12v 5.9 intermittent power drop and white smoke

[brokedown]

So this is new. We started our trip south for Christmas visits and after a few minutes o the highway my bus started running like poo. Well, intermittently like poo. It seems to run just fine for 10 seconds then you feel it lose power and start belching white smoke for 10 seconds, and then repeat. it's a chore to try to average 45 mph or so!

So far I've used soapy water to check for leaks around the injectors, I've tested the turbo and intercooler for basic function and looked for any big leaks, and I've given dirty looks to basically everything. My understanding is that white smoke is going to be unburned fuel, but I'm having trouble coming up with something that wouldn't just 'stay bad" instead of going between running great and falling over.

In the last week or so i've done an oil change and filter, changed the transmission spin-on filter and topped it off, and monkeyed around in the cooling system a bit. Bus seems to start and idle just fine but RPM doesn't seem to be a factor for it going good/bad.

The bus is a 1997 BB TC2000FE, 5.9 6BTA with AT545. It has the Bosch P7100 which makes it a 3 wire motor.

So looking for advice on things I can do to diagnose/repair!

[cadillackid]

does that have an electric or mechanical lift pump? does it seem to be load rated? if its running good can you make it run bad by punching it into full load for more than a few seconds.. ?


ive seen white smoke on an electronic engine due to an injector sticking and dumping fuel into a cylinder.. more than it can possibly burn so that cylinder misses and pushes white smoke..



seems more unlikely on a mechanical pump but possibly an injector that has a sticking nozzle?



when its running bad does it feel like some cylinders are runningf fine but there is a definite "skip" or miss on 1 or 2 others?



when it goes into its bad phase, if you immediately shift to N and idle down, does it immediately start idliong smooth or will it idle badly for awhile?



im thinking if its a fuel supply issue, you would notice the engine smooth right out if you take the load off of it.. maybe the tank vent isnt working? or its sucking air into the lines (im assuming a mechanical lift pump here)..



a sticking injector would be more likely to continue to run poorly after it idled down..



intermittent air in the fuel lines can cause this type of thing.. my DT360 has had issues with losing its prime afteer the bus sits for awhile.. when that happens i start it up and it runs rough and puffs a little smoke till it gets primed back up.. in my case the manual primer pump was the culprit of the leak..



that bus has a mechanical lift pump up at the engine so the fuel system is negatively pressurized.. you wont see leaks since its sucking air vs blowing out fuel..

-Christopher

[BlackJohn]

Does the engine operate at the normal running temp while doing this dance?
If it isn't hot enough the glow plugs should be assisting the combustion. Look for an air blockage in the cooling system. Could be if you were playing with that .

Maybe check the fuel solenoid out to, it might be intermittent if grounded poorly or have a weak coil in it.

The bus has been sitting for a while hasn't it? Might be moisture in the fuel working itself out, filter condition?

Good luck and let us know any developments.


John

[brokedown]

Originally Posted by cadillackid

does that have an electric or mechanical lift pump? does it seem to be load rated? if its running good can you make it run bad by punching it into full load for more than a few seconds.. ?

It's a mechanical lift pump with a big rubber prime button on it. While sitting here at Travis' place I tried to make it act up just punching it from idle and it seemed like I could get it barfing doing that.

Originally Posted by cadillackid

seems more unlikely on a mechanical pump but possibly an injector that has a sticking nozzle?

I'm not sure how to actually test for it... And...

Originally Posted by cadillackid

when its running bad does it feel like some cylinders are runningf fine but there is a definite "skip" or miss on 1 or 2 others?

...if I had to make a call on this I would say it acts more like the whole engine is bogged down not just one or two.

Originally Posted by cadillackid

when it goes into its bad phase, if you immediately shift to N and idle down, does it immediately start idliong smooth or will it idle badly for awhile?

I'll test for this today. I was pretty focused on getting where we were going yesterday, but I think I can test for this just punching it in neutral.

Originally Posted by cadillackid

im thinking if its a fuel supply issue, you would notice the engine smooth right out if you take the load off of it.. maybe the tank vent isnt working? or its sucking air into the lines (im assuming a mechanical lift pump here)..

I'm headed to NAPA in a few minutes to get replacements for the fuel filter and water separator. They both look pretty clean on the outside but I don't have records of when they were replaced so I'll eliminate that.

On the tank vent, is this something that just pupping the filler cap off would eliminate?

Originally Posted by cadillackid

a sticking injector would be more likely to continue to run poorly after it idled down..

I would add that if you're rolling down the road and it starts messing up, the white smoke disappears if you let off the throttle but comes right back if you apply it again.. Letting off doesn't seem to impact the duration of how long it messes up but it does make it a bit less embarrassing.

Originally Posted by cadillackid

intermittent air in the fuel lines can cause this type of thing.. my DT360 has had issues with losing its prime afteer the bus sits for awhile.. when that happens i start it up and it runs rough and puffs a little smoke till it gets primed back up.. in my case the manual primer pump was the culprit of the leak..

I was getting some smoke on start up but just attributed it to the cold temperatures. I haven't really driven it more than to the gas station and back since springtime, but yesterday we did more than 100 miles and it was just peachy until we had been on the highway for a few minutes.

[brokedown]

Originally Posted by BlackJohn

Does the engine operate at the normal running temp while doing this dance?

Temp gauge is where I'd expect it. Takes a good while to get to the thermostat opening level and never goes above that. 190-ish under load, less if not under load.

Originally Posted by BlackJohn

If it isn't hot enough the glow plugs should be assisting the combustion. Look for an air blockage in the cooling system. Could be if you were playing with that .

