Alex3000 Posted November 20, 2018 Report Share Posted November 20, 2018 It's been a long journey in my rebuild but I am finally attempting to start the old rx7 with my new megasquirt setup. I'll try to keep this brief: I spent last weekend in the garage trying to get the car to start. When I turn it over it JUST barely won't catch. If I hold the starter down for longer than I would like, it starts to sputter a bit like it's about to start but ultimately does not. A decent bit of exhaust puffs out the exhaust when this happens. - I sprayed starting fluid in the intake. This made it sputter a bit harder, but still act the same. To me, this means it's not a simple fuel issue, or else ether would start it. - Unscientifically, I started decreasing and increasing the cranking advance to see effects. With 0 crank advance it seemed to sputter harder, but still no start. - When I hold the throttle open, it seems to also help it sputter harder. (not sure what this tells me exactly) - I checked the Leading plugs to make sure they are actually sparking and they are... so this means I'm getting spark at least. My working hypothesis is that my timing is off. Potentially significantly. The first question for anyone with knowledge is about my trigger wheel and hall sensor. It is a 60-2 wheel with the sensor at the bottom. In this picture the motor is at the first timing mark which is 5 deg ATDC. My understanding is that when setting up the trigger wheel in TunerStudio I need to input the degrees after the -2 teeth which corresponds to TDC. So in my case: There are 2 gaps before the wheel gets back to the missing teeth which means 58 gaps after TDC. 360 degrees/ 60 teeth = 6 degrees/tooth. 58 x 6 = 348 degrees. Subtract 5 degrees because my reference mark is 5 deg ATDC = 343 degrees. The thing is: During my time in the car I kept adjusting this number up and down to see if that would help it start. It seemed to try and catch better when I set it a little farther down, around 324 degrees. That's about it.... I tried fixing the timing to 10 degrees advance and generally went up and down with the numbers. Sometimes it seemed a little closer and sometimes not. This leads me to believe I may be very off in my settings.... Any suggestions would be crazy appreciated. I spent a whole day just blindly adjusting things and it got me nowhere so I'm open to suggestions. I am posting my MSQ file (ms2 v3.0 using msextra firmware), if anyone is specifically an rx7 person and a megasquirt person **COUGH COUGH @mhr650 *** Maybe I have something totally off-base? Thanks in advance! CurrentTune.msq Quote Link to comment Share on other sites More sharing options...
mhr650 Posted November 20, 2018 Report Share Posted November 20, 2018 This is one that I don’t have any experience with, I didn’t use a trigger wheel and hall effect sensor, I used a standard second gen crank angle sensor. That is also the biggest reason I used the MS3Pro, when you read about MS problems trigger and sync are by far the number one problem, the Pro series have much better VR trigger circuits but not sure if that affects you with the hall sensor. Do you see a stable tach signal when you are cranking? You could set up logging to the trigger signal and look at it after you try cranking. Have you tried test mode in turner studio to make sure that all of the plugs are firing, at one point I had my car set for wasted spark instead of coil on plug and the rear leading plug would never fire, it ran but was way better after I got it sorted out. Do you have a good TDC mark on your pulley so you can check timing with a timing light if you get it started? At this point I would try pull starting it, try to keep it running until you can get a timing light on it to find out where you are. Set the timing to fixed so it is not trying to apply timing numbers from the timing table. If you have a RB pulley it has marks at 0⁰ 12.5⁰ and 25⁰, I set the timing at fixed 12.5 and adjusted the crank angle sensor until the marks lined up with the timing light. You should be able to do the same by setting the timing at a fixed value and adjust the trigger angle until it matches up. I really think that pull starting is your answer at this point rotaries are very tolerant of mistiming, once when I was using the GSL-SE electronics I put the distributor in almost 90⁰ off and was able to get it to run with pull starting. Quote Link to comment Share on other sites More sharing options...
Alex3000 Posted November 20, 2018 Author Report Share Posted November 20, 2018 17 minutes ago, mhr650 said: I really think that pull starting is your answer at this point rotaries are very tolerant of mistiming, once when I was using the GSL-SE electronics I put the distributor in almost 90⁰ off and was able to get it to run with pull starting. Funny, I did literally the same thing, and got it running as well.... albeit with the headers glowing red. Pull start is not an option really because the car is almost entirely disassembled, suspension and body work wise. Currently I am hooking the battery to a Toyota Highlander with jumper cables so I can endlessly crank the starter. I think one of my other issue is that the data logs really confuse me. I just don't know how to interpret any of it in order to trouble shoot. Fixed timing I think would be a good idea though, just another variable to keep constant. Quote Link to comment Share on other sites More sharing options...
mhr650 Posted November 20, 2018 Report Share Posted November 20, 2018 The MS forum on RX7club is really helpful, that is where I got most of my help when I was setting my car up. Quote Link to comment Share on other sites More sharing options...
