LBZ 63mm Fleece Cheetah Issues

[rtx447]

Swapped a brand new 63mm cheetah turboh from fleece into my truck and have been getting p0299 underboost codes since, it is much more lag and black smoke then the stock turbo unit. Bumped VPS MAX and low alt table for now (I'm at 1k feet above sea level). Still just barely getting it to hit desired boost levels and very slow to spool from idle. Table is up to 90 on the bottom end for desired VP so will not have much room when using the truck to haul trailers in the mountains.

Whats been done to the truck:
headgaskets
heads rebuilt
ARP Head studs
EGR not leaking
PPE high flow up pipes
lmm driverside manifold
new donaldson filter
swapped MAF with a known good one
swapped MAP with a known good one
Swapped VPS with known good one
IAT and ECT sensors reading accurate
barometric pressure sensor in ECU reading accurate
pressurized post compressor to 30 psi and no boost leaks found
pressurized turbine drive side, slight bubbling found on passenger side manifold to up pipe connection (cannot hear this while driving the truck)
measured pre CAC pressure VS post and see about 1 psi delta at low load and 4 psi delta at high load (pressure loss good with the change in air temp accross the CAC)

Anyone else running a turbo similiar to this size and running into the same issue? or is this possibly a bad turbo from fleece (possible wrong clocking of the VPS wheel to the actual vanes)?

I have been in contact with fleece and they basicly have been zero help saying there turbo does not set underboost codes, and suggested that all trucks are different and do not know if it needs a tune or will run ok on the stock cal. GM sells all the LBZs with the same calibration so that kinda goes against what fleece is saying when they say it may or may not need a tune to work good.

Any help or suggestions appreciated. Thanks

[TAG DIESEL]

Swapped a brand new 63mm cheetah turboh from fleece into my truck and have been getting p0299 underboost codes since, it is much more lag and black smoke then the stock turbo unit. Bumped VPS MAX and low alt table for now (I'm at 1k feet above sea level). Still just barely getting it to hit desired boost levels and very slow to spool from idle. Table is up to 90 on the bottom end for desired VP so will not have much room when using the truck to haul trailers in the mountains.

Whats been done to the truck:
headgaskets
heads rebuilt
ARP Head studs
EGR not leaking
PPE high flow up pipes
lmm driverside manifold
new donaldson filter
swapped MAF with a known good one
swapped MAP with a known good one
Swapped VPS with known good one
IAT and ECT sensors reading accurate
barometric pressure sensor in ECU reading accurate
pressurized post compressor to 30 psi and no boost leaks found
pressurized turbine drive side, slight bubbling found on passenger side manifold to up pipe connection (cannot hear this while driving the truck)
measured pre CAC pressure VS post and see about 1 psi delta at low load and 4 psi delta at high load (pressure loss good with the change in air temp accross the CAC)

Anyone else running a turbo similiar to this size and running into the same issue? or is this possibly a bad turbo from fleece (possible wrong clocking of the VPS wheel to the actual vanes)?

I have been in contact with fleece and they basicly have been zero help saying there turbo does not set underboost codes, and suggested that all trucks are different and do not know if it needs a tune or will run ok on the stock cal. GM sells all the LBZs with the same calibration so that kinda goes against what fleece is saying when they say it may or may not need a tune to work good.

Any help or suggestions appreciated. Thanks

If you indeed do not have any boost leaks or exhaust leaks at the manifolds or uppipe I would pull your VPS out and push it in and out by hand while watching live data to see if the VPS % moves in conjunction with the plunger. Let me know what it does

[rtx447]

I have moved it in and out watching scanner and it moves smoothly from 0 to 100%. Also measured and got correct voltage on the sensor supply and the ground circuit tested out good. When driving actual VP follows very closely to desired VP. Fleece did send me a new VPS as the first one set a VPS not learned DTC and got into a vane sweep cycling trying to learn, the new sensor they sent solved that.

