akeboshi Posted December 13, 2011 Share Posted December 13, 2011 (edited) hello, I have a feeling that im gonna be walking into a flame ball fest with this question but i thought i would just ask before going back to help my buddy out. OK, lets see, my buddy just bought a 240z w/ ms l28et swap. bone stock with intercooler/bov setup. It is a real ***** to start up at first sometime, then other times it starts up fine. When it acts up it sounds like the starter is having a hard time turning it over. Almost as if there is resistance on some of the rotations. Im assuming its because the turbo is compressing some air in the cylinders????? I dont know but my supra does it sometimes too so I figure its a boosted engine thing. So anyways we take it for a spin and it runs fine, boosts good then when it warms up a little it starts missing and cutting out. It is intermittent though. It also wont start back up after driving it even after cycling the ingition off and back on. Timing with a gun looks good, advances like it should so I dont know. I havent looked at what his map looks like because he doesnt have a computer. Ill go over tomorrow and hook one up to really see what is happening and post an msq for everyone to look at. I know I havent done everything but I figured I would ask to see if there was anything obvious that I missed. The wiring looks good to me but one thing that caught my eye was his iat sensor was mounted in the middle of the intake manifold. that wouldnt have anything to do with his problems would it? thanks for the help and support hybrid z! marcus Edited December 13, 2011 by akeboshi Quote Link to comment Share on other sites More sharing options...
Cannonball89 Posted December 13, 2011 Share Posted December 13, 2011 (edited) It's got nothing to do with the turbo compressing air in the cylinders on cranking. The turbo is not capable of producing any positive pressure during the cranking phase. If the starter is sounding funny then it is almost definetely a problem with the battery or alternator not charging the battery fully. I would start by using a multimeter to check battery voltage at rest and at idle. If battery voltage is less than 12V at rest or less than 14V at idle then you need to go to Sears or some other place that will check batteries for free. A bad battery is nothing but a headache in an EFI system. If you read low voltages and the battery checks out good then you need to check your alternator. As far as the hard starting, I would imagine that you mainly notice this within 5 to 45 minutes after being run? If so then you are probably experiencing heat soak. Search and ye shall find a myriad of remedies on this site. From my experience it is not one ultimate fix, but a combination of all to make an L series EFI engine favorable to hot starts. Heat soak is the main cause of it all. Solutions you will find will include a vented hood, a check valve in the fuel system to maintain fuel pressure in the fuel rail after engine shutoff (especially important if you are running an aftermarket FPR), and of course lots of heat sheilding. You mention that the IAT sensor is in the middle of the intake. Mine is as well. I have mounted my IAT sensor in the large hole at the base of the #4 intake runner, which was I believe part of the factory BOV circuit. It sounds like yours is mounted in the same place. I have noticed that the sensor mounted in this location is more susceptable to heat soak than if mounted in a bung on the intake piping after the I/C. And also I have read that Tunerstudio software under the Advanced Engine-MAT Correction Tables will lean out your mixture when certian IAT's are reached. After a run (either on a simple drive on the street or after back to back 1/4 mile runs) I have noticed that within 5-45 minutes after engine shutoff the IAT's are actually registering higher than they were during the run due to heat soaking from the cylinder head, turbo, and exhaust system than they were during the run. A solution may be to mount the IAT sensor in a bung in the intake piping, but if you insist on keeping the IAT in the manifold as I have, search the MS Extra forums for the appropriate fix. I have read of it on their but forget the exact fix, and my car will still run, albeit poorly for a few minutes after hot start so I have not yet looked thouroghly into the fix myself. I believe it involved changing the default MAT correction values such as that they did not lean out the mixture during high IAT's though. Good luck, and I'm sure the solution is some simple hardware or software changes like I suggested. That's the beauty of Megasquirt, it is completely fixable by YOU! Edited December 13, 2011 by Cannonball89 Quote Link to comment Share on other sites More sharing options...
