Chapter 1 Routine maintenance and servicing

1595Ford Fiesta Remake5B•4 Ignition system3 Ignition coil - checking,removal and refitting2Distributor ignition systemsChecking1 Accurate checking of the coil outputrequires the use of special test equipment andshould be left to a dealer or suitably equippedautomotive electrician. It is however possibleto check the primary and secondary windingresistance using an ohmmeter as follows.2 Disconnect the battery negative (earth) lead(refer to Part A, Section 1).3 Remove the vehicle jack from its storageposition by unscrewing its retainer. Theignition coil is mounted below.4 To check the primary resistance (with allleads disconnected if the coil is fitted),connect the ohmmeter across the coil positiveand negative terminals. The resistance shouldbe as given in the Specifications at thebeginning of this Chapter.5 To check the secondary resistance (with allleads disconnected if the coil is fitted),connect one lead from the ohmmeter to thecoil negative terminal, and the other lead tothe centre HT terminal. Again the resistanceshould be as given in the Specifications.6 If any of the measured values varysignificantly from the figures given in theSpecifications, the coil should be renewed.7 If a new coil is to be fitted, ensure that it isof the correct type. The appropriate Fordsupplied ignition coil is identified by a redlabel, and will be one of three different makes,all of which are fully interchangeable. Boschand Femsa coils are fitted with protectiveplastic covers, and Polmot coils are fitted withan internal fusible link. Note that contactbreaker ignition coils are not interchangeablewith the required breakerless type and couldcause ignition module failure if used.Removal8 If not already done, remove the vehicle jackfrom its storage position by unscrewing itsretainer. The ignition coil is mounted below.9 Disconnect the battery negative (earth) lead(refer to Part A, Section 1).10 Disconnect the HT lead and the lowtension (LT) connections from the ignition coil.Note that the LT connections on the ignitioncoil are of different sizes. As an aid to refittingthe positive (+) terminal is larger than thenegative (-) terminal (see illustration).11 Remove the two screws or bolts securingthe coil mounting bracket to the inner wingpanel, and withdraw the coil and mountingbracket assembly.Refitting12 Refitting is a reversal of the removalprocedure, ensuring correct LT lead polarity.Distributorless ignition systemsCheckingNote: The ignition coil is located on the rearfacing side of the cylinder block on HCSengines; on the left-hand end of the cylinderhead on CVH, PTE and Zetec engines.13 Having checked that full battery voltage isavailable at the centre terminal of the coil’selectrical connector (see Section 2),disconnect the battery negative (earth) lead(refer to Part A, Section 1).14 Unplug the coil’s electrical connector, ifnot already disconnected.15 Using an ohmmeter, measure theresistance of the coil’s primary windings,connecting the meter between the coil’sterminal pins as follows. Measure first fromone outer pin to the centre pin, then from theother outer pin to the centre. Compare thereadings with the coil primary resistance listedin the Specifications.16 Disconnect the spark plug (HT) leads -note their connections or label them carefully,as described in Chapter 1. Use the meter tocheck that there is continuity between eachpair of (HT) lead terminals; Nos 1 and 4terminals are connected by their secondarywinding, as are Nos 2 and 3. Now switch tothe highest resistance scale, and check thatthere is no continuity between either pair ofterminals and the other - ie, there should beinfinite resistance between terminals 1 and 2,or 4 and 3 - and between any terminal andearth.17 If either of the above tests yield resistancevalues outside the specified amount, orresults other than those described, renew thecoil. Any further testing should be left to adealer service department or other qualifiedrepair facility.RemovalNote: The ignition coil is located on the rearfacing side of the cylinder block on HCSengines; on the left-hand end of the cylinderhead on CVH, PTE and Zetec engines.18 Disconnect the battery negative (earth)lead (refer to Part A, Section 1).19 Disconnect the coil main electricalconnector and (where fitted) the electricalconnector to the suppressor.20 The coil can be removed with the HTleads left attached, in which case disconnectthe leads from their respective spark plugsand from the location clips in the rocker coveror air inlet duct (as applicable). If preferred,the HT leads can be disconnected from thecoil. First check that both the ignition HTleads and their fitted positions are clearlymarked numerically to ensure correct refitting.Spot mark them accordingly if necessary,using quick-drying paint.21 If disconnecting the leads from the sparkplugs, pull them free by gripping on theconnector, not the lead. To detach the leadsfrom the ignition coil, compress the retainingarms of each lead connector at the coil, anddetach each lead in turn (see illustration).22 Unscrew the Torx-type retaining screws,and remove the coil from its mounting on theengine (see illustration).Refitting23 Refitting is the reverse of the removalprocedure. Ensure that the spark plug (HT)leads are correctly reconnected, and tightenthe coil screws securely.3.10 Ignition coil fitted to distributorignition systemsA Retaining boltsB LT connectionsC HT lead to distributor cap3.21 Removing an HT lead from thedistributorless ignition system ignition coil.Note the corresponding markings on theignition coil and HT lead (arrowed)3.22 Distributorless ignition system ignitioncoil and mounting bracket removal (HCSengine shown)