S40 T4 #3 Cylinder not firing?

[Scotia3030]

Hi,

My 1997 S40 T4 has developed a major misfire running or at idle. Seems like a cylinder isn't firing.

I done all the checks with plugs, coil packs and wiring. Swapping coil packs makes no difference, nor does changing the plugs. It's always in #3 cylinder. With plug out, can see top of cylinder - Black.

Any ideas? Thanks

Iain

[m1tch1987]

What plugs are you using? If they aren't Volvo OEM then you have your problem.

[Scotia3030]

Hi,

They are genuine Volvo (1.9 turbo), replaced 4 months ago.

[magnuz]

If the ignition side checks out ok, then do a compression test !
If compression is good, then it may be a dodgy injector!

[960kg]

Originally Posted by Scotia3030

Hi,

My 1997 S40 T4 has developed a major misfire running or at idle. Seems like a cylinder isn't firing.

I done all the checks with plugs, coil packs and wiring. Swapping coil packs makes no difference, nor does changing the plugs. It's always in #3 cylinder. With plug out, can see top of cylinder - Black.

Any ideas? Thanks

Iain

How long have you owned the T4 and what make of fuel and octane rating / ron do you use?

Also where is number 3 cylinder?.......nearest the timing belt end or nearer the battery end?

[Scotia3030]

I've had the T4 for over 4 years and it's generally been run on Asda's unleaded - without a hitch.

However, day prior to the cylinder incident, I had to fill up at Tesco's, couldn't get normal unleaded so filled up with their premium 99 Ron.

I had booted the car a wee bit up a long hill and was suddenly met with the misfire (all of a sudden) when coming down the other side.

I was told that looking at the engine bay, the cylinders run from 1-4 (left to right). So it's not the one nearest battery but one in from that, if thats correct?

[960kg]

Originally Posted by Scotia3030

I've had the T4 for over 4 years and it's generally been run on Asda's unleaded - without a hitch.

However, day prior to the cylinder incident, I had to fill up at Tesco's, couldn't get normal unleaded so filled up with their premium 99 Ron.

I had booted the car a wee bit up a long hill and was suddenly met with the misfire (all of a sudden) when coming down the other side.

I was told that looking at the engine bay, the cylinders run from 1-4 (left to right). So it's not the one nearest battery but one in from that, if thats correct?

You will have to check the compressions on all 4 cylinders don`t worry about what they read so long as they are within 2bar or 29psi of one another, all the reading is relative under the same conditions when checking the compression.

I do believe if your No. 3 cylinder, as you rightly said 1 on the left and 4 on the right looking at the engine, is low on compression that this is the reward for using Supermarket cheap lowgrade fuel in a high powered T4 for a long time, 4yrs. 95ron is only ok to get you out of trouble of not finding the correct grade, one is supposed to use 98ron and not the dirtier 95ron.

The carbon collects around the valve stem and will not allow the valve to open or shut fully so then you put in 99ron and thrash it so probably a piece has broken off the valve just like in the pic.......an expensive job!

Always best to pay more for your fuel over time then you won`t have the huge bill in one go when it faulters!.......it will eventually faulter, there are scores of problems on these Volvo sites about the same thing, using the incorrect fuel.

I hope it isn`t that for your sake but 99% it will be if the compression is low only on number 3 cylinder.

Usually it happens on number 1 or 2!....why, who know`s?

[Scotia3030]

Thanks 960kg, it's going into a local garage on monday for compression check then.............The mechanic reckons a valve too by the description.

Will post result when known.

Many thanks for the advice given.

Iain