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TSB 01-1-4

Engine - Spark Knock on Cruise/Acceleration
Article No.
01-1-4

01/22/01

^ ENGINE - SPARK KNOCK - SPARK KNOCK ON
STEADY CRUISE OR LIGHT ACCELERATION -
VEHICLES EQUIPPED WITH 2.5L ENGINE

^ NOISE - SPARK KNOCK - SPARK KNOCK ON
STEADY CRUISE OR LIGHT ACCELERATION -
VEHICLES EQUIPPED WITH 2.5L ENGINE

FORD:
1998-2000 CONTOUR

MERCURY:
1998-2000 MYSTIQUE
1999-2000 COUGAR

This article applies to 1998-2000 Contour/Mystique vehicles equipped with 2.5L engine built from 2/2/1998 only and all 1999-2000 Cougars equipped with 2.5L engine.

ISSUE
A spark knock or pre-ignition condition may exist on some vehicles with an automatic or manual transmission during steady cruise driving or under light acceleration.

ACTION
Reprogram the Powertrain Control Module (PCM). The revised calibration will reduce the potential for spark knock. Refer to the following Service Procedure for details.

NOTE: SOME LIGHT DETONATION ON TIP-IN IS NORMAL AND CONSIDERED CHARACTERISTIC

---ok read the above, light detonation on tip-in is normal and characteristic?! Detonation destroys pistons and the engine in general, how is this programmed in as being normal?!---

Just thought I would post this TSB I found on AllData and vent. Cheers

Light detonation is not harmful. It damages nothing. Ocassional light detonation before the advent of computer controlled engine management systems was considered as a sign that ignition timing was optimal.

Big Jim is right. Light detonation (Pinging) is/was considered the optimal place to be with timing and mixture. Meant you had maximum cylinder pressure for the mixture/timing therefore most power.

I would prefer not to have pinging, but I figure Ford will just retard the timing and I will end up with less performance.

Nail on the Head.

The last ASE magazine had a nice article about this.

Also both Taurus 3L's suffer the same "problem" The cure is to reflash (reprogram) the PCM with a slightly less aggressive spark & fuel curve to quell the detonation.