Megasquirt Car runs...a few minor issues
05-11-10, 08:40 PM
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Car runs...a few minor issues
OK, so I finally fixed my air temp issue, but I discovered another.
Attached is a my MSQ and my latest datalog.
First issue, you can see spikes and drops consistently, running or not. I would expect, if this was a noise issue, the spikes and drops would only happen when the car is running...not all the time. I would also expect there to be noise on the Coolant temp sensor signal...but its solid.
Would a faulty air temp sensor have this effect? I've never seen a thermistor fail like this before.
2nd issue, I have the Tooth #1 Angle set at 30 deg...that's the only way I can get the spark close. Then I lock the timing and adjust the CAS. No big deal, right? This car was running on the stock ECU pretty well previously. I'm not sure why the timing is so far off otherwise, except maybe the previously owner had stabbed the CAS 1 tooth off. That is a 30 degree difference...but why would the stock ECU run so well?
The 3rd issue is actually dealing with the DIYPNP setup. The relay control on the DIY board pulls the line low when the car is off, turning the fan on. For the fan to work properly, I need to invert output signals in order for the fan to work. I guess this more of a pain then an issue...lacking a schematic is really getting on my nerves.
This is all on 3.0.3s.
Attached is a my MSQ and my latest datalog.
First issue, you can see spikes and drops consistently, running or not. I would expect, if this was a noise issue, the spikes and drops would only happen when the car is running...not all the time. I would also expect there to be noise on the Coolant temp sensor signal...but its solid.
Would a faulty air temp sensor have this effect? I've never seen a thermistor fail like this before.
2nd issue, I have the Tooth #1 Angle set at 30 deg...that's the only way I can get the spark close. Then I lock the timing and adjust the CAS. No big deal, right? This car was running on the stock ECU pretty well previously. I'm not sure why the timing is so far off otherwise, except maybe the previously owner had stabbed the CAS 1 tooth off. That is a 30 degree difference...but why would the stock ECU run so well?
The 3rd issue is actually dealing with the DIYPNP setup. The relay control on the DIY board pulls the line low when the car is off, turning the fan on. For the fan to work properly, I need to invert output signals in order for the fan to work. I guess this more of a pain then an issue...lacking a schematic is really getting on my nerves.
This is all on 3.0.3s.
05-13-10, 10:17 AM
#2
MegaSquirt Mod
OK, so I finally fixed my air temp issue, but I discovered another.
Attached is a my MSQ and my latest datalog.
First issue, you can see spikes and drops consistently, running or not. I would expect, if this was a noise issue, the spikes and drops would only happen when the car is running...not all the time. I would also expect there to be noise on the Coolant temp sensor signal...but its solid.
Would a faulty air temp sensor have this effect? I've never seen a thermistor fail like this before.
2nd issue, I have the Tooth #1 Angle set at 30 deg...that's the only way I can get the spark close. Then I lock the timing and adjust the CAS. No big deal, right? This car was running on the stock ECU pretty well previously. I'm not sure why the timing is so far off otherwise, except maybe the previously owner had stabbed the CAS 1 tooth off. That is a 30 degree difference...but why would the stock ECU run so well?
The 3rd issue is actually dealing with the DIYPNP setup. The relay control on the DIY board pulls the line low when the car is off, turning the fan on. For the fan to work properly, I need to invert output signals in order for the fan to work. I guess this more of a pain then an issue...lacking a schematic is really getting on my nerves.
This is all on 3.0.3s.
Attached is a my MSQ and my latest datalog.
First issue, you can see spikes and drops consistently, running or not. I would expect, if this was a noise issue, the spikes and drops would only happen when the car is running...not all the time. I would also expect there to be noise on the Coolant temp sensor signal...but its solid.
Would a faulty air temp sensor have this effect? I've never seen a thermistor fail like this before.
2nd issue, I have the Tooth #1 Angle set at 30 deg...that's the only way I can get the spark close. Then I lock the timing and adjust the CAS. No big deal, right? This car was running on the stock ECU pretty well previously. I'm not sure why the timing is so far off otherwise, except maybe the previously owner had stabbed the CAS 1 tooth off. That is a 30 degree difference...but why would the stock ECU run so well?
