Misfire, running on 3 cylinders

[Saxo-Will]

Car has suddenly decided to run on 3 cylinders. Car is shaking like hell, no power AT ALL and a rather strange noise when revving.

Has recently been given service, plugs, oil, filters etc. Been put on diagnostics machine which came up with 2 sensor errors. ECT sensor and knock sensor. Have replaced ECT with brand new one and no luck. Hoping its the knock sensor...

Any other ideas incase that doesn't solve the problem? Coilpack doesn't show any errors in diagnostics but could it still be that?

[rookie-rod101]

it could still be the coil pack buddy you need to try finding out which cylindor it aint fireing on really we have at special tool at work to do that but cant bloody remember what its called cos it could just be it isn't fireing and a coil pack is down. have you tryed blanking the fault codes and seeing if it helps or to see if the code comes back?

[Saxo-Will]

yea he had the machine that tested the coilpack and it was apparently running even on all 4 according to that... so seriously stumped. just hoping to god that its this knock sensor as i dont wanna fork out another £50+ on coilpack to find out it isn't that

[Jaytee]

Mines doing this. Could be the ecu. But im on saying this because on mine i have no fault codes so i think thats what the problem with mine is.

[BobC]

Hi,

If ECT = Engine Coolant Temp sensor then that would not cause the engine to run on three, and I doubt that it would be the knock sensor.

You'll need to narrow down to one of the three following areas:

1) fuel supply - sticky injector
2) electrical - coilpack or plug
3) low compression on a cylinder

Beware of trying to test for a spark on each plug as unburnt fuel entering your catalytic converter will damage it.

Depending on the year of your Saxo then an OBD reader should help you pinpoint a misfire to one cylinder.

[Saxo-Will]

Electrical seems fine as had new plugs and coilpack reads no errors.

Had an OBD reader and said 0.3 on the 4 cylinders? Something to do with coilpack anyway...

How can i check fuel supply?

[gaz4399]

do you know any mates with a vts, you could just swap coilpacks. i have one to lend but i you are a bit far from me

[BobC]

For the injector electrics a NOID light test set like: http://cgi.ebay.co.uk/Noid-Light--Test-set-with-Free-Extension-Lead.-T526100_W0QQitemZ270446058847QQcmdZViewItemQQimsxZ 20090823?IMSfp=TL090823157003r4899 will help.

A mechanic's stethoscope will let you hear the injector opening/closing. Like: http://cgi.ebay.co.uk/Heavy-Duty-Pro-Quality-Mechanic's-Stethoscope_W0QQitemZ220412872883QQcmdZViewItem

Ensure that the plug gaps are correctly set, or swap the plugs from cylinder to cylinder to see if the fault moves.

I don't know what you mean by "0.3 on the 4 cylinders" but if you have a fault pointing to the coilpack then I'd start there.

[Saxo-Will]

On the machine he plugged in it said 0.3 on all 4 cylinders or something. Which he said was perfect... not sure if its something to do with the spark or what.

I'm guessing most garages will have that NOID light test and stethoscope?

[rd85tri]

i had this on my vtr it was a injector down replaced it and all fine now may be that mate?

[Saxo-Will]

Is there a difference between injectors on vtr and vts? was it an easy/cheap fix? as don't wanna spend lots of money on stuff that might be ok