Barrel_Ball Posted May 28, 2011 Share Posted May 28, 2011 So I finally got my car on the road for tuning/driving a couple days ago, learned that ignition timing still needs some tweaking, and that I still need long enough vacuum line for the boost gauge. Anyway, it's been raining non-stop here in Calgary for the past couple days, and because of that, water got in my relay plugs (specifically, my fuel pump relay, no board here). This evening I pull it into the shop at my work to wrap the relays in duct tape to temporarily waterproof them until I can get a separate enclosure for them or something, and after topping up my tire pressures, I get in to start it, and sure, it cranks over, but it won't start. No signal to the coil, all three LEDs on the Megasquirt are on constantly. So I had to leave the poor thing in the shop overnight and walk it home this evening. Normally, the middle LED is on when the MS is on, and the bottom one blinks on and off at different intervals depending on the engine speed. I can't say I've seen the top one ever come on, or if it did, I probably wasn't paying attention. So if they're all on solid at the same time, does this mean I did something wrong? If so, is there anything I can do to find, and fix this issue because I hate the idea of driving my underpowered 4x4 all summer! P.S. Sorry for the wall of text. Also, I would've logged the situation as it happened, but the battery on my laptop died around then. Bad day... Quote Link to comment Share on other sites More sharing options...
Barrel_Ball Posted May 29, 2011 Author Share Posted May 29, 2011 Okay, so after some pulling apart and diagnosis, all I know is that my fuel pump relay burnt itself out by shorting 12volt live throught the whole thing I would assume. Now I'm going through the MS box itself, and I have yet to see a burnt component. I even traced pin 37 back (which is where the fuel pump relay's windings go to, and all it connects to is D4, a zenner diode, which then grounds through the board. All that's working. Is it possible that it's noticing that there's a connection problem with the relay that's supposed to be running the fuel pump, and error-ing out because of it? Quote Link to comment Share on other sites More sharing options...
thayeti Posted May 30, 2011 Share Posted May 30, 2011 When I recently (2 weeks ago) took my MS unit out of my car to flash some new firmware on it. I had the same problem, all my LEDs lit up. Turns out the firmware was corrupt and after I flashed it everything went back to normal. My relays were also shorted out due to an unexpected rain storm. I have new ones on the way. Try re-flashing some firmware and see if that helps. Quote Link to comment Share on other sites More sharing options...
Barrel_Ball Posted May 30, 2011 Author Share Posted May 30, 2011 Okay, I reflashed it, and that didn't fix it yet, but when I replaced the fuel pump relay with a new one (they're cheap, generic relays), everything started to work again. Weird. Anyway, since I reflashed the firmware already at that time, I had to punch in my VE and Spark tables from scratch really quickly before the laptop's battery died again. I limped it over to my friend's place yesterday to return some tools, and adjust the timing. I still runs a bit rough on the low side, but it pulls hard under full load/boost, so it's working better than ever. And just as a preventative measure, I used silicone on the relay pigtails to seal the contacts from water damage. I don't want to leave the car in a mall parking lot over night again. This winter, I'm going to redo the harness again, and maybe get an actual relay board this time. Might actually have to sacrifice my glove box for it, but as long as it's all protected from the elements, that's all that matters at this point. Quote Link to comment Share on other sites More sharing options...
mario_82_ZXT Posted May 30, 2011 Share Posted May 30, 2011 Make sure you leave a loop at both the relays and megasquirt so that water can't crawl up the harness. Just a little thing like this -._.- in the harness before the box is ok. My friend learned this the hard way when his car wouldn't run and would curropy the firmware every time it rained. Quote Link to comment Share on other sites More sharing options...
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