How to get the fuel sender level to be seen by the obdII (Page 2/3)
Tweeder MAY 28, 12:14 AM

quote
Originally posted by phonedawgz:

You will have to figure out how to get a potentiometer type sending unit into the tank.



I thought that sending units are potentiometer as they vary the voltage depending on where the float is. Going back to your earlier comment " The fuel level input needs to be from a 0 - 5v sender, not the stock Fiero one. The fuel gauge output will then run to your dash. I am not sure if it will work with the Fiero dash gauge however." How is the fiero sending unit calculated?

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86 SE Convertible 3800sc 4t65e HD.

Tweeder MAY 28, 01:57 AM
I was just looking over that link I posted earlier and was thinking since I can change the fuel sender ohms, why can't I put them to match the fiero values? Then it would tell the PCM the same levels the fiero guage is showing thus giving me a proper distance to empty. If that is so, what wires do I need from where to where? I'm thinking I only need one, pin 69 coming from the fuel guage sending wire( which would be?).

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86 SE Convertible 3800sc 4t65e HD.

PaulJK MAY 28, 05:06 AM

quote
Originally posted by Tweeder:

... what wires do I need from where to where? I'm thinking I only need one, pin 69 coming from the fuel guage sending wire( which would be?).




The bottom line is that it is not possible to do by running wires.

Think of it like this: The fiero sender was not designed to output the signal you're trying to get (it's OBD-1). You need to change the sender completely (and modify the tank because there are no alternatives that are plug-n-play) or redesign the fiero sender then fabricate the changes to the fiero sender (i also have a 3800SC car and would like to have the OBD-2 fuel output).



quote
Originally posted by Tweeder:

So what's the easy way around this?




There isn't one.

Hope this helps.

[This message has been edited by PaulJK (edited 05-28-2014).]

phonedawgz MAY 28, 07:47 AM
Crap

I made a mistake. I was thinking it was the fuel level sender but instead it was the fuel tank pressure sender that is the potentiometer. The OBD2 sender is just a variable resistor. I do not know what the resistive range of the sender is.
Tweeder MAY 28, 01:36 PM

quote
Originally posted by phonedawgz:

Crap

I made a mistake. I was thinking it was the fuel level sender but instead it was the fuel tank pressure sender that is the potentiometer. The OBD2 sender is just a variable resistor. I do not know what the resistive range of the sender is.




I read that the fender values are 0-90 ohms

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86 SE Convertible 3800sc 4t65e HD.

Tweeder MAY 28, 01:40 PM

quote
Originally posted by PaulJK:


There isn't one.

Hope this helps.




I'm not arguing just chewing on this. I realize the sender values are obdI and the swapped PCM wants obdII, but aren't ohms, ohms regardless of obd? If that's the case then it should be as simple as putting in the fiero values..... As I can change tank size and sender readings in hptuners ad per the gto link. Please correct my way of thinking as I am wrong more that right, lol

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86 SE Convertible 3800sc 4t65e HD.

PaulJK MAY 28, 11:31 PM
Well, if you just need ohms you should be able to tap into the wire going into the fuel guage from the sender. There are only 3 wires from the fuel tank; power (for the fuel pump, ohms out to the fuel level guage, and ground. The pink wire from the sender at C3, 7 plugging into the instrument cluster.





I guess you can try it and tell us all if it works .

The (other) problem i see is that the fiero sender is notoriously inaccurate. The sender itself is a poorly designed piece of junk that wiggles in every direction as it wears. I've stopped rebuilding them because the quality is so bad. I rebuilt my own and ran out of gas when my digital guage read 40%. Other times it's just fine. You can read through the archives and find the same problem many many times (Almost Everybody uses mileage as an indicator of fuel remaining, not the gas guage). So i'm saying that even if you get the output you need, it still might not be worth much.

First I'd try tapping into the guage wire and see if the signal is compatible. If it works, I'd rebuild the sender using a VDO sender board or something else that will give reliable, consistent 0-90 ohm readings. Here's how one PFF did it using the VDO sender:

http://www.fiero.nl/forum/A...090219-2-078597.html

Good luck. Hope it works for you Keep us informed.

[This message has been edited by PaulJK (edited 05-29-2014).]

Tweeder MAY 29, 01:28 AM
Crap, after all that I just found out that they don't have that option set up for my vehicle, and I,m not sure if and when it will be available.

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86 SE Convertible 3800sc 4t65e HD.

PaulJK MAY 29, 03:13 AM
Well, i think there may be a way to get what you want (assuming that the input was ohms as previously discussed).

Feed the ohms reading into the PCM by running the correct wiring ;
Turn ON the input in the PCM software so the PCM accepts the ohms input;
Use an Android tablet and the Torque Pro ($4.95) or similar software (it is not vehicle specific and will allow you to set PIDs or sensor inputs).

That's what i would do if your ohm thing works. I've been using Torque Pro on my android tablet in my car and it's pretty good (not perfect) software.

https://play.google.com/sto...?id=org.prowl.torque

OK. now you owe me a +

[This message has been edited by PaulJK (edited 05-29-2014).]

Tweeder MAY 29, 11:11 AM

quote
Originally posted by PaulJK:

Well, i think there may be a way to get what you want (assuming that the input was ohms as previously discussed).

Feed the ohms reading into the PCM by running the correct wiring ;
Turn ON the input in the PCM software so the PCM accepts the ohms input;
Use an Android tablet and the Torque Pro ($4.95) or similar software (it is not vehicle specific and will allow you to set PIDs or sensor inputs).

That's what i would do if your ohm thing works. I've been using Torque Pro on my android tablet in my car and it's pretty good (not perfect) software.

https://play.google.com/sto...?id=org.prowl.torque

OK. now you owe me a +




You sir have a +. I'll look into turning on the input in the PCM, I believe it would already be enabled as that feature would have been used in the original car"..I hope for simplicity sakes. Unfortunately I do not own an android but multiple apples. I am using dashcommand and will look into that to see if it can be done. Thanks for your info.

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86 SE Convertible 3800sc 4t65e HD.