300tdi edc tachometer faltering

darland · Mar 14, 2019

Hi
97 300tdi auto with EDC...
Noticed a few times recently that when driving the tachometer momentarily cuts out (ie the indicated revs drop) and the ignition light flashes on.
There is no performance issues at all ie the revs don't "actually" drop.
Any advice welcome please.

dieseldog69 · Mar 14, 2019

darland said:
Hi
97 300tdi auto with EDC...
Noticed a few times recently that when driving the tachometer momentarily cuts out (ie the indicated revs drop) and the ignition light flashes on.
There is no performance issues at all ie the revs don't "actually" drop.
Any advice welcome please.

Tacho uses a signal from the alternator to indicate RPMs, the ignition lights you see flash alongside the tacho faltering could be a sign of the alternator failing.

Have you checked that the alternator is charging correctly?

darland · Mar 14, 2019

Hi thanks for the prompt response. I think the alternator is OK as it's kicking out a steady 14.1 when driving and close to that when idling. From what you've told me though perhaps I need to check for a loose connection on the alternator.
Cheers.

Gazbo · Mar 14, 2019

darland said:
Hi thanks for the prompt response. I think the alternator is OK as it's kicking out a steady 14.1 when driving and close to that when idling. From what you've told me though perhaps I need to check for a loose connection on the alternator.
Cheers.

It's a very common problem on the D1
Check the small guage white wire on back of the alternator, the female spade connector gets loose, pull it off the back of the alternator, squeeze it up a bit with pliers and refit it to the alternator, should be fine.

darland · Mar 14, 2019

Gazbo said:
It's a very common problem on the D1
Check the small guage white wire on back of the alternator, the female spade connector gets loose, pull it off the back of the alternator, squeeze it up a bit with pliers and refit it to the alternator, should be fine.

Many thanks

Nig43 · Mar 14, 2019

When that happened to mine all I did was to liberally spray WD40 in the back of the alternator. Fixed it and never faltered after that.

darland · Mar 14, 2019

I'll try that first

darland · Jun 14, 2019

Just to let you know I pulled the small wire, sprayed wd40 and all sorts now good. Many thanks for replies.

300tdi edc tachometer faltering

darland

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