Bad turbo?

[Krcrandall]

This is my first issue I haven't found the answers by searching!

I have a 71 m35a2 with a turbocharged multi fuel continental. I use it for marketing - and have thus far worked on cosmetics more than mechanics. I'm just getting the time to do the important stuff. It is running a 4" lift with 16r 20's and half Rhino Lined.

I just installed a pyro and boost gauge, and .. No boost! The only time the gauge even moves is full speed full throttle - around 4lbs. It does not rise with the throttle.

As for egt's it will not go above 800ish taking off, but if your not careful cruising around in 4th it will get to 1200..probably partially being underpowered with the huge tires..but it seems like it has become less and less powerful and harder to get going full speed, especially keeping reasonable egt's.

Any other possible culprits besides bad turbo? I am going to check tomorrow which turbo it is and have been told to test fuel pressure. I would love to turn up the fuel, but not if I can already hit 1200deg!

 

[acesneights1]

It is a non wastegated turbo so the only thing that adds boost is fuel. That said I am not sure on the specs of this motor.
I don't think they run a ton of boost. Is the FDC bypassed and also is the air fliter nice and clean. Also check the turbo discharge hose.
You can pull the intake hose off and feel the shaft for play or tightness on the bearings.

 

[gimpyrobb]

Also make sure your tubing from the air filter to the intake is good and tight. Might also check for exhaust leaks at the manifold. I know more than one turbo has been swapped out due to loose bolts.

Might even wash your air filter.

 

[Krcrandall]

The fdc is not bypassed and the air filter is very clean. Will check play tomorrow and report back thanks.

Will check thanks gimpy.

 

[Jeepsinker]

Change your fuel filters too if you haven't recently. All three. And crack the bleed screw on top of the two fuel filters on the driver side and see if fuel flows out with the truck off, but the accessory power switch on. The in tank pump needs to work for good performance
And you NEED to bypass that Fdc.

 

[Krcrandall]

Ok so -

in tank pump works good
air filter tubing is all tight
exhaust manifold is all tight
the turbo seems tight, all the fins are still there
fuel filters are also fresh

Thinking the next step is to check oil is getting to the turbo..and if so try rebuilding it.. Any other thoughts?

 

[Jeepsinker]

Yeah, turn the fuel up. More fuel will net you more boost.

 

[steelandcanvas]

Yeah, turn the fuel up. More fuel will net you more boost.

Not a good idea if he's already running up to 1200*, is it?

 

[Jeepsinker]

I forgot about that.

 

[steelandcanvas]

I forgot about that.

 

[Flyingvan911]

My deuce has an LDS and c turbo. It will get up to 13 psi boost on the highway at almost 1,200 degrees egt.

 

[rustystud]

Remember aluminum starts to melt around 1200 degrees. Pistons are made of aluminum.

 

[Jeepsinker]

Maybe the injectors are popping at too low pressure.

 

[Krcrandall]

Agreed. 1200 degrees is the highest I want to be. I should run some injector cleaner through, I haven't yet. Can't imagine they would be the problem here though?

 

[Jeepsinker]

Looks like it is either going to be your injectors or turbo maybe. Only way to know is to pull the turbo off and check it out. Well, you don't have to pull it off. Just pull the intake pipe off of it and check for play and damaged vanes on the turbine wheel.

 

[Krcrandall]

Did that. Seems tight.

 

[welldigger]

You may need to have the injectors serviced. Dirty injectors won't atomize the fuel correctly and will cause incomplete combustion. This could lead to high egt's and low turbo boost.

 

[m-35tom]

i don't see where you say how much smoke it makes and what color it is. too much fuel and not enough air will give high egt and black smoke. bypassing the fdc is a good idea, but you have to be real careful and probably turn the fuel down when done. usually that will result in higher fuel rate, that is why many think it gives more power, they are just adding fuel. sometimes way too much.
the in tank pump, on a truck with a good fuel system, is completely unnessacery. the booster pump is the main fuel supply pump, making sure the HH plunger gets a full load of fuel. if you constantly need to run the tank pump to bleed the system, you have a leak. air will leak in before fuel will leak out.

 

[Krcrandall]

Smoke is plentiful but not black. More a haze of white/gray.

I don't have access to the truck for a few weeks but will have injectors serviced and look for a fuel leak.

Thanks for the input.

 

[hklvette]

Have you checked to make sure that the pump is timed to the engine correctly? Late timing can cause high EGTs and low power.