Service slants

Motor,  Feb 2002  by Marcy, Thomas

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GM

Lift point advisory. Camaros and Firebirds have a wrap-under fiberglass fender as well as a plastic ground-effects extension and a fender tab that's bolted to the pinch weld seam. According to the Automotive Lift Institute (ALI), when picking up one of these vehicles, the pinch weld seam should not be engaged by the lift adapter, to prevent damage to the aforementioned parts.

ALI notes that, for several years, the publication "Vehicle Lifting Point Quick Reference Guide for Cars and Light Trucks" has shown the pinch weld seams as the lift points for these models. An alternate for lift adapter engagement can be the stub frame areas (see illustration). According to the Institute, using these revised lift points can help avoid damage to the fender parts.

Chrysler

Knocking from rear strut area. Some 1997-99 Avenger, Sebring and Talon models have been known to produce a light knocking noise from the rear suspension when the vehicle is driven on bumpy roads. If a customer comes in with this complaint, ask when he notices the noise in relation to speed, turns and road conditions. Take a test drive to try to duplicate the condition. If no suspension defects are found and you determine that the noise is coming from the rear strut tower area, remove the strut assembly from the vehicle.

Next, remove the upper bracket insulator by compressing the coil spring, then hold the piston rod and remove the self-locking nut. Inspect the upper seat bracket for raised areas on the circumference of the seat. If the bracket seat does not have raised pads, replace it with Part No. MR311114.

Now remove and discard the upper and lower insulator bushings and collar. Replace the upper bushing with Part No. MR235627, the lower bushing with Part No. MR235628 and the collar with Part No. MB87 1748. Next, reassemble the rear strut assembly by compressing the coil spring and installing it onto the strut. Make sure the lower edge of the spring fits into the spring seat properly and that the upper bracket mounting studs align with the lower mounting boss hole. Install the locking nut and tighten to 16 ft-lb. Do not use an impact wrench.

Next, reinstall the strut assembly and repeat the procedure to service the rear strut at the opposite side. Afterward, verify the repair by test-driving the vehicle under the same conditions to make sure the noise has been eliminated.

Ford Truck

Hesitation, MIL on, DTC stored. If a driver of a 1999 Econoline complains of hesitation and the feedback system has set the MIL accompanied by a DTC P0306, the condition often can be traced to the EGR system. According to Ford, carbon can build up in the EGR ports in the lower intake manifold, especially on vehicles with 50,000 miles or more on the odometer. To diagnose the problem, remove the vacuum hose to the EGR valve, cap off the hose, then increase the engine speed to determine if the condition abates. If it does, remove only the upper intake manifold and inspect the EGR ports in the lower manifold for carbon deposits. If contamination is evident, clean the ports using a pick and an appropriate solvent.

Hyundai

Erratic shifts. Hyundai advises us of certain problems that can result from faulty pulse generator signals in the automatic transmission of all its models except the Sonata. These include a delayed or erratic 1-2 shift (engine hot or cold), a harsh 1-2 shift (at an elevated speed), an erratic downshift during light acceleration, 3rd gear "fail-safe" and/or an illuminated MIL and bucking or hesitation. Any of these problems, the carmaker informs us, may be intermittent and difficult to duplicate.

To begin diagnosis, check for any DTCs that may have set. If you find DTC P0717 or P0722, signaling problems with a pulse generator, replace the offending part. The carmaker notes, however, that you should also check for engine and transaxle codes (P0732, P0733, P0734 and P1624). If none of these are found, disconnect the pulse generator connector and use a low-impedance meter to test between pins 1-2 and 3-4 of the generator. If the resistance is below 215 or above 275 ohms, replace the part.

If the resistance measurement is within the acceptable range, use a small needle nose pliers to gently twist the male pins in the pulse generator's main connector. Rotate the pliers about 100 clockwise to ensure good electrical contact. Next, clean the ends of the connector terminals with electrical contact cleaner, then reconnect the connector to the pulse generator. Remove the connector from the tranny mounting bracket. Leave the connector loose, so no tension exists in the wiring. Now verify proper pulse generator signaling.

Finally, drive the vehicle at a steady speed in 3rd gear with the Overdrive switch off, while an assistant monitors the PG-A and PG-B signals. Make sure the signals agree with the engine speed in 3rd gear. If they do, the pulse generators are functioning properly.

Infiniti

4x4 indicator on, wheels bind or drag. Some 1999 QX4 trucks may exhibit binding or dragging of the drivetrain in turns, even though the 4WD system isn't activated. Another symptom is that the 4WD lamp will flash three times and then stay on continuously each time the vehicle is started. A "Duty Solenoid Failure" DTC may also be stored in computer memory. The cause of this problem could be a broken 4WD solenoid ground wire.