Flexicoker Posted December 26, 2008 Share Posted December 26, 2008 Merry Christmas!! I've been fighting a problem for the past week or so, where all of a sudden on the highway the car loses power and starts running really lean. The only thing that I can correlate this too is really noisy vbatt. I've been trying to limp it along until I can figure it out, as it doesn't happen all the time, but when it does I can only go about 50mph or so, any more throttle and it goes super lean. Sometimes though, the car drives fine. Today on the way to my parents house to open presents the car loses all power and I'm stuck on the side of the road. I tried to restart it and it fired, then died, and I could hear a relay click a few times. After that, nothing. I can't connect normally, or with the boot jumper on, no LED's, no fuel pump, nothing. So... I think that the spikey voltage finally killed something. I hooked the stim up with a laptop charger, ~15v, and almost immediately something stinks. no LED's come on the stim. I get about 0.5V on the U5 pin closest to the DB9, zero to the other 2 pins, the MOV gets hot, and I'm not getting any voltage across it. Infinite resistance between ground and +5 on the proto area. I get resistance both ways on D9, D12, and D19... but I suppose that could be through other parts of the circuit. Where do I start? I think its safe to saw that the MOV needs replacing, but should that be it? will U5 be OK? I've attached a datalog, you can see where it goes super lean (around 730s), the battery voltage is going berserk, X-tau is also going nuts (I thought I had it off) but I was having the same problem with x-tau disabled for sure another time. At the very end of the datalog you can see where it dies. Could EMI be causing this much noise in the voltage? Its got a "new" autozone reman alternator, but with my multimeter I measured 30VAC across the battery terminals, I read somewhere it should be less than 1. thanks!! 2008-12-25_10.39.40.zip Quote Link to comment Share on other sites More sharing options...
Careless Posted December 26, 2008 Share Posted December 26, 2008 I replaced the power circuit (there are steps to testing it on the ms website), and the MS started right up after that. You could have friend the cpu, but even then it's not a bad idea to have a spare laying around. Quote Link to comment Share on other sites More sharing options...
big-phil Posted December 26, 2008 Share Posted December 26, 2008 in this video I had to re solder that loose part, it controlled voltage Quote Link to comment Share on other sites More sharing options...
jeffer949 Posted December 26, 2008 Share Posted December 26, 2008 On the part of it where your car goes lean. I had a problem like that and it turned out to be really dirty battery terminals. I was amazed at how much clean terminals made my car run better. Im on a mac so i cant look at your datelog. But what does your battery voltage look like? is it all over the place? Ive been fighting some resetting issues for probably about a 4-5 months now. Ive finally gotten it to where the car is drivable but im this close to ordering another MS probably the 3.57 board because its supposed to have different ground plans for less noise. But there is still a few things i need to try. Go read this thread on this other forum. I did the part with the R/C filter on the backside of the board and it really stablized my voltage. I was pretty impressed. Im still getting a voltage spike every now and then but its livable. I have made the seperate ground board for it on the back but i dont have any extra FET mounting kits laying around so that i can mount it. I just need to order them. Well here is the link http://www.diyefi.org/forum/viewtopic.php?f=6&t=285&st=0&sk=t&sd=a&start=10 Quote Link to comment Share on other sites More sharing options...
Flexicoker Posted December 27, 2008 Author Share Posted December 27, 2008 OK, I think my plan as of now is: 1) replace entire power circuit on MS, hopefully that will be all the ECU needs 2) resistor spark-plugs 3) redo grounds and battery cables 4) if that doesn't help enough, buy some magnecore wires 5) if none of that fixes the noise issue, then maybe a power filter, and then possible the mod in that diyefi forum. Anything else that I other simple/cheap things I should try before I dish out the money on the plug wires? Quote Link to comment Share on other sites More sharing options...
Flexicoker Posted January 8, 2009 Author Share Posted January 8, 2009 AHHHH MORE SCREAMING!!! okay, I redid the voltage regulator circuit per Carelessesses advice, and it seemed to work fine at first. Connected with the lappy, all the lights on the stim worked, and everything in Tunerstudio looked go for launch. However, it wouldn start tonight once I got everything plugged in, reflashed the firmware and everythang. I got a few sputters, and the occasional random flash from the timing light. But mostly no spark. The coil has 12+ on the + side, the ign light on the stim flashes, and until the car died on christmas it seemed like everything was working fine. The coil to distributor wire will not arc if I put it near ground, so its either the coil, wiring, or megasquirt. If the light works on the stim though, what could be wrong? Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted January 8, 2009 Share Posted January 8, 2009 Distributor bad? My L28ET dizzy became intermittent and started sending erratic signals to MS. It only failed when it was really hot and then worked again in my case. I got rid of it and went with EDIS. Just a possibility? What does your tach do when you are cranking the key? Quote Link to comment Share on other sites More sharing options...
Flexicoker Posted January 8, 2009 Author Share Posted January 8, 2009 the tach jumps up a little, and stays, doesn't jump around at all. MS says 200-ish while cranking, but the RPM there is not jumpy or intermittent either. Could something else have fried on the board when the voltage regulator circuit went bad that would still allow the stim to light up but not actually fire the coil? Quote Link to comment Share on other sites More sharing options...
