Ignition Timing - Procedure Revision

87chrysler13

Models


1987 Caravan, Voyager & Ram Van


Subject


Service Manual Revision - Ignition Timing Procedure


Index


ELECTRICAL


Date

January 20, 1987

No..


08-01-87 (C2-08)
This bulletin is issued as a correction to the 1987 Front

Drive Van/Wagon Electrical and Engine Performance Service

Manual, Publication #81-370-7006. The attached pages 8D-16 and

17 have a revised procedure for checking the ignition timing on

2.2L equipped Caravan, Voyager, and Mini Ram Van vehicles.


The attached pages should be inserted into the service manual.


POLICY: Information only
To test coil to distributor cap high tension cable, remove distributor cap with the cable intact. Do not remove cable from the coil or cap. Connect the ohmmeter between center contact in the cap and the other end of the high tension cable. Resistance should be within tolerance shown in the resistance chart. If resistance is not, remove the cable at coil tower and check cable resistance. If resistance is still not within tolerance, replace the cable. Also check for a loose connection at the tower or for a faulty coil. Inspect coil tower for cracks, carbon tracking or oil leaks.

SPARK PLUGS

Resistor spark plugs are used in all engines and have resistance values of 7,500 to 15,000 ohms.

FIGURE 11 - NORMAL AND COLD FOULING:

Normal Conditions Normal conditions (Fig. 11 left). This plug has been running at the correct temperature in a "healthy" engine. The few deposits present will probably be light tan or gray in color with most regular grades of commercial gasoline. Electrode burning will not be in evidence; gap growth will average not more than about 0.025 mm (0.001 in.) 1600 km (1000 miles). Chances are the plug as pictured, could be cleaned, the gap electrodes filed, regapped and reinstalled with good results.

Cold Fouling Cold fouling or carbon deposits (Fig. 11 right). This dry black appearance is fuel carbon and can be due to over rich fuel-air mixture, possibly resulting from a faulty choke, clogged air cleaner, improper carburetor idle adjustment, or dirty carburetor. However, if only one or two plugs in a set are fouled like this it is a good idea to check for worn or improperly installed valve guide seals, or faulty ignition cables. This condition also results from prolonged operation at idle.

FIGURE 12 - WET FOULING AND OVERHEATING:

Wet Fouling Wet fouling (Fig. 12 left) tells you that the plug has drowned in excess oil. In an old engine, suspect worn rings or excessive cylinder wear. Remember that "break-in" fouling of new engines may occur before normal oil control is achieved. In new or recently overhauled jobs, such fouled plugs can be cleaned and reinstalled.

Overheating Overheating (Fig. 12 right) is indicated by a white or light gray insulator which appears "blistered". Electrode wear rate will be considerably in excess of 0.025 mm (0.001 in.)/1600 km (1000 miles). Over-advanced ignition timing detonation and cooling system stoppages can overheat the spark plug.

FIGURE 13 - OIL AND ASH INCRUSTED:

Oil or Ash Incrusted (Fig. 13) If one or more plugs are oil or oil ash incrusted, the engine should be evaluated for the true cause of oil entry into the combustion chamber.
Lead Deposits Lead deposits are the result of using leaded gasoline.

High Speed Miss When replacing spark plugs because of a high speed miss condition; wide open throttle operation must be avoided for approximately 80 km (50 miles) after installation of new plugs. This will allow deposit shifting in the combustion chamber to take place gradually and avoid plug destroying splash fouling shortly after the plug change.

Cleaning and Regapping Carefully clean the spark plugs in an abrasive type cleaner. Use a feeler gauge to check spark plug gap. Reset gaps to Specifications. Before setting spark plug gap, file center electrode flat, make adjustment by bending ground (side) electrode, never bend the center electrode. When installing spark plugs, first clean dirt and grit from spark plug seats, tighten to 27 N-m (20 ft.lbs.).

IDLE RPM TEST

Engine idle set RPM should be tested and recorded as it is when the vehicle Is first brought Into the shop for testing. This will assist in diagnosing complaints of engine stalling, creeping and hard shifting on vehicles equipped with automatic transmissions. See Group 14 Fuel System for idle set procedures.

FIGURE 1 - ADJUSTABLE TIMING LAMP:

IGNITION TIMING PROCEDURE

To obtain optimum engine performance, the distributor must be correctly positioned on the engine to give proper ignition timing.
Test procedures are as follows:
(1) Connect a suitable Power Timing Light (Fig. 1) to number one cylinder (refer to equipment manufacturer's instructions for correct connecting procedures). Do not puncture cables, boots or nipples with test probes. Always use proper adapters. Puncturing the spark plug cables with a probe will damage the cables. The probe can separate the conductor and cause high resistance. In addition breaking the rubber insulation may permit secondary current to arc to ground.

