Engine Controls - Stall On Start Up or deceleration
Article No.97-21-7
10/13/97
STALL - DURING START UP AND/OR DECEL WITH
COLD ENGINE - VEHICLES EQUIPPED WITH 2.5L
ENGINE AND MTX - 75 TRANSAXLE
FORD:
1998 CONTOUR
MERCURY:
1998 MYSTIQUE
CALIBRATION
8-11B-R07, 8-11T-R07
WARNING
THIS MODIFICATION IS AUTHORIZED ONLY FOR THE LISTED ENGINE(S). PERFORMING THIS MODIFICATION ON OTHER ENGINE CALIBRATIONS IS UNAUTHORIZED AND COULD CREATE LIABILITY UNDER APPLICABLE FEDERAL OR LOCAL LAWS.
ISSUE
Some vehicles may stall when first started in the morning during deceleration and/or have a tip-in detonation. The stalling concern usually will occur during the first 3 minutes of engine operation; the detonation concern may occur at higher engine operating and ambient temperatures. This may be caused by the Powertrain Control Module (PCM) calibration allowing too much fuel to flow and then going too lean during those conditions.
ACTION
Reprogram the PCM. The revised calibration should reduce the fuel flow to the engine during warm up, reduce the possibility of stall, and also reduce the amount of spark advance to reduce the possibility of detonation. Refer to the following PCM Application Chart for correct PCM calibration usage and the following text to verify stall condition and detonation.
NOTE
DEALERS WITH SERVICE BAY DIAGNOSTIC SYSTEM (SBDS) MUST REPROGRAM PCM. IF IT BECOMES NECESSARY TO REPLACE THE PCM, REGIONAL APPROVAL MUST BE OBTAINED.
To verify stall condition: Leave the vehicle parked overnight. Start the vehicle after an overnight soak. Accelerate at moderate throttle. Shift into 2nd gear at about 2500 rpm and accelerate to 56 km/h (35 mph). Back out to closed throttle and allow the vehicle to decelerate in gear. Brake moderately to a stop from 32 km/h (20 mph), and declutch between 1200-1500 rpms. Repeat the moderate acceleration followed by a stop for a total distance of 1.5 km (1 mile). If the vehicle stalls on declutch, reprogram the PCM using the latest level CD-ROM.
To verify detonation: Drive the vehicle until engine temperature is stabilized. Idle vehicle for 15-20 minutes. Use New Generation Star (NGS) Tester to verify the Engine Coolant Temperature (ECT) reads above 99°C (210°F) and Air Charge Temperature (ACT) reads above 60°C (140°F). If the ECT and ACT will not reach these levels then accelerate the vehicle at heavy throttle 3-4 times to raise ECT and ACT and then repeat the extended idle. If the ECT and ACT will not reach these levels, the ambient temperature is not high enough.
With the engine and underhood hot, drive the vehicle between 1000-1500 rpms in 4th gear. Tip-in to a moderate throttle position and listen for detonation. Evaluate the vehicle in 5th gear the same way. Repeat at least 5 times in both gears. If any detonation is observed, reprogram the PCM using the latest level CD-ROM.
Obtain an Authorized Modifications Decal (FPS 8262 - obtainable through DOES II, 25/pkg) and list the date, dealer number, and summary of modifications 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.
Parts Block
OTHER APPLICABLE ARTICLES: NONE
WARRANTY STATUS: Eligible Under The Provisions Of Bumper To Bumper Warranty Coverage
OPERATION DESCRIPTION TIME
972107A Reprogram Powertrain 0.2 Hr.
Control Module (PCM)
972107B Replace Powertrain Control 0.3 Hr.
Module (PCM)
DEALER CODING
CONDITION
BASIC PART NO. CODE
RECAL 42
OASIS CODES: 607000, 607400, 607700, 615000, 615500
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