Diagnosis And Testing: Turbocharger-SRT-4
WARNING: This page is about a different car, the 2007 Chrysler PT Cruiser. However, it is still accessible from the selected car via links, so may be relevant.
During normal operation the SRT - 4 turbocharger will emit a very high frequency whistle at full boost 68.9 - 103.4 kPa (10 - 15 psi) during WOT acceleration.
During throttle tip-out, the surge valve will emit a light air "woosh" noise. If there is excessive NVH or other air leak/turbocharger noises, the intercooler plumbing or turbocharger control system may be compromised.
TO identify the source of the concern, check for Diagnostic Trouble Codes (DTCs) stored in PCM memory. If any DTCs are present, refer to the appropriate Engine ELECTRICAL DIAGNOSTICS article.
If there are no DTCs stored, use the following chart.
| CONDITION | POSSIBLE CAUSES | CORRECTION |
|---|---|---|
| UNDERBOOST - 20.6 - 27.5 kPa and turbocharger lag at WOT with some air leak noise OVERBOOST - 103.4 kPa (10 psi) or more even at part throttle (could be as high as 137.8 kPa (20 psi) or more). A "Fluttering" noise can be heard during overboost. CAUTION: Engine damage can result from prolonged Overboost. |
Waste Gate control hose plumbing compromised/disconnected | Refer to. See INSTALLATION . |
| UNDERBOOST - 27.5 - 62 kPa (4 - 9 psi) @ WOT with "horse laugh" on throttle tip-out. | Surge valve control hose plumbing compromised. | Repair plumbing. See INSTALLATION . |
| NORMAL BOOST - but turbocharger lag and "horse laugh" noise on throttle tip-out. | Surge valve scroll and vacuum feeds reversed | Reverse vacuum lines. See INSTALLATION . |
| UNDERBOOST - 0-20.6 kPa (0-3 psi) a WOT with loud air leak noise outside vehicle. Turbocharger may emit a "howling" noise. | Intercooler plumbing hose disconnected | Inspect plumbing and install. See INSTALLATION . |
| Very rough idle | TIP/MAP sensor hoses connected improperly or TIP disconnected | Inspect hoses. See INSTALLATION . |