Engine - Backfire On Deceleration
88ford2
BACKFIRE ON DECEL - 2.3L HSC - WITH CARBURETOR AND MTX - CANADIAN CALIBRATION ONLY
Article No. 88-2-12
FORD: 1985-86 TEMPO
LINCOLN-MERCURY: 1985-86 TOPAZ
CALIBRATIONS: 5-25G-R00 5-25G-R13 (Canadian calibration)
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.
ISSUE: Engine backfiring during decel or during transmission downshifting on Canadian calibrated vehicles may be caused by a delayed vacuum signal to the thermactor air bypass valve. The delayed signal allows the air pump to dump air into the exhaust system creating a backfire condition.
ACTION: To correct this, modify the vacuum hoses using the following service procedure.
FIGURE 16:
1. Locate rubber connector that is attached to the EGR solenoid valve, Disconnect nylon vacuum elbow that is attached to RED vacuum tubing from rubber connector, Figure 16.
FIGURE 17:
2. Follow RED vacuum tubing and locate where it connects to the air bypass valve. Remove RED vacuum tubing connector from air bypass valve and plug it by installing a nylon connector (383003-S) and a rubber vacuum cap (382444-S), Figure 17.
FIGURE 18:
3. Using one (1) nylon vacuum tee fitting (373846-S), one (1) nylon vacuum elbow 90~ fitting (387065-S), two (2) 1-1/2 inch lengths and one (1) 13-1/2 inch length of rubber vacuum hose cut from bulk stock (D0PZ-12226-B), make a vacuum bypass line as shown in Figure 18.
FIGURE 19:
4. To install vacuum bypass line, connect RED vacuum tubing to the 1-1/2 inch rubber vacuum hose on the nylon vacuum tee fitting. Connect opposite side of nylon vacuum tee fitting to rubber connector. Attach other 1-1/2 inch vacuum hose that is attached to nylon vacuum elbow 90~ fitting to air bypass valve assembly vacuum fitting, Figure 19.
FIGURE 20:
5. Modify Vehicle Emission Control Information sticker vacuum routing diagram with a SHARPIE PEN as shown in Figure 20.
Obtain an Authorized Modifications Decal and list the date, dealer number, and summary of alterations performed. Select a prominent place adjacent to the Vehicle Emission Control Information Decal suitable for installing the Authorized Modifications Decal. Clean the area, install the decal, and cover it with a clear plastic decal shield.
PART NUMBER PART NAME CLASS
383003-S Nylon Connector - AG
Package of 5
382444-S Vacuum Cap - BS
Package of 10
373846-S Tee BR
387065-S 90~ Fitting - BS
Package of 2
D0PZ-12226-B Vacuum Hose - 50 Ft. AG
OTHER APPLICABLE ARTICLES: None
WARRANTY STATUS: Eligible Under Basic Warranty Coverage
OPERATION: 880212A
TIME: 0.4 Hr. DLR. CODING: Basic Part No. DRIVE - Code: T1