t4 maf problem

[sortedt4]

Right guys my T4 has held back and missed since I got it
I have replaced spark plugs new volvo.. coils new ngk ...leads new volvo... the plugs that go to the coils new volvo.. 1 second hand maf sensor 2 reproduction mafs.
it ran well with the first repro for 400 miles then started stalling. the second one lasted 70 miles then last week on motorway it died on me...repo maf...unplugged maf and it ran.... in limp home dsa light and engine light on fan run on after stop....i tryed a used one also but it ran really bad.
I’ve got a new maf from FRF Volvo Swansea it still wont run with maf installed it starts and can be revved but can’t be driven.... dies at lift of clutch.
Did notice that my main battery earth is getting hot and have installed another earth from battery to block and cleaned up the earth on inner wing... what sort of ohms would I expect from battery earth to engine block and chassis....
can anyone tell me what I would expect to see volts wise at maf plug key on and running
Thanks

[magnuz]

If the EML is lit then check for fault codes ?
I would probably be checking for air/ vacuum leaks before going any further, also don't forget to check pipes to the carbon canister, & its the purge valve, etc, because it is hidden, it often gets overlooked !

[Clan]

Originally Posted by sortedt4

Right guys my T4 has held back and missed since I got it
I have replaced spark plugs new volvo.. coils new ngk ...leads new volvo... the plugs that go to the coils new volvo.. 1 second hand maf sensor 2 reproduction mafs.
it ran well with the first repro for 400 miles then started stalling. the second one lasted 70 miles then last week on motorway it died on me...repo maf...unplugged maf and it ran.... in limp home dsa light and engine light on fan run on after stop....i tryed a used one also but it ran really bad.
I’ve got a new maf from FRF Volvo Swansea it still wont run with maf installed it starts and can be revved but can’t be driven.... dies at lift of clutch.
Did notice that my main battery earth is getting hot and have installed another earth from battery to block and cleaned up the earth on inner wing... what sort of ohms would I expect from battery earth to engine block and chassis....
can anyone tell me what I would expect to see volts wise at maf plug key on and running
Thanks

You seem to have checked a lot except the fuel pressure , The T4 pumps go weak over 100.000 miles ...

[CharlesStevenson]

As magnuz has said, you've not mentioned anything about fault codes. I'd suggest you plug in a reader (I've posted on here about the two I used, one would read and clear codes, the other would only read them) and then you'd be more able to know what the system *thinks* the problem might be.

Also, with a fault code reader you'll see whether there are any 'pending' or 'historic' codes, which I believe are ones that haven't tripped the CEL to come on, but may themselves be relevant.

Otherwise you could play the 'swap this, swap that' game for a long time and still be none-the wiser.

FWIW, if you've swapped MAF, plugs etc then perhaps the fuel pressure is to blame, as Clan mentioned.

I too have a T4 manual and that sometimes will stall at low revs, eg turn in the road, and then when restarting will be lumpy and have a tendency to stall again. It's been suggested that the FPR could be the cause of this, but I've not yet swapped it out.

It seems to be ok on fuel otherwise, as I've achieved 35.4 mpg on a fair few motorway runs using the cruise control, however, that drops to 27-29 mpg when doing the usual local stop-start journeys.

I don't know whether this is a possibility but, is the MAF for a T4 in anyway different to a 'standard' MAF and if so might that be the reason that it won't hold idle?

I noticed you'd mentioned '... fan on after a run ...' I had that on my last V40 which was a 1.6 manual and eventually I scrapped that due to a combination of MOT issues. I too had swapped over the MAF with a used spare but the running on of the fan never cleared and that too had a couple of OBD error codes that indicated issues around the MAF and suchlike. My garage were going to play the 'swap over with new' game but I called time on the car before that happened.

Hopefully you'll find a cost-effective solution as a T4 is a much-rarer car than the 1.6 model.

Good luck

[sortedt4]

cheers guys

this morning i have found a boost leak on the intercooler to throttle body area hose lucky im a hoarder and had one...its now running a lot better but i have eml and traction light no fan run on

code P0103 mass or volume air A circuit high

i have cleared the code and restarted code is there straight away

driven 170 miles this morning no other codes preset

power felt good

need to get a fuel test rig any recommendations

thanks again luke

[clarkey1984]

While you should never touch the internals of the MAF as they're extremely delicate, removing it and giving it a blast with a good quality electrical contact or brake and clutch cleaner may make a difference, as they can pick up crap over time, although when I had the eml and TC light on with my t4 due to the MAF I only had about 6psi of boost, she was well flat compared to normal.

[Clan]

Originally Posted by clarkey1984

While you should never touch the internals of the MAF as they're extremely delicate, removing it and giving it a blast with a good quality electrical contact or brake and clutch cleaner may make a difference, as they can pick up crap over time, although when I had the eml and TC light on with my t4 due to the MAF I only had about 6psi of boost, she was well flat compared to normal.

it's myth , and old wives tale🙄 the air mass meter is fed with very clean filtered air and every time you turn the ignition off the hot wire element glows white hot to do any " cleaning" necessary ..
With my my experience working with them since they were introduced 30 years ago I have seen first hand a few £350 air mass meters written off by " cleaning" when there was nothing wrong with them . If you are 100% sure it is faulty , nothing to loose of course !🎅

[sortedt4]

It’s now running a lot better the one way valves on evap had been replaced by previous owner with them aluminium sping rubber flap valves from eBay I expect both of them had flipped and leaking,repaired but need to replace..

Still looking for leaks l found the the v band that holds the turbo together was fullY loose. Was able to turn the whole thing to the top to tighten the clamp..

My waste gate lever seams to have a fair bit of play in it And there’s a bit of soot on the 3 bolt flange join. I’ve got a full jt tuning 3inch turbo back exhaust to go on but want to get it running better first

Although it’s not setting any lean codes atm fuel trims are indicating a lean condition

Fuel trims have now come down from 30 long term to 15.6

I’ve Ordered a Walbro 225 pump incase it’s the pump also I have a new FPR ready to go....

Cheers