496HO very random running issue
 

2002 purchased with 170hrs in 2018 and issue only happens a few times a summer. Once engine is normal running temperature and I stop to chat for about 20 minutes on restart it's down on cylinders. If I restart after a few minutes all cylinders are back... sometimes not to the 3rd or 4th after a few minutes pause between attempts. Fast forward now w/300hrs and ran fine all summer with 20hrs this season. This time took about 10 restarts before all cylinders were running and ran 4800rpm back to dock as always has dome.

Finally have faults as none were ever set before (rinda scan) with injectors open on 1,3,6. Being retired tech I checked all connections by unplug/plugin back in, etc. did injector ohm check from PCM and all were 13ohms which also includes harness. spec at injector is 12.5ohm.

So far:
PCM sent out last winter and was bench tested many times
Injectors cleaned/serviced
New Plugs and wires
Fuel PSI 42 even under load
Open to ideas????

On another thought how many injectors drivers are in PCM, one for each or batched fired(?).
Has never left us stranded.

thanks

i,m seeing this weird issue on a volvo 496 its eating injectors suddenly down on cylinders put a new set in and its fine for a while anyone know what kills injectors?

Paint inside of the fuel cooler comes off and clogs them. Known issue.

Is it the same cylinders going down every time or random?

What way are they failing... fault code(electrical) or plugging up?

UPDATE:

Fuel PSI 42-43 even under load.
Ohm checked all 8 injectors from 12v fuse removed to PCM connector.
All were 13ohms
Ran Allday yesterday and no issues.

My only guess at this time is coils in injectors opening up when hot???

Igntion could also go bad.

What gap are you running on the plugs?

NGK plugs set to spec in manual which I think is 0.60. Ignition coil don't think would set open injector faults.