The 3rd issue is actually dealing with the DIYPNP setup. The relay control on the DIY board pulls the line low when the car is off, turning the fan on. For the fan to work properly, I need to invert output signals in order for the fan to work. I guess this more of a pain then an issue...lacking a schematic is really getting on my nerves.
This is all on 3.0.3s.
I can't answer you on the IAT sensor. I'd make sure it's grounded all the way back to the MS. Otherwise I'd replace it. It might also be that you need a larger bias resistor on it. On my v3 boards I use a 41k resistor.
I don't know about the relay driver. How do you have the relay wired? Sounds like it's turning on from feedback into the DIYPNP. The power to the relay coil on the relay that powers the fan should be coming from a switched +12v source (preferably the main relay). If you're running it straight to +12v then you can get feedback that'll leave the MS on when you power down the car, and will switch on outputs.
Ken
Last edited by muythaibxr; 05-13-10 at 10:19 AM.
05-14-10, 06:50 AM
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The 30 degrees off issue sounds like you are triggering on the wrong edge of the input capture signal or you wired the + and - lines on the CAS backwards. You probably need to reverse it.
I can't answer you on the IAT sensor. I'd make sure it's grounded all the way back to the MS. Otherwise I'd replace it. It might also be that you need a larger bias resistor on it. On my v3 boards I use a 41k resistor.
I don't know about the relay driver. How do you have the relay wired? Sounds like it's turning on from feedback into the DIYPNP. The power to the relay coil on the relay that powers the fan should be coming from a switched +12v source (preferably the main relay). If you're running it straight to +12v then you can get feedback that'll leave the MS on when you power down the car, and will switch on outputs.
Ken
I can't answer you on the IAT sensor. I'd make sure it's grounded all the way back to the MS. Otherwise I'd replace it. It might also be that you need a larger bias resistor on it. On my v3 boards I use a 41k resistor.
I don't know about the relay driver. How do you have the relay wired? Sounds like it's turning on from feedback into the DIYPNP. The power to the relay coil on the relay that powers the fan should be coming from a switched +12v source (preferably the main relay). If you're running it straight to +12v then you can get feedback that'll leave the MS on when you power down the car, and will switch on outputs.
Ken
The only issue with the bias resistor is that its a surface mount part, and one of the smaller packages at that.
05-15-10, 03:16 PM
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OK, checked and checked again the VR signals...they all go the right spot. I'll check the trigger polarity and re-time the car.
The fan is currently hooked up to a constant +12v source. I'll fix that, but it still doesn't address the issue of the transistor polarity. But I guess it won't matter in the end.
Dug up a couple of other air temp sensors, I'm going to throw one on and re-check. I'm going to check them against a resistor to see if I get noise with the sensor itself being out of the equation.
The fan is currently hooked up to a constant +12v source. I'll fix that, but it still doesn't address the issue of the transistor polarity. But I guess it won't matter in the end.
Dug up a couple of other air temp sensors, I'm going to throw one on and re-check. I'm going to check them against a resistor to see if I get noise with the sensor itself being out of the equation.
05-15-10, 06:13 PM
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OK, back to the air temp sensor issue.
If I connect a resistor to the Megasquirt instead of the air temp sensor, I get the graph "Direct_wired".
If I connect a resistor directly to the Microsquirt module, I get the other graph "Ecu_No_board".
Now, the 2nd one looks really terrible, but the difference is less than 1 degree...where the first one the difference is 20+ degrees. This is a nice solid connection to the ground and a lab power supply. It appears that the issue is with my DIYPNP board. I just rechecked all of my solders, they are solid and clean.
This makes it impossible to tune, as the ECU keeps dumping fuel into the engine at random points in time.
If I connect a resistor to the Megasquirt instead of the air temp sensor, I get the graph "Direct_wired".
If I connect a resistor directly to the Microsquirt module, I get the other graph "Ecu_No_board".
Now, the 2nd one looks really terrible, but the difference is less than 1 degree...where the first one the difference is 20+ degrees. This is a nice solid connection to the ground and a lab power supply. It appears that the issue is with my DIYPNP board. I just rechecked all of my solders, they are solid and clean.
This makes it impossible to tune, as the ECU keeps dumping fuel into the engine at random points in time.
