Turbocharger: Testing and Inspection

Two pressure gauges attached at two different points are required for this test.
1. Obtain two 6828 fuel pressure test gauges (equivalent gauges are OK). Gauge Consistency Test: Connect the gauges together to a common pressure source and verify pressure consistency of both gauges. Do this consistency test at approximately 206 kPa (30 psi). If pressures are different, they can still be used for test. Note and record differences in pressures before testing. Make adjustments as necessary.

Fig. 17 Boost Pressure Test At Intake Manifold:

2. Remove 3/4" pipe plug fitting at rear of intake manifold (Fig. 17). Temporarily replace this fitting with fitting reducer to adapt to pressure gauge.

Note: This pipe plug is located to front of MAP sensor. Do not remove plug to rear of MAP sensor. This is a COOLANT passage plug.

Fig. 18 Boost Pressure Test At Turbocharger:

3. Loosen hose clamp and disconnect rubber signal line (Fig. 18) from 1/8" brass fitting at front of turbocharger.
4. Remove 1/8" brass fitting (Fig. 18) from turbocharger. Temporarily replace this fitting with a 1/8" "T" fitting to adapt to pressure gauge.
5. Reattach signal line to temporary "T".
6. Attach first pressure gauge to intake manifold fitting.
7. Attach second pressure gauge to "T" fitting at turbocharger.

Engine must be at rated rpm and full load for the test.

If gauge pressure differential is greater than 3 psi (6 in.Hg), check intercooler and associated piping for restrictions, plugging or damage.

Maximum pressure at intake manifold (rated rpm and load) is 36 - 37 in.Hg ± 3 in.Hg (17.7 - 18.2 psi ± 1.5 psi).

Wastegate should open at no higher than 38.7 in.Hg (19 psi) at wide open throttle, full load. If wastegate is out of adjustment, a DTC may have been set. Refer to Wastegate Adjustment in Engines for adjustment procedures.