sync loss reason 2

[Yves]

I already posted this in the tuning section, but maybe this is more appropriate.

Experiencing a sync loss (reason 2). Have one instance in this log with a sync loss.
60-2 trigger wheel with hall sensor (diyautotune) and Vortec distributor for cam sensor (also hall)

Any ideas ?

[Yves]

A tooth log. I'm seeing a long line and directly after that a short one.

[grom_e30]

try 'ignition input capture' falling edge to see if it clears up the tooth log.

[Yves]

Thanks Grom for chiming in.

I had it idling on falling edge. Unfortunately, I only have a composite log of it. While doing that I had to go from the tooth number 1 angle of 50 to 48. I also saw that the cam signal line was appearing at times 2 per block of lines whereas with rising edge it appears only once and right in the middle of the block. Is it supposed to be like that ? (see attached)

[grom_e30]

the comp log does not look great on falling it appears to be getting extra cam pulses and also extra teeth seem to be missing yet it does not declare sync was lost, seems strange.

[Yves]

the comp log does not look great on falling it appears to be getting extra cam pulses and also extra teeth seem to be missing yet it does not declare sync was lost, seems strange.

Yes it didn't look great, so that is why I didn't persue it. Maybe someone has an idea.

What could cause that second tooth to be longer than the rest in that first tooth log ?

[Yves]

I have rewired in the sense that I separated the sensor ground from other and put the sensor grounds to ms. However I seem to get the same double tooth in the log. Not sure how it will perform as I've not driven like that.

[grom_e30]

the issue you have is the logs do not clearly show the sync issue you could driving about with the 'sync error logger' till it loses sync that way it will only show the pattern leading up to the sync error and not hundreds of pages

[Yves]

I had the sync loss logger on during some drives, but it didn't show an issue despite the fact that in the regular log files the rpm drops to zero momentarily.

[Yves]

I tried it again with the sync loss logger. I'm sure that there is a sync loss as I see the rpm momentarily drop to 0 in the log (couldn't feel it at the time though). However it doesn't show up in the log as mlv reports the file to be empty...

any ideas ?

[Yves]

I went out with the car today and had 5 sync losses that are evident by the momentarily drop to 0 rpm. Nothing shows up in my sync loss logs. What am I doing wrong here ?

Is this an issue with the hall sensors from DIYautotune ?

Thanks

[grom_e30]

how are you doing the log? changing to sync error log, ticking capture log file save, then hitting start?

[Yves]

how are you doing the log? changing to sync error log, ticking capture log file save, then hitting start?

Yes

Thinking out loud : I currently have the crank sensor taking it's 5V power from Vref on the relay board and with the ground connected over the coolant sensor.
Would it help if the crank sensor ground was put directly to pin 2 (i think that is the one) and the shield to pin 1? I personally doubt it will help since based on the wiring diagram for the V3.57 board everything from ground is at the same connection behind the DB37 but maybe I'm missing something here.

I also run the tach from the board. The ground however is routed to chassis ground. Maybe change the ground to a power ground or so.

[Yves]

I found that one generic sensor line was open and that the sync loss was in exactly the same spot as a spike in that sensor line. Set the sensor to off. Still have to drive it though.

[Yves]

I have sync error log. However I don't know what to look for.

Input appreciated.

The generic sensor line wasn't it.

Not sure what I have to do next. I have put the screens of the shielded wires to the ground cable that connects the relay board to the engine. Would it help to connect them to the ms ?

[grom_e30]

if you zoom right it at the end you pick up a 59th tooth that should not be there noise

[Yves]

if you zoom right it at the end you pick up a 59th tooth that should not be there noise

Thanks

Is it possible to see where the noise is coming from ? How to proceed with this ?

[grom_e30]

the log just tells you that you are seeing noise, teeth that are on the log but not really there, as opposed to missing some teeth, that are there but are absent from the log. is the crank sensor wiring clear of any ignition coil wires? resistor spark plugs fitted??

[Yves]

I use Bosch FR7DC+ spark plugs. The R in the designation is for a spark plug with interference suppression.

The spark sensor is mounted on the passenger side of the balancer. The wire runs up around the front of the engine and then under the ITB stacks alongside the wiring loom. The injectors are there as well.
I run LS1 coils and those are mounted above the stacks. The logic coil wires run in the main MS3X wiring loom.

The wires of the sensor are all shielded. I had to make a connection to the hall sensor and I used some old wire shield that I pulled over the wires so that they were covered right up to the sensor. I had to use some alu foil to cover the section where I made the connection.

I did however connect all shields to the main ground wire going from the relay board to the engine. Would it make a difference if those are connected through sensor ground ?

Anyway grom, thanks for sticking with me on this

Edit : went over my logs. This image might be interesting.



I'm logging the maf and I see a maf spike preceeding the sync loss. Then after the sync loss my iac steps in, I can even see the map move because of it.

[grom_e30]

the iac steps is prob normal as the engine will go from running then sync loss and go from cranking back to running when the rpm gets re established, again the ase should kick in as well. not sure if this will help with your grounding scheme http://www.diyautotune.com/tech_articles/grounds.html

iv not personally used maf so not sure if the spike is normal as a result of sync loss or not though.