My 6v92 is starting up a bit funny, any ideas?

neoneddy · May 07, 2018, 11:28:50 AM

So this has been going on for a while. I start it up and it will sound like it's down a cylinder or 2 or 3, I shut it off right away, then refire, it will either startup fine this second time or we do it one more time. I know it's running right when there is no smoke from the exhaust, even when cold it doesn't really smoke. Power seems good, she'll run past 80 if I let her.

https://youtu.be/thVBVz3KUd0 Here is a video from today showing how it acts at around 70 degrees.

https://www.youtube.com/watch?v=FHqbLanmH3I This video here had lead me to believe this might be injector and or rack related.

Last year it did this as well, but I didn't know it was an issue. https://youtu.be/saUhVEeB8oA Being newbie bus owner, just figured it was cold. It does would work itself out on it's own, but shutting it off and refiring seems to be faster, and unburnt diesel washing down the walls is not good.

luvrbus · May 07, 2018, 11:36:30 AM

You most likely have a couple of injector that bleed off (dribbling) during the shut down and they need fuel sorta like a prime

Scott & Heather · May 07, 2018, 11:51:09 AM

Second video is of a boat..and injector spray pattern testing. Listen, for years my 6v92 would miss a little on startup and then all cylinders would fire. It was noticeable but I drove her for years that way (mainly when it was cold tho).

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neoneddy · May 07, 2018, 12:17:20 PM

@scott Re:second video, it showed smoke from the exhaust due to poor spray pattern, so I was thinking, maybe I'm getting a poor pattern on startup. Now thinking from @luvurbus's comment that it could be from low pressure due to the fuel dribbling off. Also thank you on mentioning this is not uncommon, my biggest fear of course is having some catastrophic engine issue. I figure so long as she makes good power, runs clean, I'm good to go for the big picture.

Maybe a bit more context here overall. When I first got the bus, and even now if I would let it run in this condition, it will run like this for a while and then in a cloud of white + black grey smoke it would roar to life and then clean right up. It seemed to take 2-4 minutes for that to happen. I can seem to shorten that up by doing a few start / stop cycles.

luvrbus · May 07, 2018, 01:15:11 PM

What injector number is in the 6v92 ?

neoneddy · May 07, 2018, 01:16:38 PM

Don't know, how can I tell?

thomasinnv · May 07, 2018, 04:24:06 PM

Pop off a valve cover and check the tag on the injector

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chessie4905 · May 07, 2018, 04:58:24 PM

Plug in block heater for 4 to 5 hours after it sets overnight and try it and see if any difference. Could be a low cylinder or two.

Lee Bradley · May 07, 2018, 05:23:33 PM

Probably tried injector or two.

ArtGill · May 07, 2018, 05:58:37 PM

I have had the same problem. I have also had the engine cutoff before all the cylinders caught up. I would have to prime the engine to get it start. I think Luvrbus has the right idea. Mine didn't miss every time I start the engine, so I think the cam/rack position on the injectors that leak down cause them to leak or not. The engine heater seems to make a difference.

I did replace three injectors and that has appeared to help, but not eliminate totally the missing on start.

chessie4905 · May 07, 2018, 06:00:02 PM

If that makes no difference, then consider an injector issue. I would check all valve and injector settings with your gauges or have them checked. Then you can think about pulling injectors and have them tested and replaced if necessary. Do the cheap diagnostics first.

Geoff · May 07, 2018, 06:07:51 PM

How much oil are you using? Do your air box drains go to the ground or into a canister? In other words, are you using a lot of oil?

If not, I would not worry about it. The video shows a well used engine. Until you start using a lot of oil you can get by.

Brassman · May 07, 2018, 09:33:48 PM

Does anybody swap out injectors for rebuilts? Shouldn't be too expensive or difficult to do. It's always good to have a test stand to test the replacements. White smoke = bad injector.

neoneddy · May 07, 2018, 10:36:51 PM

Quote from: Geoff on May 07, 2018, 06:07:51 PM
How much oil are you using? Do your air box drains go to the ground or into a canister? In other words, are you using a lot of oil?

If not, I would not worry about it. The video shows a well used engine. Until you start using a lot of oil you can get by.

Just changed the oil , I think the PO had a multi grade in, since the change it leaks less from the airbox drains, consumes much less as well.

chessie4905 · May 08, 2018, 04:43:42 AM

any chace you are getting some fuel in your oil?