MSefi.com read only forum (Jan.15,2018)

Just finished assembling my V3 board and can't it to connect to megatune or make the stim do anything. I built my last 2.2 board, so I have experience. I'm getting voltage to the appropriate pins on the ecu socket as per the tests in the assembly guide. I tested the connection through hyper terminal exactly as the assembly guide states. The board passes these tests with flying colors. When I install the processor and try to connect to the laptop, I get nothing. I can't even get boot mode to load. I verified proper part numbers on all the capacitors as well as the polarities of all the components that require it. I am fairly confident that it is assembled properly. The LEDs on the stim for inj1 and inj2 are lit constantly and don't change with the RPM pot. I've used this usb-com cable before and know I have it connected properly (checked via the hyper terminal procedure). What might be my problem? I'm running out of ideas and things to check... Thanks

Start with a communications check. To do this check, you'll need the program portcheck.exe, which comes with most MegaTune versions, including the one on the DIYAutoTune.com website. You'll find it in the MegaTune2.25 folder. If you don't have a copy, download it here:

http://www.DIYAutoTune.com/downloads/tu ... tCheck.zip

Power up the Megasquirt and connect it to your PC. You do not need to open the case and should not put the boot jumper in place for this test. Close MegaTune if it's running, and run the portcheck.exe program. When this program starts, it will scan the available COM ports.

If the port it's scanning is not connected to a working Megasquirt, or it's on the wrong speed, it'll say "No connection made." If it's on the right port and right speed, it will give you the version of the Megasquirt firmware that's on the Megasquirt. Note that some Megasquirt firmware versions will look like earlier versions with this test - for example, 029V identifies it as 029Q. This is for backwards compatibility.

If you get a port where it replies with "S" or something else that doesn't look like a firmware version, this port is probably a fake COM port that echos back everything that's typed. Let me know what you find.

Com7 is definitely my usb adapter, and again, I've used it on other megasquirts before with the same settings. Also, I repeated all the hyperterminal tests again, and they came back successful.

It's looping back, looks like somewhere RX and TX are shorted together.

Any places to check for? I'm fairly confident that my soldering is correct. When I'm not jumping the pins on the processor socket, I don't get anything back in hyperterminal, which kind of leads me to believe its not a communications short somewhere. Also, as I see it, the stim should still be flashing injector lights and whatnot even if there was a communications problem. I'm going to borrow a spare processor today and see if maybe its a processor issue.

nickanicus wrote:Any places to check for? I'm fairly confident that my soldering is correct. When I'm not jumping the pins on the processor socket, I don't get anything back in hyperterminal, which kind of leads me to believe its not a communications short somewhere. Also, as I see it, the stim should still be flashing injector lights and whatnot even if there was a communications problem. I'm going to borrow a spare processor today and see if maybe its a processor issue.

Ok, that was tested with the pins shorted together? That explains the results.

What error message do you get if trying to load the firmware?

I'm not in front of the laptop right now to give a screenshot, but I get the error message that goes something like,

Expected "<boot>"
but received ""


I'll be trying out the different MC68HC908 later on today, I'll report back

If it said it expected a boot message, make sure the boot jumper is firmly in place. A loose-fitting one may look like the two pins are shorted when they aren't, so you may need to press down on it when you power it up.

Yeah, I tried that.... I usually install a microswitch there, but I'm not expecting to have to change the firmware again after I get the car going.

It turns out my processor was DOA. Installed the one I pulled from another unit and everything works. I guess I'll have to order another and hope there's no problems!

Thanks for your help.