Where does the Rev Counter get its feed

[Barreti]

I don't think my rev counter is reading properly. I've cleaned the stepper because the revs weren't droppng very quickly, thats solved now, but I think the rev counter is telling lies.

I can hear the revs drop as they should but the rev counter is still telling me its doing 2000rpm

I guess it might mean something has been disturbed or needs a bit of a clean?

FYI, the rev counter is resetting to 0 when the ignition is switched off/on

Cheers guys,
Ian

[steve-V8s]

The standard arrangement is a spiky high voltage feed off the back of the coil ( not as high as the plugs ) but it does need fairly big spikes to get it going. This causes a problem when dumping the distributor and fitting coil packs as the single feed of ignition frequency spikes is no longer available. If yours is reading high there could be extra spikes if there is a fault around the coil or associated connections. Perhaps also worth checking the earth for the counter itself.

[blitzracing]

Magnacores or low resistance HT leads can cause the coils primary to produce larger glitches that get mistaken as extra "pulses" by the rev counter.

[davetherave1970]

blitzracing said:

Magnacores or low resistance HT leads can cause the coils primary to produce larger glitches that get mistaken as extra "pulses" by the rev counter.

This is what's happening with mine seen I changed to Mag's.
Any ideas how to put it right other than changing to other HT leads?

[steve-V8s]

Are the "extenders" resistive ? If not that may help. Putting a small resistance in the HT leads calms things down a bit.

[Barreti]

I do indeed have Magnacores. I also have resistive extenders. Both are about 5 years old now as I changed them at the same time when I first got the car.
I've probably only done 15k miles in that time though.

Perhaps this is indicative of the breaking down of the king lead?

Edited by Barreti on Sunday 13th June 21:56

[steve-V8s]

Barreti said:

I do indeed have Magnacores. I also have resistive extenders. Both are about 5 years old now as I changed them at the same time when I first got the car.
I've probably only done 15k miles in that time though.

Perhaps this is indicative of the breaking down of the king lead?

Or the coil.

[Barreti]

Ooooo. Thanks Steve.
New coil on order.

I'm going to finally give in and accept the recommendation of Johno and get some new Moroso leads, if the new coil doesn't fix it.

Mind you, I'm tempted to do it anyway, they look nice

[Ballistic Banana]

Barreti said:

Ooooo. Thanks Steve.
New coil on order.

I'm going to finally give in and accept the recommendation of Johno and get some new Moroso leads, if the new coil doesn't fix it.

Mind you, I'm tempted to do it anyway, they look nice

Moroso's are the best by far you'll have to borrow his crimping tool as you make them to your own lengths

BB

[blitzracing]

If you think the Magnecores are the cause of your glitches, then a single normal high resistance king lead will normally do the trick to calm things down enough.

[Barreti]

Another wierd thing I hope you can explain chaps.

To test the theory of the coil dying, I swapped the coil with a mate who has a Chimaera 400

The coil is non-branded and ever so slightly fatter than the Intermotor one I took off my car because the bracket clamp bolt closed about 8 threads through the nut with mine, but wouldn't even reach with his coil in.

Here's the odd thing. The engine raced at about 2,500rpm and wouldn't settle down. I stopped and started the engine a number of times but it always did exactly the same.

Put my coil back on and all is well again. The car starts on the button and settles through the 3 steps you'd except as the stepper does its thing.

WTF

Edited by Barreti on Monday 14th June 21:19

[Ant.]

I bet you didnt put the bolt back into the plenum, where the coil mounts?????

Guessing from what you said about the coil clamp not fitting.

[Barreti]

Good call Ant. But I didn't remove that part of the bracket.
The bracket is a 2 piece affair. 1st piece bolts to the plenum, 2nd to the coil with just a single clamping bolt and then to the 1st piece with 2 bolts.

It was the 2nd piece that attaches to the coil body which wouldn't fit because the clamping bolt on mine is shorter. So I used the bolt off my mates bracket.

Its a thought though. Maybe I just didn't tighten his up properly, though I thought I did because I planned to take the car for a run (never actually bothered in the end because of it revving its nuts off)

[Johno]

Ian, I'll stick the crimp tool in the same envelope as the bit's for Andy if you want and get it in the post tomorrow as I' ve gotta go to the PO anyway . . Need to speak to you about something else anyway . . . LM related

Real Steel best for Moroso's, they also do the crimp tool for only about £7 for the vice one which is best IMHO. Also make sure you buy the ones with 135 degree plug ends, keeps them more vertical away from the manifolds, one of many points where they're better than Magnawk.

I use the 8mm rather than the 10mm . .

[AMsquared]

Hey Ian, Does that mean I'll be getting some new leads to partner my unbranded slightly rotund but fully operational coil?

[Barreti]

Thanks Johno. Looks like you've finally got your way after all eh
I'll save the king lead for you to wang away

AMsquared, your slightly rotund coil has confused the hell out of me. But at least it looks nice now eh


the in jokes here ...

Johno hates Mangycores with passion. In Le Mans he was convinced my breakdown was due to these and threw my king lead over his shoulder and into a tree!

AMsquared leant me his coil last night for testing. Top man Andy. thanks
It looked so scratched and manky that I stripped the black paint off it, polished it to a brush finish and carnauba waxed it before taking it back tonight
Mrs AMsquared is now convinced I'm completely mental

[Johno]

Barreti said:

Mrs AMsquared is now convinced I'm completely mental

Let's face it . . she's right !

Andy, post going tomorrow, I promise !

[Barreti]

Will you shove that lead tool thing in the parcel for Andy please Johno.

Give me a ring any time to discuss LMC. I can't believe you're having withdrawal symptoms after less than 24hours you nut !

[Johno]

Barreti said:

Will you shove that lead tool thing in the parcel for Andy please Johno.

Give me a ring any time to discuss LMC. I can't believe you're having withdrawal symptoms after less than 24hours you nut !

Will do . ..

I just didn't engage with the race this year somehow, normally we're 12-14 hrs of watching, but only managed 8hrs and didn't realise that an agenda of Amsterdam working on Monday, dashing all over SE England Tuesday, dash to Le Mans Wednesday left me absolutely knackered for the weekend . .

Also, kinda want to surprise Vix, taking her to the 24 isn't going to work given the normal team etc . . so thought I'd surprise her with a weekend down for the Classic, she'd love it like she did the revival, so need to work through whether I can nail a Maison Blanche ticket. Seems I can get a Bleu Nord, but was hoping to try and get in where you and Jeff are, Bridget etc . . . Also, much prefer to be driving to Griffith than sitting looking at it in a car park so it's an excuse for another great drive

I'll call you tomorrow . .

[AMsquared]

Mrs M knew you were mad way before that little event, what she's realy concerned about is that I appear to be going the same way.

Coil looks lovely - lets just hope that removing the heat resistant paint doen't give it a problem!!!!!! What do you mean you didn't think of that?