Misfire under load on the T4

[Dave86]

Started about 2 weeks ago with the odd hiccup when i put my foot down got worse over the last week so went and fitted new plugs on Sunday and ordered new leads and both coil packs. I went to pick them up today and the leads were the right ones but the coil packs were wrong so hopefully they will be in tomorrow. However with the new plugs and leads the misfire is even worse, checked the spark plug gap and all the connections and they're all fine so im hoping that its the coils failing other than that what else could it be?

[mitchyboy01]

Misfire under load my bet is on coilpacks. I have 2 spare. You can borrow these if you want to troubleshoot before you buy?

[Dave86]

Misfire under load my bet is on coilpacks. I have 2 spare. You can borrow these if you want to troubleshoot before you buy?

Cheers for the offer mate but I've ordered them, they should be here tomorrow and im going away to devon on Friday morning for a week and haven't really got the time to come and get them.

[Haizum74]

Cheers for the offer mate but I've ordered them, they should be here tomorrow and im going away to devon on Friday morning for a week and haven't really got the time to come and get them.

Yeh if sparks havent solved it its usually coil packs thats the next bet.

[merc85]

I reckon it could be Crank/flywheel sensor mate,

[Haizum74]

I reckon it could be Crank/flywheel sensor mate,

Would that throw a code at all?

[Dave86]

I reckon it could be Crank/flywheel sensor mate,

Cheers mate that will be next on the list if the coilpacks don't solve the problem

[960kg]

What new plugs at what gap?? Your a T4, very fussy!

Misfire under boost damn nigh always ignition!

Just have to find the culprit.

[Dave86]

What new plugs at what gap?? Your a T4, very fussy!

Misfire under boost damn nigh always ignition!

Just have to find the culprit.

New bosch plugs set at 0.75

[960kg]

New bosch plugs set at 0.75

Only in my own opinion I would be very surprised if it wasn`t your plugs!!

It sounds very strange but on a standard T4 the plugs to use are Volvo own ones with no problems. The Volvo part number is 272344-3 and is a different number to all the other models, so that means it must be important.

[Haizum74]

Only in my own opinion I would be very surprised if it wasn`t your plugs!!

It sounds very strange but on a standard T4 the plugs to use are Volvo own ones with no problems. The Volvo part number is 272344-3 and is a different number to all the other models, so that means it must be important.

Yeh its a bit hit and miss with non volvo plugs on them, some are fine others aren't. Not come across any issues with volvo ones so far.

[fassi1]

Fuel pump or fuel pressure regulator.
Lean mixture can cause misfire under high load.
It would be very helpfull to check fuel trims.
If it's coil pack then fuel trims will be negative cause fuel doesn't get burned and ECU will try to lean the mixture.
If it's low fuel pressure then fuel trims will be positive cause ECU will try to enrich the mixture.
Take the spark plugs out.
If they are covered in dark smokes that means there is problem with the ignition.

[Dave86]

Only in my own opinion I would be very surprised if it wasn`t your plugs!!

It sounds very strange but on a standard T4 the plugs to use are Volvo own ones with no problems. The Volvo part number is 272344-3 and is a different number to all the other models, so that means it must be important.

Yeh its a bit hit and miss with non volvo plugs on them, some are fine others aren't. Not come across any issues with volvo ones so far.

Fair enough although the genuine plugs that were in the car look nearly new anyway i only changed them to rule them out. If the new coil packs don't improve the situation ill get some new genuine plugs.
Bit annoyed at having to spend money on it really as i don't even like the motor i only bought it because my c70 was knackered and i needed a car to get to work, so far I've spent over £200 on a £500 car only had it about 3 months.

[Dave86]

Fuel pump or fuel pressure regulator.
Lean mixture can cause misfire under high load.
It would be very helpfull to check fuel trims.
If it's coil pack then fuel trims will be negative cause fuel doesn't get burned and ECU will try to lean the mixture.
If it's low fuel pressure then fuel trims will be positive cause ECU will try to enrich the mixture.
Take the spark plugs out.
If they are covered in dark smokes that means there is problem with the ignition.

Will check the fuel trims tomorrow. when i took the old plugs out on Sunday they were a very light brown.

[merc85]

Would that throw a code at all?

nope

[fassi1]

Will check the fuel trims tomorrow. when i took the old plugs out on Sunday they were a very light brown.

Keep an eye on oxygen sensor voltage too, if it's standard 0-1V then about 0.1-0.2V is lean and 0.8-0.9V is rich.

[960kg]

Bit annoyed at having to spend money on it really as i don't even like the motor i only bought it because my c70 was knackered and i needed a car to get to work, so far I've spent over £200 on a £500 car only had it about 3 months.

I understand where your coming from, but owners only usually sell there motors because there is something wrong with them and the buyer picks up the problems.

As you have the OBD11 socket onboard it is wise to spend about £20 on a code reader which will read and erase the error codes.

When you read the codes and if you have any they will then point you to the area where the problem is.

Guessing does cost a fortune before you hit on the cause.

[mitchyboy01]

If you have an android phone, download the torque app £2.95 and get a bluetooth reader on ebay £10. You plug the bluetooth into your ECU and using your phone you get ALL and I mean ALL of the realtime data from the ECU. You can read and clear codes and it tells you what the codes are. You can also datalog voltages, ignition timing etc etc. It's the best thing i've ever had on my phone, saves a fortune in guesswork.

[fassi1]

If you have an android phone, download the torque app £2.95 and get a bluetooth reader on ebay £10. You plug the bluetooth into your ECU and using your phone you get ALL and I mean ALL of the realtime data from the ECU. You can read and clear codes and it tells you what the codes are. You can also datalog voltages, ignition timing etc etc. It's the best thing i've ever had on my phone, saves a fortune in guesswork.

Does it work on all the phase 2 OBDII volvos?
That sounds really good.

[Dave86]

Already got a Bluetooth obd2 reader and torque on my phone there are no fault codes and the engine management light isnt on