This motor has no glow of any sort, it's all compression! I will check that the cooling system is still at the full level, doing 100 miles should have burped any air bubbles that may have been there.

Originally Posted by BlackJohn

Maybe check the fuel solenoid out to, it might be intermittent if grounded poorly or have a weak coil in it.

I'll give this a test today as well, I'm not really sure what it's supposed do do differently when the "start" circuit is hot that it wouldn't be doing when the "run" is on, so I'll make sure the "start" stays off and the "run" stays on.

Originally Posted by BlackJohn

The bus has been sitting for a while hasn't it? Might be moisture in the fuel working itself out, filter condition?

It hasn't driven much in the last 6 months, maybe 20 miles, but I've been running it regularly to use the air compressor. I'm gonna replace the fuel filter and water separator today though!

[brokedown]

Update:

Coolant level is good. Replaced fuel filters, the rear one was marked as batting replaced in 2013, the front wasn't marked but had significant rusty innards. After the painful process of priming it, I let it warm up and took it for a 15 minute drive. Drove it kind of hard to make sure I was getting it fully to temp and it did not mess up. Cautiously optimistic as it took 25 minutes before it messed up for the first time yesterday.... Another hundred miles to drive tomorrow so fingers crossed.

[BlackJohn]

Originally Posted by brokedown

Update:

Coolant level is good. Replaced fuel filters, the rear one was marked as batting replaced in 2013, the front wasn't marked but had significant rusty innards. After the painful process of priming it, I let it warm up and took it for a 15 minute drive. Drove it kind of hard to make sure I was getting it fully to temp and it did not mess up. Cautiously optimistic as it took 25 minutes before it messed up for the first time yesterday.... Another hundred miles to drive tomorrow so fingers crossed.

Attachment 28299

Well some progress is good news. I didn't know that engine had no glows or a grid heater. Why does it have a wait to start cycle then?

Just cranking is enough to heat it there maybe? Not likely in this climate,

had a similar engine in a pickup but never a problem stating when cold out. Pretty sure it had glow plugs





Your tank is getting stirred up now driving, think I'd be carrying spare fuel filters for a while. Hope you nailed it for now, but does running and idling better get rid of the white smoke?


John

[Tango]

The "Wait to Start" lite means...wait till spring.

[brokedown]

I've started this bus in temps down to about 28 degrees, that's as cold as it's gotten since I've had it. Starts up real good then. Meanwhile my T444E won't start without glow below 45.

[Mark_In_MA]

Would it hurt to add a can of diesel additive to the tank if it's been sitting a bit too?

I don't know off the top of my head if there's one like dry gas for cars, or maybe an anti-algae mix? Maybe keep topping off the tank to help blend the old fuel with fresh fuel for this trip.

It might not directly help, but I don't think it could hurt anything either.

[brokedown]

I put 50+ gallons in in maybe 2 months ago, it's a 60 gallon tank. I'll be filling it up again tomorrow when we get back on the road, I'd estimate I need 45 gallons right now to get full. So the fuel shouldn't be particularly old, but until yesterday I hadn't driven it any distance since spring. I drove it 600 miles or so home in January when I bought it so I used a lot of fuel then as well.

I will get some diesel additive next time I am somewhere that sells it.

[BlackJohn]

Don't you just love dependable diesel power. When they are good nothing is better. Best to never shut one off I guess, eliminates all starting problems.
How old is your air filter too Josh?
And she may have burped like you said but check if it needs topping up? Can take some patients longer to recover.
Safe and uneventful travels tomorrow....



John

[cadillackid]

Hopefully your fuel filters are it!!

Mechanical diesels seem to do much better than electronics in the cold..
I started my dra360 at 0f, it struggled but started. And it has no plugs and wasn’t plugged in.
That engine starts like it’s hot all the way down to about 15-20.

Christopher

[MIKE N STEPH]

i deff think you prob have it fixed after looking at that filter hopefully the tank doesnt have similar rust concerns

[Brad_SwiftFur]

The absolute first thing that came to my mind, when reading this thread, was "when were the fuel filters last changed?" These should be replaced about every oil change. You should keep some on hand at all times, and after a lengthy time sitting, you may find they'll need to be replaced again.

[david.dgeorge07]

Originally Posted by Tango

The "Wait to Start" lite means...wait till spring.

LOL! Literally!

[david.dgeorge07]

I had very plugged up filters after my bus was only driven occasionally during my conversion. Had an algae issue. I add additive now any time the bus needs to sit for more than a week or two and make sure to park it full.

Also I keep extra filters, a filter wrench and a couple quarts of ATF onboard in case I need to do a change on the road.

I hope your fix is that simple! Sounds like it is!

[brokedown]

Drive another hundred miles today without issue. Looks like the fuel filters solved it, so I'll be picking up another set next week. I also need to check/replaced my air filter and look into getting my fuel tank cleaned

[MIKE N STEPH]

glad to hear its running better for you. i would deff keep some spares and when you can take a look in the tank to see if there is any signs of moisture

[Booyah45828]

Dear god that filter is horrible. I would say that was your problem. Inspect your tank for sure. Have the fuel checked for water content as well. I've never seen a filter that badly rusted before and can only imagine what the tanks look like. A fuel additive wouldn't be a bad idea for you either. I prefer power service branded products.

I change my fuel filters once a year. When you're dealing with an injection pump and injectors that have super tight tolerances, any dirt or water is bad. And the cost of replacing those parts is huge compared to the cost of frequent filter changes.