[TheMechanic]

KOEO is your boost and baro withing 3 kpa?
If it is Remove the boost sensor from the intake manifold Inspect for the following conditions:
A plugged sensor port
A damaged or leaking seal
If that is OK
Connect the electrical connector to the boost sensor.
Connect a Mityvac vacuum pump to the sensor port.
Turn ON the ignition, with the engine OFF.
Observe the Boost Pressure Sensor parameter with a scan tool.
Slowly apply vacuum with the Miyvac to the sensor until 10 inches Hg is reached.
Does the Boost Pressure Sensor parameter decrease?
Unplug it vac and see if it goes back to the original value on the first step when we compared the baro to the boost sensor.

Connect a jumper wire between the 5-volt reference circuit and the signal circuit of the boost pressure sensor at the connector.
Observe the Boost Pressure Sensor parameter with the scan tool. Should read 254 kPa (36 psi)
If it doesn't make sure you didn't pinch/cut a wire. Otherwise it is likely you have a bad ECM. I say unlikely because it happened "after" the turbo not on it's own.
Yes it could be a very slow spooling turbo. This would definitely explain the smoke. I still do a lot of work on old 2 stroke Detroit Diesels and I have always known from guys even before my time that smoke is not enough air, Not to much fuel.

[TAG DIESEL]

Fuel rail psi good ? I'd have a hard time deeming a bad ecm just because of boost

[rtx447]

KOEO is your boost and baro withing 3 kpa?
If it is Remove the boost sensor from the intake manifold Inspect for the following conditions:
A plugged sensor port
A damaged or leaking seal
If that is OK
Connect the electrical connector to the boost sensor.
Connect a Mityvac vacuum pump to the sensor port.
Turn ON the ignition, with the engine OFF.
Observe the Boost Pressure Sensor parameter with a scan tool.
Slowly apply vacuum with the Miyvac to the sensor until 10 inches Hg is reached.
Does the Boost Pressure Sensor parameter decrease?
Unplug it vac and see if it goes back to the original value on the first step when we compared the baro to the boost sensor.

Connect a jumper wire between the 5-volt reference circuit and the signal circuit of the boost pressure sensor at the connector.
Observe the Boost Pressure Sensor parameter with the scan tool. Should read 254 kPa (36 psi)
If it doesn't make sure you didn't pinch/cut a wire. Otherwise it is likely you have a bad ECM. I say unlikely because it happened "after" the turbo not on it's own.
Yes it could be a very slow spooling turbo. This would definitely explain the smoke. I still do a lot of work on old 2 stroke Detroit Diesels and I have always known from guys even before my time that smoke is not enough air, Not to much fuel.

I've tested the MAP sensor with regulated shop air and it shows the same PSI in my boost channel in scanner (Map-Baro). Also verified again during a boost leak check in the same manner, my mechanical gauge and scanner math channel for boost read the same.

Everyone says the cheetah 63mm turbo spools nice, but maybe they have alot more done in there tune? I have pulled timing, and have bumped desired VP to 90% just off idle.

[rtx447]

Fuel rail psi good ? I'd have a hard time deeming a bad ecm just because of boost

I haven't paid too much attention to this but have it recorded in scanner and desired and actual follow very quickly. Max at WOT is getting to around 26k psi, Could it still be a fuel pressure issue if theres alot of black smoke during a WOT stab, the smoke cleans up once RPM comes up.

[TAG DIESEL]

No probably not rail , just wanted to see where it was at. Who tuned it ? Can you post the tune that's on the truck so we can look through it.

[TAG DIESEL]

Also have you verified that your egr isn't stuck or sticking open ? Post the tune when you get a chance and I'll comb through it

[rtx447]

Also have you verified that your egr isn't stuck or sticking open ? Post the tune when you get a chance and I'll comb through it

Yes LB7 up pipe and no leaks on charge pipe to Y bridge.

Heres the tune, I dropped the 10/10 tune in (fuel and air) to see if that made any difference, I used the timing calc excel tools also to make the SOI right now 50%/50% BTDC. Also note the desired vane position is dropped low to get the nice rumble at idle, I have also tried with it up at 90% and its still not any better at building initial boost.

[TAG DIESEL]

10/4 brotha. Lemme check it out

[TAG DIESEL]

still looking over your tune. Nothing at first glance jumps out at me as anything outrageous. Is the turbine housing on your charger clamped all the way ? You arent leaking through the charger?

