectorclinic.com/GM-DATA/HP-TUNERS-1200

    The link is where I got the data for the tune. It's over 1MB so I can't upload the image.
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    Last edited by marksrig; 05-22-2022 at 12:28 AM.

  3. #23
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    The reason my OFFSET vs.Press vs. IGN looks different in the picture compared to the tune is I have a fixed pressure of 43.5 psi so I used the voltage reference from their data sheet.

    An example is at 12Volts 43.5 psi should be 1.50ms 10 volts is 1.20 ms across the whole table. I interpolated the voltages between the data given.
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    Last edited by marksrig; 05-22-2022 at 01:09 AM.

  4. #24
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    if sensor is working right it should be bang on even if u keep driving does it come good ? is yours the flex sensor that has the built in fuel temp offset in the sensor ? there is a continental brand that does its the one i use and i can have mine idling almost out of petrol and fill with ethanol and it stays within a couple % error the whole way, maby test yours make sure its accurate, if ethanol gets too hot it can affect it

  5. #25
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    im not a fan of that flow rate v IAT either i usually set that to 1.0 and retune otherwise ur chasing a variable based on map, only populate it if u need to but should be fine

  6. #26
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    My sensor only has 3 wires 12+, earth, and signal. I never even knew they had a temperature compensating one. I try to keep my tank 1/2 full to keep the fuel cool. It's been in the 50*F/11*C zone here so a bit cooler. I would think if it was a temp problem, it would go away at cold start since the fuel is cold. It doesn't seem to matter.

    So you think my inector data looks fine even though I interpolated and flatlined it? Sorry, I wasn't quite understanding your last response on the issue. It's really the only table I see that's different from what FIC uses. Maybe I'll call them Monday. In the meantime, I'm looking for a new sensor p/n.

    Thanks for the reply

    Mark

  7. #27
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    the flex sensor still has same wires its just build in temp offset, may only come into play in summer real hot days sitting in traffic style, just googled this to show u https://lamspeedracing.com/products/...erature-sensor yes as long as u have manifold referenced mechanical fuel pressure the offset.volts.press is fine flatlined and same with the IFR

  8. #28
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    in the injector data tab the multiplier for IAT against flow rate is populated usually from factory, i like it to be 1 as its a moving target if populated and not needed if the rest is setup properly unless u want a bit of added fuel for a high intake temp

  9. #29
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    Ok, yes my IFR vs IAT is 1.00 until it reaches 212*F This is factory. I never see those intake temps anyway.
    So what do you guess my rich issue is with respect to changing ethanol content? Ran perfect on E85, now in OL at E28 it's 11% rich.

  10. #30
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    I don't see that HP Tuners has a provision for the temperature of fuel. I do see HALTECH does.

  11. #31
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    its built into the flex sensor no extra wiring or anything it just adjusts the hz to compensate the offset i assume, sorry i put IAT but i was meaning the MAP multiplier it varies all the way thru its range on yours, not sure on exact issue these are all just little things to help but none that would make a 10% shift, i can only think of testing the sensor or if u can test the fuel to find its percent then see if reading is the same

  12. #32
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    Thank you, I just bought a new sensor from GMParts. (I dont want a Chinese counterfeit)
    I'm reading many places that the stock GM sensor has the temp measuring capability and as you said, it's varied by the pulse width in ms. I'll put the new sensor in and see what happens. I know the old one has been off on its calibration since day1 so might as well get new.