Flexicoker Posted January 9, 2009 Author Share Posted January 9, 2009 UPDATE! The car is still not getting any spark. I reflowed the solder at any questionable looking joints, and scrubbed the board with alcohol. On the stim the IG LED just stays lit, and I could not get it to flash no matter how low I turned the RPM pot. I ordered a new BIPXXX from DIY. Is there anything else that I should check? I really need to figure this out, the Z is my daily, and winter break is over soon =/ Quote Link to comment Share on other sites More sharing options...
Matt Cramer Posted January 9, 2009 Share Posted January 9, 2009 Having the IG LED lit could either mean that you have burned Q16, or it could happen if you have Spark Output set to Going Low (normal) which might damage the BIP373 or might also damage the coil. Quote Link to comment Share on other sites More sharing options...
Flexicoker Posted January 12, 2009 Author Share Posted January 12, 2009 Okay, BIP373 fixed the no spark issue. Car is now running, but I still have noisy voltage. I put new resistor spark plugs in, new battery cables and checked all of the grounds and most of the charging system, disconnected the wideband, disconnected the alternator, all with no change. at idle, and decel the voltage is steady, but the faster I go, or the harder I am on the gas, the more spikey the voltage gets. I am reluctant to put a power filter on it, because it seems like a band-aid to something I should be able to solve. And I don't really want to start throwing $100 plug wires at it until I've exhausted cheaper options. Any recommendations on what to do next? Quote Link to comment Share on other sites More sharing options...
jeffer949 Posted January 12, 2009 Share Posted January 12, 2009 magnacor's are worth every penny. and its not a baind aid on the power filter. Its just fixing a problem that the MS guys didnt see. and have you checked your alternator? does it go up and down wiht your rpm cause if so thats just the normal Z alternator. Quote Link to comment Share on other sites More sharing options...
Matt Cramer Posted January 12, 2009 Share Posted January 12, 2009 Are you running low or high impedance injectors? Quote Link to comment Share on other sites More sharing options...
Flexicoker Posted January 12, 2009 Author Share Posted January 12, 2009 Low Z injectors. I did run the car with the alternator disconnected and the problem was still there. Its more vehicle speed and load dependent than RPM. I can rev it while not moving and not have a problem. Say I'm cruising on the highway, it will be a little bit noisy, with occasional large spikes and dips. If I hit the gas, it will immediately become more noisy, with large spikes happening more frequently. If I let off the gas and coast, the noise will almost entirely disappear. highway speed at a certain RPM will produce more noise than lower speed at the same RPM. I might just go ahead and buy the magnecor wires... does the diameter matter? Does anyone have a source for the 8.5mm wires in a color other than red? Quote Link to comment Share on other sites More sharing options...
Matt Cramer Posted January 13, 2009 Share Posted January 13, 2009 Ok, you might want to try the low Z noise reduction mod. Clip the center legs of Q9 and Q12 off the PCB, then solder a wire to these center legs on the transistor. Wire both of these to a separate 12 volt source. This routes noise from the injector flyback away from the Megasquirt's own 12 volt supply. Quote Link to comment Share on other sites More sharing options...
Flexicoker Posted January 14, 2009 Author Share Posted January 14, 2009 Where would be the best place to get a separate +12? I'm using the switched +12 lug on the relay board to also power the wideband, would that be OK? I did go ahead and order some Magnecor KV85's, so we'll what that does... Quote Link to comment Share on other sites More sharing options...
Matt Cramer Posted January 15, 2009 Share Posted January 15, 2009 If you're powering the wideband, I would not use that wire - I'd probably grab 12 volts from some point in the fuse box. Quote Link to comment Share on other sites More sharing options...
Flexicoker Posted January 17, 2009 Author Share Posted January 17, 2009 sigh I got the Magnecor plug wires in... didn't do anything. I've attached the most recent datalog, you can see that the voltage is noisy most of the time, but it only goes really crazy if I'm hard on the gas, but it doesn't happen all the time. I can drive it on the highway OK, as long as I don't go too fast or floor it, if I do then it'll go into super-lean mode, and it will stay that way (goes spicy lean at higher throttole) for the rest of the drive unless i stop. It seems sorta like something on the board is overheating, and it only happens at high loads/higher RPM's. I took off the lid and felt everything along the heatsink, they all felt pretty warm, especially R37, and R38. I'm going to splice some plastic tube into the vacuum line for the MAP sensor, and then do the mod that Matt suggested and see if either of those work... 2009-01-16_17.58.51.zip Quote Link to comment Share on other sites More sharing options...
Flexicoker Posted January 19, 2009 Author Share Posted January 19, 2009 Really close to smashing things... Can I run my low-Z injectors as high-Z for short time at lower duty cycles? If that solves my problem then the PWM flyback circuit is to blame? Quote Link to comment Share on other sites More sharing options...
mobythevan Posted January 19, 2009 Share Posted January 19, 2009 You could install dropping resistors and forget the PWM all together. Quote Link to comment Share on other sites More sharing options...
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