Thumper Posted August 2, 2006 Share Posted August 2, 2006 I just installed megasquirt v3.0 into a friends 260z. It won't rev past 1500rpms I am using a HEI 4pin module. It starts perfectly but after 30-45seconds of running it will slowly die. The module and coil are very hot. Is it my dwell settings? Would should I use. I have a 1k resistor between the fidle and tps 5v ref. Besides dwell what else could cause this? Thanks for your time. Quote Link to comment Share on other sites More sharing options...
mario_82_ZXT Posted August 2, 2006 Share Posted August 2, 2006 If you have it wired up like in the sticky with the 4 pin HEI, MS should NOT be controlling dwell. If I recall correctly, 4 pin HEI modules have some sort of dwell control built in. Mario Quote Link to comment Share on other sites More sharing options...
z-ya Posted August 2, 2006 Share Posted August 2, 2006 What coil are you using? If it is the stock 260Z coil, it might require a ballast resistor. If you don't use one, the coil will draw too much current, causing both the module and coil to get too hot. The resistance of the primary on those coils is much lower than a newer 280Z or 280ZX coil. Get one of those, or an MSD blaster 2 coil. Quote Link to comment Share on other sites More sharing options...
mobythevan Posted August 2, 2006 Share Posted August 2, 2006 I seem to recall HEI units getting hot when spark inverted box was set the wrong way? Quote Link to comment Share on other sites More sharing options...
trwebb26 Posted August 2, 2006 Share Posted August 2, 2006 Are you using an MSD box? If you are - you need to put a timing light on it and rev the engine. Make sure that the timing matches the timing map. If it doesn't - post back and I can help with the problem. Quote Link to comment Share on other sites More sharing options...
Thumper Posted August 2, 2006 Author Share Posted August 2, 2006 Ok I have got it running better. But still not driveable. I have changed the dwell to 50% and it now goes up to about 3k rpms. No matter what I do it will not rev higher. I have changed the dwell, inverted spark, changed the timing, locked the timing, and changed fuel values but it will not rev past 3k. When I hook up my timing light, timing seems to be right at idle but the higher in the rpms you go the more the timing retards. Then right around 3k rpms and 10 degrees my timing light starts to not show a spark. So it seems like the module is trying to either fire it at the wrong time or just plain ain't working at that rpm. I have wired the coil and module up perfectly. Just as it was decribed in the sticky. I even installed the condensor. I hate letting a car win so if necessary I will buy a msd box which I know for 100% I can hook up right. Any suggestions thanks!? Quote Link to comment Share on other sites More sharing options...
mobythevan Posted August 2, 2006 Share Posted August 2, 2006 Is the HEI module grounded well? One of the bolt holes should have a metal ring around it that allows the module to be grounded through the bolt. Quote Link to comment Share on other sites More sharing options...
Thumper Posted August 2, 2006 Author Share Posted August 2, 2006 Yes I have two bolts holding down the hei and both are going through the sheet metal and touching the metal rings. Also I have the terminal W grounded to the ignition coil bracket bolt. Thanks any other ideas? Quote Link to comment Share on other sites More sharing options...
badjuju Posted August 2, 2006 Share Posted August 2, 2006 There is something wrong, this is not a solution, but just fyi, the hei will always get hot, so once this is all sorted out, you might look at putting arctic silver under it as a heatsink compound http://www.arcticsilver.com/as5.htm just to help out with heat dissipation. going with a silver compound is a little verbose, but that is right in line with the theme of this whole site. Quote Link to comment Share on other sites More sharing options...
mobythevan Posted August 3, 2006 Share Posted August 3, 2006 Yes, it does have to have heat compound and some way of cooling, heat sink, fan, etc. The GM HEI distributor provides a good heat sink and the bottom of the rotor acts as a cooling fan. Without the heat sink compound the modules will overheat in the GM distributor, I found out the hard way. Quote Link to comment Share on other sites More sharing options...
evildky Posted August 10, 2006 Share Posted August 10, 2006 what makes you sure the problem is the spark? I recall having rev issues when my fuel pump was dying, it simply couldn't keep up with the demand, you got a fuel pressure gauge? also I burnt a few HEI's before I bought a flamethrower HEI and it has far outlasted the delco units Quote Link to comment Share on other sites More sharing options...
Thumper Posted August 10, 2006 Author Share Posted August 10, 2006 I am not running hei anymore but when I was I was using artic silver. Same stuff I used on my cpu. I am now running msd 6a and I found the relay board was built wrong. Also I knew it was timing because of the above mentioned timing light going out. Quote Link to comment Share on other sites More sharing options...
evildky Posted August 11, 2006 Share Posted August 11, 2006 sorry I didn't read through your second post, how about the distributor? you still running the stock optical? I had one fail intermitantly, also the pulup resistor for the dist signal good? and from a good power source? Quote Link to comment Share on other sites More sharing options...
Thumper Posted August 11, 2006 Author Share Posted August 11, 2006 Well I figured the problem was between my megasquirt and msd box. So it was either my relay board was messing up the signal or my megasquirt was sending a bad signal. So I bypassed the relay box and wired my white wire from my msd directly to my megasquirt fidle wire and presto its fixed. I truly don't know why it fixed it. Only that it did. I have guesses mostly bad put together of the relay board but don't really care why its fixed just that it is. So fyi if you have these symptoms bypass your relay box. Quote Link to comment Share on other sites More sharing options...
evildky Posted August 15, 2006 Share Posted August 15, 2006 so you hooked the MSD to the MS without the extra board mods? I thought you had to add a transistor and capacitor in order to run the msd? Quote Link to comment Share on other sites More sharing options...
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