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[raymie64]

I am new to the forum, and 924 as well. I have a 1985 2.0L with strange slow starting. I have replaced the battery, adjusted the drive belt as it was squeeling and checked battery cables. The car is making 13.9 volts at around 2500rpm so not sure if this may be an issue. After replacing the battery for a new 55ah one it seemed to start ok then it went back to extremely slow starting with the volt meter reading a a lowly 8 volts while cranking. I am just not sure if it is a charging fault or starter brushes possibly? I have seen in the service history mention of slow starting before and the alternator was replaced at that point. Any advice on this one would be very welcome as it is ruining an otherwise brilliant experience, except for the fuel consumption, but thats another matter.

[ideola]

I presume you have a normally aspirated model, and not a turbo?

The very next thing I would do is inspect the main starter harness. It includes the alternator harness. On the NAs, this harness runs directly under the exhaust manifold and is subject to heat fatigue. In some cases, the insulation will crack, wear, or disintegrate, exposing the 12v main wire that connects to the starter. These have been known to ground out on the manifold. Needless to say, this can have catastrophic consequences, including potential fire or damage to other electrical components (a particular concern in the late model cars like yours).

If this harness is failing, has bad connections, or the wire is heat fatigued, it will build up more resistance, delivering less voltage to the starter, making it difficult to start. So I strongly recommend that you remove the harness and rebuild a new one with heavier gauge wire, and then sleeve it in a heat resistant sleeve like firebraid. Just make sure you carefully label (and photograph) the connections before you remove the harness so you know how to put it all back.

The other distinct possibility is that the starter itself is on the way out. I wouldn't normally expect the alternator to have a role to play in starting (aside from the aforementioned harness issue).
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erstwhile owner of just about every 924 variant ever made