The problem is.....

[Chuggaboom]

.....after a few laps its like someone switches off the complete electrical supply momentarily as the engine cuts and the rev counter goes to zero (and the stack display resets). Obviously momentum is briefly lost and then the rev counter flies back round, and power returns. After a another laps or so its becomes more frequent, sometimes doing it in 3’s or for longer periods.

During the first session out it didn’t do it all and the longer the car is left after coming in, the more laps can be done before the problem resurfaces, so it definitely appears to be heat related.

OK, to start with this is not on a Cerb, but the racer has a std 4.2 engine/clutch/Gbx unit with its matching ECU.

Thoughts ?

[grahamn]

Hi Grant, now I know I am not the best technically but, this sounds exactly the same as the problems me and Nick had with the big fuse.

[touching cloth]

Getting too hot clearly means you're not driving it quick enough

[jammy_basturd]

I would suggest to look at the big fuse first (replaced it as a matter of course), then maybe coil packs.

[Tanguero]

If the stack is resetting it sounds more like a general electrical failure - the big fuse is only in the charging circuit. I know it can have some strange effects but I would be checking all the earthing points and connections carefully.

[tvrfan007]

That has to be an earth fault. Careful wiring tracing unfortunately.

[Gazzab]

Doesnt sound like big fuse. Sounds like an earthing or maybe a problem with coils?

[Chuggaboom]

What actually happens to a big fuse ?

I thought the idea of a fuse is that it burns out ie nothing at all afterwards !?!?

[Tanguero]

It tends to flex and crack and go intermittent rather than blowing. Also the design of holder is rather prone to high resistance connections. However the big fuse is in the charging circuit and would be highly unlikely to affect your Stack dash like that.

[FarmyardPants]

Chuggaboom said:

What actually happens to a big fuse ?

I thought the idea of a fuse is that it burns out ie nothing at all afterwards !?!?

The big fuse only affects charging. If you take it out completely the car will start and run fine with the dashboard battery light on, and will keep running until the battery gets too low to support life. The rev counter is very sensitive to the voltage fluctuations which can occur when the big fuse is on its way out.

I'm going with the earth theory