akeboshi Posted December 16, 2011 Author Share Posted December 16, 2011 OK, so went and played alittle with it again last night and heres what happened. First off, I couldnt get his ms2 to connect to my pc. We took his car for a spin and it started cutting out like it did the last time only this time when he turned it off it wouldnt start back up at all. The reason it wont start back up is it has no spark at all coming from the coil. I really wish I could see whats going on in TS but im willing to bet he doesnt have a tach signal in TS. So, my question is what would make him lose spark when the car warms up? Im thinking his turbo dizzy is defunct. Im gonna swap my megasquirt in this weekend and try to recreate the problem. Hw has another dizzy we can try too. Quote Link to comment Share on other sites More sharing options...
letitsnow Posted December 16, 2011 Share Posted December 16, 2011 Did you create a new project in TS for his car? If not, that could be why it doesn't connect, otherwise go through the assembly instructions and make sure the serial chip is working. Quote Link to comment Share on other sites More sharing options...
akeboshi Posted December 17, 2011 Author Share Posted December 17, 2011 I bet you're right. It was trying to look for my project Quote Link to comment Share on other sites More sharing options...
akeboshi Posted December 19, 2011 Author Share Posted December 19, 2011 OK so I set up my ecu to run an optical dizzy and made a base map to run on his engine. We were able to get it to start and I tried to set base timing but i really didnt know how to. Do I just make my whole advance table like say 10 deg and the nplay with degree offset till it matches up on the crank? I feel kind of bad because his car ran better before i touched it, but it doesnt do the weird no spark thingy anymore so im gonna open his ecu up and take a look at the jumpers. it looks to be prebuilt by diyautotune so the jumpers are probably right but ill check anyways. One other thing, when I checked it the first time it had a blown fuel pump fuse and it popped again when we let it die for the last time. would it be ok to just throw a 15 amp fuse or should i look for a problem? I tried to upload the msq but it wont let me. Quote Link to comment Share on other sites More sharing options...
Cannonball89 Posted December 19, 2011 Share Posted December 19, 2011 You can turn idle advance on in tunerstudio and set the parameters so that it holds ten degrees (or any degree, but ten is easy). Then mark you timing marks and crank pulley at ten degrees with white paint and hook up your light. Then you can either turn the distributor or change the trigger offset in tunerstudio until your ttiming marks line up. Also you shouldn't need a 15 amp fuel pump fuse. Especially just at idle. Something is wrrong there. Quote Link to comment Share on other sites More sharing options...
akeboshi Posted January 2, 2012 Author Share Posted January 2, 2012 I played with his car again yesterday. i spent a few hours looking for a map and i decided on one that cygnusx1 had done up. I will actually be using the same one for my car when I finish it. Anyways, we got it to start, I made the whole ignition map 10 degrees, and set timing using trigger offset. good to go at 10 degrees advance (and on a side note i was pleasantly surprised at how steady the timing was with the optical dizzy) and we took it for a drive. It was rough to say the least and he didnt really get into it but I think its a good starting point. I just wanted to post the datalog and msq so somebody would look at it and maybe say yay or nay. On an off note, we popped 2 more fuel pump fuses trying to start it up. I dont know why because everything looks good. I looked at the fuel pump and looks like a new walbro unit. I checked all the wiring and it is straight. The only thing i can think of is maybe the coil is somehow making it pop. the power wire comes off the relay board and then the coil gets spliced in (with its own fuse) on the wire going to the fuel pump. But thats the way it looks like its supposed to be. maybe im wrong. anyways just an update. Quote Link to comment Share on other sites More sharing options...
Cannonball89 Posted January 2, 2012 Share Posted January 2, 2012 If its only blowing fuel pump fuses when cranking then its probably due to your battery voltage dropping too low when cranking. Less volts=more amps. Congrats on getting it running though. The tuning will be a lot more fun. Quote Link to comment Share on other sites More sharing options...
akeboshi Posted January 3, 2012 Author Share Posted January 3, 2012 i tried posting up the files but it says i dont have permission to do so. i made a new account and it also says the same thing. do i hve to do something special? Quote Link to comment Share on other sites More sharing options...
akeboshi Posted October 9, 2012 Author Share Posted October 9, 2012 Just wanted to update this thread so that others who may think they have similar problems can use this info. Turns out the head gasket was starting to go out. It was like that from the previous owner. After the new headgasket it was tuned and dynoed in at 199rwhp. Dont know what the torque was though. Quote Link to comment Share on other sites More sharing options...
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