Engine: 70 T5: Help - C70 misfire and poor running

[well-dweller]

Car was working fine until last week. Then she developed a misfire. Took each plug out to find that plug 5 seemed duff. New set of plugs and she seemed to go Ok. On the weekend I took out the airbox and replaced the rotor arm and distributor cap (which I found to be in poor condition). Put it all back and now the thing has gone bonkers. I have absolutely MASSES of boost. You can hear me coming from miles away. I only have to touch the throttle and she's off like a bat out of hell (I have a reprogrammed ECU which wiorks fine). Trouble is it cuts out at junctions and has huge hesitancy at taking off. At the moment it runs better with the electrical connection to the AFM (or AMM) disconnected. I suppose I could have knocked the AFM when I removed the airbox lid (it stayed attached). Any ideas?

[MikeS100]

The air flow meter is very sensitive so it may have been damaged with the work you were doing. If it runs better with it disconnected then it could well be the fault. If you replace it pay the extra for a genuine one, the copy ones on ebay have a history or not working from the start or failing very quickly. When I needed a new one for my V70 in November I took a chance on a second hand one as funds were tight and it's been ok since, but that's always a risk and you never know how long it will last so go for new if funds allow.

[well-dweller]

Thanks for that Mike. I too have my suspicions tyhat its the AFM. And you're right, its only Bosch stuff for me. Had a Calibra turbo once and bought an aftermarket AFM. It was terrible. It used to stall the car just as you pulled out of a junction. Talk about scary, especially when you had a articulated lorry bearing down on you at speed.

[well-dweller]

Right, ordered an AFM from e-bay, for £18. It arrived today, I put it in and its still the same. I have a dilemma... What if the replacement has been damaged in the post and its also duff?!
The car will run pretty much OK without the connector to the AFM, but has just failed the MOT on emissions.
I have an LPG conversion but its the same whether running on petrol or LPG, so I don't think its an ECU problem.
This all started a couple of weeks ago when the car started running on 4 rather than 5 cylinders. A change of spark plugs appears to have it running on 5 but the car cuts out at junctions and there's huge throttle hesitation. When the AFM is diconnected it runs fine, although its down on power.
Any more ideas folks?

[RiPsTa33]

Sounds like you may have knocked one of your turbo pipes off if your getting masses of boost which could also be causing an air leak after the maf. ECU reads the amount of air flowing past the maf and adds the correct amount of fuel to the engine, if the air is leaking after the maf then it wont be adding the correct amount of fuel. If the pipe that comes off the bottom of the turbo to the turbo control valve/boost control solenoid has come off or split it will be leaking there and overboosting as it uses the pressure from the turbo to open the wastegate and control the boost.
With the MAF disconnected the ecu will revert to a base fueling map as it can no longer measure the air passing the maf

[KONRAD96]

I would definitely check the hoses. I had hesitation and cutting out as well as weird noises, which turned out to be the main air intake pipe to the turbo which had broken up at the turbo end. The plastic gets very brittle. This was past the MAF sensor, but still provided hesitation and cutting out.

[well-dweller]

Thanks guys, will check my hoses now.
Have now put another second hand AFM on and its exactly the same. I doubt that all three AFMs are duff. I had a quick look at the hoses on the weekend and there's a very small guage clear plastic pipe (with larger rubber pipes either end) just before the AFM which appears to "connect" to a heater pipe. Didn't want to pull it off is it looked a pig to get back on.
Yep, thinking about it, it must be this pipe that needs to go back on the turbo? If so, where does it attach?

[well-dweller]

Right, had another look. The pipe that attaches to the wastegate vacuum is properly arttached. The only one I'm concerned about is the white plastic one attached after the AFM, to the right as you look down on the pipework. Have attached a photo. The other end of this pipe goes into a larger bore rubber pipe which now appers to have welded itself to a water pipe coming up form the back of the engine. What I need to know is where this pipe should connect at the far end.
Anyone have any pics?

[well-dweller]

Pic of white pipe...Volvo white pipe (after AFM).JPG