Engine - Spark Knock

85ford04

Article No. 85-4-26


SPARK KNOCK 1.6L ENGINE WITH MODEL 740 CARBURETOR

FORD 1985 ESCORT

LINCOLN-MERCURY 1985 LYNX

CALIBRATIONS: 5-04A
WARNING: This modification is authorized only for the listed engines. Performing this modification on other engine calibrations is unauthorized and could create liability under applicable federal or local laws.

Two possible causes of spark knock in the subject vehicles have recently been identified: leaks in the vacuum harness due to abrasion against the dash panel, and EGR leakage due to inadequate thread engagement of the EGR tube intake manifold fining, To check for these conditions, inspect the vacuum harness for abrasion damage of the nylon vacuum hoses at the location shown in Figure 9, and service as follows:

Figure 9 - Vacuum Routing:

1. Cut and remove the tape (Figure 9), then separate the main harness from the vacuum lines containing the delay valves.

2. Repair damaged nylon vacuum hoses using an in-line splice with small I.D. rubber vacuum hose No. 387982.

Figure 9 - Vacuum Routing:

Figure 10 - Carburetor:

3. Cut and remove the strap (Figure 9), then install a new strap in the same location in a manner that loosely binds the vacuum harness to the carburetor ISC motor (Figure 10). This new configuration should result in the vacuum harness being moved no more than 1-1/2 inches toward the front of the vehicle, and should not interfere with air cleaner installation.

Figure 11 - Vacuum Routing:

Figure 12 - EGR Tube:

4. Route the main vacuum hose to the main vacuum tree via the inside position (driver side) of the bundle (Figure 11), so that it is not pulling the vacuum harness toward the dash panel.

If the above does not resolve the detonation, service the EGR tube fitting at the intake manifold. Remove the EGR tube and tighten fitting one/two additional turns (Figure 12).

OTHER APPLICABLE ARTICLES: NONE
WARRANTY STATUS: Reimbursable within the provisions of the Warranty and Policy Manual.

OPERATION: SP12127A85
TIME: .8 Hr.

DLR. CODING: Basic Part No.: 12127 - Code: H9