sim's Volvo 245 comments

All home-built FreeEMS implementations without a forum of their own, usually TA-based.
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Fred
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Re: sim's Volvo 245 comments

Post by Fred »

Thanks JD! I just found this on the PLX site in a pdf:

Values: PSI (kPA)
Volts1 0.32
Values1 -13.9 (5.48)
Volts2 4.84
Values2 10.94 (176.72)

"Interfacing with MAP Sensors Summary Supported MAP Sensors Setting"

www.plxdevices.com/AppNotes/PLXApp013.pdf

From that, with some simple math, I get:

182.78kPa for 5V

and, wait for it...

-6.64kPa (a physical impossibility) for 0V

IIRC the firmware doesn't handle that case. I'll have to redo the way these sensors are calculated. Perhaps it will be better to throw away the idea of calculating it and just do a lookup. We'll see. I'll post an issue for that shortly if it turns out that I'm right.

Fred.
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Re: sim's Volvo 245

Post by sim »

Joseph Davis wrote:Hi, sim. Hi, everyone.

You have in your hand a Honda firewall mounted MAP sensor. Honda
MAP are all the "same" calibration from 88-present, across four
different form factors and three plug styles. I suspect some of
the 85-87 MAPs are the same, but certain are not - 86-87 Integra,
for example, is more akin to a GM 1 bar with 5 volts being at or
slightly above atmo.

Anyway, all is not as it seems with those MAP sensors. They are
all limited so that they never reach 5v on the signal line. It's
been years since I did the measurements, but the firewall mounted
jobbers return up to 4.7x which results in 9.25 psi. The later
OBD1/OBD2 throttle body mounted sensor (with the same plug) reads
4.8x volts, which is 10.6-10.7 psi - the Hyundaidata site claims
11.3 psi, but this is a number easily reproduced by rounding
errors and is not correct. I'm not sure of the last two flavors
used on the K-series cars, but I ASSume they are like the
OBD1/OBD2 units.
Thanks for the information Joseph.

I could find hardly anything about these sensors online. It does
not surprise me that the range does not go all the way to 5v.

It will be a while before I bolt up a turbo, so these will do for
now. The one hooked up for atmospheric correction will do
forever.

They are easy sensors to get, I'll do my best to leave some good
information on the internet for the next person.
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Re: sim's Volvo 245 comments

Post by Fred »

Fred wrote:and, wait for it...

-6.64kPa (a physical impossibility) for 0V

IIRC the firmware doesn't handle that case. I'll have to redo the way these sensors are calculated.
Fixed! The change was extremely minor, however is not safe in the case of the sensor going outside the programmed range. We need a better system for this. Sim, you can be the tester :-) For now this will get you correct values inside range, and you can just be careful to make sure the thing never goes lower than it should, or you might get a big splash of fuel when you should have none.
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Re: sim's Volvo 245 comments

Post by Fred »

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Running with LS1 Coils, test bench.

Post by sim »

We have Ignition!

Image

I built a wiring harness for the LS1 coils.

Really, it is just a long adapter from a single bank LS1 harness
to the TA board.

Works great:
http://puddle.ca/~sim/volvo/FreeEMS/Sequential.3gp
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Re: sim's Volvo 245 comments

Post by Fred »

http://www.youtube.com/watch?v=Ec80QrdIrB0

It's official now, you're famous :-)

Well done! Thanks for your efforts :-)
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Re: sim's Volvo 245 comments

Post by jonr »

> regulate to 12v under all operating conditions

You can, but it has to be able to step up the voltage. Or use a small separate battery.

I suggest getting knock detection and retard working perfectly before the turbocharging. Saves throwing a rod through the block :-).
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FreeEMS engine #7

Post by sim »

Well, I wired up the board and coils to the car today.

It did run, and can run, but it is not yet running correctly.

I suspect there are some timing issues to sort out, but I don't
know yet.
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Re: sim's Volvo 245 comments

Post by Fred »

Congratulations, sort of. More when it runs right. I gave you some advice in IRC, but I'll bang it here for you too:
[08:40] <Cheetah_> simis: sounds like your firing order is wrong, or it is gaining and losing sync from electrical noise, you NEED a datalog.
[09:23] <Cheetah_> simis, did you attempt to verify that all four coils fired where you thought they should rather than just one?
[09:24] <Cheetah_> also, can you please verify that your output is high high and low low and not inverting. IE, those LS1 coils will never smoke, they'll just always have wildly varying timing if the signal is inverted.
[09:24] <Cheetah_> put it in SM mode and pull the CPU pin low and check that output pin to coil is low, and then high and check that it's high
Additionally, when verifying the two cylinders that fire 180 out from the other two, it is VERY helpful to have a mark on the back of the pulley, 180 out from which ever mark you're using, just a bit of pink nail polish from the mrs, or silver marker pen or white paint, something visible in a timing light, but distinct from the main markings (so you can tell which it is).

Good luck, hit me up when you're next going to take a crack!

Fred.
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Re: sim's Volvo 245 comments

Post by Fred »

Sim, re your comment about losing sync and running on the first cylinders after the sync point:

http://issues.freeems.org/view.php?id=256

Thanks for the reminder! :-)

There is another issue which, when combined with this one, explains your firing at random times. In the mean time, clean up the signal. I might get you to put some crap wire back in there in future to test the code once I improve it to handle such cases better :-)

Fred.
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