S80 d5 inlet noise

[mr zefect]

My 55 plate s80 d5 has a missfiring noise coming from the intake sounds like its pumping air as well as sucking and seems like it has a missfire at low reves ive done leak off test on injectors and all seem fine cleaned egr ect has anyone got any ideas its driving me mad it drives very well apart from that no smoke i thought if it was a burnt valve of head gaskit it would be smokey.

[Diesel Convert]

Had a similar problem. Seal on the injector was gone.

http://www.volvoforums.org.uk/showthread.php?t=146743

[mr zefect]

Thanks for the reply but i dont think its that it defo coming form the air box and when i disconected the inlet pipe from the air box its quite a loud burbling noise and when you put your hand over it it feels like its blowing as well as sucking like head gaskit has gone between two bores i suppose the only way of telling is to have a compreson test done does any one no how much one costs to have done and like i said i thought it would lose power but still pulls like a train with no smoke its only on idle and low revs.

[carl4u44]

Hi sounds like a worn cam lobe.

[mr zefect]

Thanks for the reply i did wonder about that and it does make sence as it is a bit top end noisey does any one no how hard it is eg does head have to come off to change cams ect.

[colzak]

Hi Mr zefect,,,Ive been chasing my tail, trying to sort the very same symptom as your S80,,you may find this of interest:-

http://www.volvoforums.org.uk/showthread.php?t=89198

Since doing the plenum cover removal, I,ve done a compression check on each cylinder to deturmine valve train and piston integrity...

results ranged from 420psi to 450psi,,,which is very normal,,,
Injectors had a low tech pulse test at our local diesel specialist who said they are ok,,,?

The symtoms are still there,,chugging from the airbox,,,tapping from the top end of the engine at idle,,,which I think may be turnning to a rattle when the car is excellerated ,,,

The rattle

The rattle is too similar to pinking to be conclusive...
When i excellerate, the engine
is rattly till 3000 revs,,,but if I take my foot off the throttle suddenly,,,,there is a short rattle,,,followed by smooth silence,,,This short rattle seems to always imediately follow my taking my foot off the excellerator,,,like between changing gears,,,..

I too am begining to think this is possibly a worn cam lobe or two on cylinders 1 and 5,,but if the tappets are hydaulicly ajusted then maybe some wareing has occured there,,,I think the rocker cover should come off to reveal the 2 cam shafts, though i don,t relish the idea of doing this....Are you planning anything investagative?

[mr zefect]

thanks for your reply im trying to sell it at the mo as i have spent way to much time and money on it and has been nothing but trouble and doing 35 on a good day ompg is not my idea of a economic deisel car and if i can sell it i will have to sort it out im good at machnics but looks a nightmeare to just take the rocker cover off and everything i have done on the car has been a nightmere. please let me no if you sort yours out.

[colzak]

Selling your Volvo?,,,
You say your car isn,t smoking,,to be sure try driving at night with someone behind you and floor it,,,,if you notice a misty haze in your rear view mirror,,,thats the type of smoke mine emmits,,,very difficult to see during the daylight hours though,,,

My car isn,t sorted yet,,,but something i,m going to do tommorrow is:-

count top end of engine taps within a 10 second period

count air inlet dugga noises within a 10 second period

if the 2 numbers coincide,,we may have a lead?

my engine is nothing but challanging lol,,,,when they run correctly apparently they are an absolute joy to behold ?