PRECISION AUTO REPAIR 870-425-1111

Vehicle

2004 Dodge Ram 1500 4.7L 4wd

Customer Concern

Surge when cold. No power over 2500rpm. Check engine light on at times.

Repair Procedure

Verified Customer Concern

Tech notes: Vehicle feels like it is hitting an engine revolution limiter

Check MIL Codes: P Camshaft/Crankshaft position sensor circuit intermittent

Test camshaft and crankshaft position sensor circuits: Passed

Test Camshaft and crankshaft position sensors by graphing on oscilloscope: Passed

Tech notes that stacking the pattern indicates that the camshaft position sensor to show 18deg retarted camshaft timing.

Inspect camshaft timing: Found failed timing chain and tensioner

Replace timing components and retest: Passed

Verify repair with a road test: Passed

Vehicle

1997 Chevy Express 1500 5.7L

Customer Concern

Idle Surge When Cold/High Idle When Engine is Warm. No Check Engine Light On.

Repair Procedure

Verified Customer Concern

Tech notes: Vehicle feels like it has a vacuum leak for the idle concern. A look at data shows that all of the 5volt reference signal engine sensors are 1volt above normal readings

Check MIL Codes: No trouble codes found

Test 5volt reference sensors for proper signal voltage: Passed (All sensors are reading correct voltage with a volt meter)

Test powertrain control module for a short in engine wiring harness by disconnecting all circuits individualy

Tech notes that isolating the fuel pump circuit corrects datastream voltages

Remove fuel tank and found burnt wiring in fuel tank causing 12v fuel pump circuit to backfeed voltage on the 5v fuel level sensor circuit into the pcm

Replaced fuel pump and wiring

Verify repair with a road test: Passed