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Old 09-17-2014, 06:35 PM   #1
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Location: Atlanta, GA
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Default MS2 + VVTuner + NA = Sync Loss

Hey all. Here's the setup I'm using. Gen1 MSPNP 9697 with a 3.57 board, it's been converted to use an MS2 daughterboard. I have a VVT engine in my 96, I'm using all factory wiring, except where the NB cam/crank signal wires are being run back through the 2 signals wires in the factory CAS wiring, then T-d off so the MS2 and VVTuner get the same NB signals. The pullups in the VVTuner have been pulled out. q2, q3, r2, r3 all pulled out and jumpered exactly like the picture shows here.
The car has a really hard time cranking, almost feels like it's flooding. And the car will not start with the VVTuner plugged in. It will crank and crank and crank, but never catch. It will crank and run if I put the vvtuner in after it's started, but really wants to die. But the bigger issue to me is the sync loss. Sync loss when cranking and sync loss when idling. Once the car is hot and running, it's pretty good with sync loss only happening when I come to a stop for longer than a minute. I've attached logs aptly named with what the conditions were, as well as my tune.

Edit: Sorry about number of logs. I figure more is better, right?
Attached Files
File Type: msq CurrentTune.msq (114.0 KB, 72 views)
File Type: csv cranking-composite.csv (33.6 KB, 41 views)
File Type: csv cranking-sync-loss.csv (18.2 KB, 42 views)
File Type: csv running-sync-loss-log.csv (65.3 KB, 44 views)
File Type: csv VVT-unplugged-whole-time.csv (10.7 KB, 43 views)
File Type: csv VVT-unplugged-for-start-then-connected.csv (67.4 KB, 43 views)
File Type: csv VVT-unplugged-whole-time-actually-started.csv (190.5 KB, 43 views)
File Type: csv VVT-plugged-in-always.csv (30.4 KB, 44 views)
File Type: csv plugging-in-vvtuner.csv (101.9 KB, 41 views)
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Old 09-18-2014, 02:32 AM   #2
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Played with R56/R52 some. All with VVTuner disconnected, and also don't forget I am using a 3.57 board, so 6 turns "lock to lock" on the turnpots.
Started by turning them both all the way CCW. Car wouldn't start.
Turned R52 4 turns CW - reconnecting and trying to start on each turn. Nothing. Zero'd it back out by going CCW again.
Turned R56 2 turns CW - Started, but not without a lot of pissing and moaning. Flooded it starting, had to go to flood clear mode, try again. Same thing. Clear it. Changed the temp-related added fueling to be 100% across the board. Still Flooding on start. Pull fuel from table at 85-100kpa @ <600 RPMs. Still flooding, but better.
Turn R56 another 1 turn CW - Starts much easier. Let it run to do some logging and check the engine bay (odd noise, turns out I had a pre-tb leak). Car's up to temp now. Plug in VVTuner and it keeps running! Stumbles some, but keeps running.
Add another turn CW and
Car gets up to temp. Occasional Sync loss popping up every now and then. Zip tie a few things in place, let's drive! Feels better, but still getting sync loss below 2k. Tried attaching logs but can't for some reason.
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Old 09-19-2014, 07:59 AM   #3
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Specifically this deals with the DIYPNP but since you have MS2 it should be relative. Look at post #15.

BTW, search is your friend.

Oh, just noticed you were in Atlanta, close enough to the good people of DIYAutotune.
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Old 09-19-2014, 02:38 PM   #4
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Hector, thanks for pointing that out. Search is really a wonderful thing. I've already been through that post and as many others as I could find before starting this thread. Having dealt with this yourself, you know there's not a wealth of information on the vvtuner. I changed the pullups from 12v to 5v already, changed the pullups in the VVTuner, tried setting my table in vvtuner to all 0's, and have been ping-ponging emails with DIY.
I've got it running pretty well when it's hot. Had to play with R56/R52 until I found a good combo, then took an abrasive wheel to all ground surfaces in the engine bay. Then find a loose ground on the back of the ppf. Sync loss is gone. I feel a little silly.
Only things left is to redo ASE so it's not trying to idle at 10:1 until it's hot and figure out why it's flooding on start.
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