Power stroke 7.3l turbo

Technician Turbocharger Guide for the Powerstroke Engine
Floating bearings Wastegate actuator

Turbine wheel

Compressor wheel Shaft seals

EBP regulator

Turbochargers are precision pieces of machinery which operate at high speed, using heat of expanding exhaust gasses to “boost” intake manifold pressure. Turbochargers increase performance and decrease exhaust smoke through improving anengine’s volumetric efficiency. Turbochargers are often replaced by mistake for the following reasons:

. Low power
Most turbocharger failures result from:

.Oil leaks

.Noise . Modifications (increasing turbocharger speed)

. Poor maintenance (air/oil)

Turbochargers are relatively simple devices. This simplicity also should apply to diagnosing them.

LOW POWER
In cases where theengine performance is in question, as evidenced by a boost reading below the specification for the vehicle, the following is true: If neither of the wheels rub, the blades are not damaged, and the shaft and wheels spin freely, there is no reason to replace the turbocharger. In cases where performance is low and no fault lies with the turbocharger, the low performance will be due to low fueldelivery, a restriction or leak in the intake or exhaust systems, or worn engine components (low compression, check crankcase pressure). The condition of the turbocharger relative to performance can be visually identified.

WARNING: ALL VISUAL INSPECTIONS OF THE TURBOCHARGER MUST BE MADE WITH THE ENGINE OFF AND THE TURBOCHARGER NOT SPINNING. TURBOCHARGER COMPONENTS MAY BE EXTREMELY HOT. BOTH WHEELSARE VERY SHARP AND MAY SPIN AT HIGH SPEED. USE CAUTION
First, inspect the compressor wheel for damage.

1
Good Turbocharger: Compressor blades are clean and straight. There are no large gaps between the compressor housing and the compressor wheel. No visible damage to blades. This turbocharger should not be replaced.

2
Foreign Object Damage: This compressor wheel shows signs of some outsideobject (nuts, bolts, screws, etc.) coming in contact with the blades while they were spinning.

3
Dirt Ingestion: Also called dusting. The compressor wheel blades show signs of erosion from dirt entering the intake air system. The blades are rounded off and there is dirt accumulation in the compressor inlet.

Note: If damage to the compressor wheel is found, the intake air system should becleaned and inspected for foreign objects, poor maintenance, broken components, or improper installation. 1

LOW POWER Cont’d
Does any evidence of wheel to housing contact exist, such as witness marks on the housing or rolled edges on the wheel? Before testing a service part replacement, pour some clean oil into the lube oil passages. NOTE: Do not perform this inspection on a dry serviceturbocharger. It may exhibit wheel rub until it is lubed. The shaft bearings are floating bearings, requiring lubricating oil to provide proper running clearance.

Warning: Visually assure that wheel is not turning before inserting your hand into the compressor. Do not place fingers in turbo with engine running.

4
Spin the compressor wheel to make sure that it spins freely. The wheel should notcontact the housing. If the customer concern is low power (low boost) and inspecting the turbocharger reveals:

. no wheel damage . no wheel rub . no binding when turning the wheel
DO NOT REPLACE THE TURBOCHARGER
Refer to engine performance diagnostics in the PCED.

2

NORMAL OIL CARRYOVER
Another condition that often leads to replacement of the turbocharger is the presence of oil at thehose connections of the charge-air-cooling system. Oil vapors from the crankcase are vented into the turbocharger compressor from the crankcase breather on the left valve cover. This venting will over time lead to the presence of oil in the pipes between the turbocharger and the charge air cooler. A leak or seepage that is visible at the hose connections is not a sign indicating the turbocharger...