FIGURE 2 - COIL TERMINALS:

(2) Connect red lead of the test tachometer unit to the negative primary terminal of the coil and the black lead to a good ground (Fig. 2).
(3) Turn selector switch to the appropriate cylinder position.
(4) Start engine and run until operating temperature is obtained.
(5) With engine at normal operating temperature (off fast idle), momentarily open the throttle and release to make sure there is no bind in the linkage and that idle speed screw is against its stop.
(6A) Disconnect and plug the vacuum hose at the computer. (6B) Disconnect carburetor 6-way electrical connector, remove violet/purple wire and reconnect connector. This disables the electronic spark advance.
(7) Read engine rpm on 1000 rpm scale. If the engine rpm is at or below the curb idle specified on the label, proceed to the next step. If it is higher, turn the idle speed screw (on top of solenoid) until the specified curb idle rpm is reached.

Revised 1-20-87, TSB 08-01-87

FIGURE 1 - ADJUSTABLE TIMING LAMP:

FIGURE 3 - TIMING MARKS:

FIGURE 4 - DISTRIBUTOR HOLD DOWN 2.2L ENGINE:

(8) Aim Power Timing Lamp (Fig. 1) at timing hole in bell housing (Fig. 3) or read magnetic timing unit. If flash occurs when timing mark is before specified degree mark, timing is advanced. To adjust, turn distributor housing in direction of rotor rotation. If flash occurs when timing mark is after specified degree mark, timing is retarded. To adjust, turn distributor housing against direction of rotor rotation. If timing is within +/- 2~ of value specified on the label, proceed to step (10). If outside specified tolerance proceed to next step.
(9) Loosen distributor hold-down arm screw just enough so the distributor housing can be rotated in its mounting (Fig. 4). Turn distributor housing until specified label value is reached. Tighten the hold-down arm screw and recheck timing. When timing is acceptable, recheck curb idle rpm. If engine rpm is not at or below the curb idle rpm shown on the label, reset engine rpm and recheck timing. Repeat above until both engine rpm and timing are acceptable.

(10) Remove timing lamp. Unplug and reconnect the vacuum host to the SCC unit. If an IDLE SPEED ADJUSTMENT is being performed, proceed to that section in Fuel System, Group 14. If not, proceed to next step.
(11) If curb idle speed is not within +/- 50 rpm of value shown on label, readjust curb idle rpm. Do not reset timing.
(12) Turn the engine off. Reconnect violet/purple wire in 6-way connector. Remove tachometer.

FIGURE 1 - PICKUP LEAD CONNECTOR AND SPLASH SHIELD:

DISTRIBUTOR REMOVAL AND INSTALLATION- 2.2L Engine

(1) Disconnect distributor pick-up lead wire at wiring harness connector and remove pick-up lead connector from retainer (Fig. 1).
(2) Remove splash shield retaining screws (Fig. 1).

FIGURE 2 - SPLASH SHIELD:

(3) Remove splash shield (Fig. 2).

FIGURE 3 - DISTRIBUTOR CAP RETAINING SCREWS:

(4) Loosen distributor cap retaining screws (Fig. 3).

FIGURE 4 - DISTRIBUTOR CAP:

(5) Lift off distributor cap (Fig. 4).
(6) Rotate engine crankshaft until the distributor rotor is pointing toward the cylinder block, scribe a mark on block at this point to indicate position of the rotor as reference when reinstalling distributor.

FIGURE 5 - DISTRIBUTOR HOLD DOWN 2.2L ENGINE:

(7) Remove distributor hold down screw (Fig. 5).
(8) Carefully lift the distributor from the engine.
Distributor Installation-2.2L Engine
(1) Position distributor in engine. Make certain that the O-ring is properly seated on distributor. If O-ring is cracked or nicked replace with new one.
(2) Carefully engage distributor drive with auxiliary shaft drive so that when distributor is installed properly, rotor will be in line with previously scribed line on cylinder block. If engine has been cranked while distributor is removed, it will be necessary to establish proper relationship between the distributor shaft and Number 1 piston position as follows:
(a) Rotate the crankshaft until number one piston is at top of compression stroke. Pointer on clutch housing should be in line with the "O" (TDC) mark on flywheel.
(b) Rotate rotor to a position under the number one distributor cap terminal.
(c) Lower the distributor into the opening, engaging distributor drive with drive on auxiliary shaft. With distributor fully seated on engine, rotor should be under the cap number 1 tower.