Rev Limiter ???

[MangoMan]

Hi Guys & Gals, first of all I hope you're all having a lovely day...

But here's the question; As you all know by now, I have a 1990 300ce 12 valve Auto.

Now yesterday I was following a longish, slow line of traffic getting onto the motorway, so when the Onramp opened up to 2 lanes I thought 'bugger' it & floored it, it changed down to 2nd. and we took off, after a few seconds I was begining to wonder when is this thing going to change, I was looking at the road not the dials, but when I did I noticed I was doing around 7000rpm. It was a quick glance so I can't be exact, sorry, but it was way round to the end of the dial. I thought these cars had a limiter? the strange thing was it was still pulling, no missfiring or anything like that! Plus I think I was doing +- 70mph. I hadn't even reached the motorwat yet.

Anyway I tapped off, and it changed up the 2 next gears quite quickly, as it should.

Is this normal? It's just that I thought; 'Bloody Hell I Could Have Blown The Bloody Thing' !!!!! But luckily it still sounds as sweet as ever.

Cheers, Bill.

 

[GrahamC230K]

Is 7000 rpm below the redline on your dial?

 

[MangoMan]

Is 7000 rpm below the redline on your dial?

Redline starts at 6250rpm and ends at 7000rpm (end of dial)

Ciao.

 

[miro]

If you stand on the "go" pedal it probably wont change up.

 

[MangoMan]

So I gather they don't have a 'Limiter' then.

Oh well, 'Happy Days'.

 

[GrahamC230K]

Forget the limiter, when was the box going to change up?!

 

[Dieselman]

I suspect it was under load so was holding maximum power. It should change up and should have a limiter function.

As the engien was under load there will have been no harm done by the revving.
I would want to give it another test to check that the box does change up sometime.

 

[Asif Kazani]

I believe that the revs in these cars are limited by a tiny spring in the ignition rotor inside the distributor cap that shorts out and cuts out the spark at high revs. Maybe dieselman can shed some more light on this..????

 

[Dieselman]

I believe that the revs in these cars are limited by a tiny spring in the ignition rotor inside the distributor cap that shorts out and cuts out the spark at high revs. Maybe dieselman can shed some more light on this..????

Not sure Asif but that is a fairly common method of limiting.

If that is the case the spring has probably broken at some point and been replaced with eiter a stronger one or the system bypassed.
The box should have changed up though.

 

[MangoMan]

I have to say that it was on a relatively uphill gradient on the onramp.

The engine didn't sound like it was taking flak, and as soon as I released the pressure on the throttle it changed up the next 2 gears in quick succession.

Also it is really the 1st and only time I've 'floored' it. Usually I'm quite a sedate driver.

But thanks for all the input and interest, really appreciated.

I'll just have to watch it next time, if there is a next time.

 

[Seamster15]

Mango, Have you hit the 230k mark yet ?

 

[MangoMan]

Almost.......

Mango, Have you hit the 230k mark yet ?

........there, 229,886 miles.

Should get there by next weekend I reckon.

Cheers, Bill.