Instantaneous rev death bounce

[yalan 0]

Driving along happily at 60 ish in top gear, my car will occasionally lose all power for a moment.

 

The tacho needle will plunge down to 0 then shoot back up to 3000. Resultant will be me lurching forward then back again as the power returns.

 

Bizarre, because the 2.0 16v isn't the most responsive of engines, and the rate of change of revs is nothing you can reproduce with the accelerator etc. Really sharp and sudden.

 

Anyone got any experiences / suggestions?

(Fuel filter changed

[Henny 0]

sounds like the hall sender is failing or has a loose connection to it somewhere... :|

 

Eitherway, it sounds like it's killing the spark completely making the engine stall and then kicking back in again almost immediately afterwards... :|

[h100vw 0]

Agreed,

[Geo 0]

It sounds to me like either what henny said or a loss of power to the ecu. The fact that the rev counter is dropping to zero instantly would indicate that either the ecu thinks the engine isn't rotating at all and cuts the spark accordingly (so suspect dodgy hall sender or connection) or the ecu is losing all power (bad connection to ecu or faulty relay)

[Henny 0]

yup, that's true Geo good point about the ECU and relay... 8)

[Roger Blassberg 0]

I had the same on 2 Golfs, Mk I and Mk 2 GTi s; it turned out to be the fuel pump relay on both.

 

Best wishes

 

RB

[yalan 0]

excellent replies there guys, thanks!

 

A few of the wires seem freyed in the engine bay - (the ones to the throttle position sensor had completely broken off inside the connector!). However the ones to the Hall sender appear OK.

 

I took the dizzy cap off and the area around the hall sender looks a bit manky - so I might clean that a bit before sourcing a new sender. Hopefully carb cleaner won't do too much damage.

 

1 - clean sender

2 - check relays are snug

3 - replace sender

4 - check wires for damage / continuity

[GIXXERUK 0]

its worth checking the battery connections and the earth strap from the battery :-)

[Henny 0]

If it's anything like the KR 16V, if you have oil inside the dizzy cap, you may find that you need a new dizzy... :|

 

There's 2 seals which can fail, one which allows oil to come in AROUND the central shaft of the dizzy which can be replaced, the other allows oil to come in down the central shaft which requires a new dizzy... :|

[yalan 0]

If it's anything like the KR 16V, if you have oil inside the dizzy cap, you may find that you need a new dizzy... :|

 

There's 2 seals which can fail, one which allows oil to come in AROUND the central shaft of the dizzy which can be replaced, the other allows oil to come in down the central shaft which requires a new dizzy... :|

 

hmm - something which I've been expecting sooner or later...... has had a bit of oil round the edges of the dizzy since I bought the car. There's no puddle inside the cap or anything - but it is a bit messy.

[Cougar 0]

My G60 did that, tracked it down to the connector on the ECU had worked loose.

[Andi 2,147,483,647]

I had the same on 2 Golfs, Mk I and Mk 2 GTi s; it turned out to be the fuel pump relay on both.

 

Best wishes

 

RB

 

I had the fuel pump relay die on mine, and rev counter did not drop, as engine was still turning and trying to spark - just no fuel - so I don't think that is the same as this incident.

[mwcarrera 0]

Try the small electrical connector on the temperature sensor on the block in front of the dizzy. This sometimes corrodes and any break in contact will kill the engine. Try moving it with the engine running - mine cut out immediately. Just clean the contact and alls well. Martin