Engine/Transmission (1998.5 - 2002) Help, smoke at 2200 rpm

[hensign]

I have recently reentered diesel ownership. My last one was an 89 Ford and what a slug it was. I purchased a "broken in" 99 Ram 350 with 170k miles. I love this thing, it is so much more powerfull than I imagined, but. I noticed that it is a little sluggish when accelerating slowly sometimes now I have learned the whole symptom. At 2200-2300 RPM while accelerating slowly it will (bog?) and puke out a huge blue cloud. This will happen cold or hot, I can pretty much get it to do it at will. If I back off or floor it it goes away. Now for the wierd part it seems to be getting worse the colder it gets here. Plus on the highway it will now do it in 5th(never noticed it before) but after about 5-10 min of driving under that rpm it will go away and I can drive at whatever RPM I want. If I have to stop to fuel up or for even at a toll I have to cruise slowly again for 5-10 min befor it will run normally. I think all is still stock on this truck even the exhaust. I did put a new APPS on due to an intermittent failure. It had about a dozen codes in it when I got it but may have been due to the APPS. None have reoccured since I replaced it. I have replaced the fuel filter(maintenance), checked for water in the housing several times, checked the air filter, replaced the thermostat(poor heat, fixed it), no oil consumpion at all in 5k miles and 2 oil changes, and I have scratched my head alot. I Think the engine sounds louder when it is most likely to do it, may be injector noise or in my head so I dont want to just throw injectors or a pump at it if I am not sure.

Thanks for any help

Hadley



PS the truck was definitly used hard by its previous owner he had a 45' race trailer and pulled it all over the south west.

 

[rspinks]

Hi, sorry to hear of your problem. You didn't say if you checked fuel filter, also check if the VP44 injection pump is getting fuel pressure (there are test ports on the fuel lines).

 

[rspinks]

Oops sorry I see you did check the filter.

 

[hensign]

Fuel pressure

I didnt use a tester but I did prime the system using the lift pump and got gobs of fuel out at the banjo on the VP44. What should the pressure be? can I use a standard gas pressure tester?

Thanks

Hadley

 

[rspinks]

I'm surprised nobody else has jumped in here, I'm not an expert but your symptoms sound similar to other posts in which the VP44 pump is on the way out. The VP44 needs 8psi or so, problem is the lift pump can generate seemingly good pressure at low fuel flows but under more demand the pressure can go to zero, you really need to hook a test gauge up and drive it so you can watch the pressure under load.



The VP44 requires 8psi pressure because excess fuel is used for cooling the VP44 - 70% of the fuel is returned to the tank. If the lift pump is no good the VP44 will sometimes work for years as far as driveability, however it will be dying a slow death the whole time if it doens't have enough pressure for cooling.



I don't want to put the fear into you, hopefully it is something else than your VP44. If it is the VP44 there was a reman. one for sale in the classifieds recently, or Piers has them for a good deal as well.



Good luck.



Rich

 

[WadePatton]

another tree

But it sounds like a low boost situation to me. When he accelerates briskly (with boost) no problem the way I read it. Could the turbo be sluggish and not pumping the air needed for the large amount of fuel supplied at that rpm?



I'm no expert, and there's my guess.



And blue smoke is a product of engine oil--turbo bearing seals?

 

[slavallee]

I'm with Wade here

I would investigate the turbo. The oil supplied to the turbo should increase and decrease with engine speed right? So at a lower RPM there may not be sufficient oil pressure to blow past the turbo bearings. Kick the RPM's to 2200, bang! The oil pressure increase pushes oil through the worn bearings and is burned in the exhaust.



Why does it stop at above 2200 RPM? Ever had a water pump bearing go bad? At idle, it pukes coolant everywhere. At cruising speeds it leaks MUCH less because the shaft is more centered in the bearing due to righer RPMs.



Why does it stop after 5-10 min? Well, metal expands when heated. After warming up, the shaft expands enough to restrict oil flow through the worn bearing.



That's my explaination. Sounds good to me, but it's still paper thin.

 

[slavallee]

oh yeah

As far as not noticing any oil consumption, 11 quarts is a lot of oil in a motor. It would take a good amount of oil loss to notice it on the dipstick.



Plus,it is not uncommon for crankcase oil levels to increase over time depending on how much idleing you do.



Also, I don't think your actually buring all that much oil if the turbo bearing theory holds up. It doesn't take much oil being burned to make noteworthy smoke.



Just don't count out the turbo bearing theory because you don't percieve oil loss. Try to wiggle the turbo shaft around. If you notice excessive play, thats the clearest culprit. I'm sure someone will chime in with the turbo shaft endplay specs.



-Scott

 

[hensign]

I will check the lift pump pressures as soon as I can along with the turbo shaft play. The oil is still clean after a little more than 1k miles, amazing my ford was always black by now. I still suspect the vp44 but am hoping it isn't. Its still strange that it starts doing it again even if I only slow down and stop for a few seconds???? Confusing. One other thing I forgot to mention but I am not sure if it is really a prob When I stop after a 20-30 min drive it feels like it is missing intermitently at an idle. Doesnt do it on shorter/longer trips.

Thanks

Hadley

 

[Steve Campbell]

You might try running.....

a fuel conditioner at 3x to 4x the normal rate for a couple of tanks.



Have the valves ever been adjusted? Hopefully the collective wisdom on this board will help you come up with a solution. A call to Piers Harry could be worthwhile.

 

[rspinks]

TTT-what happened with this situation Hensign?

 

[hensign]

I have not had a chance to check it out maybe tonight(been too busy welding the DC bed back together) 175k of no tailgate has not been kind. I have started playing around a bit, I read through lots of threads regarding low power conditions related to driving it like an old man(me) so I started pushing it harder. It will usually give a power drop as the RPM's pass 2300 or so then take off again with a puff of blue. NO change in throttle position just foot to floor the whole way. Has anyone replaced the MAP sensor?

Hadley

 

[Snow man]

It sounds like a turbo seal is starting to go bad,when it sits it loads up with oil,and it burns the oil when you rev it up,this happened to one of the big LN8000 my friend runs,its smokey until you clear it out running it hard for a few minutes. If you oull off the turbo clamp under the compressor housing you should be able to see oil running down the intercooler piping if its leaking. You want to fix this before it gets bad,if the seal lets go,the engine can run away on the motor oil,as in Ka boom from to much RPM.