Hi.. I'm new to forums but i thought id just give it a try because it looks like theres lots of useful info here!! I've just bought a 1998 Rreg vw polo 1.4 16v , i saw it parked up abandoned and fell in love so i bought it.. I've just had welding and everything done for the mot but its running on three cylinders and i dont know why! i pulled each ht lead off one by one and tested for a spark and there all sparking fine.. just put new spark plugs it aswel!! and I'm not a mechanic so i was just wondering if anyone could give me some good advice or where to look next??? I'm gona buy a haynes manual tommorow!! so any advise would be apprieciated very much !!! thank liam

Take the leads off 1 by 1 and c what hapens

ok mate ill try that tommorow and see what happens !? i pulled each lead out and earth a spark plug the the rocker cover and all four are sparking , do you reckon its a fuel problem ?? injectors maybe.. if so is it an expensive job?

pull the leads of the injectors one at a time - might find that re-attaching one of them fixes it. Failing that, pull the plugs and do a compression and/or leakdown test

ok thank you ! il try pulling the leads off injectors tommorow and let you know if its sorted!! ..also do you think its safe to drive the car on 3 cylinders?? will it cause damage ??

I wouldnt drive it far on 3 tbh

right I've tryed that and still running on three!! I'm hopin its somethin simple!! does anyone have any ideas what it could be :/

You have already done the ones that you could have got a nasty shock off of when you checked for a spark!

The injectors are low voltage, so you won't jump too far by holding them.

Did you change the plugs in an attempt to cure the fault, or did the fault occur after the new plugs were fitted? You can see where I am going here, I'm just wondering if one of your new plugs is faulty, a bit of a long shot, but not unknown.

When you take the injector leads off, make a note of which one DOESN'T affect the engines running, then swap that injector for one of the others, if the fault 'moves' with the injector, you may need a new one. If the fault stays on the same cylinder, then as said above, the next step perhaps should be a compression test.

Regards.

thanks mate.. yeah it was runnin on 3 before i changed the plugs.. because i thought it might not be sparking, but its sparking fine just no fuel in there so i hope it is the injector because apart from that its running perfect.. can't quite get another injector to reach without taking all the airbox off and its getin dark now :( but tommorow il definatly plug another injector onto the faulty one to see if it is that.. thanks again!!

when you pulled the ht leads off one at a time, did you leave the engine running? If so which cylinder wasn't firing? Did you try moving the spark plugs and leads around to see if the problem moved with them? If you do swap the leads make sure you swap both ends tho

have you checked that the firing order is correct?

yeah.. i think its the injector!! doe's anyone know where i could buy one second hand?? and is it easy to fit it myself??