Another Sync Loss Issue
#1
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Today was a huge moment for me. After months of time along with blood sweat and tears I have finally completed my forged VVT project (kinda). Maybe I'll make another post about that journey in the general chat forum.
My issue is that I lose sync when I try to change rev any faster than maybe 100 revolutions per second. I can idle and I can cruise but that's it. Another caveat is that I can't cruise past about 2,300 RPM. That made it very difficult for me driving my car home from my welder's shop. When I try to rev it's similar to hitting a rev limiter except at 2,300. I see the sync loss counter climb to 10, 20, 30, 40 all within seconds of trying to rev. It doesn't die though; It catches sync instantly when I let off the throttle. Strangely, I get 0 sync loss events when it's idling or cruising below 2,300 rpm. Another strange thing is that there is no difference in performance when I unplug the cam sensor from the ECU so I'm guessing that's the beginning of my issue.
I'm running the same MSQ that I was running when I had my 1.6 going except for the difference of required fuel and wheel decoder (Miata 36-2). I have a 36-2 trigger wheel in there from FM.
I checked my lines throughly. The same ground that went to the 1.6 CAS goes to both the new cam and crank sensor. The same 12V that went to the 1.6 CAS goes to both the new cam and crank sensor. White went to crank. Yellow/Blue went to cam.
Any idea on where I should start to diagnose this issue? Short of replacing that cam sensor I'm pretty stumped.
My issue is that I lose sync when I try to change rev any faster than maybe 100 revolutions per second. I can idle and I can cruise but that's it. Another caveat is that I can't cruise past about 2,300 RPM. That made it very difficult for me driving my car home from my welder's shop. When I try to rev it's similar to hitting a rev limiter except at 2,300. I see the sync loss counter climb to 10, 20, 30, 40 all within seconds of trying to rev. It doesn't die though; It catches sync instantly when I let off the throttle. Strangely, I get 0 sync loss events when it's idling or cruising below 2,300 rpm. Another strange thing is that there is no difference in performance when I unplug the cam sensor from the ECU so I'm guessing that's the beginning of my issue.
I'm running the same MSQ that I was running when I had my 1.6 going except for the difference of required fuel and wheel decoder (Miata 36-2). I have a 36-2 trigger wheel in there from FM.
I checked my lines throughly. The same ground that went to the 1.6 CAS goes to both the new cam and crank sensor. The same 12V that went to the 1.6 CAS goes to both the new cam and crank sensor. White went to crank. Yellow/Blue went to cam.
Any idea on where I should start to diagnose this issue? Short of replacing that cam sensor I'm pretty stumped.
Last edited by lyonnate23; 02-23-2019 at 12:54 PM.
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How would you recommend I tune the pots?
Last edited by lyonnate23; 02-25-2019 at 12:44 PM.
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I'm assuming the sensitivity pots need to be adjusted.
NB setups tend to need more of a clockwise rotation of NA setups. if anything R11 tends to need 4-5 turns.
really need to see a composite log in order to accurately diagnose. As lost sync 2 is typically not a pot related issue.
which make sme think you have the wrong trigger settings -- id switch it to falling and inverted. again the composite log would help here.
Before installing the Expander Board, take this opportunity to tune the VR input pot R56 before you cover it with the the Expander.
Turn R56 (12) turns to the fully counterclockwise, then turn it back 7½ turns clockwise.
Now do the same for the pots on the Expander itself:
Turn both R11 & R32 (6) turns to the fully counterclockwise. Turn R11 back 3½ turns clockwise. Do not turn R32 clockwise.
Turn R56 (12) turns to the fully counterclockwise, then turn it back 7½ turns clockwise.
Now do the same for the pots on the Expander itself:
Turn both R11 & R32 (6) turns to the fully counterclockwise. Turn R11 back 3½ turns clockwise. Do not turn R32 clockwise.
really need to see a composite log in order to accurately diagnose. As lost sync 2 is typically not a pot related issue.
which make sme think you have the wrong trigger settings -- id switch it to falling and inverted. again the composite log would help here.
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At 4-5 turns what should the resistance across the R11 potentiometer read?
Also, attached in the composite logger with Falling Edge and Inverted settings. It didn't fix the issue.
Also, attached in the composite logger with Falling Edge and Inverted settings. It didn't fix the issue.
Last edited by lyonnate23; 02-25-2019 at 03:41 PM.
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Thanks Brain for all the help you do for the Miata community! I'm certain that you've helped thousands of Miata owners with zero obligation to any of them. I just want to let you know that your wisdom is very much appreciated. Arigato Brain-senpai!
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