No Spark

[MartinS]

Have been struggling to check engine timing offset. Subaru EZ36.  TDC #1 cylinder found with dowel in cylinder bore and mark made on harmonic balancer.

Initially used old timing light and an adaptor from Amazon. Got weak intermittent spark and light flash.  Not consistent enough to check timing although it looked 3-4 degrees out (which concerns me given the engine crank/cam timing was set up correctly when chain tensioners installed and re-checked several times).  Couldn't find any other problem. Yesterday, got a new timing light and used a new/unused spark plug lead to bridge from coil to plug. 

When testing spark, get solid spark and light flash. When cranking to test timing offset, initially got an occasional flash but only the first couple of cranks, not enough to check timing mark position, now nothing.  Tried exiting timing adjusting mode, nothing. Used a different coil pack, tested fine, no spark on cranking.  Was getting a few crank errors from (new) crank position sensor so reversed wires, no more errors, both crank and cam sensors show signal 'ok' in runtime parameters when cranking. No spark. Tried turning fuel mode from 'off' back to 'sequential', no spark. Tested again, good spark and light flash in spark test mode.

Of note, did have the engine running at one point but with rough idle and occasional weak backfire and stall after 15-30 secs.

PCL file attached.  Help appreciated.  Stumped and frustrated, keep getting bogged down in what should be simple steps.

Martin

VWAug8AM.pcl

[MartinS]

Log file of cranking.  Battery voltage looks a little low but have been doing a lot of cranking.  Initially was over 13V.  Nothing else has changed but have been gradually discharging battery.  Now needs recharging but other than that, log represents no spark condition.

Log 11-01-80 2;39;39 am.llg

[Adamw]

The log file has no data in it.  Go to >logging>set up PC Logging and click the "Add ALL" button at the bottom.  Then do us another log of it cranking.  

[MartinS]

Didn't know that had to be set every time. 

Log 11-01-80 3;51;14 am.llg

[Adamw]

45 minutes ago, MartinS said:

Didn't know that had to be set every time. 

You dont, just once.  But you probably lost it when you deleted those .xml config files. 

Everything looks happy in the log.  RPM is stable, there are no trigger errors, no cuts and dwell is being commanded - so there should be consistent spark.   

Pull a plug out and watch it while cranking to confirm if there is actually intermittent spark or if its just the timing light not picking it up consistently.  

[MartinS]

I've been doing the testing with a plug pulled to make sure there's a visible spark.  There's great spark and light flashes when I run the spark test, now no spark and no flash when I crank although there was weak/intermittent spark initially.  The coils have their own power supply from a 'key on' relay which is connected directly to the battery via the starter motor which is the original pathway in the vehicle.  New relay and wiring though so no corrosion or bad connections.

 

[MartinS]

14 hours ago, Adamw said:

You dont, just once.  But you probably lost it when you deleted those .xml config files. 

 

Ah, right, didn't understand what you meant there at first..

[MartinS]

Ok, since you confirmed everything ok with the ECU, I've gone through what you suggested, plus the ignition circuitry and tested everything.  There is spark when cranking but it looks weaker than when doing the spark test.  My timing light picks up during the test but I guess there's just not enough of a field for the induction timing light when cranking.  

I've noticed the voltage drop when cranking is close to 3V which seems a little excessive.  That drop is consistent from the battery to the ignition coils so I don't think there's a connection fault anywhere.  I've taken the battery to be assessed by Interstate as it's only a year old and I'll find out on Monday.  If the battery is Ok, it could be I just haven't been recharging it enough between cranking sessions and it is down too much.  That brings my charger into question but I'll deal with that when I find out.

It looks like I may not be able to do the timing check until I can get the engine running (I understand some engines you just can't time until running) which I did have happening (poorly) last week but now I don't get any hint it's going to start when cranking with the injectors back on.  Again, maybe that'll all be solved when I get the battery/electrical supply sorted out.  Any tips on how to come up with a basic tune which will at least get me running so I can do the timing check and start getting things moving forward again?

Cheers,

Martin

   

[Adamw]

The timing should be close enough to run with the trigger offset at zero.  Try a squirt of starter fluid while cranking as that will confirm if there is a lack of fuel.

 

[MartinS]

Great!  Thanks Adam!