Erratic Rev Counter
Erratic Rev Counter
Author
Discussion

jeboa

Original Poster:

547 posts

291 months

Sunday 7th September 2008
quotequote all
Been driving me crazy for a while this one.

The car seems to be running fine (maybe a little rich), but the rev counter will not settle down.

Seems to be over-reading erratically at low revs and more stable as you go over 3.5k.

Tried cleaning all connections at coil with no success - any ideas on where to go next??





Bluebottle

3,498 posts

270 months

Sunday 7th September 2008
quotequote all
T.A.D.T.S.

But you can get a 5ohm suppressor that fits to the dizzy cap on the coil lead that often stops this problem.

jeboa

Original Poster:

547 posts

291 months

Sunday 7th September 2008
quotequote all
I thought that may have been coming! To be fair I have recently (miles not months) renewed all ignition components and the alternator. I may just have to look into cleaning everything up a little and checking it's all tight.

As for the suppressor - I take it is a pretty standard item - any idea what it looks like - I may have binned the original when I threw the old dissy cap away??




blitzracing

6,422 posts

250 months

Sunday 7th September 2008
quotequote all
Bet you fitted magnecors ? If you did the low resistance lead glitches the coil and causes spikes on the coil primary, the the rev counter thinks these are extra ignition pulse's.

Mark

jeboa

Original Poster:

547 posts

291 months

Sunday 7th September 2008
quotequote all
I don't think they are Magnecor branded, but they were reasonably expensive - around £60. The only branding they have are '8mm Silicon Power' printed along the length, sounds a little suspect on reflection!! I also renewed the extenders at the same time.

Where would you suggest for a new set of leads?

blitzracing

6,422 posts

250 months

Monday 8th September 2008
quotequote all
If you can get a test meter on one of them, measure its resistance. A normal lead is over 10k ohms, whilst a low resistance lead is nearer around 2 k ohms,(these values depend on its lenght) so you can tell the difference this way. If they are low resistance, you can either fit resistive plugs, or an inline "suppressor" in the king lead as suggested, but its a messy option. Otherwise a set of origional lucas leads can be had for around £20 (Try some of the Land Rovers suppliers) that work just fine. The king lead will be the wrong length, so ask the supplier if they can do the correct one. I would not want to send you down this path unless you are sure the origionals are low resistance type however.

Mark

jeboa

Original Poster:

547 posts

291 months

Monday 8th September 2008
quotequote all
Took a resistance reading on the leads:

Coil>Dist 5.5K (Shortest lead)

Dist>Rear Cylinders 7.5K

Are these too low??



blitzracing

6,422 posts

250 months

Tuesday 9th September 2008
quotequote all
Ummm ....some where in between. Your best bet is to go and buy a cheap replacement king lead from a motor factor. Take the old one with you to match the connections, and a test meter to check the resistance is higher. I would suggest 10K is a better reading, and give it a try. If the problem disappears, you know the fix.

Mark

fastandcurious

437 posts

238 months

Wednesday 10th September 2008
quotequote all
I've got Magnecores and my revcounter does a dance. I shall try changing the King lead and see if it gets better.yes

blitzracing

6,422 posts

250 months

Wednesday 24th September 2008
quotequote all
Did we get a result on this out of interest ?

Mark

V8 Animal

6,015 posts

240 months

Wednesday 24th September 2008
quotequote all
Mines ok.
Did fit the shrouds as well as supplied by ACT i believe this stops the problem.
V8 Animal

jeboa

Original Poster:

547 posts

291 months

Thursday 25th September 2008
quotequote all
Still not managed to get the time to do anything - bloody work!!!

Will report back once I have had the chance!