TSB 93-22-14 4.9L Stall on Initial Start-Up
Publication Date: OCTOBER 27, 1993
LIGHT TRUCK:
1990-1993 BRONCO, ECONOLINE, F-150-350 SERIES
CALIBRATION:
0-51R-R00, 0-51R-R02, 0-51F-R00, 0-51F-R02, 0-51H-R00, 0-51H-R02, 0-51G-R00, 0-51G-R02, 0-51E-R00, 0-51E-R02, 0-52L-R00, 0-52L-R02, 0-52R-R00, 0-52R-R02, 0-52S-R00, 0-52S-R02, 0-52Q-R00, 0-52Q-R02, 0-52K-R00, 0-52K-R01, 0-52K-R10, 0-52J-R00, 0-52J-R01, 0-52H-R00, 0-71J-R00, 0-71J-R01, 0-71J-R02, 0-72J-R00, 0-72J-R02, 1-51R-R00, 1-51F-R00, 1-51H-R00, 1-51G-R00, 1-51E-R00, 1-52L-R00, 1-52R-R00, 1-52S-R00, 1-52Q-R00, 1-52K-R00, 1-52J-R00, 1-52H-R00, 1-71J-R00, 1-72J-R00, 2-51R-R00, 2-51F-R00, 3-51F-R00, 2-51H-R00, 2-51G-R00, 2-51E-R00, 2-52L-R00, 2-52R-R00, 2-52S-R00, 2-52Q-R00, 2-52K-R00, 2-52J-R00, 2-52H-R00, 1-71J-R10, 1-72J-R10, 2-72M-R00
WARNING: THIS MODIFICATION IS AUTHORIZED ONLY FOR THE LISTED ENGINE. PERFORMING THIS MODIFICATION ON OTHER ENGINE CALIBRATIONS IS UNAUTHORIZED AND COULD CREATE LIABILITY UNDER APPLICABLE FEDERAL OR LOCAL LAWS.
ISSUE: A stall may occur in NEUTRAL or PARK on initial start-up, within 15 seconds, as the engine RPM is coming off fast idle. This occurs because of insufficient fuel pressure on the cold start.
ACTION: Install a ported vacuum switch in the heater inlet hose to delay vacuum to the fuel pressure regulator and boost fuel pressure. Refer to the following procedure for service details.
SERVICE PROCEDURE
1. Confirm that the vehicle has been properly maintained. Verify a pass code 11 or 111 in EEC IV Self Test.
2. Confirm no other concerns are present such as ignition, fuel pressure, air intake, exhaust, etc. After all these areas have been checked and no other concerns exist, then proceed to Step 3.
3. Install an 85° F (29° C) ported vacuum switch (D5VY-9D473-B) in the heater inlet hose to delay vacuum to the fuel pressure regulator, boosting fuel pressure about 10 PSI on the cold start.
a. Cut the heater inlet hose about 12" (305 mm) from the inlet tube on the the thermostat housing.
b. Install tee assembly (F2TZ-18B402-A) and clamp both sides. Install switch into truck.
c. Install a 12" (305 mm) piece of 5/32" (4mm) vacuum hose to the lower fitting (labeled S) of the ported vacuum switch. Using a vacuum elbow fitting (387065-S), connect it to the red vacuum line that goes to the fuel pressure regulator.
d. Add another 12" (305 mm) piece of 5/32" (4mm) vacuum hose to the top fitting (labeled E) of the ported vacuum switch. Connect it to the fuel pressure regulator.
4. Install a fuel pressure gauge and verify that the fuel pressure drops about 10 PSI, at idle, when the engine temperature nears 85° F (29° C).
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
D5VY-9D473-B Ported Vacuum Switch
F2TZ-18B402-A Tee Fitting
387065-S Elbow Fitting (Pk./2)
Obtain Locally Vacuum Hose - 5/32"
OTHER APPLICABLE ARTICLES: 91-22-8 , 92-12-17 , 92-18-11 , 92-9-13
SUPERSEDES: 93-9-15
OPERATION 932214A
DESCRIPTION Perform EEC IV Quick Test, Install PVS
TIME 0.9 Hr.
For other TSBs, check
here.
For the full procedure to reset the throttle stop screw, see this caption:
