MS II sync loss

[2eighTZ4me]

Mostly occurs under very light throttle/cruise while going over bumps. The car will miss for a split second (AFR's go rich) and then pick right back up. I pulled datalogs and the guys at DIY said that I have a 'sync loss' condition. This has also happened a couple times under full boost - so it's not relegated to just light throttle/bumps - it's happened during a bunch of different conditions - but MOSTLY light throttle going over bumps.

 

I have the 83 turbo dizzy with their (DIY) Hall effect wheel in it. No shaft play in the dizzy that I could feel - car only has 2200 miles on it now. Put in a new dizzy pickup/sensor as well. This is a 78 S30 turbo BTW...

 

Just replaced the relay board - thought it may have been a bad fuse holder - that didn't help.

 

Anyone ever encounter this? The DIY folks said I need to put an oscilloscope on it. Doubt I would even know how to hook one up - much less what to look for in the data.

 

Curious if this has happened to anyone, and if so - what you did to fix it.

 

 

 

 

[AkRev]

Can you take a data log? 

Based on the fact that your afr goes rich, this makes me think it is temp sensor based, as in a clt sensor or iat senor that reads dead cold for a brief moment. My experience with hall or vr sensor sync loss is that you go lean, not rich. 

Do to the fact that bumps are involved, this makes me think you have a lose connection in the wire. 

 

Good luck, and I will keep an eye out for a log. 

Edited June 20, 2014 by AkRev

[2eighTZ4me]

I've got datalogs. I need to get a few more recent ones though when it does it. I should be able to do that over the weekend. Thanks for the input!