Jerky drive to breakdown

[aks_uk 0]

something wierd happened today. as I was driving, my rev needle started dancing up and down, even when i stopped. It was fluctuating from about 200 to 2000, until it eventually died out. There I was stuck in traffic thinking that it would start up when the key was turned, well guess what, yep...it wouldn't start up. I pushed it to the side and let it cool for about ten minutes, it started up but only went about another 200 yards till it happened again. Anybody have any idea as to what it might be?

 

thanks

[Roger Blassberg 0]

Could be the fuel pump relay. I have had 2 fail in the past; one failed dramatically, burning out and wafting a cloud of smoke into the car, the other just became very unreliable. Pull the relay out - I can't remember which one it is- and check that the connector pins are not corroded, (they shouldn't be, the relay is in the fuse box inside the car), or it may be just loose.

 

Does your fuel pump prime when you switch the ignition on to the first position? You should hear it whirr for a second or two and then cut out before you start the engine.

Best wishes

 

RB

[h100vw 0]

That sounds like the hall sender in the dissy to me. Signal to the revcounter coming and going.

 

ECU relays sometimes go too as Roger suggested. They get dry joints in them over time, vibration and heat causes teh soldered joints to fail. Usually they will be a dull grey where a good joint will be shiny.. Either replace or touch the joints with a soldering iron to restore the contact.

 

gavin

[aks_uk 0]

thanks for the advice, i'll have a look at the relay and dizzy, and yes the fuel pump does prime when ignition in position 1. BTW where's the hall sender?

[h100vw 0]

It's in the dissy, it's the sensor that you plug into, on the side. It tells the ECU where the engine is pointing and from that it works out engine speed. The ECU then looks up the timing for that particular engine speed and load.

 

Without it it won't go. A good immobilisation feature if you are leaving your car anywhere dodgy. Just pull the plug up a bit so it looks like it is on.

 

Gavin