[TAG DIESEL]

Return all vane position tables back to stock and fix that manifold leak. Do you have access to a scan tool to manually do a vane pos learn? I know you said the VANE POS was following desired very closely, but I would still return vanes to stock position in your tune, fix that exhaust leak and do a manual learn. All it takes is 39kpa or 5.6 psi difference over 10 seconds to so set this code.

[rtx447]

Return all vane position tables back to stock and fix that manifold leak. Do you have access to a scan tool to manually do a vane pos learn? I know you said the VANE POS was following desired very closely, but I would still return vanes to stock position in your tune, fix that exhaust leak and do a manual learn. All it takes is 39kpa or 5.6 psi difference over 10 seconds to so set this code.

I need to get the truck into my shape and recheck for manifold leaks, but the new ppe high flow up pipes should have solved any small leaks. I had run the stock tune after installing those with the vane tables all stock and the issue persisted and set a p0299. After I bumped the vane tables up I no longer get the p0299 code and boost wasn't as far off.

[TheMechanic]

Fuel rail psi good ? I'd have a hard time deeming a bad ecm just because of boost

I agree. That is why I said it was unlikely, but the SI diagnostic does give this as a possibility.

[TAG DIESEL]

I need to get the truck into my shape and recheck for manifold leaks, but the new ppe high flow up pipes should have solved any small leaks. I had run the stock tune after installing those with the vane tables all stock and the issue persisted and set a p0299. After I bumped the vane tables up I no longer get the p0299 code and boost wasn't as far off.

Do you have access to a scan tool or one with bidirectional controls? Do a vane relearn. Anytime you replace a turbo , VPS , MAP , MAF, VCS , you must do a relearn. This way you know you have covered your basis from step 1 then we can move to step 50

[rtx447]

Do you have access to a scan tool or one with bidirectional controls? Do a vane relearn. Anytime you replace a turbo , VPS , MAP , MAF, VCS , you must do a relearn. This way you know you have covered your basis from step 1 then we can move to step 50

I do not, I thought about trying a shop or the gm dealer in town with a tech 2 to see if they can do this, but I'm not sure that's any different then the VPS relearn done after a hot restart. The truck performs this every time its run and the coolant temp gets over 160f. I can log the 2 channels for vane position learned and vane position learned this key cycle they both are showing yes after this temp is achieved and I hear the vane sweep. Would be great if all it needs is the actual commanded turbo relearn to get nice quick stock like spool back.

[TAG DIESEL]

I do not, I thought about trying a shop or the gm dealer in town with a tech 2 to see if they can do this, but I'm not sure that's any different then the VPS relearn done after a hot restart. The truck performs this every time its run and the coolant temp gets over 160f. I can log the 2 channels for vane position learned and vane position learned this key cycle they both are showing yes after this temp is achieved and I hear the vane sweep. Would be great if all it needs is the actual commanded turbo relearn to get nice quick stock like spool back.

So for the test to be done automatically at idle the truck has to be
-at idle
- ac off
- atleast 104 degrees ect
- park or neutral

Now, sometimes , and I use sometimes very loosely with these trucks, you will get a p003a or a p2563. But I wouldn't count on it lol. Best to always manually do it.

[rtx447]

So for the test to be done automatically at idle the truck has to be
-at idle
- ac off
- atleast 104 degrees ect
- park or neutral

Now, sometimes , and I use sometimes very loosely with these trucks, you will get a p003a or a p2563. But I wouldn't count on it lol. Best to always manually do it.

So if the channels Vane position learned and vane position learned this key cycle are showing yes in HPtuners Scanner, that means that a "turbo relearn" has been performed? And a commanded learn from a device like a tech 2 would not do anything different?

[TAG DIESEL]

So if the channels Vane position learned and vane position learned this key cycle are showing yes in HPtuners Scanner, that means that a "turbo relearn" has been performed? And a commanded learn from a device like a tech 2 would not do anything different?

Technically speaking, yes. The vanes should sweep 2 times 0-100 . I've had best luck out of manual relearns. Also is your sensor a name brand one or a cheapy?