Fig. 14: Camshaft and chain timing marks-3.2L (DOHC) engine
Fig. 15: Chain tensioner installed position-3.2L (DOHC) engine
Fig. 16: Apply sealant to the camshaft mounting brackets-3.2L (DOHC) engine
Isuzu has issued a recall notice for 1993-94 Troopers equipped with 3.2L DOHC engines. This is campaign number 94V-094, and involves faulty camshaft end plugs. The plugs may dislodge from the cylinder heads and can cause rapid oil loss. Remember this when ordering parts: a service kit is available for affected vehicles.
Relieve the fuel pressure:
Remove the fuel filler cap.
Remove the fuel pump relay from the underhood relay box.
Start the engine and let it run until it stalls. Then, crank the engine for an additional 30 seconds.
Turn the ignition switch to the OFF position.
Disconnect the negative battery cable. Install the fuel pump relay.
Remove the air cleaner assembly.
Remove the upper cooling fan shroud.
Remove the cooling fan assembly.
Disconnect the accelerator cable from the throttle body and remove it from the bracket.
Disconnect the canister vacuum hose from the vacuum pipe.
Disconnect the vacuum booster hose from the common chamber.
Disconnect the following connectors:
Canister vacuum switching valve (VSV)
Exhaust gas recirculation (VSV)
Intake air temperature sensor
Disconnect and label the spark plug wires.
Remove the ignition control module assembly with the spark plug wire attached.
Remove the four bolts to separate the throttle body from the common chamber.
Disconnect the vacuum hoses from the throttle body.
Disconnect the positive crankcase ventilation (PCV) hose from the common chamber.
Disconnect the fuel pressure control valve vacuum hose from the common chamber.
Disconnect the evaporative emission canister purge hose from the common chamber.
Remove the EGR valve assembly.
Remove the common chamber air duct.
Remove the common chamber from the intake manifold.
Disconnect the fuel feed and return hoses from the fuel rail assembly.
Remove the accessory drive belts.
Remove the power steering pump.
Remove the fan pulley assembly.
Remove the crankshaft pulley and damper.
Remove the oil cooler hoses and bracket.
Remove the timing belt cover.
Align the timing marks
Remove the timing belt auto tensioner (pusher). The pusher prevents air from entering the oil chamber. Its rod must always be facing upward.
Remove the timing belt.
Remove the cylinder head covers.
Remove the camshaft pulley.
Remove the camshaft front plate.
Remove the camshaft mounting bracket bolts.
Remove the camshaft chain tensioner bolts.
Remove the camshafts with the timing chain and tensioner attached.
Install a retainer on the chain tensioner to prevent the plunger from moving. Remove the retainer after installation.
Apply sealant to the cylinder head mounting surface of the front and rear camshaft mounting brackets.
Apply clean engine oil to the camshaft journals, lobes, and sprockets.
Install the camshaft assembly with the chain and tensioner. Take care not to install the wrong tensioner, the left and right tensioners are different and they are marked accordingly. Make sure the timing marks on the camshaft chain sprockets are aligned with the timing marks on the chain links. Torque the camshaft holder mounting bolts to 87 inch lbs. (10 Nm).
Install the chain tensioner. Torque the bolts to 14 ft. lbs. (19 Nm).
Install new camshaft seals and retaining plates onto the cylinder. Tighten the rear camshaft seal retaining plate 6mm bolts to 70 inch lbs. (8 Nm). Tighten the front camshaft seal retaining bolts to 65 inch lbs. (7 Nm).
Install the camshaft pulley. Hold the camshaft with an open ended wrench to prevent it from turning and torque the pulley bolts to 41 ft. lbs. (55 Nm) for 1992-94 vehicles, or 46 ft. lbs. (63 Nm) for 1995 vehicles.
Apply sealant to both sides of the front and rear camshaft mounting brackets and install the cylinder head cover(s). Torque the bolts to 69 inch lbs. (8 Nm). Don't overtorque the bolts, as the head covers may crack.
Install the timing belt.
Install the timing belt auto tensioner. Torque the mounting bolts to 14 ft. lbs. (19 Nm).
Install the timing belt cover.
Install the oil cooler hoses and bracket.
Install the crankshaft pulley assembly. Torque the center bolt to 123 ft. lbs. (167 Nm).
Install the fan pulley assembly. Torque the mounting bolts to 16 ft. lbs. (22 Nm).
Install the power steering pump.
Install the accessory drive belts.
Connect the fuel hoses to the fuel rail assembly.
Install the common chamber. Torque the bolts and nuts to 17 ft. lbs. (24 Nm).
Install the common chamber air duct. Torque the nuts and bolts to 17 ft. lbs. (24 Nm).
Connect the ground cable.
Install the EGR valve assembly. Torque the mounting bolts on the valve side to 69 inch lbs. (8 Nm) and the bolts on the exhaust side to 21 ft. lbs. (28 Nm).
Connect the evaporative emission canister purge hose.
Connect the fuel pressure control valve vacuum hose.
Reconnect the fuel lines using new washers.
Connect the positive crankcase ventilation hose.
Install the throttle body assembly. Torque the mounting bolts to 14 ft. lbs. (19 Nm).
Connect the vacuum hoses to the throttle body.
Install the ignition control module and the spark plug wires.
Connect the MAP sensor; Canister Vacuum Switching Valve (VSV); Exhaust Gas Recirculation (EGR), the Intake air temperature sensor connectors; and ground cables.
Connect the vacuum booster hose.
Connect the air vacuum hose.
Connect the accelerator cable. Adjust the accelerator cable by pulling the cable housing while closing the throttle valve and tightening the adjusting nut and screw cap by hand temporarily. Now loosen the adjusting nut by three turns and then tightening the screw cap. Make sure the throttle valve reaches the screw stop when the throttle is closed.
Install the cooling fan assembly and the upper fan shroud.
Install the air cleaner assembly.
Connect the negative battery cable.
Start the engine and check for fuel leaks.
See Figures 17, 18 and 19
Fig. 17: Measuring camshaft lobe lift
Fig. 18: Measuring camshaft run-out
Fig. 19: Measuring camshaft straightness
Using solvent, degrease the camshaft and clean out all of the oil holes. Visually inspect the cam lobes and bearing journals for excessive wear. If a lobe is questionable, check all of the lobes as indicated. If a journal or lobe is worn, the camshaft MUST BE or replaced.
If a journal is worn, there is a good chance that the bearings or journals are worn and need replacement.
If the lobes and journals appear intact, place the front and rear journals in V-blocks and rest a dial indicator on the center journal. Rotate the camshaft to check the straightness. If deviation exceeds 0.001 in. (0.0254mm), replace the camshaft.
Check the camshaft lobes with a micrometer, by measuring the lobes from the nose to the base and again at 90° (see illustration). The lobe lift is determined by subtracting the second measurement from the first. If all of the exhaust and intake lobes are not identical, the camshaft must be reground or replace.
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