Engine 850: B5252S/2.4/10v: Missfire/plug leads

[LPGjonderby]

Originally Posted by volvostu19

Another problem these can suffer from is a faulty cam sensor, this can cause ruff running & missfiring but usually bring the lambda light on

No Lambda light on at the mo though...ABS & traction lights on after reversing with wheels on lock. Sometimes after light braking on shell grip road surface as well ! Although no fault codes listed to say which wheel sensor is faulty !

Lambda light has not been on since replacing the TPS and pulling the computers out overnight.

Bet they are cheap !

Thanks again Jon

[stevo48]

Could be worth trying genuine Volvo spark plugs if you are planning on replacing them anyway.
It cured my misfire.

[LPGjonderby]

The missfire is worse than ever this morning, the engine management light is now on as well !
Its now missfiring at all revs, however having turned it off and started again the missfire is more settled.
Does anyone have experience of this problem if the cam position sensor is faulty ? I would go get a download, however am thinking of saving the £35 and just getting a new cam position sensor on order?

Cheers

Jon

[LPGjonderby]

Cam sensor. Having just had a look at its cover which is covered in oil! I will assume the cam seal has gone and the sensor is also full of oil. So a new sensor and a pair of seals are on order. Am hoping this and the new leads when they arrive will finally get rid of the missfire.

Jon

[wise old monkey]

i got one from the local parts shop so i could try it, so i didnt have to buy one, i just changed them over to try it then swapped them back again, you may find the oil around it is just spill from being filled at the cam cover as i have found that it follows the line and drips down to there

[LPGjonderby]

Have ordered the sensor from my local Partco, so will see if they will take it back if it does not work. I suspect the cam seal has gone as the front cam shaft one is leaking a fair bit, so will replace them both. Am hoping the sensor is full of oil and this is why its been missfiring. Then again !
New leads, two seals and cam sensor to go on this Friday afternoon. After that the bonnet is going to be welded shut for a few months !
Fingers crossed.

Cheers

Jon

[AUS T5]

I have just replaced my spark plugs and leads on my 94 850 T5 @ 220,000 K's since the last time I changed the leads was 100,000 K's ago so thought they should be renewed (the plugs had done 30,000 K's ) since I am off on a 3,000 K trip next week. The car was running perfectly, no probs, but now it's a different story! I fitted Bosch super 4 plugs (recommended by a local Volvo specialist) and the new leads were by Bougicord, again recommended by the Volvo specialist. Alas, poor girl is not the same, she starts OK, and runs fine under light driving around town, but when I flaw it on the freeway, she just miss fires and loses power and shudders!?
Is it the plugs, I was on genuine Volvo R6 before, or the leads? As I said before, she was running perfectly before on the old leads and plugs!!??
Thanks guys.

Sorry, think I might have stuck this in the wrong spot, will start a new thread.

[LPGjonderby]

Hi Aus

Think I am correct in saying the T5 runs better on 10mm quality leads, assuming you have bought standard 7mm ones, so it may be those.
Maybe of help !

Cheers

Jon

[LPGjonderby]

Hey Guys

My car is still missfiring !!!

This may be a long waffle.

It is a 1998 V70 2.5 10v. Was running fine on LPG, then quit on gas completely. Went to the LPG converters just after I bought it, the day after it quitting on gas. They fitted a new set of leads, rotor arm, plugs and cap. It then returned running on LPG but with a missfire on petrol & gas.

Since then I have now replaced the leads with very good quality ones from performanceleads.co.uk. In truth they are better spec than the car should need. It has had a replacement scantech rotor and cap, these have now been replaced with Volvo ones. Although it still missfires the same with the Volvo ones as it did with the Scantech ones as it did before. It has had one used coil & a new one, both Bosch. It has also had a TPS as this one showed a fault on 2 fault code reading sessions ! It has also had a new Cam sensor. This week it has had another set of plugs, twin electrode NGK's.

Alas he still missfires !!!!!

On petrol this missfire is now so slight that you hardly notice.

However on gas it still missfires at all revs below 3,000. If you gun it, there is no missfire. When crusing at 80 approx 2,900 revs there is a missfire. When accelerating slowly the missfire is all the way upto 2,900 revs then is very violent at 3,000 revs then goes. When I say violent it will shake the engine 2 or 3 times at 80mph, you can feel this throughout the cabin, then it goes.

When revving the engine on the drive you can see the slight missfire on petrol, but when on gas its shaking like it needs a whisky, a large one at that !

From what I know its a definate ignition fault as its on both fuels, but I have now run out of ideas.

However earlier this week it seemed loads better, this may be because the weather was fine and bright ? i.e not damp and misserable, so Victor frigging Volvo felt better. Then again it could just be me.

Any ideas would be greatly appreciated as my bank balance is starting to stutter.

Cheers and in anticipation

Jon

[Mike_Brace]

With lpg you have to have the right plugs - do not use platinum or split fire plugs. Use either a copper core or iridium plug. Any mis-fire will be more pronounced on lpg as lpg requires a higher voltage to produce the spark as the gas is dry and does not conduct as well as wet petrol.

Mike