Ken's Halfway House for Wayward Jeeps (trigger warning: rust)

The Something Awful Forums > Discussion > Automotive Insanity > Ken's Halfway House for Wayward Jeeps (trigger warning: rust)

Commodore_64: Feb 16, 2011; love thy likpa

kastein posted:

Headlight power switched by relays? Check one for expensive, properly designed system.
Headlight ground switched directly by the dinky little steering column multifunction stalk? Check one for half assed bullshit a first year EE grad should get fired for.
Both in the same vehicle? Yup.

So what you are saying is both the high and low sides of the bulbs are switched because of "reasons" ? Or are the grounds switched on low beams and the high beams have a relay on the high side?

# ¿ Mar 27, 2015 22:50

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# ¿ May 11, 2024 18:01

Commodore_64: Feb 16, 2011; love thy likpa

I think the damping portion is a bit more complicated than that. But at the same time, I am pretty sure ATI super dampers are just fatty O rings between aluminum rings. Dunno.

# ¿ Jun 2, 2015 06:43

Commodore_64: Feb 16, 2011; love thy likpa

Just an FYI, ATI recommends an interference of .009 to 1.2 thou on its steel super dampers. .002 on the aluminum hub versions. I've seen people recommend that they are driven on with an installer tool after heating.
http://www.atiracing.com/instructions/Super-Damper.pdf

# ¿ Jun 5, 2015 21:16

Commodore_64: Feb 16, 2011; love thy likpa

Off hand I'd guess the interference helps carry the torque associated with accessories and/or prevents fatiguing the key or keyway. The super dampers may be expected to transmit more torque than other applications.

# ¿ Jun 5, 2015 21:24

Commodore_64: Feb 16, 2011; love thy likpa

Yup! The ones they sell for Miatas use an interference fit as well.

# ¿ Jun 7, 2015 02:21

Commodore_64: Feb 16, 2011; love thy likpa

Godspeed brave goon!

# ¿ Oct 16, 2021 04:04

Commodore_64: Feb 16, 2011; love thy likpa

This probably doesn't help due to how dated the info is, but the one I bought 14+ years ago totally turned into a gooey mess the third time I used it with gas.

# ¿ Oct 20, 2022 15:58

Commodore_64: Feb 16, 2011; love thy likpa

kastein posted:

Ugh, it turns out every company has used ~10% inflation as an excuse to loving jack prices 400% since I last checked small gasket prices so I have a choice between buying two sender gaskets for $10 each (or pay 1/4 that and have rockauto ship them fedex so they never actually arrive at my address after giving the other 75% to fedex for the honor), or buy a 240-33 ohm sender on JeffMart for $20 that comes with a gasket. Guess it's getting a new sender with a larger resistance range so I'll be able to get a good calibration out of it after all.

Regarding calibrating senders in hptuners - a friend saw this post and asked if 0-90 will work with modern LS ECUs. Yes, kind of. LS ECUs essentially just have a 5V Vref for the ADCs and most sensors, and in this case a 250 ohm pull-up in series with the sender. The sender from the factory is 250-40 ohm, which means you'll get around (250/(250+250) - 40/(40+250)) * 256 or 93 ADC counts from empty to full. A 0-90 sender instead will give you 256*90/(250+90) or 68 ADC counts, only about 73% as much granularity as factory, so it'll work but it's not ideal. Meanwhile 240-33 sender should give me drat near factory accuracy, just need a slightly different calibration to linearize it which I was going to need anyways since the tank it's going in is wildly differently shaped from the factory tank.

The way the hardware works is pretty simple. From there it gets complicated because the world is not simple, get used to it. The 8 bit ADC values are used as indexes into a single dimensional table (well, 4 of them, for 2 senders, but we'll go over that later) that converts the raw ADC byte value into a gallon count for that particular tank. There are two tables per tank for reasons I'm not 100% sure of yet, and two tanks resulting in 4 total tables for linearization, once the two tank values are linearized by the 4 tables they simply get added together and then that is reported over the various data buses as the current amount of fuel on board as a 1 byte "percentage" (except 0-255 instead of 0-100). The fifth table is used to take this value and convert it into a PWM duty cycle for connector 2 (red/green) pin 38 if you are using that pin to drive an old style thermal or resistance based factory gauge, which I intend to at least try. I'm not sure that'll work yet.

Once I figure out how to use the *five* tables relating to fuel sender and gauge calibration in P01/P59 ECUs I'll probably throw together a quick guide on it since I can't find that information anywhere. I've got my primary tank sender working pretty well for the half rear end job I did but I intend to do a more careful job of it on both tanks once I have it all wired up since, well, I want it to be perfect if possible.

If anyone knows the difference between the two tables for each sender linearization I would love to hear it. For each tank there is a "xxx Volume" and a "xxx Volume gauge" table. I'm guessing that the one with the gauge suffix affects the gauge, while the other one affects... who knows what? Maybe just OBD2/SAE J2178-3 command $82/status $83 data values? Maybe it affects the evap system's knowledge of the remaining tank volume for leak detection? Maybe it allows the ECU to mute random misfire code reporting when it knows fuel is dangerously low and you request a fuckload of torque very suddenly and slosh the tank around? Maybe it affects DTE calculations for the console message center? Who loving knows, not me, but I want to change that.

It doesn't have something like a temperature sensor on the fuel rail used to interpolate between the two tables for temp? Is the second table some sort of second order coefficient for reasons?

# ¿ Sep 8, 2023 15:16

Commodore_64: Feb 16, 2011; love thy likpa

You can't just blast all the code off and reflash it? That seems... severe.

# ¿ Nov 1, 2023 15:47

Commodore_64: Feb 16, 2011; love thy likpa

Sounds like you might be in luck if you manually load or keep a record of the encryption key and reflash everything but the protected bootloader space, but yeah that sounds like a good idea to gently caress around with that on cheap bits rather than your nice custom board.

# ¿ Nov 2, 2023 00:25

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# ¿ May 11, 2024 18:01

Commodore_64: Feb 16, 2011; love thy likpa

The tall dude birdcage you guys have on that Miata is just astounding, I love it.

# ¿ Apr 25, 2024 20:22

The Something Awful Forums > Discussion > Automotive Insanity > Ken's Halfway House for Wayward Jeeps (trigger warning: rust)