Post 328372 by Mongo on 2010-08-29 01:42:09
Hello all.
My volvo t5 has started playing up this week, i had a boost leak through my dump valve which i changed but now my boost is spiking to 1.5bar!! Then droping off to 1bar then sometimes 0.7-0.5.
I disconected the electronic boost controller (ebc) and it stayed at 0.5 bar inboost through evry gear!
I brought a new ebc and replaces the pld craked pipes that go to it and now its judering in and out of boost between 70-75mph out of boost and randomly in boost, after a few miles on the motor way the engine mangement light came on. Ive swaped back to the old ebc and now its juddering only in bost in highish revs 3500rpm. Im confused now! Thinkin mayb a maf semsor or somthing dont no what too do next??
Anyone got any ideas please?
Thanks joe
Post 328375 by p fandango on 2010-08-29 08:19:01
i'd read the codes then reset the ECU (leave out overnight). You've said you've replaced some cracked hoses, if they were split the ECU might of adapted to run/boost with the air leak so now you've replaced them it might need to adapt itself again
obviously reading the codes first will give you an idea of whats wrong
Post 328380 by JelT5 on 2010-08-29 08:27:15
Agree with what Pedro says...check the codes first before doing anything else
(then fit a boost gauge and a mbc, end of boost problems ;))
Ignore the bit in brackets lol
Post 328386 by Flatout Phil on 2010-08-29 10:01:56
Now here is a curiosity. Following on from a previous post about a random misfire that I was caused by duff fuel, I have been running Vpower and it happened again. Both times (but not always - annoyingly) at motorway speeds under heaviest acceleration, get to about 5000 rpm and the whole thing just cuts for a fraction of a second, instantly returns to normal, and if pushed again cuts for a quarter of a second, recovers - by which time I have backed off. All settles down as boost drops and on one occasion, running was a bit uneven for a second or two.
Prior to all this, I have recently replaced the old hard and disintegrating hoses round the air flow sensor, with Volvo "cut your own" hose. WOndered if there is a periodic collapsing hose issue - since the pipes replaced were of the formed variety, rather than the bend it yourself type. The coil is Bosch and less than 2 years old, the plugs have been changed since the first occurence, It doesn't usually happen.
I am wondering if the BOV (Forge) is causing an intermittent pressure bypass? It has only been on a couple of months (and I have come across this issue on this forum before). Living in suburbia, it is a pain in the 'arris because I can't test the thing without driving quite a few miles out. May remove the BOV for a bit and see if it improves. It did not start happening until several weeks after I had changed the hoses either.
The RIP remains unfitted, and I can't fit it until I have sussed this one - otherwise it will add to the possibilities.
COuld go down the replace the ignition gear route - it does feel like a momentary electrical cut out, it isn't a persistent misfire on one or a couple of cylinders, the power just cuts and returns. Not an ignition barrel issue either.
It is absolutely related to boost levels (only have an ordinary gauge) but happens when the needle is across to the end of the white line (but only sometimes).
Frustrating.
Post 328444 by thebadger on 2010-08-29 14:49:50
Could I suggest checking the turbo boost hose.
When I replaced the hoses my turbo boost hose looked like swiss cheese & it took about a week to get the car to settle down again.
Also if the new hose is too thin (wall wise) you could be getting negative pressure collapse of the hose. This could explain the sudden boost drops & spikes.
Post 328721 by Mongo on 2010-08-31 07:14:14
I made a mistake by saying my engine management light was on its actualy the lamba/emmisions light. Thanks for youre help evry1 im waiting for a diagnostics. The thing is it was spiking then droping before i changed the hoses. I might just stick my new electric boost controler back on and reset the ecu depending on what codes i get. Thanks evry1