Intermittent Turbo

[kenbert]

Took a trip to PA this weekend, 4 hour drive. After 2.5 hrs when climbing , the turbo boost started to kick out. With the pedal to the floor the boost would go to 12, down to 5 then up to 12 then down to 5. Kept doing this through entire climb, was normal on level grade.

Pulled into rest area for a while and finished trip with no problems.
Coming home after 4 hrs driving, started the same problem. This time even did it on level grade. Boost would not come on till shifted into 3rd gear, and did the same thing. Boost would not hold, kept falling off.

I am hoping someone here has had a similar problem and give some tips on what to look for. Thanks in advance.

[CA_Traveler]

BTW Wire the exhaust brake open for a test.

[CA_Traveler]

Sounds like a turbo issue. Recently had a partially blown gasket between the manifold and turbo, boost was lower and varied on grade, fine when level. Exhaust brake was also reduced. Check for exhaust soot especially where you can't easily see.

[nevadanick]

Then its not turbo issue. If it ws it would be smoking becuse of overfueling.

[kenbert]

nevadanick wrote:
Does it blow black smoke when the boost shows low ?

No Black Smoke.

[nevadanick]

Does it blow black smoke when the boost shows low ?

[kenbert]

Bucky1320 wrote:
So how has this turned out?

Haven't had time to check, but will change fuel filters, re lube Pac Brake and see what happens.

[Bucky1320]

So how has this turned out?

[mnm_2]

We had the same problem on 8.3 Cummins turned out to be turbo shaft bearings going bad it would allow shaft to bind intermittently and loose boost at upper rpm

[Ivylog]

An indication of not getting enough fuel, change your fuel filters.

[kenbert]

wolfe10 wrote:
A 1995 B will be mechanical, not electronic, not variable vane turbo.

If turbo was loose on exhaust manifold, it could be rocking between tight and loose enough to let exhaust escape without turning the turbo. Unlikely, but worth a quick look for black soot. If a boot loose on intake side of intake side, no symptom until you get a "dusted" engine. No restriction on air (or on dirt!). If boot loose on CAC side of turbo on the intake side, you would loose boost.

All hose connections look tight,I am going to look at the Pac Brake again. Thanks for your help.

[wolfe10]

A 1995 B will be mechanical, not electronic, not variable vane turbo.

If turbo was loose on exhaust manifold, it could be rocking between tight and loose enough to let exhaust escape without turning the turbo. Unlikely, but worth a quick look for black soot. If a boot loose on intake side of intake side, no symptom until you get a "dusted" engine. No restriction on air (or on dirt!). If boot loose on CAC side of turbo on the intake side, you would loose boost.

[Passin_Thru]

Does it have variable vanes. If so they are probably stuck. You can go to Cummins or Dodge forums and search ways to free them up.

[Executive45]

Brett, if the turbo was loose and sucking air wouldn't the check engine light come on..:h. Or, because it's intermittent there's not enough "issue" for it to be triggered..?:h/ thanks... Dennis

[kenbert]

You can see the engine in my signature, 5.9 Cummins. Checked all connections and hoses, all looks good. Why would it clear up after a rest. Did have some issues with Pac Brake sticking, relubed and good. when i did have the problem with Pac Brake it did not affect the turbo.
Also not a gauge problem.