Lurching feeling

Post by **willf** » 15 Nov 2007, 20:22

Help when driving along in any gear at any kinda speed i get lurched forward like. Feels like the power stops then whams back on. quite disconcerting. any ideas???
Will

Post by **KarlT** » 15 Nov 2007, 20:44

Is this when coasting or accelerating?

I get a rocking motion at certain speeds & gears when foot is off the gas.

Post by **willf** » 15 Nov 2007, 20:51

accelerating i guess not coasting, foot on gas maintaining speed up a slight gradient that kinda thing.

Post by **v-lux** » 15 Nov 2007, 22:19

What engine?

Post by **willf** » 16 Nov 2007, 07:58

2.1dj
16" syncro

Post by **thefatsurfer** » 16 Nov 2007, 08:40

I get a similar gentle lurching in my 1.6td going uphill when under power. As it hasn't gone bang yet i won't fix what isn't broken, but if it is an ajustment i would be interested to see what it is.

Post by **manxman** » 16 Nov 2007, 12:35

I get something similar to this (2.1 Dj 16") , in mine I've not investigated it yet though.

only does it when accellerating/under load when it misses a beat occationally

recon its ignition myself but I'll let you know how I get on once I've got my brakes rebuilt.

Post by **Syncro G** » 16 Nov 2007, 18:12

thefatsurfer wrote:I get a similar gentle lurching in my 1.6td going uphill when under power. As it hasn't gone bang yet i won't fix what isn't broken, but if it is an ajustment i would be interested to see what it is.

On the diesel that'll probubly be the stupid blowoff valve on the inlet manifold. Mine usally opens momenterally when climbing hills on the motorway (usally when I'm overtaking a very slightly slower lorry and need all the power I can get). Once its dumped all my boost presure and lossed me the power I needed the valve closes, boost quickly builds back, performance is restored and then it happens again

I keep meaning to block it up, aparently its not hard to do.

Don't know much about the VW petrols (asuming they have all that modern breakerless ignition?) but a dizzy fault on my dads old series 1 (simple points inside that) caused it to sometimes loose full power but still seem to run normally - took me a while to find that fault so maybe chack that area very carefully?

Post by **Russel** » 16 Nov 2007, 20:14

You can adjust the blowoff valve.Turning the screw clock wise will stiffen the blowoff valve.But I would suggest doing this and testing with a boost guage so as not to overboost and do any damage.This is a saftey valve.
Russel

Post by **SyncroRich** » 21 Nov 2007, 15:57

My 2.1 did this lurching thing really badly on a neutral throttle or coasting in gear at low revs.
I bypassed the idle stabilisation control (really easy) and now it is much better.
It only does this very slightly now and it's worse when warm.
If anyone has any ideas of relieving this syptom completely I would be forever grateful.

Post by **syncroand101** » 21 Nov 2007, 16:24

SyncroRich wrote: I bypassed the idle stabilisation control (really easy) and now it is much better.D

Replacing the Idle Stabiliser with a new one?

Post by **airhead** » 21 Nov 2007, 17:22

Russel at Syncro-Nutz wrote:You can adjust the blowoff valve.Turning the screw clock wise will stiffen the blowoff valve.But I would suggest doing this and testing with a boost guage so as not to overboost and do any damage.This is a saftey valve.
Russel

I did this actually cause when I bought my van the damn thing was permanently dumping the boost pressure (damn it, those words "Boost pressure" really get on my nerves! It reminds me of skangers, aka chavs in honda civics and integras and all that crap. Theyre the only words relating to engines or anything that actually annoy me. My favourite words are "Compression ignition".

). I just wound in the screw until it stopped dumping the pressure.

Post by **HarryMann** » 21 Nov 2007, 20:29

I would first put a known good set of leads and plugs in it.... then check all the vac and inlet hoses for ageing, splits, leaks.

Then get it on an ignition test and ensure all sparks are good and strong at approximately the right time (advancing correctly)...

Have you checked/changed the fuel filter lately, or is it currently a 100,000 mile + item?

Post by **SyncroRich** » 03 Dec 2007, 11:40

I just bought a new cap and rotor arm for mine and noticed the arm tip was wider than the old one.
This means the contacts on the distributor cap line up with the arm for a longer period of time during each rotation.
Anyway The hunting has stopped.
I assume the timing has stabilised as a result of the wider arm.
Any thoughts?

Post by **HarryMann** » 03 Dec 2007, 19:08

The wider arm won't have made any difference to the timing, but together the new arm and cap a good idea, obviously the spark was breaking down somewhere and together they have solved it...

If its likely the timing has been messde with previously and a problem recurrs I'd have it checked properly