Administrators E. Tyler Pedersen Posted November 21, 2018 Administrators Report Share Posted November 21, 2018 @bbaker480 Quote Link to comment Share on other sites More sharing options...
turbogrill Posted November 22, 2018 Report Share Posted November 22, 2018 Have you done one of those high speed logging that shows your trigger signal? Is it possible to start with fuel only? Is your old timing system working? Quote Link to comment Share on other sites More sharing options...
wd6681 Posted November 22, 2018 Report Share Posted November 22, 2018 Ditto on logging your trigger signals and adjusting your pots accordingly. My M20 takes a lot of cranking to start since megasquirt, but it does so I have not looked into it greatly. A Canadian racer whom is aarine mechanic said this usually comes from too much ignition advance or too much voltage drop from the starter. He suggested running a jumper from the starter wire to the ignition/coils. Are you running a bip373? Where on the board? Quote Link to comment Share on other sites More sharing options...
bbaker480 Posted November 23, 2018 Report Share Posted November 23, 2018 On 11/21/2018 at 3:10 PM, E. Tyler Pedersen said: @bbaker480 No experience with a trigger wheel and hall sensor here. I do have tons of experience cranking for days without anything improving however... My MS2 is built with the Zeal daughterboard and instructions from DIY. I'm struggling to get it all checked out with the JimStim but once I get V2.0 of the dash finished I'll be wiring it in and seeing what happens. Quote Link to comment Share on other sites More sharing options...
mostmint Posted November 23, 2018 Report Share Posted November 23, 2018 Let me ask a really dumb question - did you start it with the old ECU in current configuration? Just trying to confirm something not related to the Megasquirt is causing a problem Quote Link to comment Share on other sites More sharing options...
Alex3000 Posted November 26, 2018 Author Report Share Posted November 26, 2018 Thanks for the suggestions: It turns out it was indeed a trigger syncing issue. I reduced the gap between the sensor and wheel to .5mm, which seems pretty scary but it took care of my sync loss. Now, it started-ish like crap but it is technically "running". At least now I can start looking at dialing things in. Quote Link to comment Share on other sites More sharing options...
wd6681 Posted November 26, 2018 Report Share Posted November 26, 2018 What are you running, MAPdot, speed density, alpha-n, or a hybrid? Quote Link to comment Share on other sites More sharing options...
Alex3000 Posted November 26, 2018 Author Report Share Posted November 26, 2018 2 hours ago, wd6681 said: What are you running, MAPdot, speed density, alpha-n, or a hybrid? Speed Density Quote Link to comment Share on other sites More sharing options...
wd6681 Posted November 27, 2018 Report Share Posted November 27, 2018 (edited) Apologies, I think I had a brainfart, mapdot and speed density refer to the same thing. For my M20 I just hand entererd basically a stock ignition table and fuel I just let megasquirt figure it out itself based off enginep peramiters I do have a wideband and do allow it to 'learn'. At the Dyno nearly all the power increase came from leaning the car out. I guess my point is that once running your car should run reasonably well, maybe not idle but it should run and sound healthty. Edited November 27, 2018 by wd6681 Quote Link to comment Share on other sites More sharing options...
ironworks Posted November 27, 2018 Report Share Posted November 27, 2018 You may want to try the age old unflooding a rotary and see if that helps? Normally after a long winter I have to yank the plugs out of my FD and put about 5 pumps of oil in each rotor housing. the oil helps build compression with the apex seals. I have no experience with the Megasquirt iv always run the apexi power FC with my RX-7s but they have all been street cars. Quote Link to comment Share on other sites More sharing options...
Alex3000 Posted November 27, 2018 Author Report Share Posted November 27, 2018 2 hours ago, ironworks said: You may want to try the age old unflooding a rotary and see if that helps? Normally after a long winter I have to yank the plugs out of my FD and put about 5 pumps of oil in each rotor housing. the oil helps build compression with the apex seals. I have no experience with the Megasquirt iv always run the apexi power FC with my RX-7s but they have all been street cars. Yes, I have had to do the same thing before as well. I put new plugs in though to eliminate this potential issue. There are several X factors I am going to have to work through once I can get back in the garage again... Including the gas being like 18 months old. 1 Quote Link to comment Share on other sites More sharing options...
IPF Racing Posted December 5, 2018 Report Share Posted December 5, 2018 @Alex3000 let me know if you need anymore help with this. The supra is on MS3pro and my s2k swapped Miata is on MS3X. I've gone through a bunch of these same struggles so don't hesitate to reach out. Quote Link to comment Share on other sites More sharing options...
Alex3000 Posted December 5, 2018 Author Report Share Posted December 5, 2018 1 hour ago, IPF Racing said: @Alex3000 let me know if you need anymore help with this. The supra is on MS3pro and my s2k swapped Miata is on MS3X. I've gone through a bunch of these same struggles so don't hesitate to reach out. Will do, and thanks. I like the idea of an s2000 swapped miata! Quote Link to comment Share on other sites More sharing options...
IPF Racing Posted December 5, 2018 Report Share Posted December 5, 2018 3 minutes ago, Alex3000 said: Will do, and thanks. I like the idea of an s2000 swapped miata! No problem, after getting it figured out with MS3X its been a blast! 1 Quote Link to comment Share on other sites More sharing options...
mhr650 Posted December 5, 2018 Report Share Posted December 5, 2018 Have you checked out my MSQ file that I posted earlier? It had a pretty good timing table and target AFR table. My VE table won’t be optimum for you but should get you up and running on a NA 13B CurrentTune.msq Quote Link to comment Share on other sites More sharing options...
Alex3000 Posted December 5, 2018 Author Report Share Posted December 5, 2018 26 minutes ago, mhr650 said: Have you checked out my MSQ file that I posted earlier? It had a pretty good timing table and target AFR table. My VE table won’t be optimum for you but should get you up and running on a NA 13B CurrentTune.msq I did not see it, thanks. Yeah my current tune is a hodge podge of stuff found on the internet. I have a feeling it's insanely rich. I'm actually signing a lease on my own dedicated build garage tomorrow so it's going to be a few weeks before I can really get working on the car again... Quote Link to comment Share on other sites More sharing options...
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