Volvo....never again!

[ShadeTek]

Originally Posted by T888

I will definately do that tomorrow. I am confident it will start ok, its only had one wobble since I played about with the immobiliser antenna.
I will use the camcorder on my phone, but you will have to give me some clue how to post here...bit of a computerphobe lol.

Have you got a youtube account? Also, do you know how to get the clips from your phone to a PC?

[Norwegian]

Originally Posted by T888

Where is this? I may have missed this one?

It's located in the exhaust pipe just in front of the cat. It measures the residual oxygen level in the exhaust (if there is any, engine is running lean, if not, it's running rich) and loops the signal back into the engine management system to continually adjust fuel/air mixture. If the signal is deemed to be implausible most engines will run rich to avoid overheating issues caused by a too lean mixture, thus exacerbating eventual sooting issues.

It's much discussed on the Norwegian Volvo forum - it appears that these engines are very sensitive to a malfunctioning oxygen sensor by running very badly particularly on low revs, whereas for example BMW engines (in my experience) just get bad mileage and the occasional smell of unburnt petrol.

A well functioning sensor should produce a voltage between 0,3 and 0,8 Volt, fluctuating at least a couple a times per second. A black carbon residue on the tip will slow down or even halt the fluctuations, and a white residue may point towards silicone poisoning of the sensor.

A slow O2-sensor may be tested and revived with a blow torch: http://www.ttora.com/wiki/index.php/Oxygen_Sensor_Test

[Rick Barton]

Originally Posted by Richard Brown

I'll send you an email address when I get home.

Could you send me an email address by private message and I'll send you the information on the chap who reconditioned my injectors. (I sent you a private message but you haven't replied, hence my posting here.)

[DaveNP]

Originally Posted by Norwegian

A well functioning sensor should produce a voltage between 0,3 and 0,8 Volt, fluctuating at least a couple a times per second.

I found it very difficult to really test an O2 sensor without an oscilloscope as the voltage (if I remember correctly) is step form wave, I got a reasonable estimate with an old voltmeter with a needle and dial which showed about 0.3v, my digital voltmeter was totally confused by the rapidly changing voltage.

[JezF]

Hope you get your problems sorted.

I recommended a simlar vintage car to a friend with 168k miles, he's done 25,000 additional miles in a year and it's not missed a beat.

My 850R has done 219,000 miles and still going strong save for the broken speedo!

[DaveNP]

If you do pull the injectors off (it is a quite easy job) watch out for the little rubber sealing rings on each injector, you'd probably do well to replace them, but some will stick to the injector, some will stick in the manifold and one will ping off and be a so-and-so to find

[MTerry]

Have you considered a leaking head gasket? It would cause low compression/miss and a rich running condition but wouldn't register a fault code because all the fuel and electronics would be working properly. It also wouldn't be noticiable to the eye if it were minor enough. I tried to tell the garage I work with that I suspected my wife's V70 had a head gasket failure and they wouldn't believe me until it was spewing steam out the tailpipe and wouldn't run because the compression in 2 cylinders was so low. By then it had warped the head and worn the valve lifters on both of the low compression cylinders. It would also explain why it ran like a top for the old gent that you bought it from. He only drove it occasionally and probably almost never on the motorway, while you seem to use it in a more normal fashion. After years of light use being used harder could cause it to fail.

[dinky1]

Originally Posted by DaveNP

If you do pull the injectors off (it is a quite easy job) watch out for the little rubber sealing rings on each injector, you'd probably do well to replace them, but some will stick to the injector, some will stick in the manifold and one will ping off and be a so-and-so to find

Easy? - I've had two of these rails off and they're anything but. The injectors are held into the fuel rai lwith a little metal strip that bends as the injectors try to pull from both the rail and the manifold and on the end of them (on the renault version) there is a little plastic disc that holds the o-ring in place.. naturally they snap too.

I had to take off the little metal piece under the injector rail and take it off that way. I then had random injectors still in the manifold and some still in the rail. Then pull those from the manifold and reassemble the rail again. Not a great job but there are minor differences between the volvo and renault version so maybe your setup is a bit more robust.

[DaveNP]

Originally Posted by dinky1

Easy? - I've had two of these rails off and they're anything but.

OK, fair comment, just going from my experience, now I'm thinking maybe I was lucky, but I don't often get lucky when fixing a car.

[dinky1]

Originally Posted by DaveNP

OK, fair comment, just going from my experience, now I'm thinking maybe I was lucky, but I don't often get lucky when fixing a car.

Lol.. you should read some of my threads on here then you'll realise what lack of luck is really like mate. As long as you're not suffering from mine, you're incredibly lucky!

I still gotta get those plastic bits replaced too.. can you believe renault charge £10 per plastic ring to go on the end of each injector? Might try the volvo guys instead

Seriously, if you pulled your injection rail without buggering up the o-rings and plastic bits AND the injectors all stayed on the rail you were really lucky mate. First two rails I removed (with a engine restorer of all people) they both went t!ts up