B200F poor fuel consumption, high CO reading

[trabitom99]

Hi!

The fuel consumption of my 360 has been increasing a lot lately, and now the garage checked the CO reading.

6%

I think even a carbed car shouldn't have more than 3,5 - 4% %, cat-cars around 0,5 - 1 % IIRC.

Are there any "360 injection"-specific problems anyone knows about? Air filter, plugs, leads are relatively fresh. The garage reckons the air mass meter is OK, and that the lambda sensor might not be working as it should.

Is that likely?

Cheers

Tom

[Chris_C]

Sounds reasonable to me, I'd put more money on the air mass meter than the lambda myself, but then I don't know the F setup that well bud.

Do you have a multimeter? Green book gives you a good "how to test the AMM" chapter, which will at least rule that out.

[trabitom99]

Cheers Chris. The green book description for testing the AMM is excellent, I just need to find the time and buy a multimeter.

And in the meantime live with the high fuel consumption. I used 15L/100km this weekend, which is a lot, even though I was pulling a trailer.

Tom

[pettaw]

How does it run from cold?

I wonder if it could be a dodgy temperature sensor? They always seem to run really rich from cold which I guess is vaguely normal, you know, the spluttering for the first few seconds after startup, but then suppose its staying rich the whole time. Might be worth disconnecting the sensor and making sure the contacts are clean, its the one that's annoyingly difficult to get to on the cylinder head, not the one closest to the firewall which is the cold start timer switch.

[volvodspec]

the F has only a very limited bandwith on wich it can alter the injection mapping to somewhat optimal level, a faulty sender won't be the case for such a high CO reading

i'd start with disconnecting the 5th (cold start) injector and check the CO level again, you could also try to get the fuelrailpressure measured. a blocked return line or faulty fuelpressure regulator can also cause a rich mixture

[trabitom99]

Cold starting is fine, but now that you mention it, the hot starting is poor, particularly now that the weather's warm again. It's particularly bad after a long run. If the car is started again after say 30 mins - 1 hr, it takes ages to "catch". It will eventually, but it can take up to 15 - 20 secs.

I'm not convinced it's NOT the AMM, I'd always take anything my garage says with a pinch of salt. Sticking cold start injector sound feasible too - I'm not getting under 12L/100kms ATM.

Cheers

Tom