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Author Topic: No Turbo Boost  (Read 2150 times)
niles500
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« on: July 01, 2010, 03:14:59 PM »

Just as I was climbing Mclure pass the temp started getting up there (no light or shutdown but I knew I had a hard pull coming) - near the summit I found what I thought was a more level pullout - but It must have been still about a 6% grade - I let it sit till it came down to 180 - As I tried to move out - I floored it and the tach stayed about the high idle mark, the turbo would not spool and I could not move at all - I had to back it down to a flatter spot to get moving - Any ideas?

Turbo has been putting out 25+ lbs.
ddecII 8v92ta atec 755
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Sean
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« Reply #1 on: July 01, 2010, 03:57:40 PM »

Niles,

If the turbo seized, you'd be getting tons of smoke.  I would check first and foremost for a fuel restriction -- plugged filter or screen, etc..  No fuel = no exhaust pressure = no turbo boost.  Secondly I would check the air induction system for the same reason.

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http://OurOdyssey.BlogSpot.com
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lostagain
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« Reply #2 on: July 01, 2010, 04:20:30 PM »

Your turbo did not spool up because there is no rpm, (you said it only reached high idle revs). So nothing to spin the turbo: exhaust gases velocity or heat from an engine that would be under load. I would, like Sean, first look for a lack of fuel. Maybe the linkages from the accel. pedal are buggered somehow, have someone press the pedal up front while you watch the governor for movement,  or your fuel filters are plugged. Once you find it, it'll be something simple.

JC
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JC
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« Reply #3 on: July 01, 2010, 04:27:11 PM »

Did you blow an exhaust manifold gasket or did you break one of the exhaust connector pipes going to the turbo?  They tend to break at the flange at the end near the clamp.  I would think you would hear it though, and it should rev, but give you plenty of black smoke.  Something to check once you rule out fuel/air....

Steve
 
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luvrbus
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« Reply #4 on: July 01, 2010, 04:42:40 PM »

Check the hose and the wiring going to the TBS (turbo boost sensor) 


good luck
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« Reply #5 on: July 01, 2010, 05:15:37 PM »

Niles, if you can tell us if you have any oil pouring out of your turbine housing to "Y" pipe.
Do you have the tools to remove the "cold air" air cleaner side of the turbo.

Folks if you have ruled out your fueling, and all your exhaust clamps and intake connections for a breach.   I recommend pulling the intake inlet piping to the cold side inlet of the turbocharger from your air filter.   If you have oil in the compressor housing or oil in the inlet ducting this will give you a indication of a turbine side seal failure.   This can be caused from normal wear to the sealing rings or bearing failure> excessive shaft motion will unseat the turbine seal> exhaust gases will pressurize the bearing housing oil supply and pump the oil into the compressor section.

A zero boost situation will usually point to either compressor wheel FOD or turbine wheel damage.   Years ago there was a forum member who had a turbine wheel break and he used a bolt to plug the shaft/bearing bore to limp home.
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Ace
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« Reply #6 on: July 02, 2010, 03:42:56 AM »

Niles, if you havent got going yet, you can check the temps of each head. Make sure both have some heat. If one is cold, check the 15 amp fuses that make the injectors work. Mine are located just laying on top of the start batteries.
Mine did exactly what your describing. No smoke, no acceleration except to about 1100 rpm. Wouldnt barely move.
Pete papas directed me thru the voltage checks and found one of the 2 fuses was blown even though by looking at it, it appeared to be good.
You can call me if you need further explanation.

Ace
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Ace Rossi
Lakeland, Fl. 33810
Prevost H3-40
niles500
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« Reply #7 on: July 02, 2010, 11:32:19 AM »

Sean - the turbo is definitely not siezed as I have been getting 25+ lbs off it - Just serviced before I left with new air and fuel filters and she runs just fine otherwise

Lost - I have fly by wire accel pedal - so when I say I stood on it basically I was asking the ddec for full fuel - unfortunately I am alone right now so am unable to have someone work the pedal for me -

steve - I will double check the flanges and connections but there have been no sounds to indicate any problem there

Luvr - will do - I'm thinking something along those lines - or the DDEC is just having a problem dealing with the altitude?

Zero - If a seal, bearing or wheel was damaged I would think the problem would be continuous - I'm still getting 25+ lbs of boost and absolutely no indication of any turbo problems otherwise

Ace - sounds exactly like my problem - but I can't figure why it only happened in this situation - She wasn't blowing any more smoke than normal before the turbo spools up - If Luvr is right maybe the sensor was telling the ddec not to add more fuel - just a guess - but I'll check the fuses

Thanks for the replies - BTW 65* and sunny in Crested Butte right now
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Ace
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« Reply #8 on: July 02, 2010, 01:06:20 PM »

Niles, mine didn't smoke at all. I think your fuse is blown.  Smiley

You could have had a voltage spike to blow it. Mine blew in the driveway, and no smoke at all.
« Last Edit: July 02, 2010, 01:52:20 PM by Ace » Logged

Ace Rossi
Lakeland, Fl. 33810
Prevost H3-40
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« Reply #9 on: July 02, 2010, 08:41:13 PM »

If you have a DDEC II, there are two plugs on the "box" .  Each feeds the injectors on one side of the engine.  Your problem sounds like one I had in FL several years ago.  It would run maybe twenty five like the fuel filter was stopped up, but the plug to three injectors was loose.

Art
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Art & Cheryll Gill
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« Reply #10 on: July 03, 2010, 02:51:24 PM »

Can you check for codes?  I had a problem that sounds like yours and it was the TPS.  I don't think there was turbo boost, you need power to make boost.
Jack
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« Reply #11 on: July 04, 2010, 08:17:01 PM »

I'm with Clifford or Ace on this one! (by the way Ace if I remember correct, it was suggested to you from a certain someone from TN that one of those fuses might be the problem, before Pete walked you through the voltage checks Wink ! and of course since the fuses looked good you didn't believe them Grin)
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Busted Knuckle aka Bryce Gaston
KY Lakeside Travel's Busted Knuckle Garage
Huntingdon, TN 12 minutes N of I-40 @ exit 108
www.kylakesidetravel.net

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