Club 80-90 Forums

OK, just try to tune your inner conciousness into your pride and joy's deepest emotions, but on a mechanical level

Overrun = off the throttle where the vehicle's momentum is driving the engine and usually decelerating, unless on a downward slope where, depending on selected gear, it might be holding speed or even accelerating. But the engine is holding the vehicle back one way or another.
It implies that the loads and torques are reversed throughout the engine, transmission and driveline compared to being under power.
It also implies the engine, although maybe spinning fast, is running on a low or shut throttle and fuelling through the idle jets on a carburrettored engine or with its fuel completely cut-off on most injected engines.

As it stops mucking about imemdiately you lift off and re-apply power, its unlikely to be icing up, and would be more apparent in certain humid and dewy conditions. To diagnose it you would have to stop quickly, and look down the carb for signs of frost. Maybe worth checking that the carb heater is working though, if it has one.

Ok,

Have now had van serviced, CVJ's checked and the Wheels Balanced.

Still got the bloody problem.

Any other ideas?

Could it be Engine related?

Thanks again.

Ben

Could it be Engine related?

Knock it into neutral at that speed or when it does it - that should answer that.

Even suddenly change throttle setting - ditto, though even if its chassis, box, balance related changing powe setting will change its character, but not its prescence (usually), so use your judgement - as above, tune into the vehicle.

Back again unfortunately - you'd think it'd be sorted by now eh....

Anyway to add to the problem (the shudderring continues although it's been in the garage for various things for the last 3 weeks) - and maybe it's linked, but we've now run out of petrol twice.

Fuel guage says there is plenty, but keep running out. Put more in and off you go again.

Only problem is, we can only seem to get about £25 worth in.

Can't see anything similar on the wiki

any ideas happily received.

Could it be Engine related?

Surely that's for the driver to say, its usually pretty obvious when the engine is misfiring or shuddering, or when its a chassi/body related matter - knocking it into neutral as suggested above is one way, but even that shouldn't usually be necessary - sounds like you should get someone else to drive it who's been around motor vehicles for a few years and could probably say straight away, what the likely source is.

Have you purged the tank and changed the fuel filter?

PS. Sevicing wouldn't normally cover that unless you asked specifically for the fuel system to be looked at. Water or dirt in the fuel can often be responsible for the engine shuddering but establishing if this is definitely engine or chassis based is your first priority.

It's also not consistent so you could be quite happily going along at 60 - 70mph when it will start.

If you ease off the acclerator it stops and then you can build up speed again.

Re-reading all that previous stuff sounds like the engine is misfiring, cutting out... as above, possibly fuel related.

Didn't the garage that serviced it test drive it to find and resolve the problem (presume you informed them of this 'shuddering')

It's been with Darren at VW Airfix down in Carshalton, Unfortunately he didn't manage to get it to the requisite speed in that part of London.

Could it possibly be wheels out of balance or buckled?
Have you looked at this. A bit remote I know, but may be worth a check.

Had em balanced, so I hope not.

It's been with Darren at VW Airfix down in Carshalton, Unfortunately he didn't manage to get it to the requisite speed in that part of London.

So a waste of time then... w.r.t. this fault?

NEW UPDATE!

I know it's very exciting.... well at least for me anyway.

Broke down again on Friday - Turns out the wire to the fuel pump from the engine had somehow split and got wrapped around the CVJ boot. Hence engine not firing. Spliced cable all well in the world - seem to have more power now as well

Does that mean it could have been going for a while?

Anyway - now happily cruising down road at 70mph!

Still getting the shuddering / banging above this speed though.

Ben - shuddering/banging - do you still have no idea what this is? What the source is?

Err - not specifically.

Thanks to advice from everyone....

I have my suspicions that having checked the CVJ's, got the right clips put on the engine, fixed the fuel pump, got a new starter (admittedly unrelated - but great!), had the wheeles balanced twice, that it may be a buckled wheel or something wrong with one of the bearings.

Either that or I should just stop trying to go more than 70 miles an hour.

Also - when the fuel pump went, the 3rd mechanic to look at it in shoreham after we'd explained it was the broken wire mentioned there were two fuel pumps a mechanical and an electrical - is that likely?

Thanks

Ben

Just to be on the safe side, I feel I must ask, "have you checked all your wheel retaining nuts ?"