In Soviet Russia car build YOU!
#1861
woah. That's pretty shitty. I guess you didn't check battery voltage with old alternator?
I've had issues with the MS3 voltage readings in the past, found out I hated their math, but after I fixed a dumb wiring issue (transistors used to drive dash LED's) enough of it went away I could live with it.
Like all things megasquirt - if the car runs, no one cares why it doesn't work right.
Glad this is coming together for you. Guess I should get a sender as well. :-)
I've had issues with the MS3 voltage readings in the past, found out I hated their math, but after I fixed a dumb wiring issue (transistors used to drive dash LED's) enough of it went away I could live with it.
Like all things megasquirt - if the car runs, no one cares why it doesn't work right.
Glad this is coming together for you. Guess I should get a sender as well. :-)
#1862
Elite Member
Thread Starter
iTrader: (10)
Join Date: Jan 2010
Location: VA
Posts: 3,493
Total Cats: 268
The problem came back, now its reading 1V low.
Measured VRef and its 4.9V. I'm going to look into the wiring and ask on msextra.
Any thoughts on upgrading U5, though? Its 500ma in stock form and if I'm going to use VRef to drive a bunch of sensors, I probably want more current than that.
Measured VRef and its 4.9V. I'm going to look into the wiring and ask on msextra.
Any thoughts on upgrading U5, though? Its 500ma in stock form and if I'm going to use VRef to drive a bunch of sensors, I probably want more current than that.
#1863
That's not a terrible thought. I guess you could unplug a couple sensors, see if it gets better. :-) You'd think most of the measurements would be as-a-function-of the 5V being fed them, but yeah, then wiring would mean different sensors are getting a different voltage, and things all around would be bad.
Not sure why the MS is seeing the wrong voltage, though - that's a sign of something else. I did figure out it can't really read the right voltage since the circuit it uses... But I think it's off by less than a volt. Anyway, it seems easy enough to pull that chip - or bypass it temporarily to see if things improve.
Not sure why the MS is seeing the wrong voltage, though - that's a sign of something else. I did figure out it can't really read the right voltage since the circuit it uses... But I think it's off by less than a volt. Anyway, it seems easy enough to pull that chip - or bypass it temporarily to see if things improve.
#1864
Elite Member
iTrader: (10)
Join Date: Jun 2006
Location: Athens, Greece
Posts: 5,979
Total Cats: 356
The problem came back, now its reading 1V low.
Measured VRef and its 4.9V. I'm going to look into the wiring and ask on msextra.
Any thoughts on upgrading U5, though? Its 500ma in stock form and if I'm going to use VRef to drive a bunch of sensors, I probably want more current than that.
Measured VRef and its 4.9V. I'm going to look into the wiring and ask on msextra.
Any thoughts on upgrading U5, though? Its 500ma in stock form and if I'm going to use VRef to drive a bunch of sensors, I probably want more current than that.
#1866
Elite Member
iTrader: (10)
Join Date: Jun 2006
Location: Athens, Greece
Posts: 5,979
Total Cats: 356
You could upgrade L1 and L2 with a 4A equivalent. Not sure on a digikey code, I buy them locally.
I would highly suggest that you replace C16 and C17 with 33uF/50V aluminum electrolytic caps anyway.
C20 is irrelevant, C22 should be ok at 4.7uF, I don't think these sensors have any sort of transient requirements.
I would highly suggest that you replace C16 and C17 with 33uF/50V aluminum electrolytic caps anyway.
C20 is irrelevant, C22 should be ok at 4.7uF, I don't think these sensors have any sort of transient requirements.
#1868
Elite Member
Thread Starter
iTrader: (10)
Join Date: Jan 2010
Location: VA
Posts: 3,493
Total Cats: 268
To keep this thread going...
I finally got time to work on the car. I looked at the poor state of the wiring harness - it was modified so many times over the past 3 years... that I decided to redo it.
So far:
My approach is as follows: I'm keeping the chassis wiring mostly intact because it works and I don't care. Eventually I'll redo the chassis wiring as well.
As for engine wiring, I'm removing all traces of the current engine wiring and adding a new sub-harness. I'm also adding a separate fusebox just for the engine stuff.
I finally got time to work on the car. I looked at the poor state of the wiring harness - it was modified so many times over the past 3 years... that I decided to redo it.
So far:
My approach is as follows: I'm keeping the chassis wiring mostly intact because it works and I don't care. Eventually I'll redo the chassis wiring as well.
As for engine wiring, I'm removing all traces of the current engine wiring and adding a new sub-harness. I'm also adding a separate fusebox just for the engine stuff.
#1874
Elite Member
Thread Starter
iTrader: (10)
Join Date: Jan 2010
Location: VA
Posts: 3,493
Total Cats: 268
As for the connectors, I ordered from Ballenger and really I just got the TPS, IAC and CAS because they were old and shitty.
I have a total of 5 OEM mazda connectors remaining in my car
- NA CAS (using only 3 wires, tho)
- NA CLT
- NB TPS
- NB Idle
- NA8 Crank sensor
Everything else is some generic connector, lol
#1875
Elite Member
Thread Starter
iTrader: (10)
Join Date: Jan 2010
Location: VA
Posts: 3,493
Total Cats: 268
#1878
I have 5 relays which is more than I need but hey, might as well use them all. So, boost control solenoid and idle control valve get their own relay which will be switched on by MS when car is running - so it doesn't hum when car is off - I hate that ****. I'll write up a schematic later.
And, shouldn't boost also be off when pressure is negative? I wonder if you couldn't use a generic output to do that - I mean, over ride the output when RPM < 50.
#1880
Elite Member
Thread Starter
iTrader: (10)
Join Date: Jan 2010
Location: VA
Posts: 3,493
Total Cats: 268
Good point.
I thought a bit more about the fusebox wiring and realized I forgot a bunch of circuits (cam/crank, O2)
I thought a bit more about the fusebox wiring and realized I forgot a bunch of circuits (cam/crank, O2)
Code:
Fuse Amps Relay Relay Trigger -------------------------------------- Ignition 2 Amp MS3 5 Amp Relay 1 Ignition Boost/Idle 5 Amp *** Cam/Crank 5 Amp *** Spark 10 Amp Relay 2 Ignition Injectors 10 Amp *** O2 15 Amp *** Horn 20 Amp Relay 3 Horn Button Fan 30 Amp Relay 4 MS3 Fuel 30 Amp Relay 5 MS3