simo666

hi all i have got a 97 uk wagon the problem is that between 2000 and 3000 revs the car has got a hesitation surging problem if you are on a light throttle in between this rev range the car feels like it is surging any ideas would be great thanks

Jeff_PS13

Hi, did you manage to resolve this as I have a very similar problem.

So far I've replaced the plugs and leads which didn't help. I've also removed the dump valve which seems to have helped a bit but still not fixed it.

My next thoughts are the MAF, coilpack or lambda - if you have fixed it I'd be keen to find out how, or to hear any other suggestions

McFartenplop

Unplug the lambda sensor on the top of the downpipe under the bonnet, take it a drive and see if that helps.

Jeff_PS13

Thanks, that seems to have sorted it

Guess I need a new lambda sensor though.

webster444

mine does the same and iv just replaced the lambda and the maf does this mean that the new lambda is knackered too

Jeff_PS13

Does yours run ok when you disconnect the new lambda?

webster444

just away to try it, never knew about disconnecting the lambda and driving it

webster444

just tried unplugging it and gave it a run, it seems to be running as it should so does that mean that my brand new lambda is faulty?

webster444

anyone?

kevin wrx

iTrader: (1)

yep sounds like faulty lambda just replace and see what happens.

Jeff_PS13

I don't know but perhaps you need to reset your ECU to clear a fault code left over from your previously duff sensor? It says how to do this here

https://www.scoobynet.com/general-te...af-sensor.html

webster444

i tried resetting the ecu but to no avail.

means ill most likely have to fork out for another brand new sensor-great!

Jeff_PS13

Can you not take the duff one back to where you got it and ask for an exchange or refund?

webster444

bought it off someone on here so ill need to send it back and wait!

tjmatt

iTrader: (1)

This surging quite often happens shortly after startup and is caused by going into closed loop a little be early and the mixture going weak-rich-weak-rich when it shouldn't be going too weak on a cold engine. Once warmer it tends to be better again.

Also the lambda sensor works less well/slower when it is cold so have you checked you get 12 and 0 V on the heater wires?

webster444

it does it when warm aswell.

is the heater wires the white ones?

webster444

iv now fitted another new lambda and its still doing it.

i checked the voltage accross the two white wires which i think are the heater wires and got 14v.

any one got any other suggestions coz its really getting on my **** now

Jeff_PS13

Can you not just leave the lambda unplugged? That's what I'm doing for now.

McFartenplop

I'm not saying you should, but I run my car with the lambda unplugged for 3 months with no issues.